/*
 * Core driver for the pin control subsystem
 *
 * Copyright (C) 2011-2012 ST-Ericsson SA
 * Written on behalf of Linaro for ST-Ericsson
 * Based on bits of regulator core, gpio core and clk core
 *
 * Author: Linus Walleij <linus.walleij@linaro.org>
 *
 * Copyright (C) 2012 NVIDIA CORPORATION. All rights reserved.
 *
 * License terms: GNU General Public License (GPL) version 2
 */
#define pr_fmt(fmt) "pinctrl core: " fmt

#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/list.h>
#include <linux/sysfs.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/pinctrl/consumer.h>
#include <linux/pinctrl/pinctrl.h>
#include <linux/pinctrl/machine.h>
#include "core.h"
#include "devicetree.h"
#include "pinmux.h"
#include "pinconf.h"

/**
 * struct pinctrl_maps - a list item containing part of the mapping table
 * @node: mapping table list node
 * @maps: array of mapping table entries
 * @num_maps: the number of entries in @maps
 */
struct pinctrl_maps {
        struct list_head node;
        struct pinctrl_map const *maps;
        unsigned num_maps;
};

static bool pinctrl_dummy_state;

/* Mutex taken by all entry points */
DEFINE_MUTEX(pinctrl_mutex);

/* Global list of pin control devices (struct pinctrl_dev) */
LIST_HEAD(pinctrldev_list);

/* List of pin controller handles (struct pinctrl) */
static LIST_HEAD(pinctrl_list);

/* List of pinctrl maps (struct pinctrl_maps) */
static LIST_HEAD(pinctrl_maps);

#define for_each_maps(_maps_node_, _i_, _map_) \
        list_for_each_entry(_maps_node_, &pinctrl_maps, node) \
                for (_i_ = 0, _map_ = &_maps_node_->maps[_i_]; \
                        _i_ < _maps_node_->num_maps; \
                        _i_++, _map_ = &_maps_node_->maps[_i_])

/**
 * pinctrl_provide_dummies() - indicate if pinctrl provides dummy state support
 *
 * Usually this function is called by platforms without pinctrl driver support
 * but run with some shared drivers using pinctrl APIs.
 * After calling this function, the pinctrl core will return successfully
 * with creating a dummy state for the driver to keep going smoothly.
 */
void pinctrl_provide_dummies(void)
{
        pinctrl_dummy_state = true;
}

const char *pinctrl_dev_get_name(struct pinctrl_dev *pctldev)
{
        /* We're not allowed to register devices without name */
        return pctldev->desc->name;
}
EXPORT_SYMBOL_GPL(pinctrl_dev_get_name);

void *pinctrl_dev_get_drvdata(struct pinctrl_dev *pctldev)
{
        return pctldev->driver_data;
}
EXPORT_SYMBOL_GPL(pinctrl_dev_get_drvdata);

/**
 * get_pinctrl_dev_from_devname() - look up pin controller device
 * @devname: the name of a device instance, as returned by dev_name()
 *
 * Looks up a pin control device matching a certain device name or pure device
 * pointer, the pure device pointer will take precedence.
 */
struct pinctrl_dev *get_pinctrl_dev_from_devname(const char *devname)
{
        struct pinctrl_dev *pctldev = NULL;
        bool found = false;

        if (!devname)
                return NULL;

        list_for_each_entry(pctldev, &pinctrldev_list, node) {
                if (!strcmp(dev_name(pctldev->dev), devname)) {
                        /* Matched on device name */
                        found = true;
                        break;
                }
        }

        return found ? pctldev : NULL;
}

/**
 * pin_get_from_name() - look up a pin number from a name
 * @pctldev: the pin control device to lookup the pin on
 * @name: the name of the pin to look up
 */
int pin_get_from_name(struct pinctrl_dev *pctldev, const char *name)
{
        unsigned i, pin;

        /* The pin number can be retrived from the pin controller descriptor */
        for (i = 0; i < pctldev->desc->npins; i++) {
                struct pin_desc *desc;

                pin = pctldev->desc->pins[i].number;
                desc = pin_desc_get(pctldev, pin);
                /* Pin space may be sparse */
                if (desc == NULL)
                        continue;
                if (desc->name && !strcmp(name, desc->name))
                        return pin;
        }

        return -EINVAL;
}

/**
 * pin_get_name_from_id() - look up a pin name from a pin id
 * @pctldev: the pin control device to lookup the pin on
 * @name: the name of the pin to look up
 */
const char *pin_get_name(struct pinctrl_dev *pctldev, const unsigned pin)
{
        const struct pin_desc *desc;

        desc = pin_desc_get(pctldev, pin);
        if (desc == NULL) {
                dev_err(pctldev->dev, "failed to get pin(%d) name\n",
                        pin);
                return NULL;
        }

        return desc->name;
}

/**
 * pin_is_valid() - check if pin exists on controller
 * @pctldev: the pin control device to check the pin on
 * @pin: pin to check, use the local pin controller index number
 *
 * This tells us whether a certain pin exist on a certain pin controller or
 * not. Pin lists may be sparse, so some pins may not exist.
 */
bool pin_is_valid(struct pinctrl_dev *pctldev, int pin)
{
        struct pin_desc *pindesc;

        if (pin < 0)
                return false;

        mutex_lock(&pinctrl_mutex);
        pindesc = pin_desc_get(pctldev, pin);
        mutex_unlock(&pinctrl_mutex);

        return pindesc != NULL;
}
EXPORT_SYMBOL_GPL(pin_is_valid);

