// SPDX-License-Identifier: GPL-2.0-or-later
//
// core.c  --  Voltage/Current Regulator framework.
//
// Copyright 2007, 2008 Wolfson Microelectronics PLC.
// Copyright 2008 SlimLogic Ltd.
//
// Author: Liam Girdwood <lrg@slimlogic.co.uk>

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/debugfs.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/async.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/suspend.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/of.h>
#include <linux/regmap.h>
#include <linux/regulator/of_regulator.h>
#include <linux/regulator/consumer.h>
#include <linux/regulator/coupler.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/module.h>

#define CREATE_TRACE_POINTS
#include <trace/events/regulator.h>

#include "dummy.h"
#include "internal.h"

#define rdev_crit(rdev, fmt, ...)                                       \
        pr_crit("%s: " fmt, rdev_get_name(rdev), ##__VA_ARGS__)
#define rdev_err(rdev, fmt, ...)                                        \
        pr_err("%s: " fmt, rdev_get_name(rdev), ##__VA_ARGS__)
#define rdev_warn(rdev, fmt, ...)                                       \
        pr_warn("%s: " fmt, rdev_get_name(rdev), ##__VA_ARGS__)
#define rdev_info(rdev, fmt, ...)                                       \
        pr_info("%s: " fmt, rdev_get_name(rdev), ##__VA_ARGS__)
#define rdev_dbg(rdev, fmt, ...)                                        \
        pr_debug("%s: " fmt, rdev_get_name(rdev), ##__VA_ARGS__)

static DEFINE_WW_CLASS(regulator_ww_class);
static DEFINE_MUTEX(regulator_nesting_mutex);
static DEFINE_MUTEX(regulator_list_mutex);
static LIST_HEAD(regulator_map_list);
static LIST_HEAD(regulator_ena_gpio_list);
static LIST_HEAD(regulator_supply_alias_list);
static LIST_HEAD(regulator_coupler_list);
static bool has_full_constraints;

static struct dentry *debugfs_root;

/*
 * struct regulator_map
 *
 * Used to provide symbolic supply names to devices.
 */
struct regulator_map {
        struct list_head list;
        const char *dev_name;   /* The dev_name() for the consumer */
        const char *supply;
        struct regulator_dev *regulator;
};

/*
 * struct regulator_enable_gpio
 *
 * Management for shared enable GPIO pin
 */
struct regulator_enable_gpio {
        struct list_head list;
        struct gpio_desc *gpiod;
        u32 enable_count;       /* a number of enabled shared GPIO */
        u32 request_count;      /* a number of requested shared GPIO */
};

/*
 * struct regulator_supply_alias
 *
 * Used to map lookups for a supply onto an alternative device.
 */
struct regulator_supply_alias {
        struct list_head list;
        struct device *src_dev;
        const char *src_supply;
        struct device *alias_dev;
        const char *alias_supply;
};

static int _regulator_is_enabled(struct regulator_dev *rdev);
static int _regulator_disable(struct regulator *regulator);
static int _regulator_get_current_limit(struct regulator_dev *rdev);
static unsigned int _regulator_get_mode(struct regulator_dev *rdev);
static int _notifier_call_chain(struct regulator_dev *rdev,
                                  unsigned long event, void *data);
static int _regulator_do_set_voltage(struct regulator_dev *rdev,
                                     int min_uV, int max_uV);
static int regulator_balance_voltage(struct regulator_dev *rdev,
                                     suspend_state_t state);
static struct regulator *create_regulator(struct regulator_dev *rdev,
                                          struct device *dev,
                                          const char *supply_name);
static void _regulator_put(struct regulator *regulator);

const char *rdev_get_name(struct regulator_dev *rdev)
{
        if (rdev->constraints && rdev->constraints->name)
                return rdev->constraints->name;
        else if (rdev->desc->name)
                return rdev->desc->name;
        else
                return "";
}

static bool have_full_constraints(void)
{
        return has_full_constraints || of_have_populated_dt();
}

static bool regulator_ops_is_valid(struct regulator_dev *rdev, int ops)
{
        if (!rdev->constraints) {
                rdev_err(rdev, "no constraints\n");
                return false;
        }

        if (rdev->constraints->valid_ops_mask & ops)
                return true;

        return false;
}

/**
 * regulator_lock_nested - lock a single regulator
 * @rdev:               regulator source
 * @ww_ctx:             w/w mutex acquire context
 *
 * This function can be called many times by one task on
 * a single regulator and its mutex will be locked only
 * once. If a task, which is calling this function is other
 * than the one, which initially locked the mutex, it will
 * wait on mutex.
 */
static inline int regulator_lock_nested(struct regulator_dev *rdev,
                                        struct ww_acquire_ctx *ww_ctx)
{
        bool lock = false;
        int ret = 0;

        mutex_lock(&regulator_nesting_mutex);

        if (ww_ctx || !ww_mutex_trylock(&rdev->mutex)) {
                if (rdev->mutex_owner == current)
                        rdev->ref_cnt++;
                else
                        lock = true;

                if (lock) {
                        mutex_unlock(&regulator_nesting_mutex);
                        ret = ww_mutex_lock(&rdev->mutex, ww_ctx);
                        mutex_lock(&regulator_nesting_mutex);
                }
        } else {
                lock = true;
        }

        if (lock && ret != -EDEADLK) {
                rdev->ref_cnt++;
                rdev->mutex_owner = current;
        }

        mutex_unlock(&regulator_nesting_mutex);

        return ret;
}

/**
 * regulator_lock - lock a single regulator
 * @rdev:               regulator source
 *
 * This function can be called many times by one task on
 * a single regulator and its mutex will be locked only
 * once. If a task, which is calling this function is other
 * than the one, which initially locked the mutex, it will
 * wait on mutex.
 */
void regulator_lock(struct regulator_dev *rdev)
{
        regulator_lock_nested(rdev, NULL);
}
EXPORT_SYMBOL_GPL(regulator_lock);

/**
 * regulator_unlock - unlock a single regulator
 * @rdev:               regulator_source
 *
 * This function unlocks the mutex when the
 * reference counter reaches 0.
 */
void regulator_unlock(struct regulator_dev *rdev)
{
        mutex_lock(&regulator_nesting_mutex);

        if (--rdev->ref_cnt == 0) {
                rdev->mutex_owner = NULL;
                ww_mutex_unlock(&rdev->mutex);
        }

        WARN_ON_ONCE(rdev->ref_cnt < 0);

        mutex_unlock(&regulator_nesting_mutex);
}
EXPORT_SYMBOL_GPL(regulator_unlock);

static bool regulator_supply_is_couple(struct regulator_dev *rdev)
{
        struct regulator_dev *c_rdev;
        int i;

        for (i = 1; i < rdev->coupling_desc.n_coupled; i++) {
                c_rdev = rdev->coupling_desc.coupled_rdevs[i];

                if (rdev->supply->rdev == c_rdev)
                        return true;
        }

        return false;
}

static void regulator_unlock_recursive(struct regulator_dev *rdev,
                                       unsigned int n_coupled)
{
        struct regulator_dev *c_rdev;
        int i;

        for (i = n_coupled; i > 0; i--) {
                c_rdev = rdev->coupling_desc.coupled_rdevs[i - 1];

                if (!c_rdev)
                        continue;

                if (c_rdev->supply && !regulator_supply_is_couple(c_rdev))
                        regulator_unlock_recursive(
                                        c_rdev->supply->rdev,
                                        c_rdev->coupling_desc.n_coupled);

                regulator_unlock(c_rdev);
        }
}

static int regulator_lock_recursive(struct regulator_dev *rdev,
                                    struct regulator_dev **new_contended_rdev,
                                    struct regulator_dev **old_contended_rdev,
                                    struct ww_acquire_ctx *ww_ctx)
{
        struct regulator_dev *c_rdev;
        int i, err;

        for (i = 0; i < rdev->coupling_desc.n_coupled; i++) {
                c_rdev = rdev->coupling_desc.coupled_rdevs[i];

                if (!c_rdev)
                        continue;

                if (c_rdev != *old_contended_rdev) {
                        err = regulator_lock_nested(c_rdev, ww_ctx);
                        if (err) {
                                if (err == -EDEADLK) {
                                        *new_contended_rdev = c_rdev;
                                        goto err_unlock;
                                }

                                /* shouldn't happen */
                                WARN_ON_ONCE(err != -EALREADY);
                        }
                } else {
                        *old_contended_rdev = NULL;
                }

                if (c_rdev->supply && !regulator_supply_is_couple(c_rdev)) {
                        err = regulator_lock_recursive(c_rdev->supply->rdev,
                                                       new_contended_rdev,
                                                       old_contended_rdev,
                                                       ww_ctx);
                        if (err) {
                                regulator_unlock(c_rdev);
                                goto err_unlock;
                        }
                }
        }

        return 0;

err_unlock:
        regulator_unlock_recursive(rdev, i);

        return err;
}

/**
 * regulator_unlock_dependent - unlock regulator's suppliers and coupled
 *                              regulators
 * @rdev:                       regulator source
 * @ww_ctx:                     w/w mutex acquire context
 *
 * Unlock all regulators related with rdev by coupling or supplying.
 */
static void regulator_unlock_dependent(struct regulator_dev *rdev,
                                       struct ww_acquire_ctx *ww_ctx)
{
        regulator_unlock_recursive(rdev, rdev->coupling_desc.n_coupled);
        ww_acquire_fini(ww_ctx);
}

/**
 * regulator_lock_dependent - lock regulator's suppliers and coupled regulators
 * @rdev:                       regulator source
 * @ww_ctx:                     w/w mutex acquire context
 *
 * This function as a wrapper on regulator_lock_recursive(), which locks
 * all regulators related with rdev by coupling or supplying.
 */
static void regulator_lock_dependent(struct regulator_dev *rdev,
                                     struct ww_acquire_ctx *ww_ctx)
{
        struct regulator_dev *new_contended_rdev = NULL;
        struct regulator_dev *old_contended_rdev = NULL;
        int err;

        mutex_lock(&regulator_list_mutex);

        ww_acquire_init(ww_ctx, &regulator_ww_class);

        do {
                if (new_contended_rdev) {
                        ww_mutex_lock_slow(&new_contended_rdev->mutex, ww_ctx);
                        old_contended_rdev = new_contended_rdev;
                        old_contended_rdev->ref_cnt++;
                }

                err = regulator_lock_recursive(rdev,
                                               &new_contended_rdev,
                                               &old_contended_rdev,
                                               ww_ctx);

                if (old_contended_rdev)
                        regulator_unlock(old_contended_rdev);

        } while (err == -EDEADLK);

        ww_acquire_done(ww_ctx);

        mutex_unlock(&regulator_list_mutex);
}

/**
 * of_get_child_regulator - get a child regulator device node
 * based on supply name
 * @parent: Parent device node
 * @prop_name: Combination regulator supply name and "-supply"
 *
 * Traverse all child nodes.
 * Extract the child regulator device node corresponding to the supply name.
 * returns the device node corresponding to the regulator if found, else
 * returns NULL.
 */
static struct device_node *of_get_child_regulator(struct device_node *parent,
                                                  const char *prop_name)
{
        struct device_node *regnode = NULL;
        struct device_node *child = NULL;

        for_each_child_of_node(parent, child) {
                regnode = of_parse_phandle(child, prop_name, 0);

                if (!regnode) {
                        regnode = of_get_child_regulator(child, prop_name);
                        if (regnode)
                                return regnode;
                } else {
                        return regnode;
                }
        }
        return NULL;
}

/**
 * of_get_regulator - get a regulator device node based on supply name
 * @dev: Device pointer for the consumer (of regulator) device
 * @supply: regulator supply name
 *
 * Extract the regulator device node corresponding to the supply name.
 * returns the device node corresponding to the regulator if found, else
 * returns NULL.
 */
static struct device_node *of_get_regulator(struct device *dev, const char *supply)
{
        struct device_node *regnode = NULL;
        char prop_name[32]; /* 32 is max size of property name */

        dev_dbg(dev, "Looking up %s-supply from device tree\n", supply);

        snprintf(prop_name, 32, "%s-supply", supply);
        regnode = of_parse_phandle(dev->of_node, prop_name, 0);

        if (!regnode) {
                regnode = of_get_child_regulator(dev->of_node, prop_name);
                if (regnode)
                        return regnode;

                dev_dbg(dev, "Looking up %s property in node %pOF failed\n",
                                prop_name, dev->of_node);
                return NULL;
        }
        return regnode;
}

/* Platform voltage constraint check */
int regulator_check_voltage(struct regulator_dev *rdev,
                            int *min_uV, int *max_uV)
{
        BUG_ON(*min_uV > *max_uV);

        if (!regulator_ops_is_valid(rdev, REGULATOR_CHANGE_VOLTAGE)) {
                rdev_err(rdev, "voltage operation not allowed\n");
                return -EPERM;
        }

        if (*max_uV > rdev->constraints->max_uV)
                *max_uV = rdev->constraints->max_uV;
        if (*min_uV < rdev->constraints->min_uV)
                *min_uV = rdev->constraints->min_uV;

        if (*min_uV > *max_uV) {
                rdev_err(rdev, "unsupportable voltage range: %d-%duV\n",
                         *min_uV, *max_uV);
                return -EINVAL;
        }

        return 0;
}

/* return 0 if the state is valid */
static int regulator_check_states(suspend_state_t state)
{
        return (state > PM_SUSPEND_MAX || state == PM_SUSPEND_TO_IDLE);
}

/* Make sure we select a voltage that suits the needs of all
 * regulator consumers
 */
int regulator_check_consumers(struct regulator_dev *rdev,
                              int *min_uV, int *max_uV,
                              suspend_state_t state)
{
        struct regulator *regulator;
        struct regulator_voltage *voltage;

        list_for_each_entry(regulator, &rdev->consumer_list, list) {
                voltage = &regulator->voltage[state];
                /*
                 * Assume consumers that didn't say anything are OK
                 * with anything in the constraint range.
                 */
                if (!voltage->min_uV && !voltage->max_uV)
                        continue;

                if (*max_uV > voltage->max_uV)
                        *max_uV = voltage->max_uV;
                if (*min_uV < voltage->min_uV)
                        *min_uV = voltage->min_uV;
        }

        if (*min_uV > *max_uV) {
                rdev_err(rdev, "Restricting voltage, %u-%uuV\n",
                        *min_uV, *max_uV);
                return -EINVAL;
        }

        return 0;
}

/* current constraint check */
static int regulator_check_current_limit(struct regulator_dev *rdev,
                                        int *min_uA, int *max_uA)
{
        BUG_ON(*min_uA > *max_uA);

        if (!regulator_ops_is_valid(rdev, REGULATOR_CHANGE_CURRENT)) {
                rdev_err(rdev, "current operation not allowed\n");
                return -EPERM;
        }

        if (*max_uA > rdev->constraints->max_uA)
                *max_uA = rdev->constraints->max_uA;
        if (*min_uA < rdev->constraints->min_uA)
                *min_uA = rdev->constraints->min_uA;

        if (*min_uA > *max_uA) {
                rdev_err(rdev, "unsupportable current range: %d-%duA\n",
                         *min_uA, *max_uA);
                return -EINVAL;
        }

        return 0;
}

/* operating mode constraint check */
static int regulator_mode_constrain(struct regulator_dev *rdev,
                                    unsigned int *mode)
{
        switch (*mode) {
        case REGULATOR_MODE_FAST:
        case REGULATOR_MODE_NORMAL:
        case REGULATOR_MODE_IDLE:
        case REGULATOR_MODE_STANDBY:
                break;
        default:
                rdev_err(rdev, "invalid mode %x specified\n", *mode);
                return -EINVAL;
        }

        if (!regulator_ops_is_valid(rdev, REGULATOR_CHANGE_MODE)) {
                rdev_err(rdev, "mode operation not allowed\n");
                return -EPERM;
        }

