drivers/power/bq27x00_battery.c - kernel/msm-4.9 - Gitiles

 /*
  * BQ27x00 battery driver
  *
  * Copyright (C) 2008 Rodolfo Giometti <giometti@linux.it>
  * Copyright (C) 2008 Eurotech S.p.A. <info@eurotech.it>
  * Copyright (C) 2010-2011 Lars-Peter Clausen <lars@metafoo.de>
  *
  * 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
  */

 #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 capaciy */
 #define BQ27x00_REG_LMD			0x12 /* Last measured discharge */
 #define BQ27x00_REG_CYCT		0x2A /* Cycle count total */
 #define BQ27x00_REG_AE			0x22 /* Available enery */

 #define BQ27000_REG_RSOC		0x0B /* Relative State-of-Charge */
 #define BQ27000_REG_ILMD		0x76 /* Initial last measured discharge */
 #define BQ27000_FLAG_CHGS		BIT(7)
 #define BQ27000_FLAG_FC			BIT(5)

 #define BQ27500_REG_SOC			0x2C
 #define BQ27500_REG_DCAP		0x3C /* Design capacity */
 #define BQ27500_FLAG_DSC		BIT(0)
 #define BQ27500_FLAG_FC			BIT(9)

 #define BQ27000_RS			20 /* Resistor sense */

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

 enum bq27x00_chip { BQ27000, BQ27500 };

 struct bq27x00_reg_cache {
 	int temperature;
 	int time_to_empty;
 	int time_to_empty_avg;
 	int time_to_full;
 	int charge_full;
 	int charge_counter;
 	int capacity;
 	int flags;

 	int current_now;
 };

 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_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_CHARGE_COUNTER,
 	POWER_SUPPLY_PROP_ENERGY_NOW,
 };

 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)
 {
 	return di->bus.read(di, reg, single);
 }

 /*
  * 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
 		rsoc = bq27x00_read(di, BQ27000_REG_RSOC, true);

 	if (rsoc < 0)
 		dev_err(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_err(di->dev, "error reading nominal available capacity\n");
 		return charge;
 	}

 	if (di->chip == BQ27500)
 		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 (di->chip == BQ27500)
 		ilmd = bq27x00_read(di, BQ27500_REG_DCAP, false);
 	else
 		ilmd = bq27x00_read(di, BQ27000_REG_ILMD, true);

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

 	if (di->chip == BQ27500)
 		ilmd *= 1000;
 	else
 		ilmd = ilmd * 256 * 3570 / BQ27000_RS;

 	return ilmd;
 }

 /*
  * 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_err(di->dev, "error reading register %02x: %d\n", reg, tval);
 		return tval;
 	}

 	if (tval == 65535)
 		return -ENODATA;

 	return tval * 60;
 }

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

 	cache.flags = bq27x00_read(di, BQ27x00_REG_FLAGS, is_bq27500);
 	if (cache.flags >= 0) {
 		cache.capacity = bq27x00_battery_read_rsoc(di);
 		cache.temperature = bq27x00_read(di, BQ27x00_REG_TEMP, false);
 		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.charge_counter = bq27x00_battery_read_cyct(di);

 		if (!is_bq27500)
 			cache.current_now = bq27x00_read(di, BQ27x00_REG_AI, false);

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

 	/* Ignore current_now which is a snapshot of the current battery state
 	 * and is likely to be different even between two consecutive reads */
 	if (memcmp(&di->cache, &cache, sizeof(cache) - sizeof(int)) != 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 temperature in tenths of degree Celsius
  * Or < 0 if something fails.
  */
 static int bq27x00_battery_temperature(struct bq27x00_device_info *di,
 	union power_supply_propval *val)
 {
 	if (di->cache.temperature < 0)
 		return di->cache.temperature;

 	if (di->chip == BQ27500)
 		val->intval = di->cache.temperature - 2731;
 	else
 		val->intval = ((di->cache.temperature * 5) - 5463) / 2;

 	return 0;
 }

 /*
  * 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;

 	if (di->chip == BQ27500)
 	    curr = bq27x00_read(di, BQ27x00_REG_AI, false);
 	else
 	    curr = di->cache.current_now;

 	if (curr < 0)
 		return curr;

 	if (di->chip == BQ27500) {
 		/* bq27500 returns signed value */
 		val->intval = (int)((s16)curr) * 1000;
 	} else {
 		if (di->cache.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 (di->chip == BQ27500) {
 		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;
 }

 /*
  * Return the battery Voltage in milivolts
  * 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)
 		return volt;

 	val->intval = volt * 1000;

 	return 0;
 }

 /*
  * Return the battery Available energy in µWh
  * Or < 0 if something fails.
  */
 static int bq27x00_battery_energy(struct bq27x00_device_info *di,
 	union power_supply_propval *val)
 {
 	int ae;

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

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

 	val->intval = ae;