/* Deletes a range of pin descriptors */
static void pinctrl_free_pindescs(struct pinctrl_dev *pctldev,
                                  const struct pinctrl_pin_desc *pins,
                                  unsigned num_pins)
{
        int i;

        for (i = 0; i < num_pins; i++) {
                struct pin_desc *pindesc;

                pindesc = radix_tree_lookup(&pctldev->pin_desc_tree,
                                            pins[i].number);
                if (pindesc != NULL) {
                        radix_tree_delete(&pctldev->pin_desc_tree,
                                          pins[i].number);
                        if (pindesc->dynamic_name)
                                kfree(pindesc->name);
                }
                kfree(pindesc);
        }
}

static int pinctrl_register_one_pin(struct pinctrl_dev *pctldev,
                                    unsigned number, const char *name)
{
        struct pin_desc *pindesc;

        pindesc = pin_desc_get(pctldev, number);
        if (pindesc != NULL) {
                pr_err("pin %d already registered on %s\n", number,
                       pctldev->desc->name);
                return -EINVAL;
        }

        pindesc = kzalloc(sizeof(*pindesc), GFP_KERNEL);
        if (pindesc == NULL) {
                dev_err(pctldev->dev, "failed to alloc struct pin_desc\n");
                return -ENOMEM;
        }

        /* Set owner */
        pindesc->pctldev = pctldev;

        /* Copy basic pin info */
        if (name) {
                pindesc->name = name;
        } else {
                pindesc->name = kasprintf(GFP_KERNEL, "PIN%u", number);
                if (pindesc->name == NULL) {
                        kfree(pindesc);
                        return -ENOMEM;
                }
                pindesc->dynamic_name = true;
        }

        radix_tree_insert(&pctldev->pin_desc_tree, number, pindesc);
        pr_debug("registered pin %d (%s) on %s\n",
                 number, pindesc->name, pctldev->desc->name);
        return 0;
}

static int pinctrl_register_pins(struct pinctrl_dev *pctldev,
                                 struct pinctrl_pin_desc const *pins,
                                 unsigned num_descs)
{
        unsigned i;
        int ret = 0;

        for (i = 0; i < num_descs; i++) {
                ret = pinctrl_register_one_pin(pctldev,
                                               pins[i].number, pins[i].name);
                if (ret)
                        return ret;
        }

        return 0;
}

/**
 * pinctrl_match_gpio_range() - check if a certain GPIO pin is in range
 * @pctldev: pin controller device to check
 * @gpio: gpio pin to check taken from the global GPIO pin space
 *
 * Tries to match a GPIO pin number to the ranges handled by a certain pin
 * controller, return the range or NULL
 */
static struct pinctrl_gpio_range *
pinctrl_match_gpio_range(struct pinctrl_dev *pctldev, unsigned gpio)
{
        struct pinctrl_gpio_range *range = NULL;

        /* Loop over the ranges */
        list_for_each_entry(range, &pctldev->gpio_ranges, node) {
                /* Check if we're in the valid range */
                if (gpio >= range->base &&
                    gpio < range->base + range->npins) {
                        return range;
                }
        }

        return NULL;
}

/**
 * pinctrl_get_device_gpio_range() - find device for GPIO range
 * @gpio: the pin to locate the pin controller for
 * @outdev: the pin control device if found
 * @outrange: the GPIO range if found
 *
 * Find the pin controller handling a certain GPIO pin from the pinspace of
 * the GPIO subsystem, return the device and the matching GPIO range. Returns
 * -EPROBE_DEFER if the GPIO range could not be found in any device since it
 * may still have not been registered.
 */
static int pinctrl_get_device_gpio_range(unsigned gpio,
                                         struct pinctrl_dev **outdev,
                                         struct pinctrl_gpio_range **outrange)
{
        struct pinctrl_dev *pctldev = NULL;

        /* Loop over the pin controllers */
        list_for_each_entry(pctldev, &pinctrldev_list, node) {
                struct pinctrl_gpio_range *range;

                range = pinctrl_match_gpio_range(pctldev, gpio);
                if (range != NULL) {
                        *outdev = pctldev;
                        *outrange = range;
                        return 0;
                }
        }

        return -EPROBE_DEFER;
}

/**
 * pinctrl_add_gpio_range() - register a GPIO range for a controller
 * @pctldev: pin controller device to add the range to
 * @range: the GPIO range to add
 *
 * This adds a range of GPIOs to be handled by a certain pin controller. Call
 * this to register handled ranges after registering your pin controller.
 */
void pinctrl_add_gpio_range(struct pinctrl_dev *pctldev,
                            struct pinctrl_gpio_range *range)
{
        mutex_lock(&pinctrl_mutex);
        list_add_tail(&range->node, &pctldev->gpio_ranges);
        mutex_unlock(&pinctrl_mutex);
}
EXPORT_SYMBOL_GPL(pinctrl_add_gpio_range);

void pinctrl_add_gpio_ranges(struct pinctrl_dev *pctldev,
                             struct pinctrl_gpio_range *ranges,
                             unsigned nranges)
{
        int i;

        for (i = 0; i < nranges; i++)
                pinctrl_add_gpio_range(pctldev, &ranges[i]);
}
EXPORT_SYMBOL_GPL(pinctrl_add_gpio_ranges);

struct pinctrl_dev *pinctrl_find_and_add_gpio_range(const char *devname,
                struct pinctrl_gpio_range *range)
{
        struct pinctrl_dev *pctldev = get_pinctrl_dev_from_devname(devname);

        /*
         * If we can't find this device, let's assume that is because
         * it has not probed yet, so the driver trying to register this
         * range need to defer probing.
         */
        if (!pctldev)
                return ERR_PTR(-EPROBE_DEFER);

        pinctrl_add_gpio_range(pctldev, range);
        return pctldev;
}
EXPORT_SYMBOL_GPL(pinctrl_find_and_add_gpio_range);

/**
 * pinctrl_find_gpio_range_from_pin() - locate the GPIO range for a pin
 * @pctldev: the pin controller device to look in
 * @pin: a controller-local number to find the range for
 */
struct pinctrl_gpio_range *
pinctrl_find_gpio_range_from_pin(struct pinctrl_dev *pctldev,
                                 unsigned int pin)
{
        struct pinctrl_gpio_range *range = NULL;

