bq27x00_battery.c

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/*
 * BQ27x00 battery driver
 *
 * Copyright (C) 2008 Rodolfo Giometti <[email protected]>
 * Copyright (C) 2008 Eurotech S.p.A. <[email protected]>
 * Copyright (C) 2010-2011 Lars-Peter Clausen <[email protected]>
 * Copyright (C) 2011 Pali Rohár <[email protected]>
 *
 * Based on a previous work by Copyright (C) 2008 Texas Instruments, Inc.
 *
 * This package 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.
 *
 * THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 */

/*
 * Datasheets:
 * http://focus.ti.com/docs/prod/folders/print/bq27000.html
 * http://focus.ti.com/docs/prod/folders/print/bq27500.html
 * http://www.ti.com/product/bq27425-g1
 */

#include <linux/module.h>
#include <linux/param.h>
#include <linux/jiffies.h>
#include <linux/workqueue.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/idr.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <asm/unaligned.h>

#include <linux/power/bq27x00_battery.h>

#define DRIVER_VERSION          "1.2.0"

#define BQ27x00_REG_TEMP        0x06
#define BQ27x00_REG_VOLT        0x08
#define BQ27x00_REG_AI          0x14
#define BQ27x00_REG_FLAGS       0x0A
#define BQ27x00_REG_TTE         0x16
#define BQ27x00_REG_TTF         0x18
#define BQ27x00_REG_TTECP       0x26
#define BQ27x00_REG_NAC         0x0C /* Nominal available capacity */
#define BQ27x00_REG_LMD         0x12 /* Last measured discharge */
#define BQ27x00_REG_CYCT        0x2A /* Cycle count total */
#define BQ27x00_REG_AE          0x22 /* Available energy */
#define BQ27x00_POWER_AVG       0x24

#define BQ27000_REG_RSOC        0x0B /* Relative State-of-Charge */
#define BQ27000_REG_ILMD        0x76 /* Initial last measured discharge */
#define BQ27000_FLAG_EDVF       BIT(0) /* Final End-of-Discharge-Voltage flag */
#define BQ27000_FLAG_EDV1       BIT(1) /* First End-of-Discharge-Voltage flag */
#define BQ27000_FLAG_CI         BIT(4) /* Capacity Inaccurate flag */
#define BQ27000_FLAG_FC         BIT(5)
#define BQ27000_FLAG_CHGS       BIT(7) /* Charge state flag */

#define BQ27500_REG_SOC         0x2C
#define BQ27500_REG_DCAP        0x3C /* Design capacity */
#define BQ27500_FLAG_DSC        BIT(0)
#define BQ27500_FLAG_SOCF       BIT(1) /* State-of-Charge threshold final */
#define BQ27500_FLAG_SOC1       BIT(2) /* State-of-Charge threshold 1 */
#define BQ27500_FLAG_FC         BIT(9)
#define BQ27500_FLAG_OTC        BIT(15)

/* bq27425 register addresses are same as bq27x00 addresses minus 4 */
#define BQ27425_REG_OFFSET      0x04
#define BQ27425_REG_SOC         0x18 /* Register address plus offset */

#define BQ27000_RS          20 /* Resistor sense */
#define BQ27x00_POWER_CONSTANT      (256 * 29200 / 1000)

struct bq27x00_device_info;
struct bq27x00_access_methods {
    int (*read)(struct bq27x00_device_info *di, u8 reg, bool single);
};

enum bq27x00_chip { BQ27000, BQ27500, BQ27425};

struct bq27x00_reg_cache {
    int temperature;
    int time_to_empty;
    int time_to_empty_avg;
    int time_to_full;
    int charge_full;
    int cycle_count;
    int capacity;
    int energy;
    int flags;
    int power_avg;
    int health;
};

struct bq27x00_device_info {
    struct device       *dev;
    int         id;
    enum bq27x00_chip   chip;

    struct bq27x00_reg_cache cache;
    int charge_design_full;

    unsigned long last_update;
    struct delayed_work work;

    struct power_supply bat;

    struct bq27x00_access_methods bus;

