// SPDX-License-Identifier: GPL-2.0-only
/*
 *  Universal power supply monitor class
 *
 *  Copyright © 2007  Anton Vorontsov <cbou@mail.ru>
 *  Copyright © 2004  Szabolcs Gyurko
 *  Copyright © 2003  Ian Molton <spyro@f2s.com>
 *
 *  Modified: 2004, Oct     Szabolcs Gyurko
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/notifier.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/power_supply.h>
#include <linux/property.h>
#include <linux/thermal.h>
#include "power_supply.h"

/* exported for the APM Power driver, APM emulation */
struct class *power_supply_class;
EXPORT_SYMBOL_GPL(power_supply_class);

ATOMIC_NOTIFIER_HEAD(power_supply_notifier);
EXPORT_SYMBOL_GPL(power_supply_notifier);

static struct device_type power_supply_dev_type;

#define POWER_SUPPLY_DEFERRED_REGISTER_TIME     msecs_to_jiffies(10)

static bool __power_supply_is_supplied_by(struct power_supply *supplier,
                                         struct power_supply *supply)
{
        int i;

        if (!supply->supplied_from && !supplier->supplied_to)
                return false;

        /* Support both supplied_to and supplied_from modes */
        if (supply->supplied_from) {
                if (!supplier->desc->name)
                        return false;
                for (i = 0; i < supply->num_supplies; i++)
                        if (!strcmp(supplier->desc->name, supply->supplied_from[i]))
                                return true;
        } else {
                if (!supply->desc->name)
                        return false;
                for (i = 0; i < supplier->num_supplicants; i++)
                        if (!strcmp(supplier->supplied_to[i], supply->desc->name))
                                return true;
        }

        return false;
}

static int __power_supply_changed_work(struct device *dev, void *data)
{
        struct power_supply *psy = data;
        struct power_supply *pst = dev_get_drvdata(dev);

        if (__power_supply_is_supplied_by(psy, pst)) {
                if (pst->desc->external_power_changed)
                        pst->desc->external_power_changed(pst);
        }

        return 0;
}

static void power_supply_changed_work(struct work_struct *work)
{
        unsigned long flags;
        struct power_supply *psy = container_of(work, struct power_supply,
                                                changed_work);

        dev_dbg(&psy->dev, "%s\n", __func__);

        spin_lock_irqsave(&psy->changed_lock, flags);
        /*
         * Check 'changed' here to avoid issues due to race between
         * power_supply_changed() and this routine. In worst case
         * power_supply_changed() can be called again just before we take above
         * lock. During the first call of this routine we will mark 'changed' as
         * false and it will stay false for the next call as well.
         */
        if (likely(psy->changed)) {
                psy->changed = false;
                spin_unlock_irqrestore(&psy->changed_lock, flags);
                class_for_each_device(power_supply_class, NULL, psy,
                                      __power_supply_changed_work);
                power_supply_update_leds(psy);
                atomic_notifier_call_chain(&power_supply_notifier,
                                PSY_EVENT_PROP_CHANGED, psy);
                kobject_uevent(&psy->dev.kobj, KOBJ_CHANGE);
                spin_lock_irqsave(&psy->changed_lock, flags);
        }

        /*
         * Hold the wakeup_source until all events are processed.
         * power_supply_changed() might have called again and have set 'changed'
         * to true.
         */
        if (likely(!psy->changed))
                pm_relax(&psy->dev);
        spin_unlock_irqrestore(&psy->changed_lock, flags);
}

void power_supply_changed(struct power_supply *psy)
{
        unsigned long flags;

        dev_dbg(&psy->dev, "%s\n", __func__);

        spin_lock_irqsave(&psy->changed_lock, flags);
        psy->changed = true;
        pm_stay_awake(&psy->dev);
        spin_unlock_irqrestore(&psy->changed_lock, flags);
        schedule_work(&psy->changed_work);
}
EXPORT_SYMBOL_GPL(power_supply_changed);

/*
 * Notify that power supply was registered after parent finished the probing.
 *
 * Often power supply is registered from driver's probe function. However
 * calling power_supply_changed() directly from power_supply_register()
 * would lead to execution of get_property() function provided by the driver
 * too early - before the probe ends.
 *
 * Avoid that by waiting on parent's mutex.
 */
static void power_supply_deferred_register_work(struct work_struct *work)
{
        struct power_supply *psy = container_of(work, struct power_supply,
                                                deferred_register_work.work);

        if (psy->dev.parent) {
                while (!mutex_trylock(&psy->dev.parent->mutex)) {
                        if (psy->removing)
                                return;
                        msleep(10);
                }
        }

        power_supply_changed(psy);

        if (psy->dev.parent)
                mutex_unlock(&psy->dev.parent->mutex);
}

#ifdef CONFIG_OF
static int __power_supply_populate_supplied_from(struct device *dev,
                                                 void *data)
{
        struct power_supply *psy = data;
        struct power_supply *epsy = dev_get_drvdata(dev);
        struct device_node *np;
        int i = 0;

        do {
                np = of_parse_phandle(psy->of_node, "power-supplies", i++);
                if (!np)
                        break;

                if (np == epsy->of_node) {
                        dev_info(&psy->dev, "%s: Found supply : %s\n",
                                psy->desc->name, epsy->desc->name);
                        psy->supplied_from[i-1] = (char *)epsy->desc->name;
                        psy->num_supplies++;
                        of_node_put(np);
                        break;
                }
                of_node_put(np);
        } while (np);

        return 0;
}

static int power_supply_populate_supplied_from(struct power_supply *psy)
{
        int error;

        error = class_for_each_device(power_supply_class, NULL, psy,
                                      __power_supply_populate_supplied_from);

        dev_dbg(&psy->dev, "%s %d\n", __func__, error);

        return error;
}

static int  __power_supply_find_supply_from_node(struct device *dev,
                                                 void *data)
{
        struct device_node *np = data;
        struct power_supply *epsy = dev_get_drvdata(dev);

