/*
 * OF helpers for regulator framework
 *
 * Copyright (C) 2011 Texas Instruments, Inc.
 * Rajendra Nayak <rnayak@ti.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/regulator/machine.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/of_regulator.h>

#include "internal.h"

static const char *const regulator_states[PM_SUSPEND_MAX + 1] = {
        [PM_SUSPEND_MEM]        = "regulator-state-mem",
        [PM_SUSPEND_MAX]        = "regulator-state-disk",
};

static void of_get_regulation_constraints(struct device_node *np,
                                        struct regulator_init_data **init_data,
                                        const struct regulator_desc *desc)
{
        struct regulation_constraints *constraints = &(*init_data)->constraints;
        struct regulator_state *suspend_state;
        struct device_node *suspend_np;
        int ret, i;
        u32 pval;

        constraints->name = of_get_property(np, "regulator-name", NULL);

        if (!of_property_read_u32(np, "regulator-min-microvolt", &pval))
                constraints->min_uV = pval;

        if (!of_property_read_u32(np, "regulator-max-microvolt", &pval))
                constraints->max_uV = pval;

        /* Voltage change possible? */
        if (constraints->min_uV != constraints->max_uV)
                constraints->valid_ops_mask |= REGULATOR_CHANGE_VOLTAGE;

        /* Do we have a voltage range, if so try to apply it? */
        if (constraints->min_uV && constraints->max_uV)
                constraints->apply_uV = true;

        if (!of_property_read_u32(np, "regulator-microvolt-offset", &pval))
                constraints->uV_offset = pval;
        if (!of_property_read_u32(np, "regulator-min-microamp", &pval))
                constraints->min_uA = pval;
        if (!of_property_read_u32(np, "regulator-max-microamp", &pval))
                constraints->max_uA = pval;

        if (!of_property_read_u32(np, "regulator-input-current-limit-microamp",
                                  &pval))
                constraints->ilim_uA = pval;

        /* Current change possible? */
        if (constraints->min_uA != constraints->max_uA)
                constraints->valid_ops_mask |= REGULATOR_CHANGE_CURRENT;

        constraints->boot_on = of_property_read_bool(np, "regulator-boot-on");
        constraints->always_on = of_property_read_bool(np, "regulator-always-on");
        if (!constraints->always_on) /* status change should be possible. */
                constraints->valid_ops_mask |= REGULATOR_CHANGE_STATUS;

        constraints->pull_down = of_property_read_bool(np, "regulator-pull-down");

        if (of_property_read_bool(np, "regulator-allow-bypass"))
                constraints->valid_ops_mask |= REGULATOR_CHANGE_BYPASS;

        if (of_property_read_bool(np, "regulator-allow-set-load"))
                constraints->valid_ops_mask |= REGULATOR_CHANGE_DRMS;

        ret = of_property_read_u32(np, "regulator-ramp-delay", &pval);
        if (!ret) {
                if (pval)
                        constraints->ramp_delay = pval;
                else
                        constraints->ramp_disable = true;
        }

        ret = of_property_read_u32(np, "regulator-settling-time-us", &pval);
        if (!ret)
                constraints->settling_time = pval;

        ret = of_property_read_u32(np, "regulator-settling-time-up-us", &pval);
        if (!ret)
                constraints->settling_time_up = pval;
        if (constraints->settling_time_up && constraints->settling_time) {
                pr_warn("%s: ambiguous configuration for settling time, ignoring 'regulator-settling-time-up-us'\n",
                        np->name);
                constraints->settling_time_up = 0;
        }

        ret = of_property_read_u32(np, "regulator-settling-time-down-us",
                                   &pval);
        if (!ret)
                constraints->settling_time_down = pval;
        if (constraints->settling_time_down && constraints->settling_time) {
                pr_warn("%s: ambiguous configuration for settling time, ignoring 'regulator-settling-time-down-us'\n",
                        np->name);
                constraints->settling_time_down = 0;
        }