    struct mutex lock;
};

static enum power_supply_property bq27x00_battery_props[] = {
    POWER_SUPPLY_PROP_STATUS,
    POWER_SUPPLY_PROP_PRESENT,
    POWER_SUPPLY_PROP_VOLTAGE_NOW,
    POWER_SUPPLY_PROP_CURRENT_NOW,
    POWER_SUPPLY_PROP_CAPACITY,
    POWER_SUPPLY_PROP_CAPACITY_LEVEL,
    POWER_SUPPLY_PROP_TEMP,
    POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
    POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
    POWER_SUPPLY_PROP_TIME_TO_FULL_NOW,
    POWER_SUPPLY_PROP_TECHNOLOGY,
    POWER_SUPPLY_PROP_CHARGE_FULL,
    POWER_SUPPLY_PROP_CHARGE_NOW,
    POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
    POWER_SUPPLY_PROP_CYCLE_COUNT,
    POWER_SUPPLY_PROP_ENERGY_NOW,
    POWER_SUPPLY_PROP_POWER_AVG,
    POWER_SUPPLY_PROP_HEALTH,
};

static enum power_supply_property bq27425_battery_props[] = {
    POWER_SUPPLY_PROP_STATUS,
    POWER_SUPPLY_PROP_PRESENT,
    POWER_SUPPLY_PROP_VOLTAGE_NOW,
    POWER_SUPPLY_PROP_CURRENT_NOW,
    POWER_SUPPLY_PROP_CAPACITY,
    POWER_SUPPLY_PROP_CAPACITY_LEVEL,
    POWER_SUPPLY_PROP_TEMP,
    POWER_SUPPLY_PROP_TECHNOLOGY,
    POWER_SUPPLY_PROP_CHARGE_FULL,
    POWER_SUPPLY_PROP_CHARGE_NOW,
    POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
};

static unsigned int poll_interval = 360;
module_param(poll_interval, uint, 0644);
MODULE_PARM_DESC(poll_interval, "battery poll interval in seconds - " \
                "0 disables polling");

/*
 * Common code for BQ27x00 devices
 */

static inline int bq27x00_read(struct bq27x00_device_info *di, u8 reg,
        bool single)
{
    if (di->chip == BQ27425)
        return di->bus.read(di, reg - BQ27425_REG_OFFSET, single);
    return di->bus.read(di, reg, single);
}

/*
 * Higher versions of the chip like BQ27425 and BQ27500
 * differ from BQ27000 and BQ27200 in calculation of certain
 * parameters. Hence we need to check for the chip type.
 */
static bool bq27xxx_is_chip_version_higher(struct bq27x00_device_info *di)
{
    if (di->chip == BQ27425 || di->chip == BQ27500)
        return true;
    return false;
}

/*
 * Return the battery Relative State-of-Charge
 * Or < 0 if something fails.
 */
static int bq27x00_battery_read_rsoc(struct bq27x00_device_info *di)
{
    int rsoc;

    if (di->chip == BQ27500)
        rsoc = bq27x00_read(di, BQ27500_REG_SOC, false);
    else if (di->chip == BQ27425)
        rsoc = bq27x00_read(di, BQ27425_REG_SOC, false);
    else
        rsoc = bq27x00_read(di, BQ27000_REG_RSOC, true);

    if (rsoc < 0)
        dev_dbg(di->dev, "error reading relative State-of-Charge\n");

    return rsoc;
}

/*
 * Return a battery charge value in µAh
 * Or < 0 if something fails.
 */
static int bq27x00_battery_read_charge(struct bq27x00_device_info *di, u8 reg)
{
    int charge;

    charge = bq27x00_read(di, reg, false);
    if (charge < 0) {
        dev_dbg(di->dev, "error reading charge register %02x: %d\n",
            reg, charge);
        return charge;
    }

    if (bq27xxx_is_chip_version_higher(di))
        charge *= 1000;
    else
        charge = charge * 3570 / BQ27000_RS;

    return charge;
}

/*
 * Return the battery Nominal available capaciy in µAh
 * Or < 0 if something fails.
 */
static inline int bq27x00_battery_read_nac(struct bq27x00_device_info *di)
{
    return bq27x00_battery_read_charge(di, BQ27x00_REG_NAC);
}