        /* returning non-zero breaks out of class_for_each_device loop */
        if (epsy->of_node == np)
                return 1;

        return 0;
}

static int power_supply_find_supply_from_node(struct device_node *supply_node)
{
        int error;

        /*
         * class_for_each_device() either returns its own errors or values
         * returned by __power_supply_find_supply_from_node().
         *
         * __power_supply_find_supply_from_node() will return 0 (no match)
         * or 1 (match).
         *
         * We return 0 if class_for_each_device() returned 1, -EPROBE_DEFER if
         * it returned 0, or error as returned by it.
         */
        error = class_for_each_device(power_supply_class, NULL, supply_node,
                                       __power_supply_find_supply_from_node);

        return error ? (error == 1 ? 0 : error) : -EPROBE_DEFER;
}

static int power_supply_check_supplies(struct power_supply *psy)
{
        struct device_node *np;
        int cnt = 0;

        /* If there is already a list honor it */
        if (psy->supplied_from && psy->num_supplies > 0)
                return 0;

        /* No device node found, nothing to do */
        if (!psy->of_node)
                return 0;

        do {
                int ret;

                np = of_parse_phandle(psy->of_node, "power-supplies", cnt++);
                if (!np)
                        break;

                ret = power_supply_find_supply_from_node(np);
                of_node_put(np);

                if (ret) {
                        dev_dbg(&psy->dev, "Failed to find supply!\n");
                        return ret;
                }
        } while (np);

        /* Missing valid "power-supplies" entries */
        if (cnt == 1)
                return 0;

        /* All supplies found, allocate char ** array for filling */
        psy->supplied_from = devm_kzalloc(&psy->dev, sizeof(psy->supplied_from),
                                          GFP_KERNEL);
        if (!psy->supplied_from)
                return -ENOMEM;

        *psy->supplied_from = devm_kcalloc(&psy->dev,
                                           cnt - 1, sizeof(char *),
                                           GFP_KERNEL);
        if (!*psy->supplied_from)
                return -ENOMEM;

        return power_supply_populate_supplied_from(psy);
}
#else
static int power_supply_check_supplies(struct power_supply *psy)
{
        int nval, ret;

        if (!psy->dev.parent)
                return 0;

        nval = device_property_read_string_array(psy->dev.parent,
                                                 "supplied-from", NULL, 0);
        if (nval <= 0)
                return 0;

        psy->supplied_from = devm_kmalloc_array(&psy->dev, nval,
                                                sizeof(char *), GFP_KERNEL);
        if (!psy->supplied_from)
                return -ENOMEM;

        ret = device_property_read_string_array(psy->dev.parent,
                "supplied-from", (const char **)psy->supplied_from, nval);
        if (ret < 0)
                return ret;

        psy->num_supplies = nval;

        return 0;
}
#endif

struct psy_am_i_supplied_data {
        struct power_supply *psy;
        unsigned int count;
};

static int __power_supply_am_i_supplied(struct device *dev, void *_data)
{
        union power_supply_propval ret = {0,};
        struct power_supply *epsy = dev_get_drvdata(dev);
        struct psy_am_i_supplied_data *data = _data;

        if (__power_supply_is_supplied_by(epsy, data->psy)) {
                data->count++;
                if (!epsy->desc->get_property(epsy, POWER_SUPPLY_PROP_ONLINE,
                                        &ret))
                        return ret.intval;
        }

        return 0;
}

int power_supply_am_i_supplied(struct power_supply *psy)
{
        struct psy_am_i_supplied_data data = { psy, 0 };
        int error;

        error = class_for_each_device(power_supply_class, NULL, &data,
                                      __power_supply_am_i_supplied);

        dev_dbg(&psy->dev, "%s count %u err %d\n", __func__, data.count, error);

        if (data.count == 0)
                return -ENODEV;

        return error;
}
EXPORT_SYMBOL_GPL(power_supply_am_i_supplied);

static int __power_supply_is_system_supplied(struct device *dev, void *data)
{
        union power_supply_propval ret = {0,};
        struct power_supply *psy = dev_get_drvdata(dev);
        unsigned int *count = data;

        (*count)++;
        if (psy->desc->type != POWER_SUPPLY_TYPE_BATTERY)
                if (!psy->desc->get_property(psy, POWER_SUPPLY_PROP_ONLINE,
                                        &ret))
                        return ret.intval;

        return 0;
}

int power_supply_is_system_supplied(void)
{
        int error;
        unsigned int count = 0;

        error = class_for_each_device(power_supply_class, NULL, &count,
                                      __power_supply_is_system_supplied);