        /* Loop over the ranges */
        list_for_each_entry(range, &pctldev->gpio_ranges, node) {
                /* Check if we're in the valid range */
                if (pin >= range->pin_base &&
                    pin < range->pin_base + range->npins) {
                        return range;
                }
        }

        return NULL;
}
EXPORT_SYMBOL_GPL(pinctrl_find_gpio_range_from_pin);

/**
 * pinctrl_remove_gpio_range() - remove a range of GPIOs fro a pin controller
 * @pctldev: pin controller device to remove the range from
 * @range: the GPIO range to remove
 */
void pinctrl_remove_gpio_range(struct pinctrl_dev *pctldev,
                               struct pinctrl_gpio_range *range)
{
        mutex_lock(&pinctrl_mutex);
        list_del(&range->node);
        mutex_unlock(&pinctrl_mutex);
}
EXPORT_SYMBOL_GPL(pinctrl_remove_gpio_range);

/**
 * pinctrl_get_group_selector() - returns the group selector for a group
 * @pctldev: the pin controller handling the group
 * @pin_group: the pin group to look up
 */
int pinctrl_get_group_selector(struct pinctrl_dev *pctldev,
                               const char *pin_group)
{
        const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
        unsigned ngroups = pctlops->get_groups_count(pctldev);
        unsigned group_selector = 0;

        while (group_selector < ngroups) {
                const char *gname = pctlops->get_group_name(pctldev,
                                                            group_selector);
                if (!strcmp(gname, pin_group)) {
                        dev_dbg(pctldev->dev,
                                "found group selector %u for %s\n",
                                group_selector,
                                pin_group);
                        return group_selector;
                }

                group_selector++;
        }

        dev_err(pctldev->dev, "does not have pin group %s\n",
                pin_group);

        return -EINVAL;
}

/**
 * pinctrl_request_gpio() - request a single pin to be used in as GPIO
 * @gpio: the GPIO pin number from the GPIO subsystem number space
 *
 * This function should *ONLY* be used from gpiolib-based GPIO drivers,
 * as part of their gpio_request() semantics, platforms and individual drivers
 * shall *NOT* request GPIO pins to be muxed in.
 */
int pinctrl_request_gpio(unsigned gpio)
{
        struct pinctrl_dev *pctldev;
        struct pinctrl_gpio_range *range;
        int ret;
        int pin;

        mutex_lock(&pinctrl_mutex);

        ret = pinctrl_get_device_gpio_range(gpio, &pctldev, &range);
        if (ret) {
                mutex_unlock(&pinctrl_mutex);
                return ret;
        }

        /* Convert to the pin controllers number space */
        pin = gpio - range->base + range->pin_base;

        ret = pinmux_request_gpio(pctldev, range, pin, gpio);

        mutex_unlock(&pinctrl_mutex);
        return ret;
}
EXPORT_SYMBOL_GPL(pinctrl_request_gpio);

/**
 * pinctrl_free_gpio() - free control on a single pin, currently used as GPIO
 * @gpio: the GPIO pin number from the GPIO subsystem number space
 *
 * This function should *ONLY* be used from gpiolib-based GPIO drivers,
 * as part of their gpio_free() semantics, platforms and individual drivers
 * shall *NOT* request GPIO pins to be muxed out.
 */
void pinctrl_free_gpio(unsigned gpio)
{
        struct pinctrl_dev *pctldev;
        struct pinctrl_gpio_range *range;
        int ret;
        int pin;

        mutex_lock(&pinctrl_mutex);

        ret = pinctrl_get_device_gpio_range(gpio, &pctldev, &range);
        if (ret) {
                mutex_unlock(&pinctrl_mutex);
                return;
        }

        /* Convert to the pin controllers number space */
        pin = gpio - range->base + range->pin_base;

        pinmux_free_gpio(pctldev, pin, range);

        mutex_unlock(&pinctrl_mutex);
}
EXPORT_SYMBOL_GPL(pinctrl_free_gpio);

static int pinctrl_gpio_direction(unsigned gpio, bool input)
{
        struct pinctrl_dev *pctldev;
        struct pinctrl_gpio_range *range;
        int ret;
        int pin;

        ret = pinctrl_get_device_gpio_range(gpio, &pctldev, &range);
        if (ret)
                return ret;

        /* Convert to the pin controllers number space */
        pin = gpio - range->base + range->pin_base;

        return pinmux_gpio_direction(pctldev, range, pin, input);
}

/**
 * pinctrl_gpio_direction_input() - request a GPIO pin to go into input mode
 * @gpio: the GPIO pin number from the GPIO subsystem number space
 *
 * This function should *ONLY* be used from gpiolib-based GPIO drivers,
 * as part of their gpio_direction_input() semantics, platforms and individual
 * drivers shall *NOT* touch pin control GPIO calls.
 */
int pinctrl_gpio_direction_input(unsigned gpio)
{
        int ret;
        mutex_lock(&pinctrl_mutex);
        ret = pinctrl_gpio_direction(gpio, true);
        mutex_unlock(&pinctrl_mutex);
        return ret;
}
EXPORT_SYMBOL_GPL(pinctrl_gpio_direction_input);