 	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_TEMP:
 		ret = bq27x00_battery_temperature(di, 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_CHARGE_COUNTER:
 		ret = bq27x00_simple_value(di->cache.charge_counter, val);
 		break;
 	case POWER_SUPPLY_PROP_ENERGY_NOW:
 		ret = bq27x00_battery_energy(di, 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->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)
 {
 	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;

 	if (bq27x00_powersupply_init(di))
 		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 },
 	{},
 };
 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 <giometti@linux.it>");
 MODULE_DESCRIPTION("BQ27x00 battery monitor driver");
 MODULE_LICENSE("GPL");
	/*
	* BQ27x00 battery driver
	*
	* Copyright (C) 2008 Rodolfo Giometti <giometti@linux.it>
	* Copyright (C) 2008 Eurotech S.p.A. <info@eurotech.it>
	* Copyright (C) 2010-2011 Lars-Peter Clausen <lars@metafoo.de>
	*
	* 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
	*/

	#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 capaciy */
	#define BQ27x00_REG_LMD 0x12 /* Last measured discharge */
	#define BQ27x00_REG_CYCT 0x2A /* Cycle count total */
	#define BQ27x00_REG_AE 0x22 /* Available enery */

	#define BQ27000_REG_RSOC 0x0B /* Relative State-of-Charge */
	#define BQ27000_REG_ILMD 0x76 /* Initial last measured discharge */
	#define BQ27000_FLAG_CHGS BIT(7)
	#define BQ27000_FLAG_FC BIT(5)

	#define BQ27500_REG_SOC 0x2C
	#define BQ27500_REG_DCAP 0x3C /* Design capacity */
	#define BQ27500_FLAG_DSC BIT(0)
	#define BQ27500_FLAG_FC BIT(9)

	#define BQ27000_RS 20 /* Resistor sense */

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

	enum bq27x00_chip { BQ27000, BQ27500 };

	struct bq27x00_reg_cache {
	int temperature;
	int time_to_empty;
	int time_to_empty_avg;
	int time_to_full;
	int charge_full;
	int charge_counter;
	int capacity;
	int flags;

	int current_now;
	};

	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_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_CHARGE_COUNTER,
	POWER_SUPPLY_PROP_ENERGY_NOW,
	};

	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)
	{
	return di->bus.read(di, reg, single);
	}

	/*
	* 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
	rsoc = bq27x00_read(di, BQ27000_REG_RSOC, true);

	if (rsoc < 0)
	dev_err(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_err(di->dev, "error reading nominal available capacity\n");
	return charge;
	}

	if (di->chip == BQ27500)
	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 (di->chip == BQ27500)
	ilmd = bq27x00_read(di, BQ27500_REG_DCAP, false);
	else
	ilmd = bq27x00_read(di, BQ27000_REG_ILMD, true);

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

	if (di->chip == BQ27500)
	ilmd *= 1000;
	else
	ilmd = ilmd * 256 * 3570 / BQ27000_RS;

	return ilmd;
	}

	/*
	* 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_err(di->dev, "error reading register %02x: %d\n", reg, tval);
	return tval;
	}

	if (tval == 65535)
	return -ENODATA;

	return tval * 60;
	}

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

	cache.flags = bq27x00_read(di, BQ27x00_REG_FLAGS, is_bq27500);
	if (cache.flags >= 0) {
	cache.capacity = bq27x00_battery_read_rsoc(di);
	cache.temperature = bq27x00_read(di, BQ27x00_REG_TEMP, false);
	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.charge_counter = bq27x00_battery_read_cyct(di);

	if (!is_bq27500)
	cache.current_now = bq27x00_read(di, BQ27x00_REG_AI, false);

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

	/* Ignore current_now which is a snapshot of the current battery state
	* and is likely to be different even between two consecutive reads */
	if (memcmp(&di->cache, &cache, sizeof(cache) - sizeof(int)) != 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 temperature in tenths of degree Celsius
	* Or < 0 if something fails.
	*/
	static int bq27x00_battery_temperature(struct bq27x00_device_info *di,
	union power_supply_propval *val)
	{
	if (di->cache.temperature < 0)
	return di->cache.temperature;

	if (di->chip == BQ27500)
	val->intval = di->cache.temperature - 2731;
	else
	val->intval = ((di->cache.temperature * 5) - 5463) / 2;

	return 0;
	}

	/*
	* 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;

	if (di->chip == BQ27500)
	curr = bq27x00_read(di, BQ27x00_REG_AI, false);
	else
	curr = di->cache.current_now;

	if (curr < 0)
	return curr;

	if (di->chip == BQ27500) {
	/* bq27500 returns signed value */
	val->intval = (int)((s16)curr) * 1000;
	} else {
	if (di->cache.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 (di->chip == BQ27500) {
	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;
	}

	/*
	* Return the battery Voltage in milivolts
	* 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)
	return volt;

	val->intval = volt * 1000;

	return 0;
	}

	/*
	* Return the battery Available energy in µWh
	* Or < 0 if something fails.
	*/
	static int bq27x00_battery_energy(struct bq27x00_device_info *di,
	union power_supply_propval *val)
	{
	int ae;

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

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

	val->intval = ae;

	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_TEMP:
	ret = bq27x00_battery_temperature(di, 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_CHARGE_COUNTER:
	ret = bq27x00_simple_value(di->cache.charge_counter, val);
	break;
	case POWER_SUPPLY_PROP_ENERGY_NOW:
	ret = bq27x00_battery_energy(di, 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->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)
	{
	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 = ®
	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;

	if (bq27x00_powersupply_init(di))
	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 },
	{},
	};
	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 <giometti@linux.it>");
	MODULE_DESCRIPTION("BQ27x00 battery monitor driver");
	MODULE_LICENSE("GPL");