        /*
         * If no power class device was found at all, most probably we are
         * running on a desktop system, so assume we are on mains power.
         */
        if (count == 0)
                return 1;

        return error;
}
EXPORT_SYMBOL_GPL(power_supply_is_system_supplied);

static int __power_supply_get_supplier_max_current(struct device *dev,
                                                   void *data)
{
        union power_supply_propval ret = {0,};
        struct power_supply *epsy = dev_get_drvdata(dev);
        struct power_supply *psy = data;

        if (__power_supply_is_supplied_by(epsy, psy))
                if (!epsy->desc->get_property(epsy,
                                              POWER_SUPPLY_PROP_CURRENT_MAX,
                                              &ret))
                        return ret.intval;

        return 0;
}

int power_supply_set_input_current_limit_from_supplier(struct power_supply *psy)
{
        union power_supply_propval val = {0,};
        int curr;

        if (!psy->desc->set_property)
                return -EINVAL;

        /*
         * This function is not intended for use with a supply with multiple
         * suppliers, we simply pick the first supply to report a non 0
         * max-current.
         */
        curr = class_for_each_device(power_supply_class, NULL, psy,
                                      __power_supply_get_supplier_max_current);
        if (curr <= 0)
                return (curr == 0) ? -ENODEV : curr;

        val.intval = curr;

        return psy->desc->set_property(psy,
                                POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT, &val);
}
EXPORT_SYMBOL_GPL(power_supply_set_input_current_limit_from_supplier);

int power_supply_set_battery_charged(struct power_supply *psy)
{
        if (atomic_read(&psy->use_cnt) >= 0 &&
                        psy->desc->type == POWER_SUPPLY_TYPE_BATTERY &&
                        psy->desc->set_charged) {
                psy->desc->set_charged(psy);
                return 0;
        }

        return -EINVAL;
}
EXPORT_SYMBOL_GPL(power_supply_set_battery_charged);

static int power_supply_match_device_by_name(struct device *dev, const void *data)
{
        const char *name = data;
        struct power_supply *psy = dev_get_drvdata(dev);

        return strcmp(psy->desc->name, name) == 0;
}

/**
 * power_supply_get_by_name() - Search for a power supply and returns its ref
 * @name: Power supply name to fetch
 *
 * If power supply was found, it increases reference count for the
 * internal power supply's device. The user should power_supply_put()
 * after usage.
 *
 * Return: On success returns a reference to a power supply with
 * matching name equals to @name, a NULL otherwise.
 */
struct power_supply *power_supply_get_by_name(const char *name)
{
        struct power_supply *psy = NULL;
        struct device *dev = class_find_device(power_supply_class, NULL, name,
                                        power_supply_match_device_by_name);

        if (dev) {
                psy = dev_get_drvdata(dev);
                atomic_inc(&psy->use_cnt);
        }

        return psy;
}
EXPORT_SYMBOL_GPL(power_supply_get_by_name);

/**
 * power_supply_put() - Drop reference obtained with power_supply_get_by_name
 * @psy: Reference to put
 *
 * The reference to power supply should be put before unregistering
 * the power supply.
 */
void power_supply_put(struct power_supply *psy)
{
        might_sleep();

        atomic_dec(&psy->use_cnt);
        put_device(&psy->dev);
}
EXPORT_SYMBOL_GPL(power_supply_put);

#ifdef CONFIG_OF
static int power_supply_match_device_node(struct device *dev, const void *data)
{
        return dev->parent && dev->parent->of_node == data;
}

/**
 * power_supply_get_by_phandle() - Search for a power supply and returns its ref
 * @np: Pointer to device node holding phandle property
 * @property: Name of property holding a power supply name
 *
 * If power supply was found, it increases reference count for the
 * internal power supply's device. The user should power_supply_put()
 * after usage.
 *
 * Return: On success returns a reference to a power supply with
 * matching name equals to value under @property, NULL or ERR_PTR otherwise.
 */
struct power_supply *power_supply_get_by_phandle(struct device_node *np,
                                                        const char *property)
{
        struct device_node *power_supply_np;
        struct power_supply *psy = NULL;
        struct device *dev;

        power_supply_np = of_parse_phandle(np, property, 0);
        if (!power_supply_np)
                return ERR_PTR(-ENODEV);

        dev = class_find_device(power_supply_class, NULL, power_supply_np,
                                                power_supply_match_device_node);

        of_node_put(power_supply_np);

        if (dev) {
                psy = dev_get_drvdata(dev);
                atomic_inc(&psy->use_cnt);
        }

        return psy;
}
EXPORT_SYMBOL_GPL(power_supply_get_by_phandle);

static void devm_power_supply_put(struct device *dev, void *res)
{
        struct power_supply **psy = res;

        power_supply_put(*psy);
}

/**
 * devm_power_supply_get_by_phandle() - Resource managed version of
 *  power_supply_get_by_phandle()
 * @dev: Pointer to device holding phandle property
 * @property: Name of property holding a power supply phandle
 *
 * Return: On success returns a reference to a power supply with
 * matching name equals to value under @property, NULL or ERR_PTR otherwise.
 */
struct power_supply *devm_power_supply_get_by_phandle(struct device *dev,
                                                      const char *property)
{
        struct power_supply **ptr, *psy;

        if (!dev->of_node)
                return ERR_PTR(-ENODEV);

