// SPDX-License-Identifier: GPL-2.0-only
/*
 * 1-wire client/driver for the Maxim/Dallas DS2781 Stand-Alone Fuel Gauge IC
 *
 * Author: Renata Sayakhova <renata@oktetlabs.ru>
 *
 * Based on ds2780_battery drivers
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/param.h>
#include <linux/pm.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/idr.h>

#include <linux/w1.h>
#include "../../w1/slaves/w1_ds2781.h"

/* Current unit measurement in uA for a 1 milli-ohm sense resistor */
#define DS2781_CURRENT_UNITS    1563
/* Charge unit measurement in uAh for a 1 milli-ohm sense resistor */
#define DS2781_CHARGE_UNITS             6250
/* Number of bytes in user EEPROM space */
#define DS2781_USER_EEPROM_SIZE         (DS2781_EEPROM_BLOCK0_END - \
                                        DS2781_EEPROM_BLOCK0_START + 1)
/* Number of bytes in parameter EEPROM space */
#define DS2781_PARAM_EEPROM_SIZE        (DS2781_EEPROM_BLOCK1_END - \
                                        DS2781_EEPROM_BLOCK1_START + 1)

struct ds2781_device_info {
        struct device *dev;
        struct power_supply *bat;
        struct power_supply_desc bat_desc;
        struct device *w1_dev;
};

enum current_types {
        CURRENT_NOW,
        CURRENT_AVG,
};

static const char model[] = "DS2781";
static const char manufacturer[] = "Maxim/Dallas";

static inline struct ds2781_device_info *
to_ds2781_device_info(struct power_supply *psy)
{
        return power_supply_get_drvdata(psy);
}

static inline int ds2781_battery_io(struct ds2781_device_info *dev_info,
        char *buf, int addr, size_t count, int io)
{
        return w1_ds2781_io(dev_info->w1_dev, buf, addr, count, io);
}

static int w1_ds2781_read(struct ds2781_device_info *dev_info, char *buf,
                int addr, size_t count)
{
        return ds2781_battery_io(dev_info, buf, addr, count, 0);
}

static inline int ds2781_read8(struct ds2781_device_info *dev_info, u8 *val,
        int addr)
{
        return ds2781_battery_io(dev_info, val, addr, sizeof(u8), 0);
}

static int ds2781_read16(struct ds2781_device_info *dev_info, s16 *val,
        int addr)
{
        int ret;
        u8 raw[2];

        ret = ds2781_battery_io(dev_info, raw, addr, sizeof(raw), 0);
        if (ret < 0)
                return ret;

        *val = (raw[0] << 8) | raw[1];

        return 0;
}

static inline int ds2781_read_block(struct ds2781_device_info *dev_info,
        u8 *val, int addr, size_t count)
{
        return ds2781_battery_io(dev_info, val, addr, count, 0);
}

static inline int ds2781_write(struct ds2781_device_info *dev_info, u8 *val,
        int addr, size_t count)
{
        return ds2781_battery_io(dev_info, val, addr, count, 1);
}

static inline int ds2781_store_eeprom(struct device *dev, int addr)
{
        return w1_ds2781_eeprom_cmd(dev, addr, W1_DS2781_COPY_DATA);
}

static inline int ds2781_recall_eeprom(struct device *dev, int addr)
{
        return w1_ds2781_eeprom_cmd(dev, addr, W1_DS2781_RECALL_DATA);
}

static int ds2781_save_eeprom(struct ds2781_device_info *dev_info, int reg)
{
        int ret;

        ret = ds2781_store_eeprom(dev_info->w1_dev, reg);
        if (ret < 0)
                return ret;

        ret = ds2781_recall_eeprom(dev_info->w1_dev, reg);
        if (ret < 0)
                return ret;

        return 0;
}

/* Set sense resistor value in mhos */
static int ds2781_set_sense_register(struct ds2781_device_info *dev_info,
        u8 conductance)
{
        int ret;

        ret = ds2781_write(dev_info, &conductance,
                                DS2781_RSNSP, sizeof(u8));
        if (ret < 0)
                return ret;

        return ds2781_save_eeprom(dev_info, DS2781_RSNSP);
}

/* Get RSGAIN value from 0 to 1.999 in steps of 0.001 */
static int ds2781_get_rsgain_register(struct ds2781_device_info *dev_info,
        u16 *rsgain)
{
        return ds2781_read16(dev_info, rsgain, DS2781_RSGAIN_MSB);
}