/**
 * pinctrl_gpio_direction_output() - request a GPIO pin to go into output mode
 * @gpio: the GPIO pin number from the GPIO subsystem number space
 *
 * This function should *ONLY* be used from gpiolib-based GPIO drivers,
 * as part of their gpio_direction_output() semantics, platforms and individual
 * drivers shall *NOT* touch pin control GPIO calls.
 */
int pinctrl_gpio_direction_output(unsigned gpio)
{
        int ret;
        mutex_lock(&pinctrl_mutex);
        ret = pinctrl_gpio_direction(gpio, false);
        mutex_unlock(&pinctrl_mutex);
        return ret;
}
EXPORT_SYMBOL_GPL(pinctrl_gpio_direction_output);

static struct pinctrl_state *find_state(struct pinctrl *p,
                                        const char *name)
{
        struct pinctrl_state *state;

        list_for_each_entry(state, &p->states, node)
                if (!strcmp(state->name, name))
                        return state;

        return NULL;
}

static struct pinctrl_state *create_state(struct pinctrl *p,
                                          const char *name)
{
        struct pinctrl_state *state;

        state = kzalloc(sizeof(*state), GFP_KERNEL);
        if (state == NULL) {
                dev_err(p->dev,
                        "failed to alloc struct pinctrl_state\n");
                return ERR_PTR(-ENOMEM);
        }

        state->name = name;
        INIT_LIST_HEAD(&state->settings);

        list_add_tail(&state->node, &p->states);

        return state;
}

static int add_setting(struct pinctrl *p, struct pinctrl_map const *map)
{
        struct pinctrl_state *state;
        struct pinctrl_setting *setting;
        int ret;

        state = find_state(p, map->name);
        if (!state)
                state = create_state(p, map->name);
        if (IS_ERR(state))
                return PTR_ERR(state);

        if (map->type == PIN_MAP_TYPE_DUMMY_STATE)
                return 0;

        setting = kzalloc(sizeof(*setting), GFP_KERNEL);
        if (setting == NULL) {
                dev_err(p->dev,
                        "failed to alloc struct pinctrl_setting\n");
                return -ENOMEM;
        }

        setting->type = map->type;

        setting->pctldev = get_pinctrl_dev_from_devname(map->ctrl_dev_name);
        if (setting->pctldev == NULL) {
                dev_info(p->dev, "unknown pinctrl device %s in map entry, deferring probe",
                        map->ctrl_dev_name);
                kfree(setting);
                /*
                 * OK let us guess that the driver is not there yet, and
                 * let's defer obtaining this pinctrl handle to later...
                 */
                return -EPROBE_DEFER;
        }

        setting->dev_name = map->dev_name;

        switch (map->type) {
        case PIN_MAP_TYPE_MUX_GROUP:
                ret = pinmux_map_to_setting(map, setting);
                break;
        case PIN_MAP_TYPE_CONFIGS_PIN:
        case PIN_MAP_TYPE_CONFIGS_GROUP:
                ret = pinconf_map_to_setting(map, setting);
                break;
        default:
                ret = -EINVAL;
                break;
        }
        if (ret < 0) {
                kfree(setting);
                return ret;
        }

        list_add_tail(&setting->node, &state->settings);

        return 0;
}

static struct pinctrl *find_pinctrl(struct device *dev)
{
        struct pinctrl *p;

        list_for_each_entry(p, &pinctrl_list, node)
                if (p->dev == dev)
                        return p;

        return NULL;
}

static void pinctrl_put_locked(struct pinctrl *p, bool inlist);

static struct pinctrl *create_pinctrl(struct device *dev)
{
        struct pinctrl *p;
        const char *devname;
        struct pinctrl_maps *maps_node;
        int i;
        struct pinctrl_map const *map;
        int ret;

        /*
         * create the state cookie holder struct pinctrl for each
         * mapping, this is what consumers will get when requesting
         * a pin control handle with pinctrl_get()
         */
        p = kzalloc(sizeof(*p), GFP_KERNEL);
        if (p == NULL) {
                dev_err(dev, "failed to alloc struct pinctrl\n");
                return ERR_PTR(-ENOMEM);
        }
        p->dev = dev;
        INIT_LIST_HEAD(&p->states);
        INIT_LIST_HEAD(&p->dt_maps);

        ret = pinctrl_dt_to_map(p);
        if (ret < 0) {
                kfree(p);
                return ERR_PTR(ret);
        }

        devname = dev_name(dev);

        /* Iterate over the pin control maps to locate the right ones */
        for_each_maps(maps_node, i, map) {
                /* Map must be for this device */
                if (strcmp(map->dev_name, devname))
                        continue;

                ret = add_setting(p, map);
                if (ret < 0) {
                        pinctrl_put_locked(p, false);
                        return ERR_PTR(ret);
                }
        }

        /* Add the pinctrl handle to the global list */
        list_add_tail(&p->node, &pinctrl_list);

        return p;
}

static struct pinctrl *pinctrl_get_locked(struct device *dev)
{
        struct pinctrl *p;

        if (WARN_ON(!dev))
                return ERR_PTR(-EINVAL);

        p = find_pinctrl(dev);
        if (p != NULL)
                return ERR_PTR(-EBUSY);

        return create_pinctrl(dev);
}

/**
 * pinctrl_get() - retrieves the pinctrl handle for a device
 * @dev: the device to obtain the handle for
 */
struct pinctrl *pinctrl_get(struct device *dev)
{
        struct pinctrl *p;

        mutex_lock(&pinctrl_mutex);
        p = pinctrl_get_locked(dev);
        mutex_unlock(&pinctrl_mutex);

        return p;
}
EXPORT_SYMBOL_GPL(pinctrl_get);

static void pinctrl_put_locked(struct pinctrl *p, bool inlist)
{
        struct pinctrl_state *state, *n1;
        struct pinctrl_setting *setting, *n2;

        list_for_each_entry_safe(state, n1, &p->states, node) {
                list_for_each_entry_safe(setting, n2, &state->settings, node) {
                        switch (setting->type) {
                        case PIN_MAP_TYPE_MUX_GROUP:
                                if (state == p->state)
                                        pinmux_disable_setting(setting);
                                pinmux_free_setting(setting);
                                break;
                        case PIN_MAP_TYPE_CONFIGS_PIN:
                        case PIN_MAP_TYPE_CONFIGS_GROUP:
                                pinconf_free_setting(setting);
                                break;
                        default:
                                break;
                        }
                        list_del(&setting->node);
                        kfree(setting);
                }
                list_del(&state->node);
                kfree(state);
        }

        pinctrl_dt_free_maps(p);