/*
 * Return the battery Last measured discharge in µAh
 * Or < 0 if something fails.
 */
static inline int bq27x00_battery_read_lmd(struct bq27x00_device_info *di)
{
    return bq27x00_battery_read_charge(di, BQ27x00_REG_LMD);
}

/*
 * Return the battery Initial last measured discharge in µAh
 * Or < 0 if something fails.
 */
static int bq27x00_battery_read_ilmd(struct bq27x00_device_info *di)
{
    int ilmd;

    if (bq27xxx_is_chip_version_higher(di))
        ilmd = bq27x00_read(di, BQ27500_REG_DCAP, false);
    else
        ilmd = bq27x00_read(di, BQ27000_REG_ILMD, true);

    if (ilmd < 0) {
        dev_dbg(di->dev, "error reading initial last measured discharge\n");
        return ilmd;
    }

    if (bq27xxx_is_chip_version_higher(di))
        ilmd *= 1000;
    else
        ilmd = ilmd * 256 * 3570 / BQ27000_RS;

    return ilmd;
}

/*
 * Return the battery Available energy in µWh
 * Or < 0 if something fails.
 */
static int bq27x00_battery_read_energy(struct bq27x00_device_info *di)
{
    int ae;

    ae = bq27x00_read(di, BQ27x00_REG_AE, false);
    if (ae < 0) {
        dev_dbg(di->dev, "error reading available energy\n");
        return ae;
    }

    if (di->chip == BQ27500)
        ae *= 1000;
    else
        ae = ae * 29200 / BQ27000_RS;

    return ae;
}

/*
 * Return the battery temperature in tenths of degree Celsius
 * Or < 0 if something fails.
 */
static int bq27x00_battery_read_temperature(struct bq27x00_device_info *di)
{
    int temp;

    temp = bq27x00_read(di, BQ27x00_REG_TEMP, false);
    if (temp < 0) {
        dev_err(di->dev, "error reading temperature\n");
        return temp;
    }

    if (bq27xxx_is_chip_version_higher(di))
        temp -= 2731;
    else
        temp = ((temp * 5) - 5463) / 2;

    return temp;
}

/*
 * Return the battery Cycle count total
 * Or < 0 if something fails.
 */
static int bq27x00_battery_read_cyct(struct bq27x00_device_info *di)
{
    int cyct;

    cyct = bq27x00_read(di, BQ27x00_REG_CYCT, false);
    if (cyct < 0)
        dev_err(di->dev, "error reading cycle count total\n");

    return cyct;
}

/*
 * Read a time register.
 * Return < 0 if something fails.
 */
static int bq27x00_battery_read_time(struct bq27x00_device_info *di, u8 reg)
{
    int tval;

    tval = bq27x00_read(di, reg, false);
    if (tval < 0) {
        dev_dbg(di->dev, "error reading time register %02x: %d\n",
            reg, tval);
        return tval;
    }

    if (tval == 65535)
        return -ENODATA;

    return tval * 60;
}

/*
 * Read a power avg register.
 * Return < 0 if something fails.
 */
static int bq27x00_battery_read_pwr_avg(struct bq27x00_device_info *di, u8 reg)
{
    int tval;

    tval = bq27x00_read(di, reg, false);
    if (tval < 0) {
        dev_err(di->dev, "error reading power avg rgister  %02x: %d\n",
            reg, tval);
        return tval;
    }

    if (di->chip == BQ27500)
        return tval;
    else
        return (tval * BQ27x00_POWER_CONSTANT) / BQ27000_RS;
}