/* Set RSGAIN value from 0 to 1.999 in steps of 0.001 */
static int ds2781_set_rsgain_register(struct ds2781_device_info *dev_info,
        u16 rsgain)
{
        int ret;
        u8 raw[] = {rsgain >> 8, rsgain & 0xFF};

        ret = ds2781_write(dev_info, raw,
                                DS2781_RSGAIN_MSB, sizeof(raw));
        if (ret < 0)
                return ret;

        return ds2781_save_eeprom(dev_info, DS2781_RSGAIN_MSB);
}

static int ds2781_get_voltage(struct ds2781_device_info *dev_info,
        int *voltage_uV)
{
        int ret;
        char val[2];
        int voltage_raw;

        ret = w1_ds2781_read(dev_info, val, DS2781_VOLT_MSB, 2 * sizeof(u8));
        if (ret < 0)
                return ret;
        /*
         * The voltage value is located in 10 bits across the voltage MSB
         * and LSB registers in two's compliment form
         * Sign bit of the voltage value is in bit 7 of the voltage MSB register
         * Bits 9 - 3 of the voltage value are in bits 6 - 0 of the
         * voltage MSB register
         * Bits 2 - 0 of the voltage value are in bits 7 - 5 of the
         * voltage LSB register
         */
        voltage_raw = (val[0] << 3) |
                (val[1] >> 5);

        /* DS2781 reports voltage in units of 9.76mV, but the battery class
         * reports in units of uV, so convert by multiplying by 9760. */
        *voltage_uV = voltage_raw * 9760;

        return 0;
}

static int ds2781_get_temperature(struct ds2781_device_info *dev_info,
        int *temp)
{
        int ret;
        char val[2];
        int temp_raw;

        ret = w1_ds2781_read(dev_info, val, DS2781_TEMP_MSB, 2 * sizeof(u8));
        if (ret < 0)
                return ret;
        /*
         * The temperature value is located in 10 bits across the temperature
         * MSB and LSB registers in two's compliment form
         * Sign bit of the temperature value is in bit 7 of the temperature
         * MSB register
         * Bits 9 - 3 of the temperature value are in bits 6 - 0 of the
         * temperature MSB register
         * Bits 2 - 0 of the temperature value are in bits 7 - 5 of the
         * temperature LSB register
         */
        temp_raw = ((val[0]) << 3) |
                (val[1] >> 5);
        *temp = temp_raw + (temp_raw / 4);

        return 0;
}

static int ds2781_get_current(struct ds2781_device_info *dev_info,
        enum current_types type, int *current_uA)
{
        int ret, sense_res;
        s16 current_raw;
        u8 sense_res_raw, reg_msb;

        /*
         * The units of measurement for current are dependent on the value of
         * the sense resistor.
         */
        ret = ds2781_read8(dev_info, &sense_res_raw, DS2781_RSNSP);
        if (ret < 0)
                return ret;

        if (sense_res_raw == 0) {
                dev_err(dev_info->dev, "sense resistor value is 0\n");
                return -EINVAL;
        }
        sense_res = 1000 / sense_res_raw;

        if (type == CURRENT_NOW)
                reg_msb = DS2781_CURRENT_MSB;
        else if (type == CURRENT_AVG)
                reg_msb = DS2781_IAVG_MSB;
        else
                return -EINVAL;

        /*
         * The current value is located in 16 bits across the current MSB
         * and LSB registers in two's compliment form
         * Sign bit of the current value is in bit 7 of the current MSB register
         * Bits 14 - 8 of the current value are in bits 6 - 0 of the current
         * MSB register
         * Bits 7 - 0 of the current value are in bits 7 - 0 of the current
         * LSB register
         */
        ret = ds2781_read16(dev_info, &current_raw, reg_msb);
        if (ret < 0)
                return ret;

        *current_uA = current_raw * (DS2781_CURRENT_UNITS / sense_res);
        return 0;
}

static int ds2781_get_accumulated_current(struct ds2781_device_info *dev_info,
        int *accumulated_current)
{
        int ret, sense_res;
        s16 current_raw;
        u8 sense_res_raw;

