ds2781_battery.c

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/*
 * 1-wire client/driver for the Maxim/Dallas DS2781 Stand-Alone Fuel Gauge IC
 *
 * Author: Renata Sayakhova <[email protected]>
 *
 * Based on ds2780_battery drivers
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#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 "../w1/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 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 container_of(psy, struct ds2781_device_info, bat);
}

static inline struct power_supply *to_power_supply(struct device *dev)
{
    return dev_get_drvdata(dev);
}

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);

    count = min_t(loff_t, count, DS2781_PARAM_EEPROM_SIZE - off);

    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;

    count = min_t(loff_t, count, DS2781_PARAM_EEPROM_SIZE - off);

    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);

    count = min_t(loff_t, count, DS2781_USER_EEPROM_SIZE - off);

    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;

    count = min_t(loff_t, count, DS2781_USER_EEPROM_SIZE - off);

    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_attributes[] = {
    &dev_attr_pmod_enabled.attr,
    &dev_attr_sense_resistor_value.attr,
    &dev_attr_rsgain_setting.attr,
    &dev_attr_pio_pin.attr,
    NULL
};

static const struct attribute_group ds2781_attr_group = {
    .attrs = ds2781_attributes,
};

static int __devinit ds2781_battery_probe(struct platform_device *pdev)
{
    int ret = 0;
    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.name      = dev_name(&pdev->dev);
    dev_info->bat.type      = POWER_SUPPLY_TYPE_BATTERY;
    dev_info->bat.properties    = ds2781_battery_props;
    dev_info->bat.num_properties    = ARRAY_SIZE(ds2781_battery_props);
    dev_info->bat.get_property  = ds2781_battery_get_property;

    ret = power_supply_register(&pdev->dev, &dev_info->bat);
    if (ret) {
        dev_err(dev_info->dev, "failed to register battery\n");
        goto fail;
    }

    ret = sysfs_create_group(&dev_info->bat.dev->kobj, &ds2781_attr_group);
    if (ret) {
        dev_err(dev_info->dev, "failed to create sysfs group\n");
        goto fail_unregister;
    }

    ret = sysfs_create_bin_file(&dev_info->bat.dev->kobj,
                    &ds2781_param_eeprom_bin_attr);
    if (ret) {
        dev_err(dev_info->dev,
                "failed to create param eeprom bin file");
        goto fail_remove_group;
    }

    ret = sysfs_create_bin_file(&dev_info->bat.dev->kobj,
                    &ds2781_user_eeprom_bin_attr);
    if (ret) {
        dev_err(dev_info->dev,
                "failed to create user eeprom bin file");
        goto fail_remove_bin_file;
    }

    return 0;

fail_remove_bin_file:
    sysfs_remove_bin_file(&dev_info->bat.dev->kobj,
                &ds2781_param_eeprom_bin_attr);
fail_remove_group:
    sysfs_remove_group(&dev_info->bat.dev->kobj, &ds2781_attr_group);
fail_unregister:
    power_supply_unregister(&dev_info->bat);
fail:
    return ret;
}

static int __devexit ds2781_battery_remove(struct platform_device *pdev)
{
    struct ds2781_device_info *dev_info = platform_get_drvdata(pdev);

    /* remove attributes */
    sysfs_remove_group(&dev_info->bat.dev->kobj, &ds2781_attr_group);

    power_supply_unregister(&dev_info->bat);

    return 0;
}

static struct platform_driver ds2781_battery_driver = {
    .driver = {
        .name = "ds2781-battery",
    },
    .probe    = ds2781_battery_probe,
    .remove   = __devexit_p(ds2781_battery_remove),
};
module_platform_driver(ds2781_battery_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Renata Sayakhova <[email protected]>");
MODULE_DESCRIPTION("Maxim/Dallas DS2781 Stand-Alone Fuel Gauage IC driver");
MODULE_ALIAS("platform:ds2781-battery");