        ret = of_property_read_u32(np, "regulator-enable-ramp-delay", &pval);
        if (!ret)
                constraints->enable_time = pval;

        constraints->soft_start = of_property_read_bool(np,
                                        "regulator-soft-start");
        ret = of_property_read_u32(np, "regulator-active-discharge", &pval);
        if (!ret) {
                constraints->active_discharge =
                                (pval) ? REGULATOR_ACTIVE_DISCHARGE_ENABLE :
                                        REGULATOR_ACTIVE_DISCHARGE_DISABLE;
        }

        if (!of_property_read_u32(np, "regulator-initial-mode", &pval)) {
                if (desc && desc->of_map_mode) {
                        ret = desc->of_map_mode(pval);
                        if (ret == -EINVAL)
                                pr_err("%s: invalid mode %u\n", np->name, pval);
                        else
                                constraints->initial_mode = ret;
                } else {
                        pr_warn("%s: mapping for mode %d not defined\n",
                                np->name, pval);
                }
        }

        if (!of_property_read_u32(np, "regulator-system-load", &pval))
                constraints->system_load = pval;

        constraints->over_current_protection = of_property_read_bool(np,
                                        "regulator-over-current-protection");

        for (i = 0; i < ARRAY_SIZE(regulator_states); i++) {
                switch (i) {
                case PM_SUSPEND_MEM:
                        suspend_state = &constraints->state_mem;
                        break;
                case PM_SUSPEND_MAX:
                        suspend_state = &constraints->state_disk;
                        break;
                case PM_SUSPEND_ON:
                case PM_SUSPEND_FREEZE:
                case PM_SUSPEND_STANDBY:
                default:
                        continue;
                }

                suspend_np = of_get_child_by_name(np, regulator_states[i]);
                if (!suspend_np || !suspend_state)
                        continue;

                if (!of_property_read_u32(suspend_np, "regulator-mode",
                                          &pval)) {
                        if (desc && desc->of_map_mode) {
                                ret = desc->of_map_mode(pval);
                                if (ret == -EINVAL)
                                        pr_err("%s: invalid mode %u\n",
                                               np->name, pval);
                                else
                                        suspend_state->mode = ret;
                        } else {
                                pr_warn("%s: mapping for mode %d not defined\n",
                                        np->name, pval);
                        }
                }

                if (of_property_read_bool(suspend_np,
                                        "regulator-on-in-suspend"))
                        suspend_state->enabled = true;
                else if (of_property_read_bool(suspend_np,
                                        "regulator-off-in-suspend"))
                        suspend_state->disabled = true;

                if (!of_property_read_u32(suspend_np,
                                        "regulator-suspend-microvolt", &pval))
                        suspend_state->uV = pval;

                if (i == PM_SUSPEND_MEM)
                        constraints->initial_state = PM_SUSPEND_MEM;

                of_node_put(suspend_np);
                suspend_state = NULL;
                suspend_np = NULL;
        }
}

/**
 * of_get_regulator_init_data - extract regulator_init_data structure info
 * @dev: device requesting for regulator_init_data
 * @node: regulator device node
 * @desc: regulator description
 *
 * Populates regulator_init_data structure by extracting data from device
 * tree node, returns a pointer to the populated struture or NULL if memory
 * alloc fails.
 */
struct regulator_init_data *of_get_regulator_init_data(struct device *dev,
                                          struct device_node *node,
                                          const struct regulator_desc *desc)
{
        struct regulator_init_data *init_data;

        if (!node)
                return NULL;

        init_data = devm_kzalloc(dev, sizeof(*init_data), GFP_KERNEL);
        if (!init_data)
                return NULL; /* Out of memory? */

        of_get_regulation_constraints(node, &init_data, desc);
        return init_data;
}
EXPORT_SYMBOL_GPL(of_get_regulator_init_data);

struct devm_of_regulator_matches {
        struct of_regulator_match *matches;
        unsigned int num_matches;
};

static void devm_of_regulator_put_matches(struct device *dev, void *res)
{
        struct devm_of_regulator_matches *devm_matches = res;
        int i;

        for (i = 0; i < devm_matches->num_matches; i++)
                of_node_put(devm_matches->matches[i].of_node);
}