        /*
         * The units of measurement for accumulated current are dependent on
         * the value of the sense resistor.
         */
        ret = ds2781_read8(dev_info, &sense_res_raw, DS2781_RSNSP);
        if (ret < 0)
                return ret;

        if (sense_res_raw == 0) {
                dev_err(dev_info->dev, "sense resistor value is 0\n");
                return -EINVAL;
        }
        sense_res = 1000 / sense_res_raw;

        /*
         * The ACR value is located in 16 bits across the ACR MSB and
         * LSB registers
         * Bits 15 - 8 of the ACR value are in bits 7 - 0 of the ACR
         * MSB register
         * Bits 7 - 0 of the ACR value are in bits 7 - 0 of the ACR
         * LSB register
         */
        ret = ds2781_read16(dev_info, &current_raw, DS2781_ACR_MSB);
        if (ret < 0)
                return ret;

        *accumulated_current = current_raw * (DS2781_CHARGE_UNITS / sense_res);
        return 0;
}

static int ds2781_get_capacity(struct ds2781_device_info *dev_info,
        int *capacity)
{
        int ret;
        u8 raw;

        ret = ds2781_read8(dev_info, &raw, DS2781_RARC);
        if (ret < 0)
                return ret;

        *capacity = raw;
        return 0;
}

static int ds2781_get_status(struct ds2781_device_info *dev_info, int *status)
{
        int ret, current_uA, capacity;

        ret = ds2781_get_current(dev_info, CURRENT_NOW, &current_uA);
        if (ret < 0)
                return ret;

        ret = ds2781_get_capacity(dev_info, &capacity);
        if (ret < 0)
                return ret;

        if (power_supply_am_i_supplied(dev_info->bat)) {
                if (capacity == 100)
                        *status = POWER_SUPPLY_STATUS_FULL;
                else if (current_uA > 50000)
                        *status = POWER_SUPPLY_STATUS_CHARGING;
                else
                        *status = POWER_SUPPLY_STATUS_NOT_CHARGING;
        } else {
                *status = POWER_SUPPLY_STATUS_DISCHARGING;
        }
        return 0;
}

static int ds2781_get_charge_now(struct ds2781_device_info *dev_info,
        int *charge_now)
{
        int ret;
        u16 charge_raw;

        /*
         * The RAAC value is located in 16 bits across the RAAC MSB and
         * LSB registers
         * Bits 15 - 8 of the RAAC value are in bits 7 - 0 of the RAAC
         * MSB register
         * Bits 7 - 0 of the RAAC value are in bits 7 - 0 of the RAAC
         * LSB register
         */
        ret = ds2781_read16(dev_info, &charge_raw, DS2781_RAAC_MSB);
        if (ret < 0)
                return ret;

        *charge_now = charge_raw * 1600;
        return 0;
}

static int ds2781_get_control_register(struct ds2781_device_info *dev_info,
        u8 *control_reg)
{
        return ds2781_read8(dev_info, control_reg, DS2781_CONTROL);
}

static int ds2781_set_control_register(struct ds2781_device_info *dev_info,
        u8 control_reg)
{
        int ret;

        ret = ds2781_write(dev_info, &control_reg,
                                DS2781_CONTROL, sizeof(u8));
        if (ret < 0)
                return ret;

        return ds2781_save_eeprom(dev_info, DS2781_CONTROL);
}

static int ds2781_battery_get_property(struct power_supply *psy,
        enum power_supply_property psp,
        union power_supply_propval *val)
{
        int ret = 0;
        struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);

        switch (psp) {
        case POWER_SUPPLY_PROP_VOLTAGE_NOW:
                ret = ds2781_get_voltage(dev_info, &val->intval);
                break;

        case POWER_SUPPLY_PROP_TEMP:
                ret = ds2781_get_temperature(dev_info, &val->intval);
                break;

        case POWER_SUPPLY_PROP_MODEL_NAME:
                val->strval = model;
                break;

        case POWER_SUPPLY_PROP_MANUFACTURER:
                val->strval = manufacturer;
                break;

        case POWER_SUPPLY_PROP_CURRENT_NOW:
                ret = ds2781_get_current(dev_info, CURRENT_NOW, &val->intval);
                break;