/*
 * Read flag register.
 * Return < 0 if something fails.
 */
static int bq27x00_battery_read_health(struct bq27x00_device_info *di)
{
    int tval;

    tval = bq27x00_read(di, BQ27x00_REG_FLAGS, false);
    if (tval < 0) {
        dev_err(di->dev, "error reading flag register:%d\n", tval);
        return tval;
    }

    if ((di->chip == BQ27500)) {
        if (tval & BQ27500_FLAG_SOCF)
            tval = POWER_SUPPLY_HEALTH_DEAD;
        else if (tval & BQ27500_FLAG_OTC)
            tval = POWER_SUPPLY_HEALTH_OVERHEAT;
        else
            tval = POWER_SUPPLY_HEALTH_GOOD;
        return tval;
    } else {
        if (tval & BQ27000_FLAG_EDV1)
            tval = POWER_SUPPLY_HEALTH_DEAD;
        else
            tval = POWER_SUPPLY_HEALTH_GOOD;
        return tval;
    }

    return -1;
}

static void bq27x00_update(struct bq27x00_device_info *di)
{
    struct bq27x00_reg_cache cache = {0, };
    bool is_bq27500 = di->chip == BQ27500;
    bool is_bq27425 = di->chip == BQ27425;

    cache.flags = bq27x00_read(di, BQ27x00_REG_FLAGS, !is_bq27500);
    if (cache.flags >= 0) {
        if (!is_bq27500 && !is_bq27425
                && (cache.flags & BQ27000_FLAG_CI)) {
            dev_info(di->dev, "battery is not calibrated! ignoring capacity values\n");
            cache.capacity = -ENODATA;
            cache.energy = -ENODATA;
            cache.time_to_empty = -ENODATA;
            cache.time_to_empty_avg = -ENODATA;
            cache.time_to_full = -ENODATA;
            cache.charge_full = -ENODATA;
            cache.health = -ENODATA;
        } else {
            cache.capacity = bq27x00_battery_read_rsoc(di);
            if (!is_bq27425) {
                cache.energy = bq27x00_battery_read_energy(di);
                cache.time_to_empty =
                    bq27x00_battery_read_time(di,
                            BQ27x00_REG_TTE);
                cache.time_to_empty_avg =
                    bq27x00_battery_read_time(di,
                            BQ27x00_REG_TTECP);
                cache.time_to_full =
                    bq27x00_battery_read_time(di,
                            BQ27x00_REG_TTF);
            }
            cache.charge_full = bq27x00_battery_read_lmd(di);
            cache.health = bq27x00_battery_read_health(di);
        }
        cache.temperature = bq27x00_battery_read_temperature(di);
        if (!is_bq27425)
            cache.cycle_count = bq27x00_battery_read_cyct(di);
        cache.cycle_count = bq27x00_battery_read_cyct(di);
        cache.power_avg =
            bq27x00_battery_read_pwr_avg(di, BQ27x00_POWER_AVG);

        /* We only have to read charge design full once */
        if (di->charge_design_full <= 0)
            di->charge_design_full = bq27x00_battery_read_ilmd(di);
    }

    if (memcmp(&di->cache, &cache, sizeof(cache)) != 0) {
        di->cache = cache;
        power_supply_changed(&di->bat);
    }

    di->last_update = jiffies;
}

static void bq27x00_battery_poll(struct work_struct *work)
{
    struct bq27x00_device_info *di =
        container_of(work, struct bq27x00_device_info, work.work);

    bq27x00_update(di);

    if (poll_interval > 0) {
        /* The timer does not have to be accurate. */
        set_timer_slack(&di->work.timer, poll_interval * HZ / 4);
        schedule_delayed_work(&di->work, poll_interval * HZ);
    }
}

/*
 * Return the battery average current in µA
 * Note that current can be negative signed as well
 * Or 0 if something fails.
 */
static int bq27x00_battery_current(struct bq27x00_device_info *di,
    union power_supply_propval *val)
{
    int curr;
    int flags;

    curr = bq27x00_read(di, BQ27x00_REG_AI, false);
    if (curr < 0) {
        dev_err(di->dev, "error reading current\n");
        return curr;
    }

    if (bq27xxx_is_chip_version_higher(di)) {
        /* bq27500 returns signed value */
        val->intval = (int)((s16)curr) * 1000;
    } else {
        flags = bq27x00_read(di, BQ27x00_REG_FLAGS, false);
        if (flags & BQ27000_FLAG_CHGS) {
            dev_dbg(di->dev, "negative current!\n");
            curr = -curr;
        }