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

        psy = power_supply_get_by_phandle(dev->of_node, property);
        if (IS_ERR_OR_NULL(psy)) {
                devres_free(ptr);
        } else {
                *ptr = psy;
                devres_add(dev, ptr);
        }
        return psy;
}
EXPORT_SYMBOL_GPL(devm_power_supply_get_by_phandle);
#endif /* CONFIG_OF */

int power_supply_get_battery_info(struct power_supply *psy,
                                  struct power_supply_battery_info *info)
{
        struct power_supply_resistance_temp_table *resist_table;
        struct device_node *battery_np;
        const char *value;
        int err, len, index;
        const __be32 *list;

        info->energy_full_design_uwh         = -EINVAL;
        info->charge_full_design_uah         = -EINVAL;
        info->voltage_min_design_uv          = -EINVAL;
        info->voltage_max_design_uv          = -EINVAL;
        info->precharge_current_ua           = -EINVAL;
        info->charge_term_current_ua         = -EINVAL;
        info->constant_charge_current_max_ua = -EINVAL;
        info->constant_charge_voltage_max_uv = -EINVAL;
        info->factory_internal_resistance_uohm  = -EINVAL;
        info->resist_table = NULL;

        for (index = 0; index < POWER_SUPPLY_OCV_TEMP_MAX; index++) {
                info->ocv_table[index]       = NULL;
                info->ocv_temp[index]        = -EINVAL;
                info->ocv_table_size[index]  = -EINVAL;
        }

        if (!psy->of_node) {
                dev_warn(&psy->dev, "%s currently only supports devicetree\n",
                         __func__);
                return -ENXIO;
        }

        battery_np = of_parse_phandle(psy->of_node, "monitored-battery", 0);
        if (!battery_np)
                return -ENODEV;

        err = of_property_read_string(battery_np, "compatible", &value);
        if (err)
                goto out_put_node;

        if (strcmp("simple-battery", value)) {
                err = -ENODEV;
                goto out_put_node;
        }

        /* The property and field names below must correspond to elements
         * in enum power_supply_property. For reasoning, see
         * Documentation/power/power_supply_class.rst.
         */

        of_property_read_u32(battery_np, "energy-full-design-microwatt-hours",
                             &info->energy_full_design_uwh);
        of_property_read_u32(battery_np, "charge-full-design-microamp-hours",
                             &info->charge_full_design_uah);
        of_property_read_u32(battery_np, "voltage-min-design-microvolt",
                             &info->voltage_min_design_uv);
        of_property_read_u32(battery_np, "voltage-max-design-microvolt",
                             &info->voltage_max_design_uv);
        of_property_read_u32(battery_np, "trickle-charge-current-microamp",
                             &info->tricklecharge_current_ua);
        of_property_read_u32(battery_np, "precharge-current-microamp",
                             &info->precharge_current_ua);
        of_property_read_u32(battery_np, "precharge-upper-limit-microvolt",
                             &info->precharge_voltage_max_uv);
        of_property_read_u32(battery_np, "charge-term-current-microamp",
                             &info->charge_term_current_ua);
        of_property_read_u32(battery_np, "re-charge-voltage-microvolt",
                             &info->charge_restart_voltage_uv);
        of_property_read_u32(battery_np, "over-voltage-threshold-microvolt",
                             &info->overvoltage_limit_uv);
        of_property_read_u32(battery_np, "constant-charge-current-max-microamp",
                             &info->constant_charge_current_max_ua);
        of_property_read_u32(battery_np, "constant-charge-voltage-max-microvolt",
                             &info->constant_charge_voltage_max_uv);
        of_property_read_u32(battery_np, "factory-internal-resistance-micro-ohms",
                             &info->factory_internal_resistance_uohm);

        len = of_property_count_u32_elems(battery_np, "ocv-capacity-celsius");
        if (len < 0 && len != -EINVAL) {
                err = len;
                goto out_put_node;
        } else if (len > POWER_SUPPLY_OCV_TEMP_MAX) {
                dev_err(&psy->dev, "Too many temperature values\n");
                err = -EINVAL;
                goto out_put_node;
        } else if (len > 0) {
                of_property_read_u32_array(battery_np, "ocv-capacity-celsius",
                                           info->ocv_temp, len);
        }

        for (index = 0; index < len; index++) {
                struct power_supply_battery_ocv_table *table;
                char *propname;
                int i, tab_len, size;

                propname = kasprintf(GFP_KERNEL, "ocv-capacity-table-%d", index);
                list = of_get_property(battery_np, propname, &size);
                if (!list || !size) {
                        dev_err(&psy->dev, "failed to get %s\n", propname);
                        kfree(propname);
                        power_supply_put_battery_info(psy, info);
                        err = -EINVAL;
                        goto out_put_node;
                }

                kfree(propname);
                tab_len = size / (2 * sizeof(__be32));
                info->ocv_table_size[index] = tab_len;

                table = info->ocv_table[index] =
                        devm_kcalloc(&psy->dev, tab_len, sizeof(*table), GFP_KERNEL);
                if (!info->ocv_table[index]) {
                        power_supply_put_battery_info(psy, info);
                        err = -ENOMEM;
                        goto out_put_node;
                }

                for (i = 0; i < tab_len; i++) {
                        table[i].ocv = be32_to_cpu(*list);
                        list++;
                        table[i].capacity = be32_to_cpu(*list);
                        list++;
                }
        }