        case POWER_SUPPLY_PROP_CURRENT_AVG:
                ret = ds2781_get_current(dev_info, CURRENT_AVG, &val->intval);
                break;

        case POWER_SUPPLY_PROP_STATUS:
                ret = ds2781_get_status(dev_info, &val->intval);
                break;

        case POWER_SUPPLY_PROP_CAPACITY:
                ret = ds2781_get_capacity(dev_info, &val->intval);
                break;

        case POWER_SUPPLY_PROP_CHARGE_COUNTER:
                ret = ds2781_get_accumulated_current(dev_info, &val->intval);
                break;

        case POWER_SUPPLY_PROP_CHARGE_NOW:
                ret = ds2781_get_charge_now(dev_info, &val->intval);
                break;

        default:
                ret = -EINVAL;
        }

        return ret;
}

static enum power_supply_property ds2781_battery_props[] = {
        POWER_SUPPLY_PROP_STATUS,
        POWER_SUPPLY_PROP_VOLTAGE_NOW,
        POWER_SUPPLY_PROP_TEMP,
        POWER_SUPPLY_PROP_MODEL_NAME,
        POWER_SUPPLY_PROP_MANUFACTURER,
        POWER_SUPPLY_PROP_CURRENT_NOW,
        POWER_SUPPLY_PROP_CURRENT_AVG,
        POWER_SUPPLY_PROP_CAPACITY,
        POWER_SUPPLY_PROP_CHARGE_COUNTER,
        POWER_SUPPLY_PROP_CHARGE_NOW,
};

static ssize_t ds2781_get_pmod_enabled(struct device *dev,
        struct device_attribute *attr,
        char *buf)
{
        int ret;
        u8 control_reg;
        struct power_supply *psy = to_power_supply(dev);
        struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);

        /* Get power mode */
        ret = ds2781_get_control_register(dev_info, &control_reg);
        if (ret < 0)
                return ret;

        return sprintf(buf, "%d\n",
                 !!(control_reg & DS2781_CONTROL_PMOD));
}

static ssize_t ds2781_set_pmod_enabled(struct device *dev,
        struct device_attribute *attr,
        const char *buf,
        size_t count)
{
        int ret;
        u8 control_reg, new_setting;
        struct power_supply *psy = to_power_supply(dev);
        struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);

        /* Set power mode */
        ret = ds2781_get_control_register(dev_info, &control_reg);
        if (ret < 0)
                return ret;

        ret = kstrtou8(buf, 0, &new_setting);
        if (ret < 0)
                return ret;

        if ((new_setting != 0) && (new_setting != 1)) {
                dev_err(dev_info->dev, "Invalid pmod setting (0 or 1)\n");
                return -EINVAL;
        }

        if (new_setting)
                control_reg |= DS2781_CONTROL_PMOD;
        else
                control_reg &= ~DS2781_CONTROL_PMOD;

        ret = ds2781_set_control_register(dev_info, control_reg);
        if (ret < 0)
                return ret;

        return count;
}

static ssize_t ds2781_get_sense_resistor_value(struct device *dev,
        struct device_attribute *attr,
        char *buf)
{
        int ret;
        u8 sense_resistor;
        struct power_supply *psy = to_power_supply(dev);
        struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);

        ret = ds2781_read8(dev_info, &sense_resistor, DS2781_RSNSP);
        if (ret < 0)
                return ret;

        ret = sprintf(buf, "%d\n", sense_resistor);
        return ret;
}

static ssize_t ds2781_set_sense_resistor_value(struct device *dev,
        struct device_attribute *attr,
        const char *buf,
        size_t count)
{
        int ret;
        u8 new_setting;
        struct power_supply *psy = to_power_supply(dev);
        struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);

        ret = kstrtou8(buf, 0, &new_setting);
        if (ret < 0)
                return ret;

        ret = ds2781_set_sense_register(dev_info, new_setting);
        if (ret < 0)
                return ret;

        return count;
}

static ssize_t ds2781_get_rsgain_setting(struct device *dev,
        struct device_attribute *attr,
        char *buf)
{
        int ret;
        u16 rsgain;
        struct power_supply *psy = to_power_supply(dev);
        struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);

        ret = ds2781_get_rsgain_register(dev_info, &rsgain);
        if (ret < 0)
                return ret;

        return sprintf(buf, "%d\n", rsgain);
}

static ssize_t ds2781_set_rsgain_setting(struct device *dev,
        struct device_attribute *attr,
        const char *buf,
        size_t count)
{
        int ret;
        u16 new_setting;
        struct power_supply *psy = to_power_supply(dev);
        struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);

        ret = kstrtou16(buf, 0, &new_setting);
        if (ret < 0)
                return ret;