        val->intval = curr * 3570 / BQ27000_RS;
    }

    return 0;
}

static int bq27x00_battery_status(struct bq27x00_device_info *di,
    union power_supply_propval *val)
{
    int status;

    if (bq27xxx_is_chip_version_higher(di)) {
        if (di->cache.flags & BQ27500_FLAG_FC)
            status = POWER_SUPPLY_STATUS_FULL;
        else if (di->cache.flags & BQ27500_FLAG_DSC)
            status = POWER_SUPPLY_STATUS_DISCHARGING;
        else
            status = POWER_SUPPLY_STATUS_CHARGING;
    } else {
        if (di->cache.flags & BQ27000_FLAG_FC)
            status = POWER_SUPPLY_STATUS_FULL;
        else if (di->cache.flags & BQ27000_FLAG_CHGS)
            status = POWER_SUPPLY_STATUS_CHARGING;
        else if (power_supply_am_i_supplied(&di->bat))
            status = POWER_SUPPLY_STATUS_NOT_CHARGING;
        else
            status = POWER_SUPPLY_STATUS_DISCHARGING;
    }

    val->intval = status;

    return 0;
}

static int bq27x00_battery_capacity_level(struct bq27x00_device_info *di,
    union power_supply_propval *val)
{
    int level;

    if (bq27xxx_is_chip_version_higher(di)) {
        if (di->cache.flags & BQ27500_FLAG_FC)
            level = POWER_SUPPLY_CAPACITY_LEVEL_FULL;
        else if (di->cache.flags & BQ27500_FLAG_SOC1)
            level = POWER_SUPPLY_CAPACITY_LEVEL_LOW;
        else if (di->cache.flags & BQ27500_FLAG_SOCF)
            level = POWER_SUPPLY_CAPACITY_LEVEL_CRITICAL;
        else
            level = POWER_SUPPLY_CAPACITY_LEVEL_NORMAL;
    } else {
        if (di->cache.flags & BQ27000_FLAG_FC)
            level = POWER_SUPPLY_CAPACITY_LEVEL_FULL;
        else if (di->cache.flags & BQ27000_FLAG_EDV1)
            level = POWER_SUPPLY_CAPACITY_LEVEL_LOW;
        else if (di->cache.flags & BQ27000_FLAG_EDVF)
            level = POWER_SUPPLY_CAPACITY_LEVEL_CRITICAL;
        else
            level = POWER_SUPPLY_CAPACITY_LEVEL_NORMAL;
    }

    val->intval = level;

    return 0;
}

/*
 * Return the battery Voltage in millivolts
 * Or < 0 if something fails.
 */
static int bq27x00_battery_voltage(struct bq27x00_device_info *di,
    union power_supply_propval *val)
{
    int volt;

    volt = bq27x00_read(di, BQ27x00_REG_VOLT, false);
    if (volt < 0) {
        dev_err(di->dev, "error reading voltage\n");
        return volt;
    }

    val->intval = volt * 1000;

    return 0;
}

static int bq27x00_simple_value(int value,
    union power_supply_propval *val)
{
    if (value < 0)
        return value;

    val->intval = value;

    return 0;
}

#define to_bq27x00_device_info(x) container_of((x), \
                struct bq27x00_device_info, bat);

static int bq27x00_battery_get_property(struct power_supply *psy,
                    enum power_supply_property psp,
                    union power_supply_propval *val)
{
    int ret = 0;
    struct bq27x00_device_info *di = to_bq27x00_device_info(psy);

    mutex_lock(&di->lock);
    if (time_is_before_jiffies(di->last_update + 5 * HZ)) {
        cancel_delayed_work_sync(&di->work);
        bq27x00_battery_poll(&di->work.work);
    }
    mutex_unlock(&di->lock);

    if (psp != POWER_SUPPLY_PROP_PRESENT && di->cache.flags < 0)
        return -ENODEV;