        list = of_get_property(battery_np, "resistance-temp-table", &len);
        if (!list || !len)
                goto out_put_node;

        info->resist_table_size = len / (2 * sizeof(__be32));
        resist_table = info->resist_table = devm_kcalloc(&psy->dev,
                                                         info->resist_table_size,
                                                         sizeof(*resist_table),
                                                         GFP_KERNEL);
        if (!info->resist_table) {
                power_supply_put_battery_info(psy, info);
                err = -ENOMEM;
                goto out_put_node;
        }

        for (index = 0; index < info->resist_table_size; index++) {
                resist_table[index].temp = be32_to_cpu(*list++);
                resist_table[index].resistance = be32_to_cpu(*list++);
        }

out_put_node:
        of_node_put(battery_np);
        return err;
}
EXPORT_SYMBOL_GPL(power_supply_get_battery_info);

void power_supply_put_battery_info(struct power_supply *psy,
                                   struct power_supply_battery_info *info)
{
        int i;

        for (i = 0; i < POWER_SUPPLY_OCV_TEMP_MAX; i++) {
                if (info->ocv_table[i])
                        devm_kfree(&psy->dev, info->ocv_table[i]);
        }

        if (info->resist_table)
                devm_kfree(&psy->dev, info->resist_table);
}
EXPORT_SYMBOL_GPL(power_supply_put_battery_info);

/**
 * power_supply_temp2resist_simple() - find the battery internal resistance
 * percent
 * @table: Pointer to battery resistance temperature table
 * @table_len: The table length
 * @temp: Current temperature
 *
 * This helper function is used to look up battery internal resistance percent
 * according to current temperature value from the resistance temperature table,
 * and the table must be ordered descending. Then the actual battery internal
 * resistance = the ideal battery internal resistance * percent / 100.
 *
 * Return: the battery internal resistance percent
 */
int power_supply_temp2resist_simple(struct power_supply_resistance_temp_table *table,
                                    int table_len, int temp)
{
        int i, resist;

        for (i = 0; i < table_len; i++)
                if (temp > table[i].temp)
                        break;

        if (i > 0 && i < table_len) {
                int tmp;

                tmp = (table[i - 1].resistance - table[i].resistance) *
                        (temp - table[i].temp);
                tmp /= table[i - 1].temp - table[i].temp;
                resist = tmp + table[i].resistance;
        } else if (i == 0) {
                resist = table[0].resistance;
        } else {
                resist = table[table_len - 1].resistance;
        }

        return resist;
}
EXPORT_SYMBOL_GPL(power_supply_temp2resist_simple);

/**
 * power_supply_ocv2cap_simple() - find the battery capacity
 * @table: Pointer to battery OCV lookup table
 * @table_len: OCV table length
 * @ocv: Current OCV value
 *
 * This helper function is used to look up battery capacity according to
 * current OCV value from one OCV table, and the OCV table must be ordered
 * descending.
 *
 * Return: the battery capacity.
 */
int power_supply_ocv2cap_simple(struct power_supply_battery_ocv_table *table,
                                int table_len, int ocv)
{
        int i, cap, tmp;

        for (i = 0; i < table_len; i++)
                if (ocv > table[i].ocv)
                        break;

        if (i > 0 && i < table_len) {
                tmp = (table[i - 1].capacity - table[i].capacity) *
                        (ocv - table[i].ocv);
                tmp /= table[i - 1].ocv - table[i].ocv;
                cap = tmp + table[i].capacity;
        } else if (i == 0) {
                cap = table[0].capacity;
        } else {
                cap = table[table_len - 1].capacity;
        }

        return cap;
}
EXPORT_SYMBOL_GPL(power_supply_ocv2cap_simple);

struct power_supply_battery_ocv_table *
power_supply_find_ocv2cap_table(struct power_supply_battery_info *info,
                                int temp, int *table_len)
{
        int best_temp_diff = INT_MAX, temp_diff;
        u8 i, best_index = 0;

        if (!info->ocv_table[0])
                return NULL;

        for (i = 0; i < POWER_SUPPLY_OCV_TEMP_MAX; i++) {
                temp_diff = abs(info->ocv_temp[i] - temp);

                if (temp_diff < best_temp_diff) {
                        best_temp_diff = temp_diff;
                        best_index = i;
                }
        }

        *table_len = info->ocv_table_size[best_index];
        return info->ocv_table[best_index];
}
EXPORT_SYMBOL_GPL(power_supply_find_ocv2cap_table);

int power_supply_batinfo_ocv2cap(struct power_supply_battery_info *info,
                                 int ocv, int temp)
{
        struct power_supply_battery_ocv_table *table;
        int table_len;

        table = power_supply_find_ocv2cap_table(info, temp, &table_len);
        if (!table)
                return -EINVAL;

        return power_supply_ocv2cap_simple(table, table_len, ocv);
}
EXPORT_SYMBOL_GPL(power_supply_batinfo_ocv2cap);

int power_supply_get_property(struct power_supply *psy,
                            enum power_supply_property psp,
                            union power_supply_propval *val)
{
        if (atomic_read(&psy->use_cnt) <= 0) {
                if (!psy->initialized)
                        return -EAGAIN;
                return -ENODEV;
        }