        /* Gain can only be from 0 to 1.999 in steps of .001 */
        if (new_setting > 1999) {
                dev_err(dev_info->dev, "Invalid rsgain setting (0 - 1999)\n");
                return -EINVAL;
        }

        ret = ds2781_set_rsgain_register(dev_info, new_setting);
        if (ret < 0)
                return ret;

        return count;
}

static ssize_t ds2781_get_pio_pin(struct device *dev,
        struct device_attribute *attr,
        char *buf)
{
        int ret;
        u8 sfr;
        struct power_supply *psy = to_power_supply(dev);
        struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);

        ret = ds2781_read8(dev_info, &sfr, DS2781_SFR);
        if (ret < 0)
                return ret;

        ret = sprintf(buf, "%d\n", sfr & DS2781_SFR_PIOSC);
        return ret;
}

static ssize_t ds2781_set_pio_pin(struct device *dev,
        struct device_attribute *attr,
        const char *buf,
        size_t count)
{
        int ret;
        u8 new_setting;
        struct power_supply *psy = to_power_supply(dev);
        struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);

        ret = kstrtou8(buf, 0, &new_setting);
        if (ret < 0)
                return ret;

        if ((new_setting != 0) && (new_setting != 1)) {
                dev_err(dev_info->dev, "Invalid pio_pin setting (0 or 1)\n");
                return -EINVAL;
        }

        ret = ds2781_write(dev_info, &new_setting,
                                DS2781_SFR, sizeof(u8));
        if (ret < 0)
                return ret;

        return count;
}

static ssize_t ds2781_read_param_eeprom_bin(struct file *filp,
                                struct kobject *kobj,
                                struct bin_attribute *bin_attr,
                                char *buf, loff_t off, size_t count)
{
        struct device *dev = container_of(kobj, struct device, kobj);
        struct power_supply *psy = to_power_supply(dev);
        struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);

        return ds2781_read_block(dev_info, buf,
                                DS2781_EEPROM_BLOCK1_START + off, count);
}

static ssize_t ds2781_write_param_eeprom_bin(struct file *filp,
                                struct kobject *kobj,
                                struct bin_attribute *bin_attr,
                                char *buf, loff_t off, size_t count)
{
        struct device *dev = container_of(kobj, struct device, kobj);
        struct power_supply *psy = to_power_supply(dev);
        struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);
        int ret;

        ret = ds2781_write(dev_info, buf,
                                DS2781_EEPROM_BLOCK1_START + off, count);
        if (ret < 0)
                return ret;

        ret = ds2781_save_eeprom(dev_info, DS2781_EEPROM_BLOCK1_START);
        if (ret < 0)
                return ret;

        return count;
}

static struct bin_attribute ds2781_param_eeprom_bin_attr = {
        .attr = {
                .name = "param_eeprom",
                .mode = S_IRUGO | S_IWUSR,
        },
        .size = DS2781_PARAM_EEPROM_SIZE,
        .read = ds2781_read_param_eeprom_bin,
        .write = ds2781_write_param_eeprom_bin,
};

static ssize_t ds2781_read_user_eeprom_bin(struct file *filp,
                                struct kobject *kobj,
                                struct bin_attribute *bin_attr,
                                char *buf, loff_t off, size_t count)
{
        struct device *dev = container_of(kobj, struct device, kobj);
        struct power_supply *psy = to_power_supply(dev);
        struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);

        return ds2781_read_block(dev_info, buf,
                                DS2781_EEPROM_BLOCK0_START + off, count);