        /* The modes are bitmasks, the most power hungry modes having
         * the lowest values. If the requested mode isn't supported
         * try higher modes. */
        while (*mode) {
                if (rdev->constraints->valid_modes_mask & *mode)
                        return 0;
                *mode /= 2;
        }

        return -EINVAL;
}

static inline struct regulator_state *
regulator_get_suspend_state(struct regulator_dev *rdev, suspend_state_t state)
{
        if (rdev->constraints == NULL)
                return NULL;

        switch (state) {
        case PM_SUSPEND_STANDBY:
                return &rdev->constraints->state_standby;
        case PM_SUSPEND_MEM:
                return &rdev->constraints->state_mem;
        case PM_SUSPEND_MAX:
                return &rdev->constraints->state_disk;
        default:
                return NULL;
        }
}

static ssize_t regulator_uV_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);
        ssize_t ret;

        regulator_lock(rdev);
        ret = sprintf(buf, "%d\n", regulator_get_voltage_rdev(rdev));
        regulator_unlock(rdev);

        return ret;
}
static DEVICE_ATTR(microvolts, 0444, regulator_uV_show, NULL);

static ssize_t regulator_uA_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return sprintf(buf, "%d\n", _regulator_get_current_limit(rdev));
}
static DEVICE_ATTR(microamps, 0444, regulator_uA_show, NULL);

static ssize_t name_show(struct device *dev, struct device_attribute *attr,
                         char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return sprintf(buf, "%s\n", rdev_get_name(rdev));
}
static DEVICE_ATTR_RO(name);

static const char *regulator_opmode_to_str(int mode)
{
        switch (mode) {
        case REGULATOR_MODE_FAST:
                return "fast";
        case REGULATOR_MODE_NORMAL:
                return "normal";
        case REGULATOR_MODE_IDLE:
                return "idle";
        case REGULATOR_MODE_STANDBY:
                return "standby";
        }
        return "unknown";
}

static ssize_t regulator_print_opmode(char *buf, int mode)
{
        return sprintf(buf, "%s\n", regulator_opmode_to_str(mode));
}

static ssize_t regulator_opmode_show(struct device *dev,
                                    struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return regulator_print_opmode(buf, _regulator_get_mode(rdev));
}
static DEVICE_ATTR(opmode, 0444, regulator_opmode_show, NULL);

static ssize_t regulator_print_state(char *buf, int state)
{
        if (state > 0)
                return sprintf(buf, "enabled\n");
        else if (state == 0)
                return sprintf(buf, "disabled\n");
        else
                return sprintf(buf, "unknown\n");
}

static ssize_t regulator_state_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);
        ssize_t ret;

        regulator_lock(rdev);
        ret = regulator_print_state(buf, _regulator_is_enabled(rdev));
        regulator_unlock(rdev);

        return ret;
}
static DEVICE_ATTR(state, 0444, regulator_state_show, NULL);

static ssize_t regulator_status_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);
        int status;
        char *label;

        status = rdev->desc->ops->get_status(rdev);
        if (status < 0)
                return status;

        switch (status) {
        case REGULATOR_STATUS_OFF:
                label = "off";
                break;
        case REGULATOR_STATUS_ON:
                label = "on";
                break;
        case REGULATOR_STATUS_ERROR:
                label = "error";
                break;
        case REGULATOR_STATUS_FAST:
                label = "fast";
                break;
        case REGULATOR_STATUS_NORMAL:
                label = "normal";
                break;
        case REGULATOR_STATUS_IDLE:
                label = "idle";
                break;
        case REGULATOR_STATUS_STANDBY:
                label = "standby";
                break;
        case REGULATOR_STATUS_BYPASS:
                label = "bypass";
                break;
        case REGULATOR_STATUS_UNDEFINED:
                label = "undefined";
                break;
        default:
                return -ERANGE;
        }

        return sprintf(buf, "%s\n", label);
}
static DEVICE_ATTR(status, 0444, regulator_status_show, NULL);

static ssize_t regulator_min_uA_show(struct device *dev,
                                    struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        if (!rdev->constraints)
                return sprintf(buf, "constraint not defined\n");

        return sprintf(buf, "%d\n", rdev->constraints->min_uA);
}
static DEVICE_ATTR(min_microamps, 0444, regulator_min_uA_show, NULL);

static ssize_t regulator_max_uA_show(struct device *dev,
                                    struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        if (!rdev->constraints)
                return sprintf(buf, "constraint not defined\n");

        return sprintf(buf, "%d\n", rdev->constraints->max_uA);
}
static DEVICE_ATTR(max_microamps, 0444, regulator_max_uA_show, NULL);

static ssize_t regulator_min_uV_show(struct device *dev,
                                    struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        if (!rdev->constraints)
                return sprintf(buf, "constraint not defined\n");

        return sprintf(buf, "%d\n", rdev->constraints->min_uV);
}
static DEVICE_ATTR(min_microvolts, 0444, regulator_min_uV_show, NULL);

static ssize_t regulator_max_uV_show(struct device *dev,
                                    struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        if (!rdev->constraints)
                return sprintf(buf, "constraint not defined\n");

        return sprintf(buf, "%d\n", rdev->constraints->max_uV);
}
static DEVICE_ATTR(max_microvolts, 0444, regulator_max_uV_show, NULL);

static ssize_t regulator_total_uA_show(struct device *dev,
                                      struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);
        struct regulator *regulator;
        int uA = 0;

        regulator_lock(rdev);
        list_for_each_entry(regulator, &rdev->consumer_list, list) {
                if (regulator->enable_count)
                        uA += regulator->uA_load;
        }
        regulator_unlock(rdev);
        return sprintf(buf, "%d\n", uA);
}
static DEVICE_ATTR(requested_microamps, 0444, regulator_total_uA_show, NULL);

static ssize_t num_users_show(struct device *dev, struct device_attribute *attr,
                              char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);
        return sprintf(buf, "%d\n", rdev->use_count);
}
static DEVICE_ATTR_RO(num_users);

static ssize_t type_show(struct device *dev, struct device_attribute *attr,
                         char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        switch (rdev->desc->type) {
        case REGULATOR_VOLTAGE:
                return sprintf(buf, "voltage\n");
        case REGULATOR_CURRENT:
                return sprintf(buf, "current\n");
        }
        return sprintf(buf, "unknown\n");
}
static DEVICE_ATTR_RO(type);

static ssize_t regulator_suspend_mem_uV_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return sprintf(buf, "%d\n", rdev->constraints->state_mem.uV);
}
static DEVICE_ATTR(suspend_mem_microvolts, 0444,
                regulator_suspend_mem_uV_show, NULL);

static ssize_t regulator_suspend_disk_uV_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return sprintf(buf, "%d\n", rdev->constraints->state_disk.uV);
}
static DEVICE_ATTR(suspend_disk_microvolts, 0444,
                regulator_suspend_disk_uV_show, NULL);

static ssize_t regulator_suspend_standby_uV_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return sprintf(buf, "%d\n", rdev->constraints->state_standby.uV);
}
static DEVICE_ATTR(suspend_standby_microvolts, 0444,
                regulator_suspend_standby_uV_show, NULL);

static ssize_t regulator_suspend_mem_mode_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return regulator_print_opmode(buf,
                rdev->constraints->state_mem.mode);
}
static DEVICE_ATTR(suspend_mem_mode, 0444,
                regulator_suspend_mem_mode_show, NULL);

static ssize_t regulator_suspend_disk_mode_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return regulator_print_opmode(buf,
                rdev->constraints->state_disk.mode);
}
static DEVICE_ATTR(suspend_disk_mode, 0444,
                regulator_suspend_disk_mode_show, NULL);

static ssize_t regulator_suspend_standby_mode_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return regulator_print_opmode(buf,
                rdev->constraints->state_standby.mode);
}
static DEVICE_ATTR(suspend_standby_mode, 0444,
                regulator_suspend_standby_mode_show, NULL);

static ssize_t regulator_suspend_mem_state_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return regulator_print_state(buf,
                        rdev->constraints->state_mem.enabled);
}
static DEVICE_ATTR(suspend_mem_state, 0444,
                regulator_suspend_mem_state_show, NULL);

static ssize_t regulator_suspend_disk_state_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return regulator_print_state(buf,
                        rdev->constraints->state_disk.enabled);
}
static DEVICE_ATTR(suspend_disk_state, 0444,
                regulator_suspend_disk_state_show, NULL);

static ssize_t regulator_suspend_standby_state_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return regulator_print_state(buf,
                        rdev->constraints->state_standby.enabled);
}
static DEVICE_ATTR(suspend_standby_state, 0444,
                regulator_suspend_standby_state_show, NULL);

static ssize_t regulator_bypass_show(struct device *dev,
                                     struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);
        const char *report;
        bool bypass;
        int ret;

        ret = rdev->desc->ops->get_bypass(rdev, &bypass);

        if (ret != 0)
                report = "unknown";
        else if (bypass)
                report = "enabled";
        else
                report = "disabled";

        return sprintf(buf, "%s\n", report);
}
static DEVICE_ATTR(bypass, 0444,
                   regulator_bypass_show, NULL);

/* Calculate the new optimum regulator operating mode based on the new total
 * consumer load. All locks held by caller */
static int drms_uA_update(struct regulator_dev *rdev)
{
        struct regulator *sibling;
        int current_uA = 0, output_uV, input_uV, err;
        unsigned int mode;

        /*
         * first check to see if we can set modes at all, otherwise just
         * tell the consumer everything is OK.
         */
        if (!regulator_ops_is_valid(rdev, REGULATOR_CHANGE_DRMS)) {
                rdev_dbg(rdev, "DRMS operation not allowed\n");
                return 0;
        }

        if (!rdev->desc->ops->get_optimum_mode &&
            !rdev->desc->ops->set_load)
                return 0;

        if (!rdev->desc->ops->set_mode &&
            !rdev->desc->ops->set_load)
                return -EINVAL;

        /* calc total requested load */
        list_for_each_entry(sibling, &rdev->consumer_list, list) {
                if (sibling->enable_count)
                        current_uA += sibling->uA_load;
        }

        current_uA += rdev->constraints->system_load;

        if (rdev->desc->ops->set_load) {
                /* set the optimum mode for our new total regulator load */
                err = rdev->desc->ops->set_load(rdev, current_uA);
                if (err < 0)
                        rdev_err(rdev, "failed to set load %d\n", current_uA);
        } else {
                /* get output voltage */
                output_uV = regulator_get_voltage_rdev(rdev);
                if (output_uV <= 0) {
                        rdev_err(rdev, "invalid output voltage found\n");
                        return -EINVAL;
                }

                /* get input voltage */
                input_uV = 0;
                if (rdev->supply)
                        input_uV = regulator_get_voltage(rdev->supply);
                if (input_uV <= 0)
                        input_uV = rdev->constraints->input_uV;
                if (input_uV <= 0) {
                        rdev_err(rdev, "invalid input voltage found\n");
                        return -EINVAL;
                }

                /* now get the optimum mode for our new total regulator load */
                mode = rdev->desc->ops->get_optimum_mode(rdev, input_uV,
                                                         output_uV, current_uA);

                /* check the new mode is allowed */
                err = regulator_mode_constrain(rdev, &mode);
                if (err < 0) {
                        rdev_err(rdev, "failed to get optimum mode @ %d uA %d -> %d uV\n",
                                 current_uA, input_uV, output_uV);
                        return err;
                }

                err = rdev->desc->ops->set_mode(rdev, mode);
                if (err < 0)
                        rdev_err(rdev, "failed to set optimum mode %x\n", mode);
        }

        return err;
}

static int suspend_set_state(struct regulator_dev *rdev,
                                    suspend_state_t state)
{
        int ret = 0;
        struct regulator_state *rstate;

        rstate = regulator_get_suspend_state(rdev, state);
        if (rstate == NULL)
                return 0;