        if (inlist)
                list_del(&p->node);
        kfree(p);
}

/**
 * pinctrl_put() - release a previously claimed pinctrl handle
 * @p: the pinctrl handle to release
 */
void pinctrl_put(struct pinctrl *p)
{
        mutex_lock(&pinctrl_mutex);
        pinctrl_put_locked(p, true);
        mutex_unlock(&pinctrl_mutex);
}
EXPORT_SYMBOL_GPL(pinctrl_put);

static struct pinctrl_state *pinctrl_lookup_state_locked(struct pinctrl *p,
                                                         const char *name)
{
        struct pinctrl_state *state;

        state = find_state(p, name);
        if (!state) {
                if (pinctrl_dummy_state) {
                        /* create dummy state */
                        dev_dbg(p->dev, "using pinctrl dummy state (%s)\n",
                                name);
                        state = create_state(p, name);
                } else
                        state = ERR_PTR(-ENODEV);
        }

        return state;
}

/**
 * pinctrl_lookup_state() - retrieves a state handle from a pinctrl handle
 * @p: the pinctrl handle to retrieve the state from
 * @name: the state name to retrieve
 */
struct pinctrl_state *pinctrl_lookup_state(struct pinctrl *p, const char *name)
{
        struct pinctrl_state *s;

        mutex_lock(&pinctrl_mutex);
        s = pinctrl_lookup_state_locked(p, name);
        mutex_unlock(&pinctrl_mutex);

        return s;
}
EXPORT_SYMBOL_GPL(pinctrl_lookup_state);

static int pinctrl_select_state_locked(struct pinctrl *p,
                                       struct pinctrl_state *state)
{
        struct pinctrl_setting *setting, *setting2;
        int ret;

        if (p->state == state)
                return 0;

        if (p->state) {
                /*
                 * The set of groups with a mux configuration in the old state
                 * may not be identical to the set of groups with a mux setting
                 * in the new state. While this might be unusual, it's entirely
                 * possible for the "user"-supplied mapping table to be written
                 * that way. For each group that was configured in the old state
                 * but not in the new state, this code puts that group into a
                 * safe/disabled state.
                 */
                list_for_each_entry(setting, &p->state->settings, node) {
                        bool found = false;
                        if (setting->type != PIN_MAP_TYPE_MUX_GROUP)
                                continue;
                        list_for_each_entry(setting2, &state->settings, node) {
                                if (setting2->type != PIN_MAP_TYPE_MUX_GROUP)
                                        continue;
                                if (setting2->data.mux.group ==
                                                setting->data.mux.group) {
                                        found = true;
                                        break;
                                }
                        }
                        if (!found)
                                pinmux_disable_setting(setting);
                }
        }

        p->state = state;

        /* Apply all the settings for the new state */
        list_for_each_entry(setting, &state->settings, node) {
                switch (setting->type) {
                case PIN_MAP_TYPE_MUX_GROUP:
                        ret = pinmux_enable_setting(setting);
                        break;
                case PIN_MAP_TYPE_CONFIGS_PIN:
                case PIN_MAP_TYPE_CONFIGS_GROUP:
                        ret = pinconf_apply_setting(setting);
                        break;
                default:
                        ret = -EINVAL;
                        break;
                }
                if (ret < 0) {
                        /* FIXME: Difficult to return to prev state */
                        return ret;
                }
        }

        return 0;
}

/**
 * pinctrl_select() - select/activate/program a pinctrl state to HW
 * @p: the pinctrl handle for the device that requests configuratio
 * @state: the state handle to select/activate/program
 */
int pinctrl_select_state(struct pinctrl *p, struct pinctrl_state *state)
{
        int ret;

        mutex_lock(&pinctrl_mutex);
        ret = pinctrl_select_state_locked(p, state);
        mutex_unlock(&pinctrl_mutex);

        return ret;
}
EXPORT_SYMBOL_GPL(pinctrl_select_state);

static void devm_pinctrl_release(struct device *dev, void *res)
{
        pinctrl_put(*(struct pinctrl **)res);
}

/**
 * struct devm_pinctrl_get() - Resource managed pinctrl_get()
 * @dev: the device to obtain the handle for
 *
 * If there is a need to explicitly destroy the returned struct pinctrl,
 * devm_pinctrl_put() should be used, rather than plain pinctrl_put().
 */
struct pinctrl *devm_pinctrl_get(struct device *dev)
{
        struct pinctrl **ptr, *p;

        ptr = devres_alloc(devm_pinctrl_release, sizeof(*ptr), GFP_KERNEL);
        if (!ptr)
                return ERR_PTR(-ENOMEM);

        p = pinctrl_get(dev);
        if (!IS_ERR(p)) {
                *ptr = p;
                devres_add(dev, ptr);
        } else {
                devres_free(ptr);
        }

        return p;
}
EXPORT_SYMBOL_GPL(devm_pinctrl_get);

static int devm_pinctrl_match(struct device *dev, void *res, void *data)
{
        struct pinctrl **p = res;

        return *p == data;
}

/**
 * devm_pinctrl_put() - Resource managed pinctrl_put()
 * @p: the pinctrl handle to release
 *
 * Deallocate a struct pinctrl obtained via devm_pinctrl_get(). Normally
 * this function will not need to be called and the resource management
 * code will ensure that the resource is freed.
 */
void devm_pinctrl_put(struct pinctrl *p)
{
        WARN_ON(devres_destroy(p->dev, devm_pinctrl_release,
                               devm_pinctrl_match, p));
        pinctrl_put(p);
}
EXPORT_SYMBOL_GPL(devm_pinctrl_put);

int pinctrl_register_map(struct pinctrl_map const *maps, unsigned num_maps,
                         bool dup, bool locked)
{
        int i, ret;
        struct pinctrl_maps *maps_node;

        pr_debug("add %d pinmux maps\n", num_maps);