}

static ssize_t ds2781_write_user_eeprom_bin(struct file *filp,
                                struct kobject *kobj,
                                struct bin_attribute *bin_attr,
                                char *buf, loff_t off, size_t count)
{
        struct device *dev = container_of(kobj, struct device, kobj);
        struct power_supply *psy = to_power_supply(dev);
        struct ds2781_device_info *dev_info = to_ds2781_device_info(psy);
        int ret;

        ret = ds2781_write(dev_info, buf,
                                DS2781_EEPROM_BLOCK0_START + off, count);
        if (ret < 0)
                return ret;

        ret = ds2781_save_eeprom(dev_info, DS2781_EEPROM_BLOCK0_START);
        if (ret < 0)
                return ret;

        return count;
}

static struct bin_attribute ds2781_user_eeprom_bin_attr = {
        .attr = {
                .name = "user_eeprom",
                .mode = S_IRUGO | S_IWUSR,
        },
        .size = DS2781_USER_EEPROM_SIZE,
        .read = ds2781_read_user_eeprom_bin,
        .write = ds2781_write_user_eeprom_bin,
};

static DEVICE_ATTR(pmod_enabled, S_IRUGO | S_IWUSR, ds2781_get_pmod_enabled,
        ds2781_set_pmod_enabled);
static DEVICE_ATTR(sense_resistor_value, S_IRUGO | S_IWUSR,
        ds2781_get_sense_resistor_value, ds2781_set_sense_resistor_value);
static DEVICE_ATTR(rsgain_setting, S_IRUGO | S_IWUSR, ds2781_get_rsgain_setting,
        ds2781_set_rsgain_setting);
static DEVICE_ATTR(pio_pin, S_IRUGO | S_IWUSR, ds2781_get_pio_pin,
        ds2781_set_pio_pin);

static struct attribute *ds2781_sysfs_attrs[] = {
        &dev_attr_pmod_enabled.attr,
        &dev_attr_sense_resistor_value.attr,
        &dev_attr_rsgain_setting.attr,
        &dev_attr_pio_pin.attr,
        NULL
};

static struct bin_attribute *ds2781_sysfs_bin_attrs[] = {
        &ds2781_param_eeprom_bin_attr,
        &ds2781_user_eeprom_bin_attr,
        NULL,
};

static const struct attribute_group ds2781_sysfs_group = {
        .attrs = ds2781_sysfs_attrs,
        .bin_attrs = ds2781_sysfs_bin_attrs,

};

static const struct attribute_group *ds2781_sysfs_groups[] = {
        &ds2781_sysfs_group,
        NULL,
};

static int ds2781_battery_probe(struct platform_device *pdev)
{
        struct power_supply_config psy_cfg = {};
        struct ds2781_device_info *dev_info;

        dev_info = devm_kzalloc(&pdev->dev, sizeof(*dev_info), GFP_KERNEL);
        if (!dev_info)
                return -ENOMEM;

        platform_set_drvdata(pdev, dev_info);

        dev_info->dev                   = &pdev->dev;
        dev_info->w1_dev                = pdev->dev.parent;
        dev_info->bat_desc.name         = dev_name(&pdev->dev);
        dev_info->bat_desc.type         = POWER_SUPPLY_TYPE_BATTERY;
        dev_info->bat_desc.properties   = ds2781_battery_props;
        dev_info->bat_desc.num_properties = ARRAY_SIZE(ds2781_battery_props);
        dev_info->bat_desc.get_property = ds2781_battery_get_property;

        psy_cfg.drv_data                = dev_info;
        psy_cfg.attr_grp                = ds2781_sysfs_groups;

        dev_info->bat = devm_power_supply_register(&pdev->dev,
                                                   &dev_info->bat_desc,
                                                   &psy_cfg);
        if (IS_ERR(dev_info->bat)) {
                dev_err(dev_info->dev, "failed to register battery\n");
                return PTR_ERR(dev_info->bat);
        }

        return 0;
}

static struct platform_driver ds2781_battery_driver = {
        .driver = {
                .name = "ds2781-battery",
        },
        .probe    = ds2781_battery_probe,
};
module_platform_driver(ds2781_battery_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Renata Sayakhova <renata@oktetlabs.ru>");
MODULE_DESCRIPTION("Maxim/Dallas DS2781 Stand-Alone Fuel Gauge IC driver");
MODULE_ALIAS("platform:ds2781-battery");