        /* If we have no suspend mode configuration don't set anything;
         * only warn if the driver implements set_suspend_voltage or
         * set_suspend_mode callback.
         */
        if (rstate->enabled != ENABLE_IN_SUSPEND &&
            rstate->enabled != DISABLE_IN_SUSPEND) {
                if (rdev->desc->ops->set_suspend_voltage ||
                    rdev->desc->ops->set_suspend_mode)
                        rdev_warn(rdev, "No configuration\n");
                return 0;
        }

        if (rstate->enabled == ENABLE_IN_SUSPEND &&

                rdev->desc->ops->set_suspend_enable)
                ret = rdev->desc->ops->set_suspend_enable(rdev);
        else if (rstate->enabled == DISABLE_IN_SUSPEND &&
                rdev->desc->ops->set_suspend_disable)
                ret = rdev->desc->ops->set_suspend_disable(rdev);
        else /* OK if set_suspend_enable or set_suspend_disable is NULL */
                ret = 0;

        if (ret < 0) {
                rdev_err(rdev, "failed to enabled/disable\n");
                return ret;
        }

        if (rdev->desc->ops->set_suspend_voltage && rstate->uV > 0) {
                ret = rdev->desc->ops->set_suspend_voltage(rdev, rstate->uV);
                if (ret < 0) {
                        rdev_err(rdev, "failed to set voltage\n");
                        return ret;
                }
        }

        if (rdev->desc->ops->set_suspend_mode && rstate->mode > 0) {
                ret = rdev->desc->ops->set_suspend_mode(rdev, rstate->mode);
                if (ret < 0) {
                        rdev_err(rdev, "failed to set mode\n");
                        return ret;
                }
        }

        return ret;
}

static void print_constraints(struct regulator_dev *rdev)
{
        struct regulation_constraints *constraints = rdev->constraints;
        char buf[160] = "";
        size_t len = sizeof(buf) - 1;
        int count = 0;
        int ret;

        if (constraints->min_uV && constraints->max_uV) {
                if (constraints->min_uV == constraints->max_uV)
                        count += scnprintf(buf + count, len - count, "%d mV ",
                                           constraints->min_uV / 1000);
                else
                        count += scnprintf(buf + count, len - count,
                                           "%d <--> %d mV ",
                                           constraints->min_uV / 1000,
                                           constraints->max_uV / 1000);
        }

        if (!constraints->min_uV ||
            constraints->min_uV != constraints->max_uV) {
                ret = regulator_get_voltage_rdev(rdev);
                if (ret > 0)
                        count += scnprintf(buf + count, len - count,
                                           "at %d mV ", ret / 1000);
        }

        if (constraints->uV_offset)
                count += scnprintf(buf + count, len - count, "%dmV offset ",
                                   constraints->uV_offset / 1000);

        if (constraints->min_uA && constraints->max_uA) {
                if (constraints->min_uA == constraints->max_uA)
                        count += scnprintf(buf + count, len - count, "%d mA ",
                                           constraints->min_uA / 1000);
                else
                        count += scnprintf(buf + count, len - count,
                                           "%d <--> %d mA ",
                                           constraints->min_uA / 1000,
                                           constraints->max_uA / 1000);
        }

        if (!constraints->min_uA ||
            constraints->min_uA != constraints->max_uA) {
                ret = _regulator_get_current_limit(rdev);
                if (ret > 0)
                        count += scnprintf(buf + count, len - count,
                                           "at %d mA ", ret / 1000);
        }

        if (constraints->valid_modes_mask & REGULATOR_MODE_FAST)
                count += scnprintf(buf + count, len - count, "fast ");
        if (constraints->valid_modes_mask & REGULATOR_MODE_NORMAL)
                count += scnprintf(buf + count, len - count, "normal ");
        if (constraints->valid_modes_mask & REGULATOR_MODE_IDLE)
                count += scnprintf(buf + count, len - count, "idle ");
        if (constraints->valid_modes_mask & REGULATOR_MODE_STANDBY)
                count += scnprintf(buf + count, len - count, "standby");

        if (!count)
                scnprintf(buf, len, "no parameters");

        rdev_dbg(rdev, "%s\n", buf);

        if ((constraints->min_uV != constraints->max_uV) &&
            !regulator_ops_is_valid(rdev, REGULATOR_CHANGE_VOLTAGE))
                rdev_warn(rdev,
                          "Voltage range but no REGULATOR_CHANGE_VOLTAGE\n");
}

static int machine_constraints_voltage(struct regulator_dev *rdev,
        struct regulation_constraints *constraints)
{
        const struct regulator_ops *ops = rdev->desc->ops;
        int ret;

        /* do we need to apply the constraint voltage */
        if (rdev->constraints->apply_uV &&
            rdev->constraints->min_uV && rdev->constraints->max_uV) {
                int target_min, target_max;
                int current_uV = regulator_get_voltage_rdev(rdev);

                if (current_uV == -ENOTRECOVERABLE) {
                        /* This regulator can't be read and must be initialized */
                        rdev_info(rdev, "Setting %d-%duV\n",
                                  rdev->constraints->min_uV,
                                  rdev->constraints->max_uV);
                        _regulator_do_set_voltage(rdev,
                                                  rdev->constraints->min_uV,
                                                  rdev->constraints->max_uV);
                        current_uV = regulator_get_voltage_rdev(rdev);
                }

                if (current_uV < 0) {
                        rdev_err(rdev,
                                 "failed to get the current voltage(%d)\n",
                                 current_uV);
                        return current_uV;
                }

                /*
                 * If we're below the minimum voltage move up to the
                 * minimum voltage, if we're above the maximum voltage
                 * then move down to the maximum.
                 */
                target_min = current_uV;
                target_max = current_uV;

                if (current_uV < rdev->constraints->min_uV) {
                        target_min = rdev->constraints->min_uV;
                        target_max = rdev->constraints->min_uV;
                }

                if (current_uV > rdev->constraints->max_uV) {
                        target_min = rdev->constraints->max_uV;
                        target_max = rdev->constraints->max_uV;
                }

                if (target_min != current_uV || target_max != current_uV) {
                        rdev_info(rdev, "Bringing %duV into %d-%duV\n",
                                  current_uV, target_min, target_max);
                        ret = _regulator_do_set_voltage(
                                rdev, target_min, target_max);
                        if (ret < 0) {
                                rdev_err(rdev,
                                        "failed to apply %d-%duV constraint(%d)\n",
                                        target_min, target_max, ret);
                                return ret;
                        }
                }
        }

        /* constrain machine-level voltage specs to fit
         * the actual range supported by this regulator.
         */
        if (ops->list_voltage && rdev->desc->n_voltages) {
                int     count = rdev->desc->n_voltages;
                int     i;
                int     min_uV = INT_MAX;
                int     max_uV = INT_MIN;
                int     cmin = constraints->min_uV;
                int     cmax = constraints->max_uV;

                /* it's safe to autoconfigure fixed-voltage supplies
                   and the constraints are used by list_voltage. */
                if (count == 1 && !cmin) {
                        cmin = 1;
                        cmax = INT_MAX;
                        constraints->min_uV = cmin;
                        constraints->max_uV = cmax;
                }

                /* voltage constraints are optional */
                if ((cmin == 0) && (cmax == 0))
                        return 0;

                /* else require explicit machine-level constraints */
                if (cmin <= 0 || cmax <= 0 || cmax < cmin) {
                        rdev_err(rdev, "invalid voltage constraints\n");
                        return -EINVAL;
                }

                /* initial: [cmin..cmax] valid, [min_uV..max_uV] not */
                for (i = 0; i < count; i++) {
                        int     value;

                        value = ops->list_voltage(rdev, i);
                        if (value <= 0)
                                continue;

                        /* maybe adjust [min_uV..max_uV] */
                        if (value >= cmin && value < min_uV)
                                min_uV = value;
                        if (value <= cmax && value > max_uV)
                                max_uV = value;
                }

                /* final: [min_uV..max_uV] valid iff constraints valid */
                if (max_uV < min_uV) {
                        rdev_err(rdev,
                                 "unsupportable voltage constraints %u-%uuV\n",
                                 min_uV, max_uV);
                        return -EINVAL;
                }

                /* use regulator's subset of machine constraints */
                if (constraints->min_uV < min_uV) {
                        rdev_dbg(rdev, "override min_uV, %d -> %d\n",
                                 constraints->min_uV, min_uV);
                        constraints->min_uV = min_uV;
                }
                if (constraints->max_uV > max_uV) {
                        rdev_dbg(rdev, "override max_uV, %d -> %d\n",
                                 constraints->max_uV, max_uV);
                        constraints->max_uV = max_uV;
                }
        }

        return 0;
}

static int machine_constraints_current(struct regulator_dev *rdev,
        struct regulation_constraints *constraints)
{
        const struct regulator_ops *ops = rdev->desc->ops;
        int ret;

        if (!constraints->min_uA && !constraints->max_uA)
                return 0;

        if (constraints->min_uA > constraints->max_uA) {
                rdev_err(rdev, "Invalid current constraints\n");
                return -EINVAL;
        }

        if (!ops->set_current_limit || !ops->get_current_limit) {
                rdev_warn(rdev, "Operation of current configuration missing\n");
                return 0;
        }

        /* Set regulator current in constraints range */
        ret = ops->set_current_limit(rdev, constraints->min_uA,
                        constraints->max_uA);
        if (ret < 0) {
                rdev_err(rdev, "Failed to set current constraint, %d\n", ret);
                return ret;
        }

        return 0;
}

static int _regulator_do_enable(struct regulator_dev *rdev);

/**
 * set_machine_constraints - sets regulator constraints
 * @rdev: regulator source
 * @constraints: constraints to apply
 *
 * Allows platform initialisation code to define and constrain
 * regulator circuits e.g. valid voltage/current ranges, etc.  NOTE:
 * Constraints *must* be set by platform code in order for some
 * regulator operations to proceed i.e. set_voltage, set_current_limit,
 * set_mode.
 */
static int set_machine_constraints(struct regulator_dev *rdev,
        const struct regulation_constraints *constraints)
{
        int ret = 0;
        const struct regulator_ops *ops = rdev->desc->ops;

        if (constraints)
                rdev->constraints = kmemdup(constraints, sizeof(*constraints),
                                            GFP_KERNEL);
        else
                rdev->constraints = kzalloc(sizeof(*constraints),
                                            GFP_KERNEL);
        if (!rdev->constraints)
                return -ENOMEM;

        ret = machine_constraints_voltage(rdev, rdev->constraints);
        if (ret != 0)
                return ret;

        ret = machine_constraints_current(rdev, rdev->constraints);
        if (ret != 0)
                return ret;

        if (rdev->constraints->ilim_uA && ops->set_input_current_limit) {
                ret = ops->set_input_current_limit(rdev,
                                                   rdev->constraints->ilim_uA);
                if (ret < 0) {
                        rdev_err(rdev, "failed to set input limit\n");
                        return ret;
                }
        }

        /* do we need to setup our suspend state */
        if (rdev->constraints->initial_state) {
                ret = suspend_set_state(rdev, rdev->constraints->initial_state);
                if (ret < 0) {
                        rdev_err(rdev, "failed to set suspend state\n");
                        return ret;
                }
        }

        if (rdev->constraints->initial_mode) {
                if (!ops->set_mode) {
                        rdev_err(rdev, "no set_mode operation\n");
                        return -EINVAL;
                }

                ret = ops->set_mode(rdev, rdev->constraints->initial_mode);
                if (ret < 0) {
                        rdev_err(rdev, "failed to set initial mode: %d\n", ret);
                        return ret;
                }
        } else if (rdev->constraints->system_load) {
                /*
                 * We'll only apply the initial system load if an
                 * initial mode wasn't specified.
                 */
                drms_uA_update(rdev);
        }

        if ((rdev->constraints->ramp_delay || rdev->constraints->ramp_disable)
                && ops->set_ramp_delay) {
                ret = ops->set_ramp_delay(rdev, rdev->constraints->ramp_delay);
                if (ret < 0) {
                        rdev_err(rdev, "failed to set ramp_delay\n");
                        return ret;
                }
        }

        if (rdev->constraints->pull_down && ops->set_pull_down) {
                ret = ops->set_pull_down(rdev);
                if (ret < 0) {
                        rdev_err(rdev, "failed to set pull down\n");
                        return ret;
                }
        }

        if (rdev->constraints->soft_start && ops->set_soft_start) {
                ret = ops->set_soft_start(rdev);
                if (ret < 0) {
                        rdev_err(rdev, "failed to set soft start\n");
                        return ret;
                }
        }

        if (rdev->constraints->over_current_protection
                && ops->set_over_current_protection) {
                ret = ops->set_over_current_protection(rdev);
                if (ret < 0) {
                        rdev_err(rdev, "failed to set over current protection\n");
                        return ret;
                }
        }

        if (rdev->constraints->active_discharge && ops->set_active_discharge) {
                bool ad_state = (rdev->constraints->active_discharge ==
                              REGULATOR_ACTIVE_DISCHARGE_ENABLE) ? true : false;

                ret = ops->set_active_discharge(rdev, ad_state);
                if (ret < 0) {
                        rdev_err(rdev, "failed to set active discharge\n");
                        return ret;
                }
        }

        /* If the constraints say the regulator should be on at this point
         * and we have control then make sure it is enabled.
         */
        if (rdev->constraints->always_on || rdev->constraints->boot_on) {
                if (rdev->supply) {
                        ret = regulator_enable(rdev->supply);
                        if (ret < 0) {
                                _regulator_put(rdev->supply);
                                rdev->supply = NULL;
                                return ret;
                        }
                }

                ret = _regulator_do_enable(rdev);
                if (ret < 0 && ret != -EINVAL) {
                        rdev_err(rdev, "failed to enable\n");
                        return ret;
                }
                rdev->use_count++;
        }

        print_constraints(rdev);
        return 0;
}

/**
 * set_supply - set regulator supply regulator
 * @rdev: regulator name
 * @supply_rdev: supply regulator name
 *
 * Called by platform initialisation code to set the supply regulator for this
 * regulator. This ensures that a regulators supply will also be enabled by the
 * core if it's child is enabled.
 */
static int set_supply(struct regulator_dev *rdev,
                      struct regulator_dev *supply_rdev)
{
        int err;

        rdev_info(rdev, "supplied by %s\n", rdev_get_name(supply_rdev));

        if (!try_module_get(supply_rdev->owner))
                return -ENODEV;

        rdev->supply = create_regulator(supply_rdev, &rdev->dev, "SUPPLY");
        if (rdev->supply == NULL) {
                err = -ENOMEM;
                return err;
        }
        supply_rdev->open_count++;

        return 0;
}

/**
 * set_consumer_device_supply - Bind a regulator to a symbolic supply
 * @rdev:         regulator source
 * @consumer_dev_name: dev_name() string for device supply applies to
 * @supply:       symbolic name for supply
 *
 * Allows platform initialisation code to map physical regulator
 * sources to symbolic names for supplies for use by devices.  Devices
 * should use these symbolic names to request regulators, avoiding the
 * need to provide board-specific regulator names as platform data.
 */
static int set_consumer_device_supply(struct regulator_dev *rdev,
                                      const char *consumer_dev_name,
                                      const char *supply)
{
        struct regulator_map *node;
        int has_dev;

        if (supply == NULL)
                return -EINVAL;

        if (consumer_dev_name != NULL)
                has_dev = 1;
        else
                has_dev = 0;

        list_for_each_entry(node, &regulator_map_list, list) {
                if (node->dev_name && consumer_dev_name) {
                        if (strcmp(node->dev_name, consumer_dev_name) != 0)
                                continue;
                } else if (node->dev_name || consumer_dev_name) {
                        continue;
                }

                if (strcmp(node->supply, supply) != 0)
                        continue;

                pr_debug("%s: %s/%s is '%s' supply; fail %s/%s\n",
                         consumer_dev_name,
                         dev_name(&node->regulator->dev),
                         node->regulator->desc->name,
                         supply,
                         dev_name(&rdev->dev), rdev_get_name(rdev));
                return -EBUSY;
        }

        node = kzalloc(sizeof(struct regulator_map), GFP_KERNEL);
        if (node == NULL)
                return -ENOMEM;

        node->regulator = rdev;
        node->supply = supply;

        if (has_dev) {
                node->dev_name = kstrdup(consumer_dev_name, GFP_KERNEL);
                if (node->dev_name == NULL) {
                        kfree(node);
                        return -ENOMEM;
                }
        }

        list_add(&node->list, &regulator_map_list);
        return 0;
}

static void unset_regulator_supplies(struct regulator_dev *rdev)
{
        struct regulator_map *node, *n;

        list_for_each_entry_safe(node, n, &regulator_map_list, list) {
                if (rdev == node->regulator) {
                        list_del(&node->list);
                        kfree(node->dev_name);
                        kfree(node);
                }
        }
}