        /* First sanity check the new mapping */
        for (i = 0; i < num_maps; i++) {
                if (!maps[i].dev_name) {
                        pr_err("failed to register map %s (%d): no device given\n",
                               maps[i].name, i);
                        return -EINVAL;
                }

                if (!maps[i].name) {
                        pr_err("failed to register map %d: no map name given\n",
                               i);
                        return -EINVAL;
                }

                if (maps[i].type != PIN_MAP_TYPE_DUMMY_STATE &&
                                !maps[i].ctrl_dev_name) {
                        pr_err("failed to register map %s (%d): no pin control device given\n",
                               maps[i].name, i);
                        return -EINVAL;
                }

                switch (maps[i].type) {
                case PIN_MAP_TYPE_DUMMY_STATE:
                        break;
                case PIN_MAP_TYPE_MUX_GROUP:
                        ret = pinmux_validate_map(&maps[i], i);
                        if (ret < 0)
                                return ret;
                        break;
                case PIN_MAP_TYPE_CONFIGS_PIN:
                case PIN_MAP_TYPE_CONFIGS_GROUP:
                        ret = pinconf_validate_map(&maps[i], i);
                        if (ret < 0)
                                return ret;
                        break;
                default:
                        pr_err("failed to register map %s (%d): invalid type given\n",
                               maps[i].name, i);

                        return -EINVAL;
                }
        }

        maps_node = kzalloc(sizeof(*maps_node), GFP_KERNEL);
        if (!maps_node) {
                pr_err("failed to alloc struct pinctrl_maps\n");
                return -ENOMEM;
        }

        maps_node->num_maps = num_maps;
        if (dup) {
                maps_node->maps = kmemdup(maps, sizeof(*maps) * num_maps,
                                          GFP_KERNEL);
                if (!maps_node->maps) {
                        pr_err("failed to duplicate mapping table\n");
                        kfree(maps_node);
                        return -ENOMEM;
                }
        } else {
                maps_node->maps = maps;
        }

        if (!locked)
                mutex_lock(&pinctrl_mutex);
        list_add_tail(&maps_node->node, &pinctrl_maps);
        if (!locked)
                mutex_unlock(&pinctrl_mutex);

        return 0;
}

/**
 * pinctrl_register_mappings() - register a set of pin controller mappings
 * @maps: the pincontrol mappings table to register. This should probably be
 *      marked with __initdata so it can be discarded after boot. This
 *      function will perform a shallow copy for the mapping entries.
 * @num_maps: the number of maps in the mapping table
 */
int pinctrl_register_mappings(struct pinctrl_map const *maps,
                              unsigned num_maps)
{
        return pinctrl_register_map(maps, num_maps, true, false);
}

void pinctrl_unregister_map(struct pinctrl_map const *map)
{
        struct pinctrl_maps *maps_node;

        list_for_each_entry(maps_node, &pinctrl_maps, node) {
                if (maps_node->maps == map) {
                        list_del(&maps_node->node);
                        return;
                }
        }
}

#ifdef CONFIG_DEBUG_FS

static int pinctrl_pins_show(struct seq_file *s, void *what)
{
        struct pinctrl_dev *pctldev = s->private;
        const struct pinctrl_ops *ops = pctldev->desc->pctlops;
        unsigned i, pin;

        seq_printf(s, "registered pins: %d\n", pctldev->desc->npins);

        mutex_lock(&pinctrl_mutex);

        /* The pin number can be retrived from the pin controller descriptor */
        for (i = 0; i < pctldev->desc->npins; i++) {
                struct pin_desc *desc;

                pin = pctldev->desc->pins[i].number;
                desc = pin_desc_get(pctldev, pin);
                /* Pin space may be sparse */
                if (desc == NULL)
                        continue;

                seq_printf(s, "pin %d (%s) ", pin,
                           desc->name ? desc->name : "unnamed");

                /* Driver-specific info per pin */
                if (ops->pin_dbg_show)
                        ops->pin_dbg_show(pctldev, s, pin);

                seq_puts(s, "\n");
        }

        mutex_unlock(&pinctrl_mutex);

        return 0;
}

static int pinctrl_groups_show(struct seq_file *s, void *what)
{
        struct pinctrl_dev *pctldev = s->private;
        const struct pinctrl_ops *ops = pctldev->desc->pctlops;
        unsigned ngroups, selector = 0;

        ngroups = ops->get_groups_count(pctldev);
        mutex_lock(&pinctrl_mutex);

        seq_puts(s, "registered pin groups:\n");
        while (selector < ngroups) {
                const unsigned *pins;
                unsigned num_pins;
                const char *gname = ops->get_group_name(pctldev, selector);
                const char *pname;
                int ret;
                int i;

                ret = ops->get_group_pins(pctldev, selector,
                                          &pins, &num_pins);
                if (ret)
                        seq_printf(s, "%s [ERROR GETTING PINS]\n",
                                   gname);
                else {
                        seq_printf(s, "group: %s\n", gname);
                        for (i = 0; i < num_pins; i++) {
                                pname = pin_get_name(pctldev, pins[i]);
                                if (WARN_ON(!pname)) {
                                        mutex_unlock(&pinctrl_mutex);
                                        return -EINVAL;
                                }
                                seq_printf(s, "pin %d (%s)\n", pins[i], pname);
                        }
                        seq_puts(s, "\n");
                }
                selector++;
        }

        mutex_unlock(&pinctrl_mutex);

        return 0;
}

static int pinctrl_gpioranges_show(struct seq_file *s, void *what)
{
        struct pinctrl_dev *pctldev = s->private;
        struct pinctrl_gpio_range *range = NULL;

        seq_puts(s, "GPIO ranges handled:\n");

        mutex_lock(&pinctrl_mutex);