        return psy->desc->get_property(psy, psp, val);
}
EXPORT_SYMBOL_GPL(power_supply_get_property);

int power_supply_set_property(struct power_supply *psy,
                            enum power_supply_property psp,
                            const union power_supply_propval *val)
{
        if (atomic_read(&psy->use_cnt) <= 0 || !psy->desc->set_property)
                return -ENODEV;

        return psy->desc->set_property(psy, psp, val);
}
EXPORT_SYMBOL_GPL(power_supply_set_property);

int power_supply_property_is_writeable(struct power_supply *psy,
                                        enum power_supply_property psp)
{
        if (atomic_read(&psy->use_cnt) <= 0 ||
                        !psy->desc->property_is_writeable)
                return -ENODEV;

        return psy->desc->property_is_writeable(psy, psp);
}
EXPORT_SYMBOL_GPL(power_supply_property_is_writeable);

void power_supply_external_power_changed(struct power_supply *psy)
{
        if (atomic_read(&psy->use_cnt) <= 0 ||
                        !psy->desc->external_power_changed)
                return;

        psy->desc->external_power_changed(psy);
}
EXPORT_SYMBOL_GPL(power_supply_external_power_changed);

int power_supply_powers(struct power_supply *psy, struct device *dev)
{
        return sysfs_create_link(&psy->dev.kobj, &dev->kobj, "powers");
}
EXPORT_SYMBOL_GPL(power_supply_powers);

static void power_supply_dev_release(struct device *dev)
{
        struct power_supply *psy = to_power_supply(dev);
        dev_dbg(dev, "%s\n", __func__);
        kfree(psy);
}

int power_supply_reg_notifier(struct notifier_block *nb)
{
        return atomic_notifier_chain_register(&power_supply_notifier, nb);
}
EXPORT_SYMBOL_GPL(power_supply_reg_notifier);

void power_supply_unreg_notifier(struct notifier_block *nb)
{
        atomic_notifier_chain_unregister(&power_supply_notifier, nb);
}
EXPORT_SYMBOL_GPL(power_supply_unreg_notifier);

#ifdef CONFIG_THERMAL
static int power_supply_read_temp(struct thermal_zone_device *tzd,
                int *temp)
{
        struct power_supply *psy;
        union power_supply_propval val;
        int ret;

        WARN_ON(tzd == NULL);
        psy = tzd->devdata;
        ret = power_supply_get_property(psy, POWER_SUPPLY_PROP_TEMP, &val);
        if (ret)
                return ret;

        /* Convert tenths of degree Celsius to milli degree Celsius. */
        *temp = val.intval * 100;

        return ret;
}

static struct thermal_zone_device_ops psy_tzd_ops = {
        .get_temp = power_supply_read_temp,
};

static int psy_register_thermal(struct power_supply *psy)
{
        int i, ret;

        if (psy->desc->no_thermal)
                return 0;

        /* Register battery zone device psy reports temperature */
        for (i = 0; i < psy->desc->num_properties; i++) {
                if (psy->desc->properties[i] == POWER_SUPPLY_PROP_TEMP) {
                        psy->tzd = thermal_zone_device_register(psy->desc->name,
                                        0, 0, psy, &psy_tzd_ops, NULL, 0, 0);
                        if (IS_ERR(psy->tzd))
                                return PTR_ERR(psy->tzd);
                        ret = thermal_zone_device_enable(psy->tzd);
                        if (ret)
                                thermal_zone_device_unregister(psy->tzd);
                        return ret;
                }
        }
        return 0;
}

static void psy_unregister_thermal(struct power_supply *psy)
{
        if (IS_ERR_OR_NULL(psy->tzd))
                return;
        thermal_zone_device_unregister(psy->tzd);
}

/* thermal cooling device callbacks */
static int ps_get_max_charge_cntl_limit(struct thermal_cooling_device *tcd,
                                        unsigned long *state)
{
        struct power_supply *psy;
        union power_supply_propval val;
        int ret;

        psy = tcd->devdata;
        ret = power_supply_get_property(psy,
                        POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT_MAX, &val);
        if (ret)
                return ret;

        *state = val.intval;

        return ret;
}

static int ps_get_cur_charge_cntl_limit(struct thermal_cooling_device *tcd,
                                        unsigned long *state)
{
        struct power_supply *psy;
        union power_supply_propval val;
        int ret;

        psy = tcd->devdata;
        ret = power_supply_get_property(psy,
                        POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT, &val);
        if (ret)
                return ret;

        *state = val.intval;

        return ret;
}

static int ps_set_cur_charge_cntl_limit(struct thermal_cooling_device *tcd,
                                        unsigned long state)
{
        struct power_supply *psy;
        union power_supply_propval val;
        int ret;

        psy = tcd->devdata;
        val.intval = state;
        ret = psy->desc->set_property(psy,
                POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT, &val);

        return ret;
}

static const struct thermal_cooling_device_ops psy_tcd_ops = {
        .get_max_state = ps_get_max_charge_cntl_limit,
        .get_cur_state = ps_get_cur_charge_cntl_limit,
        .set_cur_state = ps_set_cur_charge_cntl_limit,
};

static int psy_register_cooler(struct power_supply *psy)
{
        int i;