#ifdef CONFIG_DEBUG_FS
static ssize_t constraint_flags_read_file(struct file *file,
                                          char __user *user_buf,
                                          size_t count, loff_t *ppos)
{
        const struct regulator *regulator = file->private_data;
        const struct regulation_constraints *c = regulator->rdev->constraints;
        char *buf;
        ssize_t ret;

        if (!c)
                return 0;

        buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        ret = snprintf(buf, PAGE_SIZE,
                        "always_on: %u\n"
                        "boot_on: %u\n"
                        "apply_uV: %u\n"
                        "ramp_disable: %u\n"
                        "soft_start: %u\n"
                        "pull_down: %u\n"
                        "over_current_protection: %u\n",
                        c->always_on,
                        c->boot_on,
                        c->apply_uV,
                        c->ramp_disable,
                        c->soft_start,
                        c->pull_down,
                        c->over_current_protection);

        ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
        kfree(buf);

        return ret;
}

#endif

static const struct file_operations constraint_flags_fops = {
#ifdef CONFIG_DEBUG_FS
        .open = simple_open,
        .read = constraint_flags_read_file,
        .llseek = default_llseek,
#endif
};

#define REG_STR_SIZE    64

static struct regulator *create_regulator(struct regulator_dev *rdev,
                                          struct device *dev,
                                          const char *supply_name)
{
        struct regulator *regulator;
        char buf[REG_STR_SIZE];
        int err, size;

        regulator = kzalloc(sizeof(*regulator), GFP_KERNEL);
        if (regulator == NULL)
                return NULL;

        regulator_lock(rdev);
        regulator->rdev = rdev;
        list_add(&regulator->list, &rdev->consumer_list);

        if (dev) {
                regulator->dev = dev;

                /* Add a link to the device sysfs entry */
                size = snprintf(buf, REG_STR_SIZE, "%s-%s",
                                dev->kobj.name, supply_name);
                if (size >= REG_STR_SIZE)
                        goto overflow_err;

                regulator->supply_name = kstrdup(buf, GFP_KERNEL);
                if (regulator->supply_name == NULL)
                        goto overflow_err;

                err = sysfs_create_link_nowarn(&rdev->dev.kobj, &dev->kobj,
                                        buf);
                if (err) {
                        rdev_dbg(rdev, "could not add device link %s err %d\n",
                                  dev->kobj.name, err);
                        /* non-fatal */
                }
        } else {
                regulator->supply_name = kstrdup_const(supply_name, GFP_KERNEL);
                if (regulator->supply_name == NULL)
                        goto overflow_err;
        }

        regulator->debugfs = debugfs_create_dir(regulator->supply_name,
                                                rdev->debugfs);
        if (!regulator->debugfs) {
                rdev_dbg(rdev, "Failed to create debugfs directory\n");
        } else {
                debugfs_create_u32("uA_load", 0444, regulator->debugfs,
                                   &regulator->uA_load);
                debugfs_create_u32("min_uV", 0444, regulator->debugfs,
                                   &regulator->voltage[PM_SUSPEND_ON].min_uV);
                debugfs_create_u32("max_uV", 0444, regulator->debugfs,
                                   &regulator->voltage[PM_SUSPEND_ON].max_uV);
                debugfs_create_file("constraint_flags", 0444,
                                    regulator->debugfs, regulator,
                                    &constraint_flags_fops);
        }

        /*
         * Check now if the regulator is an always on regulator - if
         * it is then we don't need to do nearly so much work for
         * enable/disable calls.
         */
        if (!regulator_ops_is_valid(rdev, REGULATOR_CHANGE_STATUS) &&
            _regulator_is_enabled(rdev))
                regulator->always_on = true;

        regulator_unlock(rdev);
        return regulator;
overflow_err:
        list_del(&regulator->list);
        kfree(regulator);
        regulator_unlock(rdev);
        return NULL;
}

static int _regulator_get_enable_time(struct regulator_dev *rdev)
{
        if (rdev->constraints && rdev->constraints->enable_time)
                return rdev->constraints->enable_time;
        if (rdev->desc->ops->enable_time)
                return rdev->desc->ops->enable_time(rdev);
        return rdev->desc->enable_time;
}

static struct regulator_supply_alias *regulator_find_supply_alias(
                struct device *dev, const char *supply)
{
        struct regulator_supply_alias *map;

        list_for_each_entry(map, &regulator_supply_alias_list, list)
                if (map->src_dev == dev && strcmp(map->src_supply, supply) == 0)
                        return map;

        return NULL;
}

static void regulator_supply_alias(struct device **dev, const char **supply)
{
        struct regulator_supply_alias *map;

        map = regulator_find_supply_alias(*dev, *supply);
        if (map) {
                dev_dbg(*dev, "Mapping supply %s to %s,%s\n",
                                *supply, map->alias_supply,
                                dev_name(map->alias_dev));
                *dev = map->alias_dev;
                *supply = map->alias_supply;
        }
}

static int regulator_match(struct device *dev, const void *data)
{
        struct regulator_dev *r = dev_to_rdev(dev);

        return strcmp(rdev_get_name(r), data) == 0;
}

static struct regulator_dev *regulator_lookup_by_name(const char *name)
{
        struct device *dev;

        dev = class_find_device(&regulator_class, NULL, name, regulator_match);

        return dev ? dev_to_rdev(dev) : NULL;
}

/**
 * regulator_dev_lookup - lookup a regulator device.
 * @dev: device for regulator "consumer".
 * @supply: Supply name or regulator ID.
 *
 * If successful, returns a struct regulator_dev that corresponds to the name
 * @supply and with the embedded struct device refcount incremented by one.
 * The refcount must be dropped by calling put_device().
 * On failure one of the following ERR-PTR-encoded values is returned:
 * -ENODEV if lookup fails permanently, -EPROBE_DEFER if lookup could succeed
 * in the future.
 */
static struct regulator_dev *regulator_dev_lookup(struct device *dev,
                                                  const char *supply)
{
        struct regulator_dev *r = NULL;
        struct device_node *node;
        struct regulator_map *map;
        const char *devname = NULL;

        regulator_supply_alias(&dev, &supply);

        /* first do a dt based lookup */
        if (dev && dev->of_node) {
                node = of_get_regulator(dev, supply);
                if (node) {
                        r = of_find_regulator_by_node(node);
                        if (r)
                                return r;

                        /*
                         * We have a node, but there is no device.
                         * assume it has not registered yet.
                         */
                        return ERR_PTR(-EPROBE_DEFER);
                }
        }

        /* if not found, try doing it non-dt way */
        if (dev)
                devname = dev_name(dev);

        mutex_lock(&regulator_list_mutex);
        list_for_each_entry(map, &regulator_map_list, list) {
                /* If the mapping has a device set up it must match */
                if (map->dev_name &&
                    (!devname || strcmp(map->dev_name, devname)))
                        continue;

                if (strcmp(map->supply, supply) == 0 &&
                    get_device(&map->regulator->dev)) {
                        r = map->regulator;
                        break;
                }
        }
        mutex_unlock(&regulator_list_mutex);

        if (r)
                return r;

        r = regulator_lookup_by_name(supply);
        if (r)
                return r;

        return ERR_PTR(-ENODEV);
}

static int regulator_resolve_supply(struct regulator_dev *rdev)
{
        struct regulator_dev *r;
        struct device *dev = rdev->dev.parent;
        int ret;

        /* No supply to resolve? */
        if (!rdev->supply_name)
                return 0;

        /* Supply already resolved? */
        if (rdev->supply)
                return 0;

        r = regulator_dev_lookup(dev, rdev->supply_name);
        if (IS_ERR(r)) {
                ret = PTR_ERR(r);

                /* Did the lookup explicitly defer for us? */
                if (ret == -EPROBE_DEFER)
                        return ret;

                if (have_full_constraints()) {
                        r = dummy_regulator_rdev;
                        get_device(&r->dev);
                } else {
                        dev_err(dev, "Failed to resolve %s-supply for %s\n",
                                rdev->supply_name, rdev->desc->name);
                        return -EPROBE_DEFER;
                }
        }

        /*
         * If the supply's parent device is not the same as the
         * regulator's parent device, then ensure the parent device
         * is bound before we resolve the supply, in case the parent
         * device get probe deferred and unregisters the supply.
         */
        if (r->dev.parent && r->dev.parent != rdev->dev.parent) {
                if (!device_is_bound(r->dev.parent)) {
                        put_device(&r->dev);
                        return -EPROBE_DEFER;
                }
        }

        /* Recursively resolve the supply of the supply */
        ret = regulator_resolve_supply(r);
        if (ret < 0) {
                put_device(&r->dev);
                return ret;
        }

        ret = set_supply(rdev, r);
        if (ret < 0) {
                put_device(&r->dev);
                return ret;
        }

        /*
         * In set_machine_constraints() we may have turned this regulator on
         * but we couldn't propagate to the supply if it hadn't been resolved
         * yet.  Do it now.
         */
        if (rdev->use_count) {
                ret = regulator_enable(rdev->supply);
                if (ret < 0) {
                        _regulator_put(rdev->supply);
                        rdev->supply = NULL;
                        return ret;
                }
        }

        return 0;
}

/* Internal regulator request function */
struct regulator *_regulator_get(struct device *dev, const char *id,
                                 enum regulator_get_type get_type)
{
        struct regulator_dev *rdev;
        struct regulator *regulator;
        const char *devname = dev ? dev_name(dev) : "deviceless";
        int ret;

        if (get_type >= MAX_GET_TYPE) {
                dev_err(dev, "invalid type %d in %s\n", get_type, __func__);
                return ERR_PTR(-EINVAL);
        }

        if (id == NULL) {
                pr_err("get() with no identifier\n");
                return ERR_PTR(-EINVAL);
        }

        rdev = regulator_dev_lookup(dev, id);
        if (IS_ERR(rdev)) {
                ret = PTR_ERR(rdev);

                /*
                 * If regulator_dev_lookup() fails with error other
                 * than -ENODEV our job here is done, we simply return it.
                 */
                if (ret != -ENODEV)
                        return ERR_PTR(ret);

                if (!have_full_constraints()) {
                        dev_warn(dev,
                                 "incomplete constraints, dummy supplies not allowed\n");
                        return ERR_PTR(-ENODEV);
                }

                switch (get_type) {
                case NORMAL_GET:
                        /*
                         * Assume that a regulator is physically present and
                         * enabled, even if it isn't hooked up, and just
                         * provide a dummy.
                         */
                        dev_warn(dev,
                                 "%s supply %s not found, using dummy regulator\n",
                                 devname, id);
                        rdev = dummy_regulator_rdev;
                        get_device(&rdev->dev);
                        break;

                case EXCLUSIVE_GET:
                        dev_warn(dev,
                                 "dummy supplies not allowed for exclusive requests\n");
                        /* fall through */

                default:
                        return ERR_PTR(-ENODEV);
                }
        }

        if (rdev->exclusive) {
                regulator = ERR_PTR(-EPERM);
                put_device(&rdev->dev);
                return regulator;
        }

        if (get_type == EXCLUSIVE_GET && rdev->open_count) {
                regulator = ERR_PTR(-EBUSY);
                put_device(&rdev->dev);
                return regulator;
        }

        mutex_lock(&regulator_list_mutex);
        ret = (rdev->coupling_desc.n_resolved != rdev->coupling_desc.n_coupled);
        mutex_unlock(&regulator_list_mutex);

        if (ret != 0) {
                regulator = ERR_PTR(-EPROBE_DEFER);
                put_device(&rdev->dev);
                return regulator;
        }

        ret = regulator_resolve_supply(rdev);
        if (ret < 0) {
                regulator = ERR_PTR(ret);
                put_device(&rdev->dev);
                return regulator;
        }

        if (!try_module_get(rdev->owner)) {
                regulator = ERR_PTR(-EPROBE_DEFER);
                put_device(&rdev->dev);
                return regulator;
        }

        regulator = create_regulator(rdev, dev, id);
        if (regulator == NULL) {
                regulator = ERR_PTR(-ENOMEM);
                put_device(&rdev->dev);
                module_put(rdev->owner);
                return regulator;
        }

        rdev->open_count++;
        if (get_type == EXCLUSIVE_GET) {
                rdev->exclusive = 1;

                ret = _regulator_is_enabled(rdev);
                if (ret > 0)
                        rdev->use_count = 1;
                else
                        rdev->use_count = 0;
        }

        device_link_add(dev, &rdev->dev, DL_FLAG_STATELESS);

        return regulator;
}

/**
 * regulator_get - lookup and obtain a reference to a regulator.
 * @dev: device for regulator "consumer"
 * @id: Supply name or regulator ID.
 *
 * Returns a struct regulator corresponding to the regulator producer,
 * or IS_ERR() condition containing errno.
 *
 * Use of supply names configured via regulator_set_device_supply() is
 * strongly encouraged.  It is recommended that the supply name used
 * should match the name used for the supply and/or the relevant
 * device pins in the datasheet.
 */
struct regulator *regulator_get(struct device *dev, const char *id)
{
        return _regulator_get(dev, id, NORMAL_GET);
}
EXPORT_SYMBOL_GPL(regulator_get);

/**
 * regulator_get_exclusive - obtain exclusive access to a regulator.
 * @dev: device for regulator "consumer"
 * @id: Supply name or regulator ID.
 *
 * Returns a struct regulator corresponding to the regulator producer,
 * or IS_ERR() condition containing errno.  Other consumers will be
 * unable to obtain this regulator while this reference is held and the
 * use count for the regulator will be initialised to reflect the current
 * state of the regulator.
 *
 * This is intended for use by consumers which cannot tolerate shared
 * use of the regulator such as those which need to force the
 * regulator off for correct operation of the hardware they are
 * controlling.
 *
 * Use of supply names configured via regulator_set_device_supply() is
 * strongly encouraged.  It is recommended that the supply name used
 * should match the name used for the supply and/or the relevant
 * device pins in the datasheet.
 */
struct regulator *regulator_get_exclusive(struct device *dev, const char *id)
{
        return _regulator_get(dev, id, EXCLUSIVE_GET);
}
EXPORT_SYMBOL_GPL(regulator_get_exclusive);

/**
 * regulator_get_optional - obtain optional access to a regulator.