        /* Loop over the ranges */
        list_for_each_entry(range, &pctldev->gpio_ranges, node) {
                seq_printf(s, "%u: %s GPIOS [%u - %u] PINS [%u - %u]\n",
                           range->id, range->name,
                           range->base, (range->base + range->npins - 1),
                           range->pin_base,
                           (range->pin_base + range->npins - 1));
        }

        mutex_unlock(&pinctrl_mutex);

        return 0;
}

static int pinctrl_devices_show(struct seq_file *s, void *what)
{
        struct pinctrl_dev *pctldev;

        seq_puts(s, "name [pinmux] [pinconf]\n");

        mutex_lock(&pinctrl_mutex);

        list_for_each_entry(pctldev, &pinctrldev_list, node) {
                seq_printf(s, "%s ", pctldev->desc->name);
                if (pctldev->desc->pmxops)
                        seq_puts(s, "yes ");
                else
                        seq_puts(s, "no ");
                if (pctldev->desc->confops)
                        seq_puts(s, "yes");
                else
                        seq_puts(s, "no");
                seq_puts(s, "\n");
        }

        mutex_unlock(&pinctrl_mutex);

        return 0;
}

static inline const char *map_type(enum pinctrl_map_type type)
{
        static const char * const names[] = {
                "INVALID",
                "DUMMY_STATE",
                "MUX_GROUP",
                "CONFIGS_PIN",
                "CONFIGS_GROUP",
        };

        if (type >= ARRAY_SIZE(names))
                return "UNKNOWN";

        return names[type];
}

static int pinctrl_maps_show(struct seq_file *s, void *what)
{
        struct pinctrl_maps *maps_node;
        int i;
        struct pinctrl_map const *map;

        seq_puts(s, "Pinctrl maps:\n");

        mutex_lock(&pinctrl_mutex);

        for_each_maps(maps_node, i, map) {
                seq_printf(s, "device %s\nstate %s\ntype %s (%d)\n",
                           map->dev_name, map->name, map_type(map->type),
                           map->type);

                if (map->type != PIN_MAP_TYPE_DUMMY_STATE)
                        seq_printf(s, "controlling device %s\n",
                                   map->ctrl_dev_name);

                switch (map->type) {
                case PIN_MAP_TYPE_MUX_GROUP:
                        pinmux_show_map(s, map);
                        break;
                case PIN_MAP_TYPE_CONFIGS_PIN:
                case PIN_MAP_TYPE_CONFIGS_GROUP:
                        pinconf_show_map(s, map);
                        break;
                default:
                        break;
                }

                seq_printf(s, "\n");
        }

        mutex_unlock(&pinctrl_mutex);

        return 0;
}

static int pinctrl_show(struct seq_file *s, void *what)
{
        struct pinctrl *p;
        struct pinctrl_state *state;
        struct pinctrl_setting *setting;

        seq_puts(s, "Requested pin control handlers their pinmux maps:\n");

        mutex_lock(&pinctrl_mutex);

        list_for_each_entry(p, &pinctrl_list, node) {
                seq_printf(s, "device: %s current state: %s\n",
                           dev_name(p->dev),
                           p->state ? p->state->name : "none");

                list_for_each_entry(state, &p->states, node) {
                        seq_printf(s, "  state: %s\n", state->name);

                        list_for_each_entry(setting, &state->settings, node) {
                                struct pinctrl_dev *pctldev = setting->pctldev;

                                seq_printf(s, "    type: %s controller %s ",
                                           map_type(setting->type),
                                           pinctrl_dev_get_name(pctldev));

                                switch (setting->type) {
                                case PIN_MAP_TYPE_MUX_GROUP:
                                        pinmux_show_setting(s, setting);
                                        break;
                                case PIN_MAP_TYPE_CONFIGS_PIN:
                                case PIN_MAP_TYPE_CONFIGS_GROUP:
                                        pinconf_show_setting(s, setting);
                                        break;
                                default:
                                        break;
                                }
                        }
                }
        }

        mutex_unlock(&pinctrl_mutex);

        return 0;
}

static int pinctrl_pins_open(struct inode *inode, struct file *file)
{
        return single_open(file, pinctrl_pins_show, inode->i_private);
}

static int pinctrl_groups_open(struct inode *inode, struct file *file)
{
        return single_open(file, pinctrl_groups_show, inode->i_private);
}

static int pinctrl_gpioranges_open(struct inode *inode, struct file *file)
{
        return single_open(file, pinctrl_gpioranges_show, inode->i_private);
}

static int pinctrl_devices_open(struct inode *inode, struct file *file)
{
        return single_open(file, pinctrl_devices_show, NULL);
}

static int pinctrl_maps_open(struct inode *inode, struct file *file)
{
        return single_open(file, pinctrl_maps_show, NULL);
}

static int pinctrl_open(struct inode *inode, struct file *file)
{
        return single_open(file, pinctrl_show, NULL);
}

static const struct file_operations pinctrl_pins_ops = {
        .open           = pinctrl_pins_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

static const struct file_operations pinctrl_groups_ops = {
        .open           = pinctrl_groups_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

static const struct file_operations pinctrl_gpioranges_ops = {
        .open           = pinctrl_gpioranges_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

static const struct file_operations pinctrl_devices_ops = {
        .open           = pinctrl_devices_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

static const struct file_operations pinctrl_maps_ops = {
        .open           = pinctrl_maps_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

static const struct file_operations pinctrl_ops = {
        .open           = pinctrl_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

static struct dentry *debugfs_root;

static void pinctrl_init_device_debugfs(struct pinctrl_dev *pctldev)
{
        struct dentry *device_root;

        device_root = debugfs_create_dir(dev_name(pctldev->dev),
                                         debugfs_root);
        pctldev->device_root = device_root;

        if (IS_ERR(device_root) || !device_root) {
                pr_warn("failed to create debugfs directory for %s\n",
                        dev_name(pctldev->dev));
                return;
        }
        debugfs_create_file("pins", S_IFREG | S_IRUGO,
                            device_root, pctldev, &pinctrl_pins_ops);
        debugfs_create_file("pingroups", S_IFREG | S_IRUGO,
                            device_root, pctldev, &pinctrl_groups_ops);
        debugfs_create_file("gpio-ranges", S_IFREG | S_IRUGO,
                            device_root, pctldev, &pinctrl_gpioranges_ops);
        pinmux_init_device_debugfs(device_root, pctldev);
        pinconf_init_device_debugfs(device_root, pctldev);
}