    switch (psp) {
    case POWER_SUPPLY_PROP_STATUS:
        ret = bq27x00_battery_status(di, val);
        break;
    case POWER_SUPPLY_PROP_VOLTAGE_NOW:
        ret = bq27x00_battery_voltage(di, val);
        break;
    case POWER_SUPPLY_PROP_PRESENT:
        val->intval = di->cache.flags < 0 ? 0 : 1;
        break;
    case POWER_SUPPLY_PROP_CURRENT_NOW:
        ret = bq27x00_battery_current(di, val);
        break;
    case POWER_SUPPLY_PROP_CAPACITY:
        ret = bq27x00_simple_value(di->cache.capacity, val);
        break;
    case POWER_SUPPLY_PROP_CAPACITY_LEVEL:
        ret = bq27x00_battery_capacity_level(di, val);
        break;
    case POWER_SUPPLY_PROP_TEMP:
        ret = bq27x00_simple_value(di->cache.temperature, val);
        break;
    case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW:
        ret = bq27x00_simple_value(di->cache.time_to_empty, val);
        break;
    case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
        ret = bq27x00_simple_value(di->cache.time_to_empty_avg, val);
        break;
    case POWER_SUPPLY_PROP_TIME_TO_FULL_NOW:
        ret = bq27x00_simple_value(di->cache.time_to_full, val);
        break;
    case POWER_SUPPLY_PROP_TECHNOLOGY:
        val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
        break;
    case POWER_SUPPLY_PROP_CHARGE_NOW:
        ret = bq27x00_simple_value(bq27x00_battery_read_nac(di), val);
        break;
    case POWER_SUPPLY_PROP_CHARGE_FULL:
        ret = bq27x00_simple_value(di->cache.charge_full, val);
        break;
    case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
        ret = bq27x00_simple_value(di->charge_design_full, val);
        break;
    case POWER_SUPPLY_PROP_CYCLE_COUNT:
        ret = bq27x00_simple_value(di->cache.cycle_count, val);
        break;
    case POWER_SUPPLY_PROP_ENERGY_NOW:
        ret = bq27x00_simple_value(di->cache.energy, val);
        break;
    case POWER_SUPPLY_PROP_POWER_AVG:
        ret = bq27x00_simple_value(di->cache.power_avg, val);
        break;
    case POWER_SUPPLY_PROP_HEALTH:
        ret = bq27x00_simple_value(di->cache.health, val);
        break;
    default:
        return -EINVAL;
    }

    return ret;
}

static void bq27x00_external_power_changed(struct power_supply *psy)
{
    struct bq27x00_device_info *di = to_bq27x00_device_info(psy);

    cancel_delayed_work_sync(&di->work);
    schedule_delayed_work(&di->work, 0);
}

static int bq27x00_powersupply_init(struct bq27x00_device_info *di)
{
    int ret;

    di->bat.type = POWER_SUPPLY_TYPE_BATTERY;
    di->chip = BQ27425;
    if (di->chip == BQ27425) {
        di->bat.properties = bq27425_battery_props;
        di->bat.num_properties = ARRAY_SIZE(bq27425_battery_props);
    } else {
        di->bat.properties = bq27x00_battery_props;
        di->bat.num_properties = ARRAY_SIZE(bq27x00_battery_props);
    }
    di->bat.get_property = bq27x00_battery_get_property;
    di->bat.external_power_changed = bq27x00_external_power_changed;

    INIT_DELAYED_WORK(&di->work, bq27x00_battery_poll);
    mutex_init(&di->lock);

    ret = power_supply_register(di->dev, &di->bat);
    if (ret) {
        dev_err(di->dev, "failed to register battery: %d\n", ret);
        return ret;
    }

    dev_info(di->dev, "support ver. %s enabled\n", DRIVER_VERSION);

    bq27x00_update(di);

    return 0;
}

static void bq27x00_powersupply_unregister(struct bq27x00_device_info *di)
{
    /*
     * power_supply_unregister call bq27x00_battery_get_property which
     * call bq27x00_battery_poll.
     * Make sure that bq27x00_battery_poll will not call
     * schedule_delayed_work again after unregister (which cause OOPS).
     */
    poll_interval = 0;