/**
 * of_regulator_match - extract multiple regulator init data from device tree.
 * @dev: device requesting the data
 * @node: parent device node of the regulators
 * @matches: match table for the regulators
 * @num_matches: number of entries in match table
 *
 * This function uses a match table specified by the regulator driver to
 * parse regulator init data from the device tree. @node is expected to
 * contain a set of child nodes, each providing the init data for one
 * regulator. The data parsed from a child node will be matched to a regulator
 * based on either the deprecated property regulator-compatible if present,
 * or otherwise the child node's name. Note that the match table is modified
 * in place and an additional of_node reference is taken for each matched
 * regulator.
 *
 * Returns the number of matches found or a negative error code on failure.
 */
int of_regulator_match(struct device *dev, struct device_node *node,
                       struct of_regulator_match *matches,
                       unsigned int num_matches)
{
        unsigned int count = 0;
        unsigned int i;
        const char *name;
        struct device_node *child;
        struct devm_of_regulator_matches *devm_matches;

        if (!dev || !node)
                return -EINVAL;

        devm_matches = devres_alloc(devm_of_regulator_put_matches,
                                    sizeof(struct devm_of_regulator_matches),
                                    GFP_KERNEL);
        if (!devm_matches)
                return -ENOMEM;

        devm_matches->matches = matches;
        devm_matches->num_matches = num_matches;

        devres_add(dev, devm_matches);

        for (i = 0; i < num_matches; i++) {
                struct of_regulator_match *match = &matches[i];
                match->init_data = NULL;
                match->of_node = NULL;
        }

        for_each_child_of_node(node, child) {
                name = of_get_property(child,
                                        "regulator-compatible", NULL);
                if (!name)
                        name = child->name;
                for (i = 0; i < num_matches; i++) {
                        struct of_regulator_match *match = &matches[i];
                        if (match->of_node)
                                continue;

                        if (strcmp(match->name, name))
                                continue;

                        match->init_data =
                                of_get_regulator_init_data(dev, child,
                                                           match->desc);
                        if (!match->init_data) {
                                dev_err(dev,
                                        "failed to parse DT for regulator %s\n",
                                        child->name);
                                return -EINVAL;
                        }
                        match->of_node = of_node_get(child);
                        count++;
                        break;
                }
        }

        return count;
}
EXPORT_SYMBOL_GPL(of_regulator_match);

struct regulator_init_data *regulator_of_get_init_data(struct device *dev,
                                            const struct regulator_desc *desc,
                                            struct regulator_config *config,
                                            struct device_node **node)
{
        struct device_node *search, *child;
        struct regulator_init_data *init_data = NULL;
        const char *name;

        if (!dev->of_node || !desc->of_match)
                return NULL;

        if (desc->regulators_node)
                search = of_get_child_by_name(dev->of_node,
                                              desc->regulators_node);
        else
                search = dev->of_node;

        if (!search) {
                dev_dbg(dev, "Failed to find regulator container node '%s'\n",
                        desc->regulators_node);
                return NULL;
        }

        for_each_available_child_of_node(search, child) {
                name = of_get_property(child, "regulator-compatible", NULL);
                if (!name)
                        name = child->name;

                if (strcmp(desc->of_match, name))
                        continue;

                init_data = of_get_regulator_init_data(dev, child, desc);
                if (!init_data) {
                        dev_err(dev,
                                "failed to parse DT for regulator %s\n",
                                child->name);
                        break;
                }

                if (desc->of_parse_cb) {
                        if (desc->of_parse_cb(child, desc, config)) {
                                dev_err(dev,
                                        "driver callback failed to parse DT for regulator %s\n",
                                        child->name);
                                init_data = NULL;
                                break;
                        }
                }

                of_node_get(child);
                *node = child;
                break;
        }

        of_node_put(search);

        return init_data;
}