static void pinctrl_remove_device_debugfs(struct pinctrl_dev *pctldev)
{
        debugfs_remove_recursive(pctldev->device_root);
}

static void pinctrl_init_debugfs(void)
{
        debugfs_root = debugfs_create_dir("pinctrl", NULL);
        if (IS_ERR(debugfs_root) || !debugfs_root) {
                pr_warn("failed to create debugfs directory\n");
                debugfs_root = NULL;
                return;
        }

        debugfs_create_file("pinctrl-devices", S_IFREG | S_IRUGO,
                            debugfs_root, NULL, &pinctrl_devices_ops);
        debugfs_create_file("pinctrl-maps", S_IFREG | S_IRUGO,
                            debugfs_root, NULL, &pinctrl_maps_ops);
        debugfs_create_file("pinctrl-handles", S_IFREG | S_IRUGO,
                            debugfs_root, NULL, &pinctrl_ops);
}

#else /* CONFIG_DEBUG_FS */

static void pinctrl_init_device_debugfs(struct pinctrl_dev *pctldev)
{
}

static void pinctrl_init_debugfs(void)
{
}

static void pinctrl_remove_device_debugfs(struct pinctrl_dev *pctldev)
{
}

#endif

static int pinctrl_check_ops(struct pinctrl_dev *pctldev)
{
        const struct pinctrl_ops *ops = pctldev->desc->pctlops;

        if (!ops ||
            !ops->get_groups_count ||
            !ops->get_group_name ||
            !ops->get_group_pins)
                return -EINVAL;

        if (ops->dt_node_to_map && !ops->dt_free_map)
                return -EINVAL;

        return 0;
}

/**
 * pinctrl_register() - register a pin controller device
 * @pctldesc: descriptor for this pin controller
 * @dev: parent device for this pin controller
 * @driver_data: private pin controller data for this pin controller
 */
struct pinctrl_dev *pinctrl_register(struct pinctrl_desc *pctldesc,
                                    struct device *dev, void *driver_data)
{
        struct pinctrl_dev *pctldev;
        int ret;

        if (!pctldesc)
                return NULL;
        if (!pctldesc->name)
                return NULL;

        pctldev = kzalloc(sizeof(*pctldev), GFP_KERNEL);
        if (pctldev == NULL) {
                dev_err(dev, "failed to alloc struct pinctrl_dev\n");
                return NULL;
        }

        /* Initialize pin control device struct */
        pctldev->owner = pctldesc->owner;
        pctldev->desc = pctldesc;
        pctldev->driver_data = driver_data;
        INIT_RADIX_TREE(&pctldev->pin_desc_tree, GFP_KERNEL);
        INIT_LIST_HEAD(&pctldev->gpio_ranges);
        pctldev->dev = dev;

        /* check core ops for sanity */
        if (pinctrl_check_ops(pctldev)) {
                dev_err(dev, "pinctrl ops lacks necessary functions\n");
                goto out_err;
        }

        /* If we're implementing pinmuxing, check the ops for sanity */
        if (pctldesc->pmxops) {
                if (pinmux_check_ops(pctldev))
                        goto out_err;
        }

        /* If we're implementing pinconfig, check the ops for sanity */
        if (pctldesc->confops) {
                if (pinconf_check_ops(pctldev))
                        goto out_err;
        }

        /* Register all the pins */
        dev_dbg(dev, "try to register %d pins ...\n",  pctldesc->npins);
        ret = pinctrl_register_pins(pctldev, pctldesc->pins, pctldesc->npins);
        if (ret) {
                dev_err(dev, "error during pin registration\n");
                pinctrl_free_pindescs(pctldev, pctldesc->pins,
                                      pctldesc->npins);
                goto out_err;
        }

        mutex_lock(&pinctrl_mutex);

        list_add_tail(&pctldev->node, &pinctrldev_list);

        pctldev->p = pinctrl_get_locked(pctldev->dev);
        if (!IS_ERR(pctldev->p)) {
                struct pinctrl_state *s =
                        pinctrl_lookup_state_locked(pctldev->p,
                                                    PINCTRL_STATE_DEFAULT);
                if (IS_ERR(s)) {
                        dev_dbg(dev, "failed to lookup the default state\n");
                } else {
                        if (pinctrl_select_state_locked(pctldev->p, s))
                                dev_err(dev,
                                        "failed to select default state\n");
                }
        }

        mutex_unlock(&pinctrl_mutex);

        pinctrl_init_device_debugfs(pctldev);

        return pctldev;

out_err:
        kfree(pctldev);
        return NULL;
}
EXPORT_SYMBOL_GPL(pinctrl_register);

/**
 * pinctrl_unregister() - unregister pinmux
 * @pctldev: pin controller to unregister
 *
 * Called by pinmux drivers to unregister a pinmux.
 */
void pinctrl_unregister(struct pinctrl_dev *pctldev)
{
        struct pinctrl_gpio_range *range, *n;
        if (pctldev == NULL)
                return;

        pinctrl_remove_device_debugfs(pctldev);

        mutex_lock(&pinctrl_mutex);

        if (!IS_ERR(pctldev->p))
                pinctrl_put_locked(pctldev->p, true);

        /* TODO: check that no pinmuxes are still active? */
        list_del(&pctldev->node);
        /* Destroy descriptor tree */
        pinctrl_free_pindescs(pctldev, pctldev->desc->pins,
                              pctldev->desc->npins);
        /* remove gpio ranges map */
        list_for_each_entry_safe(range, n, &pctldev->gpio_ranges, node)
                list_del(&range->node);

        kfree(pctldev);

        mutex_unlock(&pinctrl_mutex);
}
EXPORT_SYMBOL_GPL(pinctrl_unregister);

static int __init pinctrl_init(void)
{
        pr_info("initialized pinctrl subsystem\n");
        pinctrl_init_debugfs();
        return 0;
}

/* init early since many drivers really need to initialized pinmux early */
core_initcall(pinctrl_init);