 * @dev: device for regulator "consumer"
 * @id: Supply name or regulator ID.
 *
 * Returns a struct regulator corresponding to the regulator producer,
 * or IS_ERR() condition containing errno.
 *
 * This is intended for use by consumers for devices which can have
 * some supplies unconnected in normal use, such as some MMC devices.
 * It can allow the regulator core to provide stub supplies for other
 * supplies requested using normal regulator_get() calls without
 * disrupting the operation of drivers that can handle absent
 * supplies.
 *
 * Use of supply names configured via regulator_set_device_supply() is
 * strongly encouraged.  It is recommended that the supply name used
 * should match the name used for the supply and/or the relevant
 * device pins in the datasheet.
 */
struct regulator *regulator_get_optional(struct device *dev, const char *id)
{
        return _regulator_get(dev, id, OPTIONAL_GET);
}
EXPORT_SYMBOL_GPL(regulator_get_optional);

/* regulator_list_mutex lock held by regulator_put() */
static void _regulator_put(struct regulator *regulator)
{
        struct regulator_dev *rdev;

        if (IS_ERR_OR_NULL(regulator))
                return;

        lockdep_assert_held_once(&regulator_list_mutex);

        /* Docs say you must disable before calling regulator_put() */
        WARN_ON(regulator->enable_count);

        rdev = regulator->rdev;

        debugfs_remove_recursive(regulator->debugfs);

        if (regulator->dev) {
                device_link_remove(regulator->dev, &rdev->dev);

                /* remove any sysfs entries */
                sysfs_remove_link(&rdev->dev.kobj, regulator->supply_name);
        }

        regulator_lock(rdev);
        list_del(&regulator->list);

        rdev->open_count--;
        rdev->exclusive = 0;
        put_device(&rdev->dev);
        regulator_unlock(rdev);

        kfree_const(regulator->supply_name);
        kfree(regulator);

        module_put(rdev->owner);
}

/**
 * regulator_put - "free" the regulator source
 * @regulator: regulator source
 *
 * Note: drivers must ensure that all regulator_enable calls made on this
 * regulator source are balanced by regulator_disable calls prior to calling
 * this function.
 */
void regulator_put(struct regulator *regulator)
{
        mutex_lock(&regulator_list_mutex);
        _regulator_put(regulator);
        mutex_unlock(&regulator_list_mutex);
}
EXPORT_SYMBOL_GPL(regulator_put);

/**
 * regulator_register_supply_alias - Provide device alias for supply lookup
 *
 * @dev: device that will be given as the regulator "consumer"
 * @id: Supply name or regulator ID
 * @alias_dev: device that should be used to lookup the supply
 * @alias_id: Supply name or regulator ID that should be used to lookup the
 * supply
 *
 * All lookups for id on dev will instead be conducted for alias_id on
 * alias_dev.
 */
int regulator_register_supply_alias(struct device *dev, const char *id,
                                    struct device *alias_dev,
                                    const char *alias_id)
{
        struct regulator_supply_alias *map;

        map = regulator_find_supply_alias(dev, id);
        if (map)
                return -EEXIST;

        map = kzalloc(sizeof(struct regulator_supply_alias), GFP_KERNEL);
        if (!map)
                return -ENOMEM;

        map->src_dev = dev;
        map->src_supply = id;
        map->alias_dev = alias_dev;
        map->alias_supply = alias_id;

        list_add(&map->list, &regulator_supply_alias_list);

        pr_info("Adding alias for supply %s,%s -> %s,%s\n",
                id, dev_name(dev), alias_id, dev_name(alias_dev));

        return 0;
}
EXPORT_SYMBOL_GPL(regulator_register_supply_alias);

/**
 * regulator_unregister_supply_alias - Remove device alias
 *
 * @dev: device that will be given as the regulator "consumer"
 * @id: Supply name or regulator ID
 *
 * Remove a lookup alias if one exists for id on dev.
 */
void regulator_unregister_supply_alias(struct device *dev, const char *id)
{
        struct regulator_supply_alias *map;

        map = regulator_find_supply_alias(dev, id);
        if (map) {
                list_del(&map->list);
                kfree(map);
        }
}
EXPORT_SYMBOL_GPL(regulator_unregister_supply_alias);

/**
 * regulator_bulk_register_supply_alias - register multiple aliases
 *
 * @dev: device that will be given as the regulator "consumer"
 * @id: List of supply names or regulator IDs
 * @alias_dev: device that should be used to lookup the supply
 * @alias_id: List of supply names or regulator IDs that should be used to
 * lookup the supply
 * @num_id: Number of aliases to register
 *
 * @return 0 on success, an errno on failure.
 *
 * This helper function allows drivers to register several supply
 * aliases in one operation.  If any of the aliases cannot be
 * registered any aliases that were registered will be removed
 * before returning to the caller.
 */
int regulator_bulk_register_supply_alias(struct device *dev,
                                         const char *const *id,
                                         struct device *alias_dev,
                                         const char *const *alias_id,
                                         int num_id)
{
        int i;
        int ret;

        for (i = 0; i < num_id; ++i) {
                ret = regulator_register_supply_alias(dev, id[i], alias_dev,
                                                      alias_id[i]);
                if (ret < 0)
                        goto err;
        }

        return 0;

err:
        dev_err(dev,
                "Failed to create supply alias %s,%s -> %s,%s\n",
                id[i], dev_name(dev), alias_id[i], dev_name(alias_dev));

        while (--i >= 0)
                regulator_unregister_supply_alias(dev, id[i]);

        return ret;
}
EXPORT_SYMBOL_GPL(regulator_bulk_register_supply_alias);

/**
 * regulator_bulk_unregister_supply_alias - unregister multiple aliases
 *
 * @dev: device that will be given as the regulator "consumer"
 * @id: List of supply names or regulator IDs
 * @num_id: Number of aliases to unregister
 *
 * This helper function allows drivers to unregister several supply
 * aliases in one operation.
 */
void regulator_bulk_unregister_supply_alias(struct device *dev,
                                            const char *const *id,
                                            int num_id)
{
        int i;

        for (i = 0; i < num_id; ++i)
                regulator_unregister_supply_alias(dev, id[i]);
}
EXPORT_SYMBOL_GPL(regulator_bulk_unregister_supply_alias);


/* Manage enable GPIO list. Same GPIO pin can be shared among regulators */
static int regulator_ena_gpio_request(struct regulator_dev *rdev,
                                const struct regulator_config *config)
{
        struct regulator_enable_gpio *pin;
        struct gpio_desc *gpiod;

        gpiod = config->ena_gpiod;

        list_for_each_entry(pin, &regulator_ena_gpio_list, list) {
                if (pin->gpiod == gpiod) {
                        rdev_dbg(rdev, "GPIO is already used\n");
                        goto update_ena_gpio_to_rdev;
                }
        }

        pin = kzalloc(sizeof(struct regulator_enable_gpio), GFP_KERNEL);
        if (pin == NULL)
                return -ENOMEM;

        pin->gpiod = gpiod;
        list_add(&pin->list, &regulator_ena_gpio_list);

update_ena_gpio_to_rdev:
        pin->request_count++;
        rdev->ena_pin = pin;
        return 0;
}

static void regulator_ena_gpio_free(struct regulator_dev *rdev)
{
        struct regulator_enable_gpio *pin, *n;

        if (!rdev->ena_pin)
                return;

        /* Free the GPIO only in case of no use */
        list_for_each_entry_safe(pin, n, &regulator_ena_gpio_list, list) {
                if (pin->gpiod == rdev->ena_pin->gpiod) {
                        if (pin->request_count <= 1) {
                                pin->request_count = 0;
                                gpiod_put(pin->gpiod);
                                list_del(&pin->list);
                                kfree(pin);
                                rdev->ena_pin = NULL;
                                return;
                        } else {
                                pin->request_count--;
                        }
                }
        }
}

/**
 * regulator_ena_gpio_ctrl - balance enable_count of each GPIO and actual GPIO pin control
 * @rdev: regulator_dev structure
 * @enable: enable GPIO at initial use?
 *
 * GPIO is enabled in case of initial use. (enable_count is 0)
 * GPIO is disabled when it is not shared any more. (enable_count <= 1)
 */
static int regulator_ena_gpio_ctrl(struct regulator_dev *rdev, bool enable)
{
        struct regulator_enable_gpio *pin = rdev->ena_pin;

        if (!pin)
                return -EINVAL;

        if (enable) {
                /* Enable GPIO at initial use */
                if (pin->enable_count == 0)
                        gpiod_set_value_cansleep(pin->gpiod, 1);

                pin->enable_count++;
        } else {
                if (pin->enable_count > 1) {
                        pin->enable_count--;
                        return 0;
                }

                /* Disable GPIO if not used */
                if (pin->enable_count <= 1) {
                        gpiod_set_value_cansleep(pin->gpiod, 0);
                        pin->enable_count = 0;
                }
        }

        return 0;
}

/**
 * _regulator_enable_delay - a delay helper function
 * @delay: time to delay in microseconds
 *
 * Delay for the requested amount of time as per the guidelines in:
 *
 *     Documentation/timers/timers-howto.rst
 *
 * The assumption here is that regulators will never be enabled in
 * atomic context and therefore sleeping functions can be used.
 */
static void _regulator_enable_delay(unsigned int delay)
{
        unsigned int ms = delay / 1000;
        unsigned int us = delay % 1000;

        if (ms > 0) {
                /*
                 * For small enough values, handle super-millisecond
                 * delays in the usleep_range() call below.
                 */
                if (ms < 20)
                        us += ms * 1000;
                else
                        msleep(ms);
        }

        /*
         * Give the scheduler some room to coalesce with any other
         * wakeup sources. For delays shorter than 10 us, don't even
         * bother setting up high-resolution timers and just busy-
         * loop.
         */
        if (us >= 10)
                usleep_range(us, us + 100);
        else
                udelay(us);
}

static int _regulator_do_enable(struct regulator_dev *rdev)
{
        int ret, delay;

        /* Query before enabling in case configuration dependent.  */
        ret = _regulator_get_enable_time(rdev);
        if (ret >= 0) {
                delay = ret;
        } else {
                rdev_warn(rdev, "enable_time() failed: %d\n", ret);
                delay = 0;
        }

        trace_regulator_enable(rdev_get_name(rdev));

        if (rdev->desc->off_on_delay) {
                /* if needed, keep a distance of off_on_delay from last time
                 * this regulator was disabled.
                 */
                unsigned long start_jiffy = jiffies;
                unsigned long intended, max_delay, remaining;

                max_delay = usecs_to_jiffies(rdev->desc->off_on_delay);
                intended = rdev->last_off_jiffy + max_delay;

                if (time_before(start_jiffy, intended)) {
                        /* calc remaining jiffies to deal with one-time
                         * timer wrapping.
                         * in case of multiple timer wrapping, either it can be
                         * detected by out-of-range remaining, or it cannot be
                         * detected and we get a penalty of
                         * _regulator_enable_delay().
                         */
                        remaining = intended - start_jiffy;
                        if (remaining <= max_delay)
                                _regulator_enable_delay(
                                                jiffies_to_usecs(remaining));
                }
        }

        if (rdev->ena_pin) {
                if (!rdev->ena_gpio_state) {
                        ret = regulator_ena_gpio_ctrl(rdev, true);
                        if (ret < 0)
                                return ret;
                        rdev->ena_gpio_state = 1;
                }
        } else if (rdev->desc->ops->enable) {
                ret = rdev->desc->ops->enable(rdev);
                if (ret < 0)
                        return ret;
        } else {
                return -EINVAL;
        }

        /* Allow the regulator to ramp; it would be useful to extend
         * this for bulk operations so that the regulators can ramp
         * together.  */
        trace_regulator_enable_delay(rdev_get_name(rdev));

        _regulator_enable_delay(delay);

        trace_regulator_enable_complete(rdev_get_name(rdev));

        return 0;
}

/**
 * _regulator_handle_consumer_enable - handle that a consumer enabled
 * @regulator: regulator source
 *
 * Some things on a regulator consumer (like the contribution towards total
 * load on the regulator) only have an effect when the consumer wants the
 * regulator enabled.  Explained in example with two consumers of the same
 * regulator:
 *   consumer A: set_load(100);       => total load = 0
 *   consumer A: regulator_enable();  => total load = 100
 *   consumer B: set_load(1000);      => total load = 100
 *   consumer B: regulator_enable();  => total load = 1100
 *   consumer A: regulator_disable(); => total_load = 1000
 *
 * This function (together with _regulator_handle_consumer_disable) is
 * responsible for keeping track of the refcount for a given regulator consumer
 * and applying / unapplying these things.
 *
 * Returns 0 upon no error; -error upon error.
 */
static int _regulator_handle_consumer_enable(struct regulator *regulator)
{
        struct regulator_dev *rdev = regulator->rdev;

        lockdep_assert_held_once(&rdev->mutex.base);

        regulator->enable_count++;
        if (regulator->uA_load && regulator->enable_count == 1)
                return drms_uA_update(rdev);

        return 0;
}

/**
 * _regulator_handle_consumer_disable - handle that a consumer disabled
 * @regulator: regulator source
 *
 * The opposite of _regulator_handle_consumer_enable().
 *
 * Returns 0 upon no error; -error upon error.
 */
static int _regulator_handle_consumer_disable(struct regulator *regulator)
{
        struct regulator_dev *rdev = regulator->rdev;

        lockdep_assert_held_once(&rdev->mutex.base);

        if (!regulator->enable_count) {
                rdev_err(rdev, "Underflow of regulator enable count\n");
                return -EINVAL;
        }

        regulator->enable_count--;
        if (regulator->uA_load && regulator->enable_count == 0)
                return drms_uA_update(rdev);

        return 0;
}

/* locks held by regulator_enable() */
static int _regulator_enable(struct regulator *regulator)
{
        struct regulator_dev *rdev = regulator->rdev;
        int ret;

        lockdep_assert_held_once(&rdev->mutex.base);

        if (rdev->use_count == 0 && rdev->supply) {
                ret = _regulator_enable(rdev->supply);
                if (ret < 0)
                        return ret;
        }

        /* balance only if there are regulators coupled */
        if (rdev->coupling_desc.n_coupled > 1) {
                ret = regulator_balance_voltage(rdev, PM_SUSPEND_ON);
                if (ret < 0)
                        goto err_disable_supply;
        }

        ret = _regulator_handle_consumer_enable(regulator);
        if (ret < 0)
                goto err_disable_supply;

        if (rdev->use_count == 0) {
                /* The regulator may on if it's not switchable or left on */
                ret = _regulator_is_enabled(rdev);
                if (ret == -EINVAL || ret == 0) {
                        if (!regulator_ops_is_valid(rdev,
                                        REGULATOR_CHANGE_STATUS)) {
                                ret = -EPERM;
                                goto err_consumer_disable;
                        }

                        ret = _regulator_do_enable(rdev);
                        if (ret < 0)
                                goto err_consumer_disable;

                        _notifier_call_chain(rdev, REGULATOR_EVENT_ENABLE,
                                             NULL);
                } else if (ret < 0) {
                        rdev_err(rdev, "is_enabled() failed: %d\n", ret);
                        goto err_consumer_disable;
                }
                /* Fallthrough on positive return values - already enabled */
        }

        rdev->use_count++;

        return 0;

err_consumer_disable:
        _regulator_handle_consumer_disable(regulator);

err_disable_supply:
        if (rdev->use_count == 0 && rdev->supply)
                _regulator_disable(rdev->supply);

        return ret;
}

/**
 * regulator_enable - enable regulator output
 * @regulator: regulator source
 *
 * Request that the regulator be enabled with the regulator output at
 * the predefined voltage or current value.  Calls to regulator_enable()
 * must be balanced with calls to regulator_disable().
 *
 * NOTE: the output value can be set by other drivers, boot loader or may be
 * hardwired in the regulator.
 */
int regulator_enable(struct regulator *regulator)
{
        struct regulator_dev *rdev = regulator->rdev;
        struct ww_acquire_ctx ww_ctx;
        int ret;

        regulator_lock_dependent(rdev, &ww_ctx);
        ret = _regulator_enable(regulator);
        regulator_unlock_dependent(rdev, &ww_ctx);

        return ret;
}
EXPORT_SYMBOL_GPL(regulator_enable);

static int _regulator_do_disable(struct regulator_dev *rdev)
{
        int ret;

        trace_regulator_disable(rdev_get_name(rdev));

        if (rdev->ena_pin) {
                if (rdev->ena_gpio_state) {
                        ret = regulator_ena_gpio_ctrl(rdev, false);
                        if (ret < 0)
                                return ret;
                        rdev->ena_gpio_state = 0;
                }