        /* Register for cooling device if psy can control charging */
        for (i = 0; i < psy->desc->num_properties; i++) {
                if (psy->desc->properties[i] ==
                                POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT) {
                        psy->tcd = thermal_cooling_device_register(
                                                        (char *)psy->desc->name,
                                                        psy, &psy_tcd_ops);
                        return PTR_ERR_OR_ZERO(psy->tcd);
                }
        }
        return 0;
}

static void psy_unregister_cooler(struct power_supply *psy)
{
        if (IS_ERR_OR_NULL(psy->tcd))
                return;
        thermal_cooling_device_unregister(psy->tcd);
}
#else
static int psy_register_thermal(struct power_supply *psy)
{
        return 0;
}

static void psy_unregister_thermal(struct power_supply *psy)
{
}

static int psy_register_cooler(struct power_supply *psy)
{
        return 0;
}

static void psy_unregister_cooler(struct power_supply *psy)
{
}
#endif

static struct power_supply *__must_check
__power_supply_register(struct device *parent,
                                   const struct power_supply_desc *desc,
                                   const struct power_supply_config *cfg,
                                   bool ws)
{
        struct device *dev;
        struct power_supply *psy;
        int i, rc;

        if (!parent)
                pr_warn("%s: Expected proper parent device for '%s'\n",
                        __func__, desc->name);

        if (!desc || !desc->name || !desc->properties || !desc->num_properties)
                return ERR_PTR(-EINVAL);

        for (i = 0; i < desc->num_properties; ++i) {
                if ((desc->properties[i] == POWER_SUPPLY_PROP_USB_TYPE) &&
                    (!desc->usb_types || !desc->num_usb_types))
                        return ERR_PTR(-EINVAL);
        }

        psy = kzalloc(sizeof(*psy), GFP_KERNEL);
        if (!psy)
                return ERR_PTR(-ENOMEM);

        dev = &psy->dev;

        device_initialize(dev);

        dev->class = power_supply_class;
        dev->type = &power_supply_dev_type;
        dev->parent = parent;
        dev->release = power_supply_dev_release;
        dev_set_drvdata(dev, psy);
        psy->desc = desc;
        if (cfg) {
                dev->groups = cfg->attr_grp;
                psy->drv_data = cfg->drv_data;
                psy->of_node =
                        cfg->fwnode ? to_of_node(cfg->fwnode) : cfg->of_node;
                psy->supplied_to = cfg->supplied_to;
                psy->num_supplicants = cfg->num_supplicants;
        }

        rc = dev_set_name(dev, "%s", desc->name);
        if (rc)
                goto dev_set_name_failed;

        INIT_WORK(&psy->changed_work, power_supply_changed_work);
        INIT_DELAYED_WORK(&psy->deferred_register_work,
                          power_supply_deferred_register_work);

        rc = power_supply_check_supplies(psy);
        if (rc) {
                dev_info(dev, "Not all required supplies found, defer probe\n");
                goto check_supplies_failed;
        }

        spin_lock_init(&psy->changed_lock);
        rc = device_add(dev);
        if (rc)
                goto device_add_failed;

        rc = device_init_wakeup(dev, ws);
        if (rc)
                goto wakeup_init_failed;

        rc = psy_register_thermal(psy);
        if (rc)
                goto register_thermal_failed;

        rc = psy_register_cooler(psy);
        if (rc)
                goto register_cooler_failed;

        rc = power_supply_create_triggers(psy);
        if (rc)
                goto create_triggers_failed;

        rc = power_supply_add_hwmon_sysfs(psy);
        if (rc)
                goto add_hwmon_sysfs_failed;

        /*
         * Update use_cnt after any uevents (most notably from device_add()).
         * We are here still during driver's probe but
         * the power_supply_uevent() calls back driver's get_property
         * method so:
         * 1. Driver did not assigned the returned struct power_supply,
         * 2. Driver could not finish initialization (anything in its probe
         *    after calling power_supply_register()).
         */
        atomic_inc(&psy->use_cnt);
        psy->initialized = true;

        queue_delayed_work(system_power_efficient_wq,
                           &psy->deferred_register_work,
                           POWER_SUPPLY_DEFERRED_REGISTER_TIME);

        return psy;

add_hwmon_sysfs_failed:
        power_supply_remove_triggers(psy);
create_triggers_failed:
        psy_unregister_cooler(psy);
register_cooler_failed:
        psy_unregister_thermal(psy);
register_thermal_failed:
        device_del(dev);
wakeup_init_failed:
device_add_failed:
check_supplies_failed:
dev_set_name_failed:
        put_device(dev);
        return ERR_PTR(rc);
}

/**
 * power_supply_register() - Register new power supply
 * @parent:     Device to be a parent of power supply's device, usually
 *              the device which probe function calls this
 * @desc:       Description of power supply, must be valid through whole
 *              lifetime of this power supply
 * @cfg:        Run-time specific configuration accessed during registering,
 *              may be NULL
 *
 * Return: A pointer to newly allocated power_supply on success
 * or ERR_PTR otherwise.
 * Use power_supply_unregister() on returned power_supply pointer to release
 * resources.
 */
struct power_supply *__must_check power_supply_register(struct device *parent,
                const struct power_supply_desc *desc,
                const struct power_supply_config *cfg)
{
        return __power_supply_register(parent, desc, cfg, true);
}
EXPORT_SYMBOL_GPL(power_supply_register);