    cancel_delayed_work_sync(&di->work);

    power_supply_unregister(&di->bat);

    mutex_destroy(&di->lock);
}


/* i2c specific code */
#ifdef CONFIG_BATTERY_BQ27X00_I2C

/* If the system has several batteries we need a different name for each
 * of them...
 */
static DEFINE_IDR(battery_id);
static DEFINE_MUTEX(battery_mutex);

static int bq27x00_read_i2c(struct bq27x00_device_info *di, u8 reg, bool single)
{
    struct i2c_client *client = to_i2c_client(di->dev);
    struct i2c_msg msg[2];
    unsigned char data[2];
    int ret;

    if (!client->adapter)
        return -ENODEV;

    msg[0].addr = client->addr;
    msg[0].flags = 0;
    msg[0].buf = &reg;
    msg[0].len = sizeof(reg);
    msg[1].addr = client->addr;
    msg[1].flags = I2C_M_RD;
    msg[1].buf = data;
    if (single)
        msg[1].len = 1;
    else
        msg[1].len = 2;

    ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
    if (ret < 0)
        return ret;

    if (!single)
        ret = get_unaligned_le16(data);
    else
        ret = data[0];

    return ret;
}

static int bq27x00_battery_probe(struct i2c_client *client,
                 const struct i2c_device_id *id)
{
    char *name;
    struct bq27x00_device_info *di;
    int num;
    int retval = 0;

    /* Get new ID for the new battery device */
    retval = idr_pre_get(&battery_id, GFP_KERNEL);
    if (retval == 0)
        return -ENOMEM;
    mutex_lock(&battery_mutex);
    retval = idr_get_new(&battery_id, client, &num);
    mutex_unlock(&battery_mutex);
    if (retval < 0)
        return retval;

    name = kasprintf(GFP_KERNEL, "%s-%d", id->name, num);
    if (!name) {
        dev_err(&client->dev, "failed to allocate device name\n");
        retval = -ENOMEM;
        goto batt_failed_1;
    }

    di = kzalloc(sizeof(*di), GFP_KERNEL);
    if (!di) {
        dev_err(&client->dev, "failed to allocate device info data\n");
        retval = -ENOMEM;
        goto batt_failed_2;
    }

    di->id = num;
    di->dev = &client->dev;
    di->chip = id->driver_data;
    di->bat.name = name;
    di->bus.read = &bq27x00_read_i2c;

    retval = bq27x00_powersupply_init(di);
    if (retval)
        goto batt_failed_3;

    i2c_set_clientdata(client, di);

    return 0;

batt_failed_3:
    kfree(di);
batt_failed_2:
    kfree(name);
batt_failed_1:
    mutex_lock(&battery_mutex);
    idr_remove(&battery_id, num);
    mutex_unlock(&battery_mutex);

    return retval;
}

static int bq27x00_battery_remove(struct i2c_client *client)
{
    struct bq27x00_device_info *di = i2c_get_clientdata(client);

    bq27x00_powersupply_unregister(di);

    kfree(di->bat.name);

    mutex_lock(&battery_mutex);
    idr_remove(&battery_id, di->id);
    mutex_unlock(&battery_mutex);

    kfree(di);

    return 0;
}

static const struct i2c_device_id bq27x00_id[] = {
    { "bq27200", BQ27000 }, /* bq27200 is same as bq27000, but with i2c */
    { "bq27500", BQ27500 },
    { "bq27425", BQ27425 },
    {},
};
MODULE_DEVICE_TABLE(i2c, bq27x00_id);

static struct i2c_driver bq27x00_battery_driver = {
    .driver = {
        .name = "bq27x00-battery",
    },
    .probe = bq27x00_battery_probe,
    .remove = bq27x00_battery_remove,
    .id_table = bq27x00_id,
};

static inline int bq27x00_battery_i2c_init(void)
{
    int ret = i2c_add_driver(&bq27x00_battery_driver);
    if (ret)
        printk(KERN_ERR "Unable to register BQ27x00 i2c driver\n");

    return ret;
}

static inline void bq27x00_battery_i2c_exit(void)
{
    i2c_del_driver(&bq27x00_battery_driver);
}