        } else if (rdev->desc->ops->disable) {
                ret = rdev->desc->ops->disable(rdev);
                if (ret != 0)
                        return ret;
        }

        /* cares about last_off_jiffy only if off_on_delay is required by
         * device.
         */
        if (rdev->desc->off_on_delay)
                rdev->last_off_jiffy = jiffies;

        trace_regulator_disable_complete(rdev_get_name(rdev));

        return 0;
}

/* locks held by regulator_disable() */
static int _regulator_disable(struct regulator *regulator)
{
        struct regulator_dev *rdev = regulator->rdev;
        int ret = 0;

        lockdep_assert_held_once(&rdev->mutex.base);

        if (WARN(rdev->use_count <= 0,
                 "unbalanced disables for %s\n", rdev_get_name(rdev)))
                return -EIO;

        /* are we the last user and permitted to disable ? */
        if (rdev->use_count == 1 &&
            (rdev->constraints && !rdev->constraints->always_on)) {

                /* we are last user */
                if (regulator_ops_is_valid(rdev, REGULATOR_CHANGE_STATUS)) {
                        ret = _notifier_call_chain(rdev,
                                                   REGULATOR_EVENT_PRE_DISABLE,
                                                   NULL);
                        if (ret & NOTIFY_STOP_MASK)
                                return -EINVAL;

                        ret = _regulator_do_disable(rdev);
                        if (ret < 0) {
                                rdev_err(rdev, "failed to disable\n");
                                _notifier_call_chain(rdev,
                                                REGULATOR_EVENT_ABORT_DISABLE,
                                                NULL);
                                return ret;
                        }
                        _notifier_call_chain(rdev, REGULATOR_EVENT_DISABLE,
                                        NULL);
                }

                rdev->use_count = 0;
        } else if (rdev->use_count > 1) {
                rdev->use_count--;
        }

        if (ret == 0)
                ret = _regulator_handle_consumer_disable(regulator);

        if (ret == 0 && rdev->coupling_desc.n_coupled > 1)
                ret = regulator_balance_voltage(rdev, PM_SUSPEND_ON);

        if (ret == 0 && rdev->use_count == 0 && rdev->supply)
                ret = _regulator_disable(rdev->supply);

        return ret;
}

/**
 * regulator_disable - disable regulator output
 * @regulator: regulator source
 *
 * Disable the regulator output voltage or current.  Calls to
 * regulator_enable() must be balanced with calls to
 * regulator_disable().
 *
 * NOTE: this will only disable the regulator output if no other consumer
 * devices have it enabled, the regulator device supports disabling and
 * machine constraints permit this operation.
 */
int regulator_disable(struct regulator *regulator)
{
        struct regulator_dev *rdev = regulator->rdev;
        struct ww_acquire_ctx ww_ctx;
        int ret;

        regulator_lock_dependent(rdev, &ww_ctx);
        ret = _regulator_disable(regulator);
        regulator_unlock_dependent(rdev, &ww_ctx);

        return ret;
}
EXPORT_SYMBOL_GPL(regulator_disable);

/* locks held by regulator_force_disable() */
static int _regulator_force_disable(struct regulator_dev *rdev)
{
        int ret = 0;

        lockdep_assert_held_once(&rdev->mutex.base);

        ret = _notifier_call_chain(rdev, REGULATOR_EVENT_FORCE_DISABLE |
                        REGULATOR_EVENT_PRE_DISABLE, NULL);
        if (ret & NOTIFY_STOP_MASK)
                return -EINVAL;

        ret = _regulator_do_disable(rdev);
        if (ret < 0) {
                rdev_err(rdev, "failed to force disable\n");
                _notifier_call_chain(rdev, REGULATOR_EVENT_FORCE_DISABLE |
                                REGULATOR_EVENT_ABORT_DISABLE, NULL);
                return ret;
        }

        _notifier_call_chain(rdev, REGULATOR_EVENT_FORCE_DISABLE |
                        REGULATOR_EVENT_DISABLE, NULL);

        return 0;
}

/**
 * regulator_force_disable - force disable regulator output
 * @regulator: regulator source
 *
 * Forcibly disable the regulator output voltage or current.
 * NOTE: this *will* disable the regulator output even if other consumer
 * devices have it enabled. This should be used for situations when device
 * damage will likely occur if the regulator is not disabled (e.g. over temp).
 */
int regulator_force_disable(struct regulator *regulator)
{
        struct regulator_dev *rdev = regulator->rdev;
        struct ww_acquire_ctx ww_ctx;
        int ret;

        regulator_lock_dependent(rdev, &ww_ctx);

        ret = _regulator_force_disable(regulator->rdev);

        if (rdev->coupling_desc.n_coupled > 1)
                regulator_balance_voltage(rdev, PM_SUSPEND_ON);

        if (regulator->uA_load) {
                regulator->uA_load = 0;
                ret = drms_uA_update(rdev);
        }

        if (rdev->use_count != 0 && rdev->supply)
                _regulator_disable(rdev->supply);

        regulator_unlock_dependent(rdev, &ww_ctx);

        return ret;
}
EXPORT_SYMBOL_GPL(regulator_force_disable);

static void regulator_disable_work(struct work_struct *work)
{
        struct regulator_dev *rdev = container_of(work, struct regulator_dev,
                                                  disable_work.work);
        struct ww_acquire_ctx ww_ctx;
        int count, i, ret;
        struct regulator *regulator;
        int total_count = 0;

        regulator_lock_dependent(rdev, &ww_ctx);

        /*
         * Workqueue functions queue the new work instance while the previous
         * work instance is being processed. Cancel the queued work instance
         * as the work instance under processing does the job of the queued
         * work instance.
         */
        cancel_delayed_work(&rdev->disable_work);

        list_for_each_entry(regulator, &rdev->consumer_list, list) {
                count = regulator->deferred_disables;

                if (!count)
                        continue;

                total_count += count;
                regulator->deferred_disables = 0;

                for (i = 0; i < count; i++) {
                        ret = _regulator_disable(regulator);
                        if (ret != 0)
                                rdev_err(rdev, "Deferred disable failed: %d\n", ret);
                }
        }
        WARN_ON(!total_count);

        if (rdev->coupling_desc.n_coupled > 1)
                regulator_balance_voltage(rdev, PM_SUSPEND_ON);

        regulator_unlock_dependent(rdev, &ww_ctx);
}

/**
 * regulator_disable_deferred - disable regulator output with delay
 * @regulator: regulator source
 * @ms: milliseconds until the regulator is disabled
 *
 * Execute regulator_disable() on the regulator after a delay.  This
 * is intended for use with devices that require some time to quiesce.
 *
 * NOTE: this will only disable the regulator output if no other consumer
 * devices have it enabled, the regulator device supports disabling and
 * machine constraints permit this operation.
 */
int regulator_disable_deferred(struct regulator *regulator, int ms)
{
        struct regulator_dev *rdev = regulator->rdev;

        if (!ms)
                return regulator_disable(regulator);

        regulator_lock(rdev);
        regulator->deferred_disables++;
        mod_delayed_work(system_power_efficient_wq, &rdev->disable_work,
                         msecs_to_jiffies(ms));
        regulator_unlock(rdev);

        return 0;
}
EXPORT_SYMBOL_GPL(regulator_disable_deferred);

static int _regulator_is_enabled(struct regulator_dev *rdev)
{
        /* A GPIO control always takes precedence */
        if (rdev->ena_pin)
                return rdev->ena_gpio_state;

        /* If we don't know then assume that the regulator is always on */
        if (!rdev->desc->ops->is_enabled)
                return 1;

        return rdev->desc->ops->is_enabled(rdev);
}

static int _regulator_list_voltage(struct regulator_dev *rdev,
                                   unsigned selector, int lock)
{
        const struct regulator_ops *ops = rdev->desc->ops;
        int ret;

        if (rdev->desc->fixed_uV && rdev->desc->n_voltages == 1 && !selector)
                return rdev->desc->fixed_uV;

        if (ops->list_voltage) {
                if (selector >= rdev->desc->n_voltages)
                        return -EINVAL;
                if (lock)
                        regulator_lock(rdev);
                ret = ops->list_voltage(rdev, selector);
                if (lock)
                        regulator_unlock(rdev);
        } else if (rdev->is_switch && rdev->supply) {
                ret = _regulator_list_voltage(rdev->supply->rdev,
                                              selector, lock);
        } else {
                return -EINVAL;
        }

        if (ret > 0) {
                if (ret < rdev->constraints->min_uV)
                        ret = 0;
                else if (ret > rdev->constraints->max_uV)
                        ret = 0;
        }

        return ret;
}

/**
 * regulator_is_enabled - is the regulator output enabled
 * @regulator: regulator source
 *
 * Returns positive if the regulator driver backing the source/client
 * has requested that the device be enabled, zero if it hasn't, else a
 * negative errno code.
 *
 * Note that the device backing this regulator handle can have multiple
 * users, so it might be enabled even if regulator_enable() was never
 * called for this particular source.
 */
int regulator_is_enabled(struct regulator *regulator)
{
        int ret;

        if (regulator->always_on)
                return 1;

        regulator_lock(regulator->rdev);
        ret = _regulator_is_enabled(regulator->rdev);
        regulator_unlock(regulator->rdev);

        return ret;
}
EXPORT_SYMBOL_GPL(regulator_is_enabled);

/**
 * regulator_count_voltages - count regulator_list_voltage() selectors
 * @regulator: regulator source
 *
 * Returns number of selectors, or negative errno.  Selectors are
 * numbered starting at zero, and typically correspond to bitfields
 * in hardware registers.
 */
int regulator_count_voltages(struct regulator *regulator)
{
        struct regulator_dev    *rdev = regulator->rdev;

        if (rdev->desc->n_voltages)
                return rdev->desc->n_voltages;

        if (!rdev->is_switch || !rdev->supply)
                return -EINVAL;

        return regulator_count_voltages(rdev->supply);
}
EXPORT_SYMBOL_GPL(regulator_count_voltages);

/**
 * regulator_list_voltage - enumerate supported voltages
 * @regulator: regulator source
 * @selector: identify voltage to list
 * Context: can sleep
 *
 * Returns a voltage that can be passed to @regulator_set_voltage(),
 * zero if this selector code can't be used on this system, or a
 * negative errno.
 */
int regulator_list_voltage(struct regulator *regulator, unsigned selector)
{
        return _regulator_list_voltage(regulator->rdev, selector, 1);
}
EXPORT_SYMBOL_GPL(regulator_list_voltage);

/**
 * regulator_get_regmap - get the regulator's register map
 * @regulator: regulator source
 *
 * Returns the register map for the given regulator, or an ERR_PTR value
 * if the regulator doesn't use regmap.
 */
struct regmap *regulator_get_regmap(struct regulator *regulator)
{
        struct regmap *map = regulator->rdev->regmap;

        return map ? map : ERR_PTR(-EOPNOTSUPP);
}

/**
 * regulator_get_hardware_vsel_register - get the HW voltage selector register
 * @regulator: regulator source
 * @vsel_reg: voltage selector register, output parameter
 * @vsel_mask: mask for voltage selector bitfield, output parameter
 *
 * Returns the hardware register offset and bitmask used for setting the
 * regulator voltage. This might be useful when configuring voltage-scaling
 * hardware or firmware that can make I2C requests behind the kernel's back,
 * for example.
 *
 * On success, the output parameters @vsel_reg and @vsel_mask are filled in
 * and 0 is returned, otherwise a negative errno is returned.
 */
int regulator_get_hardware_vsel_register(struct regulator *regulator,
                                         unsigned *vsel_reg,
                                         unsigned *vsel_mask)
{
        struct regulator_dev *rdev = regulator->rdev;
        const struct regulator_ops *ops = rdev->desc->ops;

        if (ops->set_voltage_sel != regulator_set_voltage_sel_regmap)
                return -EOPNOTSUPP;

        *vsel_reg = rdev->desc->vsel_reg;
        *vsel_mask = rdev->desc->vsel_mask;

         return 0;
}
EXPORT_SYMBOL_GPL(regulator_get_hardware_vsel_register);

/**
 * regulator_list_hardware_vsel - get the HW-specific register value for a selector
 * @regulator: regulator source
 * @selector: identify voltage to list
 *
 * Converts the selector to a hardware-specific voltage selector that can be
 * directly written to the regulator registers. The address of the voltage
 * register can be determined by calling @regulator_get_hardware_vsel_register.
 *
 * On error a negative errno is returned.
 */
int regulator_list_hardware_vsel(struct regulator *regulator,
                                 unsigned selector)
{
        struct regulator_dev *rdev = regulator->rdev;
        const struct regulator_ops *ops = rdev->desc->ops;

        if (selector >= rdev->desc->n_voltages)
                return -EINVAL;
        if (ops->set_voltage_sel != regulator_set_voltage_sel_regmap)
                return -EOPNOTSUPP;

        return selector;
}
EXPORT_SYMBOL_GPL(regulator_list_hardware_vsel);

/**
 * regulator_get_linear_step - return the voltage step size between VSEL values
 * @regulator: regulator source
 *
 * Returns the voltage step size between VSEL values for linear
 * regulators, or return 0 if the regulator isn't a linear regulator.
 */
unsigned int regulator_get_linear_step(struct regulator *regulator)
{
        struct regulator_dev *rdev = regulator->rdev;

        return rdev->desc->uV_step;
}
EXPORT_SYMBOL_GPL(regulator_get_linear_step);

/**
 * regulator_is_supported_voltage - check if a voltage range can be supported
 *
 * @regulator: Regulator to check.
 * @min_uV: Minimum required voltage in uV.
 * @max_uV: Maximum required voltage in uV.
 *
 * Returns a boolean.
 */
int regulator_is_supported_voltage(struct regulator *regulator,

                                   int min_uV, int max_uV)
{
        struct regulator_dev *rdev = regulator->rdev;
        int i, voltages, ret;

        /* If we can't change voltage check the current voltage */
        if (!regulator_ops_is_valid(rdev, REGULATOR_CHANGE_VOLTAGE)) {
                ret = regulator_get_voltage(regulator);
                if (ret >= 0)
                        return min_uV <= ret && ret <= max_uV;
                else
                        return ret;
        }