/**
 * power_supply_register_no_ws() - Register new non-waking-source power supply
 * @parent:     Device to be a parent of power supply's device, usually
 *              the device which probe function calls this
 * @desc:       Description of power supply, must be valid through whole
 *              lifetime of this power supply
 * @cfg:        Run-time specific configuration accessed during registering,
 *              may be NULL
 *
 * Return: A pointer to newly allocated power_supply on success
 * or ERR_PTR otherwise.
 * Use power_supply_unregister() on returned power_supply pointer to release
 * resources.
 */
struct power_supply *__must_check
power_supply_register_no_ws(struct device *parent,
                const struct power_supply_desc *desc,
                const struct power_supply_config *cfg)
{
        return __power_supply_register(parent, desc, cfg, false);
}
EXPORT_SYMBOL_GPL(power_supply_register_no_ws);

static void devm_power_supply_release(struct device *dev, void *res)
{
        struct power_supply **psy = res;

        power_supply_unregister(*psy);
}

/**
 * devm_power_supply_register() - Register managed power supply
 * @parent:     Device to be a parent of power supply's device, usually
 *              the device which probe function calls this
 * @desc:       Description of power supply, must be valid through whole
 *              lifetime of this power supply
 * @cfg:        Run-time specific configuration accessed during registering,
 *              may be NULL
 *
 * Return: A pointer to newly allocated power_supply on success
 * or ERR_PTR otherwise.
 * The returned power_supply pointer will be automatically unregistered
 * on driver detach.
 */
struct power_supply *__must_check
devm_power_supply_register(struct device *parent,
                const struct power_supply_desc *desc,
                const struct power_supply_config *cfg)
{
        struct power_supply **ptr, *psy;

        ptr = devres_alloc(devm_power_supply_release, sizeof(*ptr), GFP_KERNEL);

        if (!ptr)
                return ERR_PTR(-ENOMEM);
        psy = __power_supply_register(parent, desc, cfg, true);
        if (IS_ERR(psy)) {
                devres_free(ptr);
        } else {
                *ptr = psy;
                devres_add(parent, ptr);
        }
        return psy;
}
EXPORT_SYMBOL_GPL(devm_power_supply_register);

/**
 * devm_power_supply_register_no_ws() - Register managed non-waking-source power supply
 * @parent:     Device to be a parent of power supply's device, usually
 *              the device which probe function calls this
 * @desc:       Description of power supply, must be valid through whole
 *              lifetime of this power supply
 * @cfg:        Run-time specific configuration accessed during registering,
 *              may be NULL
 *
 * Return: A pointer to newly allocated power_supply on success
 * or ERR_PTR otherwise.
 * The returned power_supply pointer will be automatically unregistered
 * on driver detach.
 */
struct power_supply *__must_check
devm_power_supply_register_no_ws(struct device *parent,
                const struct power_supply_desc *desc,
                const struct power_supply_config *cfg)
{
        struct power_supply **ptr, *psy;

        ptr = devres_alloc(devm_power_supply_release, sizeof(*ptr), GFP_KERNEL);

        if (!ptr)
                return ERR_PTR(-ENOMEM);
        psy = __power_supply_register(parent, desc, cfg, false);
        if (IS_ERR(psy)) {
                devres_free(ptr);
        } else {
                *ptr = psy;
                devres_add(parent, ptr);
        }
        return psy;
}
EXPORT_SYMBOL_GPL(devm_power_supply_register_no_ws);

/**
 * power_supply_unregister() - Remove this power supply from system
 * @psy:        Pointer to power supply to unregister
 *
 * Remove this power supply from the system. The resources of power supply
 * will be freed here or on last power_supply_put() call.
 */
void power_supply_unregister(struct power_supply *psy)
{
        WARN_ON(atomic_dec_return(&psy->use_cnt));
        psy->removing = true;
        cancel_work_sync(&psy->changed_work);
        cancel_delayed_work_sync(&psy->deferred_register_work);
        sysfs_remove_link(&psy->dev.kobj, "powers");
        power_supply_remove_hwmon_sysfs(psy);
        power_supply_remove_triggers(psy);
        psy_unregister_cooler(psy);
        psy_unregister_thermal(psy);
        device_init_wakeup(&psy->dev, false);
        device_unregister(&psy->dev);
}
EXPORT_SYMBOL_GPL(power_supply_unregister);

void *power_supply_get_drvdata(struct power_supply *psy)
{
        return psy->drv_data;
}
EXPORT_SYMBOL_GPL(power_supply_get_drvdata);

static int __init power_supply_class_init(void)
{
        power_supply_class = class_create(THIS_MODULE, "power_supply");

        if (IS_ERR(power_supply_class))
                return PTR_ERR(power_supply_class);

        power_supply_class->dev_uevent = power_supply_uevent;
        power_supply_init_attrs(&power_supply_dev_type);

        return 0;
}

static void __exit power_supply_class_exit(void)
{
        class_destroy(power_supply_class);
}

subsys_initcall(power_supply_class_init);
module_exit(power_supply_class_exit);

MODULE_DESCRIPTION("Universal power supply monitor class");
MODULE_AUTHOR("Ian Molton <spyro@f2s.com>, "
              "Szabolcs Gyurko, "
              "Anton Vorontsov <cbou@mail.ru>");
MODULE_LICENSE("GPL");