#else

static inline int bq27x00_battery_i2c_init(void) { return 0; }
static inline void bq27x00_battery_i2c_exit(void) {};

#endif

/* platform specific code */
#ifdef CONFIG_BATTERY_BQ27X00_PLATFORM

static int bq27000_read_platform(struct bq27x00_device_info *di, u8 reg,
            bool single)
{
    struct device *dev = di->dev;
    struct bq27000_platform_data *pdata = dev->platform_data;
    unsigned int timeout = 3;
    int upper, lower;
    int temp;

    if (!single) {
        /* Make sure the value has not changed in between reading the
         * lower and the upper part */
        upper = pdata->read(dev, reg + 1);
        do {
            temp = upper;
            if (upper < 0)
                return upper;

            lower = pdata->read(dev, reg);
            if (lower < 0)
                return lower;

            upper = pdata->read(dev, reg + 1);
        } while (temp != upper && --timeout);

        if (timeout == 0)
            return -EIO;

        return (upper << 8) | lower;
    }

    return pdata->read(dev, reg);
}

static int __devinit bq27000_battery_probe(struct platform_device *pdev)
{
    struct bq27x00_device_info *di;
    struct bq27000_platform_data *pdata = pdev->dev.platform_data;
    int ret;

    if (!pdata) {
        dev_err(&pdev->dev, "no platform_data supplied\n");
        return -EINVAL;
    }

    if (!pdata->read) {
        dev_err(&pdev->dev, "no hdq read callback supplied\n");
        return -EINVAL;
    }

    di = kzalloc(sizeof(*di), GFP_KERNEL);
    if (!di) {
        dev_err(&pdev->dev, "failed to allocate device info data\n");
        return -ENOMEM;
    }

    platform_set_drvdata(pdev, di);

    di->dev = &pdev->dev;
    di->chip = BQ27000;

    di->bat.name = pdata->name ?: dev_name(&pdev->dev);
    di->bus.read = &bq27000_read_platform;

    ret = bq27x00_powersupply_init(di);
    if (ret)
        goto err_free;

    return 0;

err_free:
    platform_set_drvdata(pdev, NULL);
    kfree(di);

    return ret;
}

static int __devexit bq27000_battery_remove(struct platform_device *pdev)
{
    struct bq27x00_device_info *di = platform_get_drvdata(pdev);

    bq27x00_powersupply_unregister(di);

    platform_set_drvdata(pdev, NULL);
    kfree(di);

    return 0;
}

static struct platform_driver bq27000_battery_driver = {
    .probe  = bq27000_battery_probe,
    .remove = __devexit_p(bq27000_battery_remove),
    .driver = {
        .name = "bq27000-battery",
        .owner = THIS_MODULE,
    },
};

static inline int bq27x00_battery_platform_init(void)
{
    int ret = platform_driver_register(&bq27000_battery_driver);
    if (ret)
        printk(KERN_ERR "Unable to register BQ27000 platform driver\n");

    return ret;
}

static inline void bq27x00_battery_platform_exit(void)
{
    platform_driver_unregister(&bq27000_battery_driver);
}

#else

static inline int bq27x00_battery_platform_init(void) { return 0; }
static inline void bq27x00_battery_platform_exit(void) {};

#endif

/*
 * Module stuff
 */

static int __init bq27x00_battery_init(void)
{
    int ret;

    ret = bq27x00_battery_i2c_init();
    if (ret)
        return ret;

    ret = bq27x00_battery_platform_init();
    if (ret)
        bq27x00_battery_i2c_exit();

    return ret;
}
module_init(bq27x00_battery_init);

static void __exit bq27x00_battery_exit(void)
{
    bq27x00_battery_platform_exit();
    bq27x00_battery_i2c_exit();
}
module_exit(bq27x00_battery_exit);

MODULE_AUTHOR("Rodolfo Giometti <[email protected]>");
MODULE_DESCRIPTION("BQ27x00 battery monitor driver");
MODULE_LICENSE("GPL");