        /* Any voltage within constrains range is fine? */
        if (rdev->desc->continuous_voltage_range)
                return min_uV >= rdev->constraints->min_uV &&
                                max_uV <= rdev->constraints->max_uV;

        ret = regulator_count_voltages(regulator);
        if (ret < 0)
                return 0;
        voltages = ret;

        for (i = 0; i < voltages; i++) {
                ret = regulator_list_voltage(regulator, i);

                if (ret >= min_uV && ret <= max_uV)
                        return 1;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(regulator_is_supported_voltage);

static int regulator_map_voltage(struct regulator_dev *rdev, int min_uV,
                                 int max_uV)
{
        const struct regulator_desc *desc = rdev->desc;

        if (desc->ops->map_voltage)
                return desc->ops->map_voltage(rdev, min_uV, max_uV);

        if (desc->ops->list_voltage == regulator_list_voltage_linear)
                return regulator_map_voltage_linear(rdev, min_uV, max_uV);

        if (desc->ops->list_voltage == regulator_list_voltage_linear_range)
                return regulator_map_voltage_linear_range(rdev, min_uV, max_uV);

        if (desc->ops->list_voltage ==
                regulator_list_voltage_pickable_linear_range)
                return regulator_map_voltage_pickable_linear_range(rdev,
                                                        min_uV, max_uV);

        return regulator_map_voltage_iterate(rdev, min_uV, max_uV);
}

static int _regulator_call_set_voltage(struct regulator_dev *rdev,
                                       int min_uV, int max_uV,
                                       unsigned *selector)
{
        struct pre_voltage_change_data data;
        int ret;

        data.old_uV = regulator_get_voltage_rdev(rdev);
        data.min_uV = min_uV;
        data.max_uV = max_uV;
        ret = _notifier_call_chain(rdev, REGULATOR_EVENT_PRE_VOLTAGE_CHANGE,
                                   &data);
        if (ret & NOTIFY_STOP_MASK)
                return -EINVAL;

        ret = rdev->desc->ops->set_voltage(rdev, min_uV, max_uV, selector);
        if (ret >= 0)
                return ret;

        _notifier_call_chain(rdev, REGULATOR_EVENT_ABORT_VOLTAGE_CHANGE,
                             (void *)data.old_uV);

        return ret;
}

static int _regulator_call_set_voltage_sel(struct regulator_dev *rdev,
                                           int uV, unsigned selector)
{
        struct pre_voltage_change_data data;
        int ret;

        data.old_uV = regulator_get_voltage_rdev(rdev);
        data.min_uV = uV;
        data.max_uV = uV;
        ret = _notifier_call_chain(rdev, REGULATOR_EVENT_PRE_VOLTAGE_CHANGE,
                                   &data);
        if (ret & NOTIFY_STOP_MASK)
                return -EINVAL;

        ret = rdev->desc->ops->set_voltage_sel(rdev, selector);
        if (ret >= 0)
                return ret;

        _notifier_call_chain(rdev, REGULATOR_EVENT_ABORT_VOLTAGE_CHANGE,
                             (void *)data.old_uV);

        return ret;
}

static int _regulator_set_voltage_sel_step(struct regulator_dev *rdev,
                                           int uV, int new_selector)
{
        const struct regulator_ops *ops = rdev->desc->ops;
        int diff, old_sel, curr_sel, ret;

        /* Stepping is only needed if the regulator is enabled. */
        if (!_regulator_is_enabled(rdev))
                goto final_set;

        if (!ops->get_voltage_sel)
                return -EINVAL;

        old_sel = ops->get_voltage_sel(rdev);
        if (old_sel < 0)
                return old_sel;

        diff = new_selector - old_sel;
        if (diff == 0)
                return 0; /* No change needed. */

        if (diff > 0) {
                /* Stepping up. */
                for (curr_sel = old_sel + rdev->desc->vsel_step;
                     curr_sel < new_selector;
                     curr_sel += rdev->desc->vsel_step) {
                        /*
                         * Call the callback directly instead of using
                         * _regulator_call_set_voltage_sel() as we don't
                         * want to notify anyone yet. Same in the branch
                         * below.
                         */
                        ret = ops->set_voltage_sel(rdev, curr_sel);
                        if (ret)
                                goto try_revert;
                }
        } else {
                /* Stepping down. */
                for (curr_sel = old_sel - rdev->desc->vsel_step;
                     curr_sel > new_selector;
                     curr_sel -= rdev->desc->vsel_step) {
                        ret = ops->set_voltage_sel(rdev, curr_sel);
                        if (ret)
                                goto try_revert;
                }
        }

final_set:
        /* The final selector will trigger the notifiers. */
        return _regulator_call_set_voltage_sel(rdev, uV, new_selector);

try_revert:
        /*
         * At least try to return to the previous voltage if setting a new
         * one failed.
         */
        (void)ops->set_voltage_sel(rdev, old_sel);
        return ret;
}

static int _regulator_set_voltage_time(struct regulator_dev *rdev,
                                       int old_uV, int new_uV)
{
        unsigned int ramp_delay = 0;

        if (rdev->constraints->ramp_delay)
                ramp_delay = rdev->constraints->ramp_delay;
        else if (rdev->desc->ramp_delay)
                ramp_delay = rdev->desc->ramp_delay;
        else if (rdev->constraints->settling_time)
                return rdev->constraints->settling_time;
        else if (rdev->constraints->settling_time_up &&
                 (new_uV > old_uV))
                return rdev->constraints->settling_time_up;
        else if (rdev->constraints->settling_time_down &&
                 (new_uV < old_uV))
                return rdev->constraints->settling_time_down;

        if (ramp_delay == 0) {
                rdev_dbg(rdev, "ramp_delay not set\n");
                return 0;
        }

        return DIV_ROUND_UP(abs(new_uV - old_uV), ramp_delay);
}

static int _regulator_do_set_voltage(struct regulator_dev *rdev,
                                     int min_uV, int max_uV)
{
        int ret;
        int delay = 0;
        int best_val = 0;
        unsigned int selector;
        int old_selector = -1;
        const struct regulator_ops *ops = rdev->desc->ops;
        int old_uV = regulator_get_voltage_rdev(rdev);

        trace_regulator_set_voltage(rdev_get_name(rdev), min_uV, max_uV);

        min_uV += rdev->constraints->uV_offset;
        max_uV += rdev->constraints->uV_offset;

        /*
         * If we can't obtain the old selector there is not enough
         * info to call set_voltage_time_sel().
         */
        if (_regulator_is_enabled(rdev) &&
            ops->set_voltage_time_sel && ops->get_voltage_sel) {
                old_selector = ops->get_voltage_sel(rdev);
                if (old_selector < 0)
                        return old_selector;
        }

        if (ops->set_voltage) {
                ret = _regulator_call_set_voltage(rdev, min_uV, max_uV,
                                                  &selector);

                if (ret >= 0) {
                        if (ops->list_voltage)
                                best_val = ops->list_voltage(rdev,
                                                             selector);
                        else
                                best_val = regulator_get_voltage_rdev(rdev);
                }

        } else if (ops->set_voltage_sel) {
                ret = regulator_map_voltage(rdev, min_uV, max_uV);
                if (ret >= 0) {
                        best_val = ops->list_voltage(rdev, ret);
                        if (min_uV <= best_val && max_uV >= best_val) {
                                selector = ret;
                                if (old_selector == selector)
                                        ret = 0;
                                else if (rdev->desc->vsel_step)
                                        ret = _regulator_set_voltage_sel_step(
                                                rdev, best_val, selector);
                                else
                                        ret = _regulator_call_set_voltage_sel(
                                                rdev, best_val, selector);
                        } else {
                                ret = -EINVAL;
                        }
                }
        } else {
                ret = -EINVAL;
        }

        if (ret)
                goto out;

        if (ops->set_voltage_time_sel) {
                /*
                 * Call set_voltage_time_sel if successfully obtained
                 * old_selector
                 */
                if (old_selector >= 0 && old_selector != selector)
                        delay = ops->set_voltage_time_sel(rdev, old_selector,
                                                          selector);
        } else {
                if (old_uV != best_val) {
                        if (ops->set_voltage_time)
                                delay = ops->set_voltage_time(rdev, old_uV,
                                                              best_val);
                        else
                                delay = _regulator_set_voltage_time(rdev,
                                                                    old_uV,
                                                                    best_val);
                }
        }

        if (delay < 0) {
                rdev_warn(rdev, "failed to get delay: %d\n", delay);
                delay = 0;
        }

        /* Insert any necessary delays */
        if (delay >= 1000) {
                mdelay(delay / 1000);
                udelay(delay % 1000);
        } else if (delay) {
                udelay(delay);
        }

        if (best_val >= 0) {
                unsigned long data = best_val;

                _notifier_call_chain(rdev, REGULATOR_EVENT_VOLTAGE_CHANGE,
                                     (void *)data);
        }

out:
        trace_regulator_set_voltage_complete(rdev_get_name(rdev), best_val);

        return ret;
}

static int _regulator_do_set_suspend_voltage(struct regulator_dev *rdev,
                                  int min_uV, int max_uV, suspend_state_t state)
{
        struct regulator_state *rstate;
        int uV, sel;

        rstate = regulator_get_suspend_state(rdev, state);
        if (rstate == NULL)
                return -EINVAL;

        if (min_uV < rstate->min_uV)
                min_uV = rstate->min_uV;
        if (max_uV > rstate->max_uV)
                max_uV = rstate->max_uV;

        sel = regulator_map_voltage(rdev, min_uV, max_uV);
        if (sel < 0)
                return sel;

        uV = rdev->desc->ops->list_voltage(rdev, sel);
        if (uV >= min_uV && uV <= max_uV)
                rstate->uV = uV;

        return 0;
}

static int regulator_set_voltage_unlocked(struct regulator *regulator,
                                          int min_uV, int max_uV,
                                          suspend_state_t state)
{
        struct regulator_dev *rdev = regulator->rdev;
        struct regulator_voltage *voltage = &regulator->voltage[state];
        int ret = 0;
        int old_min_uV, old_max_uV;
        int current_uV;

        /* If we're setting the same range as last time the change
         * should be a noop (some cpufreq implementations use the same
         * voltage for multiple frequencies, for example).
         */
        if (voltage->min_uV == min_uV && voltage->max_uV == max_uV)
                goto out;

        /* If we're trying to set a range that overlaps the current voltage,
         * return successfully even though the regulator does not support
         * changing the voltage.
         */
        if (!regulator_ops_is_valid(rdev, REGULATOR_CHANGE_VOLTAGE)) {
                current_uV = regulator_get_voltage_rdev(rdev);
                if (min_uV <= current_uV && current_uV <= max_uV) {
                        voltage->min_uV = min_uV;
                        voltage->max_uV = max_uV;
                        goto out;
                }
        }

        /* sanity check */
        if (!rdev->desc->ops->set_voltage &&
            !rdev->desc->ops->set_voltage_sel) {
                ret = -EINVAL;
                goto out;
        }

        /* constraints check */
        ret = regulator_check_voltage(rdev, &min_uV, &max_uV);
        if (ret < 0)
                goto out;

        /* restore original values in case of error */
        old_min_uV = voltage->min_uV;
        old_max_uV = voltage->max_uV;
        voltage->min_uV = min_uV;
        voltage->max_uV = max_uV;

        /* for not coupled regulators this will just set the voltage */
        ret = regulator_balance_voltage(rdev, state);
        if (ret < 0) {
                voltage->min_uV = old_min_uV;
                voltage->max_uV = old_max_uV;
        }

out:
        return ret;
}

int regulator_set_voltage_rdev(struct regulator_dev *rdev, int min_uV,
                               int max_uV, suspend_state_t state)
{
        int best_supply_uV = 0;
        int supply_change_uV = 0;
        int ret;

        if (rdev->supply &&
            regulator_ops_is_valid(rdev->supply->rdev,
                                   REGULATOR_CHANGE_VOLTAGE) &&
            (rdev->desc->min_dropout_uV || !(rdev->desc->ops->get_voltage ||
                                           rdev->desc->ops->get_voltage_sel))) {
                int current_supply_uV;
                int selector;

                selector = regulator_map_voltage(rdev, min_uV, max_uV);
                if (selector < 0) {
                        ret = selector;
                        goto out;
                }

                best_supply_uV = _regulator_list_voltage(rdev, selector, 0);
                if (best_supply_uV < 0) {
                        ret = best_supply_uV;
                        goto out;
                }

                best_supply_uV += rdev->desc->min_dropout_uV;

                current_supply_uV = regulator_get_voltage_rdev(rdev->supply->rdev);
                if (current_supply_uV < 0) {
                        ret = current_supply_uV;
                        goto out;
                }

                supply_change_uV = best_supply_uV - current_supply_uV;
        }

        if (supply_change_uV > 0) {
                ret = regulator_set_voltage_unlocked(rdev->supply,
                                best_supply_uV, INT_MAX, state);
                if (ret) {
                        dev_err(&rdev->dev, "Failed to increase supply voltage: %d\n",
                                        ret);
                        goto out;
                }
        }

        if (state == PM_SUSPEND_ON)
                ret = _regulator_do_set_voltage(rdev, min_uV, max_uV);
        else
                ret = _regulator_do_set_suspend_voltage(rdev, min_uV,
                                                        max_uV, state);
        if (ret < 0)
                goto out;

        if (supply_change_uV < 0) {
                ret = regulator_set_voltage_unlocked(rdev->supply,
                                best_supply_uV, INT_MAX, state);
                if (ret)
                        dev_warn(&rdev->dev, "Failed to decrease supply voltage: %d\n",
                                        ret);
                /* No need to fail here */
                ret = 0;
        }

out:
        return ret;
}

static int regulator_limit_voltage_step(struct regulator_dev *rdev,
                                        int *current_uV, int *min_uV)
{
        struct regulation_constraints *constraints = rdev->constraints;

        /* Limit voltage change only if necessary */
        if (!constraints->max_uV_step || !_regulator_is_enabled(rdev))
                return 1;

        if (*current_uV < 0) {
                *current_uV = regulator_get_voltage_rdev(rdev);

                if (*current_uV < 0)
                        return *current_uV;
        }

        if (abs(*current_uV - *min_uV) <= constraints->max_uV_step)
                return 1;

        /* Clamp target voltage within the given step */
        if (*current_uV < *min_uV)
                *min_uV = min(*current_uV + constraints->max_uV_step,
                              *min_uV);
        else
                *min_uV = max(*current_uV - constraints->max_uV_step,
                              *min_uV);

        return 0;
}

static int regulator_get_optimal_voltage(struct regulator_dev *rdev,
                                         int *current_uV,
                                         int *min_uV, int *max_uV,
                                         suspend_state_t state,
                                         int n_coupled)
{
        struct coupling_desc *c_desc = &rdev->coupling_desc;
        struct regulator_dev **c_rdevs = c_desc->coupled_rdevs;
        struct regulation_constraints *constraints = rdev->constraints;
        int desired_min_uV = 0, desired_max_uV = INT_MAX;
        int max_current_uV = 0, min_current_uV = INT_MAX;
        int highest_min_uV = 0, target_uV, possible_uV;
        int i, ret, max_spread;
        bool done;

        *current_uV = -1;

        /*
         * If there are no coupled regulators, simply set the voltage
         * demanded by consumers.
         */
        if (n_coupled == 1) {
                /*
                 * If consumers don't provide any demands, set voltage
                 * to min_uV
                 */
                desired_min_uV = constraints->min_uV;
                desired_max_uV = constraints->max_uV;

                ret = regulator_check_consumers(rdev,
                                                &desired_min_uV,
                                                &desired_max_uV, state);
                if (ret < 0)
                        return ret;

                possible_uV = desired_min_uV;
                done = true;

                goto finish;
        }

        /* Find highest min desired voltage */
        for (i = 0; i < n_coupled; i++) {
                int tmp_min = 0;
                int tmp_max = INT_MAX;

                lockdep_assert_held_once(&c_rdevs[i]->mutex.base);

                ret = regulator_check_consumers(c_rdevs[i],
                                                &tmp_min,
                                                &tmp_max, state);
                if (ret < 0)
                        return ret;

                ret = regulator_check_voltage(c_rdevs[i], &tmp_min, &tmp_max);
                if (ret < 0)
                        return ret;

                highest_min_uV = max(highest_min_uV, tmp_min);

                if (i == 0) {
                        desired_min_uV = tmp_min;
                        desired_max_uV = tmp_max;
                }
        }

        max_spread = constraints->max_spread[0];

        /*
         * Let target_uV be equal to the desired one if possible.
         * If not, set it to minimum voltage, allowed by other coupled
         * regulators.
         */
        target_uV = max(desired_min_uV, highest_min_uV - max_spread);

        /*
         * Find min and max voltages, which currently aren't violating
         * max_spread.
         */
        for (i = 1; i < n_coupled; i++) {
                int tmp_act;

                if (!_regulator_is_enabled(c_rdevs[i]))
                        continue;

                tmp_act = regulator_get_voltage_rdev(c_rdevs[i]);
                if (tmp_act < 0)
                        return tmp_act;

                min_current_uV = min(tmp_act, min_current_uV);
                max_current_uV = max(tmp_act, max_current_uV);
        }

        /* There aren't any other regulators enabled */
        if (max_current_uV == 0) {
                possible_uV = target_uV;
        } else {
                /*
                 * Correct target voltage, so as it currently isn't
                 * violating max_spread
                 */
                possible_uV = max(target_uV, max_current_uV - max_spread);
                possible_uV = min(possible_uV, min_current_uV + max_spread);
        }

        if (possible_uV > desired_max_uV)
                return -EINVAL;

        done = (possible_uV == target_uV);
        desired_min_uV = possible_uV;

finish:
        /* Apply max_uV_step constraint if necessary */
        if (state == PM_SUSPEND_ON) {
                ret = regulator_limit_voltage_step(rdev, current_uV,
                                                   &desired_min_uV);
                if (ret < 0)
                        return ret;

                if (ret == 0)
                        done = false;
        }

        /* Set current_uV if wasn't done earlier in the code and if necessary */
        if (n_coupled > 1 && *current_uV == -1) {

                if (_regulator_is_enabled(rdev)) {
                        ret = regulator_get_voltage_rdev(rdev);
                        if (ret < 0)
                                return ret;

                        *current_uV = ret;
                } else {
                        *current_uV = desired_min_uV;
                }
        }

        *min_uV = desired_min_uV;
        *max_uV = desired_max_uV;

        return done;
}

static int regulator_balance_voltage(struct regulator_dev *rdev,
                                     suspend_state_t state)
{
        struct regulator_dev **c_rdevs;
        struct regulator_dev *best_rdev;
        struct coupling_desc *c_desc = &rdev->coupling_desc;
        struct regulator_coupler *coupler = c_desc->coupler;
        int i, ret, n_coupled, best_min_uV, best_max_uV, best_c_rdev;
        unsigned int delta, best_delta;
        unsigned long c_rdev_done = 0;
        bool best_c_rdev_done;

        c_rdevs = c_desc->coupled_rdevs;
        n_coupled = c_desc->n_coupled;

        /*
         * If system is in a state other than PM_SUSPEND_ON, don't check
         * other coupled regulators.
         */
        if (state != PM_SUSPEND_ON)
                n_coupled = 1;

        if (c_desc->n_resolved < n_coupled) {
                rdev_err(rdev, "Not all coupled regulators registered\n");
                return -EPERM;
        }

        /* Invoke custom balancer for customized couplers */
        if (coupler && coupler->balance_voltage)
                return coupler->balance_voltage(coupler, rdev, state);

        /*
         * Find the best possible voltage change on each loop. Leave the loop
         * if there isn't any possible change.
         */
        do {
                best_c_rdev_done = false;
                best_delta = 0;
                best_min_uV = 0;
                best_max_uV = 0;
                best_c_rdev = 0;
                best_rdev = NULL;

                /*
                 * Find highest difference between optimal voltage
                 * and current voltage.
                 */
                for (i = 0; i < n_coupled; i++) {
                        /*
                         * optimal_uV is the best voltage that can be set for
                         * i-th regulator at the moment without violating
                         * max_spread constraint in order to balance
                         * the coupled voltages.
                         */
                        int optimal_uV = 0, optimal_max_uV = 0, current_uV = 0;

                        if (test_bit(i, &c_rdev_done))
                                continue;

                        ret = regulator_get_optimal_voltage(c_rdevs[i],
                                                            &current_uV,
                                                            &optimal_uV,
                                                            &optimal_max_uV,
                                                            state, n_coupled);
                        if (ret < 0)
                                goto out;

                        delta = abs(optimal_uV - current_uV);

                        if (delta && best_delta <= delta) {
                                best_c_rdev_done = ret;
                                best_delta = delta;
                                best_rdev = c_rdevs[i];
                                best_min_uV = optimal_uV;
                                best_max_uV = optimal_max_uV;
                                best_c_rdev = i;
                        }
                }

                /* Nothing to change, return successfully */
                if (!best_rdev) {
                        ret = 0;
                        goto out;
                }

                ret = regulator_set_voltage_rdev(best_rdev, best_min_uV,
                                                 best_max_uV, state);

                if (ret < 0)
                        goto out;

                if (best_c_rdev_done)
                        set_bit(best_c_rdev, &c_rdev_done);

        } while (n_coupled > 1);

out:
        return ret;
}

/**
 * regulator_set_voltage - set regulator output voltage
 * @regulator: regulator source
 * @min_uV: Minimum required voltage in uV
 * @max_uV: Maximum acceptable voltage in uV
 *
 * Sets a voltage regulator to the desired output voltage. This can be set
 * during any regulator state. IOW, regulator can be disabled or enabled.
 *
 * If the regulator is enabled then the voltage will change to the new value
 * immediately otherwise if the regulator is disabled the regulator will
 * output at the new voltage when enabled.
 *
 * NOTE: If the regulator is shared between several devices then the lowest
 * request voltage that meets the system constraints will be used.
 * Regulator system constraints must be set for this regulator before
 * calling this function otherwise this call will fail.
 */
int regulator_set_voltage(struct regulator *regulator, int min_uV, int max_uV)
{
        struct ww_acquire_ctx ww_ctx;
        int ret;

        regulator_lock_dependent(regulator->rdev, &ww_ctx);

        ret = regulator_set_voltage_unlocked(regulator, min_uV, max_uV,
                                             PM_SUSPEND_ON);

        regulator_unlock_dependent(regulator->rdev, &ww_ctx);

        return ret;
}
EXPORT_SYMBOL_GPL(regulator_set_voltage);

static inline int regulator_suspend_toggle(struct regulator_dev *rdev,
                                           suspend_state_t state, bool en)
{
        struct regulator_state *rstate;

        rstate = regulator_get_suspend_state(rdev, state);
        if (rstate == NULL)
                return -EINVAL;

        if (!rstate->changeable)
                return -EPERM;

        rstate->enabled = (en) ? ENABLE_IN_SUSPEND : DISABLE_IN_SUSPEND;

        return 0;
}

int regulator_suspend_enable(struct regulator_dev *rdev,
                                    suspend_state_t state)
{
        return regulator_suspend_toggle(rdev, state, true);
}
EXPORT_SYMBOL_GPL(regulator_suspend_enable);

int regulator_suspend_disable(struct regulator_dev *rdev,
                                     suspend_state_t state)
{
        struct regulator *regulator;
        struct regulator_voltage *voltage;

        /*
         * if any consumer wants this regulator device keeping on in
         * suspend states, don't set it as disabled.
         */
        list_for_each_entry(regulator, &rdev->consumer_list, list) {
                voltage = &regulator->voltage[state];
                if (voltage->min_uV || voltage->max_uV)
                        return 0;
        }

        return regulator_suspend_toggle(rdev, state, false);
}
EXPORT_SYMBOL_GPL(regulator_suspend_disable);

static int _regulator_set_suspend_voltage(struct regulator *regulator,
                                          int min_uV, int max_uV,
                                          suspend_state_t state)
{
        struct regulator_dev *rdev = regulator->rdev;
        struct regulator_state *rstate;

        rstate = regulator_get_suspend_state(rdev, state);
        if (rstate == NULL)
                return -EINVAL;

        if (rstate->min_uV == rstate->max_uV) {
                rdev_err(rdev, "The suspend voltage can't be changed!\n");
                return -EPERM;
        }

        return regulator_set_voltage_unlocked(regulator, min_uV, max_uV, state);
}

int regulator_set_suspend_voltage(struct regulator *regulator, int min_uV,
                                  int max_uV, suspend_state_t state)
{
        struct ww_acquire_ctx ww_ctx;
        int ret;

        /* PM_SUSPEND_ON is handled by regulator_set_voltage() */
        if (regulator_check_states(state) || state == PM_SUSPEND_ON)
                return -EINVAL;

        regulator_lock_dependent(regulator->rdev, &ww_ctx);

        ret = _regulator_set_suspend_voltage(regulator, min_uV,
                                             max_uV, state);

        regulator_unlock_dependent(regulator->rdev, &ww_ctx);

        return ret;
}
EXPORT_SYMBOL_GPL(regulator_set_suspend_voltage);

/**
 * regulator_set_voltage_time - get raise/fall time
 * @regulator: regulator source
 * @old_uV: starting voltage in microvolts
 * @new_uV: target voltage in microvolts
 *
 * Provided with the starting and ending voltage, this function attempts to
 * calculate the time in microseconds required to rise or fall to this new
 * voltage.
 */
int regulator_set_voltage_time(struct regulator *regulator,
                               int old_uV, int new_uV)
{
        struct regulator_dev *rdev = regulator->rdev;
        const struct regulator_ops *ops = rdev->desc->ops;
        int old_sel = -1;
        int new_sel = -1;
        int voltage;
        int i;

        if (ops->set_voltage_time)
                return ops->set_voltage_time(rdev, old_uV, new_uV);
        else if (!ops->set_voltage_time_sel)
                return _regulator_set_voltage_time(rdev, old_uV, new_uV);

        /* Currently requires operations to do this */
        if (!ops->list_voltage || !rdev->desc->n_voltages)
                return -EINVAL;

        for (i = 0; i < rdev->desc->n_voltages; i++) {
                /* We only look for exact voltage matches here */
                voltage = regulator_list_voltage(regulator, i);
                if (voltage < 0)
                        return -EINVAL;
                if (voltage == 0)
                        continue;
                if (voltage == old_uV)
                        old_sel = i;
                if (voltage == new_uV)
                        new_sel = i;
        }

        if (old_sel < 0 || new_sel < 0)
                return -EINVAL;

        return ops->set_voltage_time_sel(rdev, old_sel, new_sel);
}
EXPORT_SYMBOL_GPL(regulator_set_voltage_time);

/**
 * regulator_set_voltage_time_sel - get raise/fall time
 * @rdev: regulator source device
 * @old_selector: selector for starting voltage
 * @new_selector: selector for target voltage
 *
 * Provided with the starting and target voltage selectors, this function
 * returns time in microseconds required to rise or fall to this new voltage
 *
 * Drivers providing ramp_delay in regulation_constraints can use this as their
 * set_voltage_time_sel() operation.
 */
int regulator_set_voltage_time_sel(struct regulator_dev *rdev,
                                   unsigned int old_selector,
                                   unsigned int new_selector)
{
        int old_volt, new_volt;

        /* sanity check */
        if (!rdev->desc->ops->list_voltage)
                return -EINVAL;

        old_volt = rdev->desc->ops->list_voltage(rdev, old_selector);
        new_volt = rdev->desc->ops->list_voltage(rdev, new_selector);

        if (rdev->desc->ops->set_voltage_time)
                return rdev->desc->ops->set_voltage_time(rdev, old_volt,
                                                         new_volt);
        else
                return _regulator_set_voltage_time(rdev, old_volt, new_volt);
}
EXPORT_SYMBOL_GPL(regulator_set_voltage_time_sel);

/**
 * regulator_sync_voltage - re-apply last regulator output voltage
 * @regulator: regulator source
 *
 * Re-apply the last configured voltage.  This is intended to be used
 * where some external control source the consumer is cooperating with
 * has caused the configured voltage to change.
 */
int regulator_sync_voltage(struct regulator *regulator)
{
        struct regulator_dev *rdev = regulator->rdev;
        struct regulator_voltage *voltage = &regulator->voltage[PM_SUSPEND_ON];
        int ret, min_uV, max_uV;

        regulator_lock(rdev);

        if (!rdev->desc->ops->set_voltage &&
            !rdev->desc->ops->set_voltage_sel) {
                ret = -EINVAL;
                goto out;
        }

        /* This is only going to work if we've had a voltage configured. */
        if (!voltage->min_uV && !voltage->max_uV) {
                ret = -EINVAL;
                goto out;
        }

        min_uV = voltage->min_uV;
        max_uV = voltage->max_uV;

        /* This should be a paranoia check... */
        ret = regulator_check_voltage(rdev, &min_uV, &max_uV);
        if (ret < 0)
                goto out;

        ret = regulator_check_consumers(rdev, &min_uV, &max_uV, 0);
        if (ret < 0)
                goto out;

        ret = _regulator_do_set_voltage(rdev, min_uV, max_uV);

out:
        regulator_unlock(rdev);
        return ret;
}
EXPORT_SYMBOL_GPL(regulator_sync_voltage);

int regulator_get_voltage_rdev(struct regulator_dev *rdev)
{
        int sel, ret;
        bool bypassed;

        if (rdev->desc->ops->get_bypass) {
                ret = rdev->desc->ops->get_bypass(rdev, &bypassed);
                if (ret < 0)
                        return ret;
                if (bypassed) {
                        /* if bypassed the regulator must have a supply */
                        if (!rdev->supply) {
                                rdev_err(rdev,
                                         "bypassed regulator has no supply!\n");
                                return -EPROBE_DEFER;
                        }

                        return regulator_get_voltage_rdev(rdev->supply->rdev);
                }
        }

        if (rdev->desc->ops->get_voltage_sel) {