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Commit bfdb46ce authored by Ryan Mallon's avatar Ryan Mallon Committed by Anton Vorontsov
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Add ds2782 battery gas gauge driver 



This patch adds a driver for ds2782 battery devices.

Signed-off-by: default avatarRyan Mallon <ryan@bluewatersys.com>
Signed-off-by: default avatarAnton Vorontsov <cbouatmailru@gmail.com>
parent 8f7e5798

drivers/power/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -43,6 +43,13 @@ config BATTERY_DS2760 
	help

	  Say Y here to enable support for batteries with ds2760 chip.



config BATTERY_DS2782

	tristate "DS2782 standalone gas-gauge"

	depends on I2C

	help

	  Say Y here to enable support for the DS2782 standalone battery

	  gas-gauge.



config BATTERY_PMU

	tristate "Apple PMU battery"

	depends on PPC32 && ADB_PMU

drivers/power/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ obj-$(CONFIG_APM_POWER) += apm_power.o 
obj-$(CONFIG_WM8350_POWER)	+= wm8350_power.o



obj-$(CONFIG_BATTERY_DS2760)	+= ds2760_battery.o

obj-$(CONFIG_BATTERY_DS2782)	+= ds2782_battery.o

obj-$(CONFIG_BATTERY_PMU)	+= pmu_battery.o

obj-$(CONFIG_BATTERY_OLPC)	+= olpc_battery.o

obj-$(CONFIG_BATTERY_TOSA)	+= tosa_battery.o

drivers/power/ds2782_battery.c

0 → 100644
+330 −0
Original line number Diff line number Diff line 
/*

 * I2C client/driver for the Maxim/Dallas DS2782 Stand-Alone Fuel Gauge IC

 *

 * Copyright (C) 2009 Bluewater Systems Ltd

 *

 * Author: Ryan Mallon <ryan@bluewatersys.com>

 *

 * 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/kernel.h>

#include <linux/module.h>

#include <linux/types.h>

#include <linux/errno.h>

#include <linux/swab.h>

#include <linux/i2c.h>

#include <linux/idr.h>

#include <linux/power_supply.h>



#define DS2782_REG_RARC		0x06	/* Remaining active relative capacity */



#define DS2782_REG_VOLT_MSB	0x0c

#define DS2782_REG_TEMP_MSB	0x0a

#define DS2782_REG_CURRENT_MSB	0x0e



/* EEPROM Block */

#define DS2782_REG_RSNSP	0x69	/* Sense resistor value */



/* Current unit measurement in uA for a 1 milli-ohm sense resistor */

#define DS2782_CURRENT_UNITS	1563



#define to_ds2782_info(x) container_of(x, struct ds2782_info, battery)



struct ds2782_info {

	struct i2c_client	*client;

	struct power_supply	battery;

	int			id;

};



static DEFINE_IDR(battery_id);

static DEFINE_MUTEX(battery_lock);



static inline int ds2782_read_reg(struct ds2782_info *info, int reg, u8 *val)

{

	int ret;



	ret = i2c_smbus_read_byte_data(info->client, reg);

	if (ret < 0) {

		dev_err(&info->client->dev, "register read failed\n");

		return ret;

	}



	*val = ret;

	return 0;

}



static inline int ds2782_read_reg16(struct ds2782_info *info, int reg_msb,

				    s16 *val)

{

	int ret;



	ret = swab16(i2c_smbus_read_word_data(info->client, reg_msb));

	if (ret < 0) {

		dev_err(&info->client->dev, "register read failed\n");

		return ret;

	}



	*val = ret;

	return 0;

}



static int ds2782_get_temp(struct ds2782_info *info, int *temp)

{

	s16 raw;

	int err;



	/*

	 * Temperature is measured in units of 0.125 degrees celcius, the

	 * power_supply class measures temperature in tenths of degrees

	 * celsius. The temperature value is stored as a 10 bit number, plus

	 * sign in the upper bits of a 16 bit register.

	 */

	err = ds2782_read_reg16(info, DS2782_REG_TEMP_MSB, &raw);

	if (err)

		return err;

	*temp = ((raw / 32) * 125) / 100;

	return 0;

}



static int ds2782_get_current(struct ds2782_info *info, int *current_uA)

{

	int sense_res;

	int err;

	u8 sense_res_raw;

	s16 raw;



	/*

	 * The units of measurement for current are dependent on the value of

	 * the sense resistor.

	 */

	err = ds2782_read_reg(info, DS2782_REG_RSNSP, &sense_res_raw);

	if (err)

		return err;

	if (sense_res_raw == 0) {

		dev_err(&info->client->dev, "sense resistor value is 0\n");

		return -ENXIO;

	}

	sense_res = 1000 / sense_res_raw;



	dev_dbg(&info->client->dev, "sense resistor = %d milli-ohms\n",

		sense_res);

	err = ds2782_read_reg16(info, DS2782_REG_CURRENT_MSB, &raw);

	if (err)

		return err;

	*current_uA = raw * (DS2782_CURRENT_UNITS / sense_res);

	return 0;

}



static int ds2782_get_voltage(struct ds2782_info *info, int *voltage_uA)

{

	s16 raw;

	int err;



	/*

	 * Voltage is measured in units of 4.88mV. The voltage is stored as

	 * a 10-bit number plus sign, in the upper bits of a 16-bit register

	 */

	err = ds2782_read_reg16(info, DS2782_REG_VOLT_MSB, &raw);

	if (err)

		return err;

	*voltage_uA = (raw / 32) * 4800;

	return 0;

}



static int ds2782_get_capacity(struct ds2782_info *info, int *capacity)

{

	int err;

	u8 raw;



	err = ds2782_read_reg(info, DS2782_REG_RARC, &raw);

	if (err)

		return err;

	*capacity = raw;

	return raw;

}



static int ds2782_get_status(struct ds2782_info *info, int *status)

{

	int err;

	int current_uA;

	int capacity;



	err = ds2782_get_current(info, &current_uA);

	if (err)

		return err;



	err = ds2782_get_capacity(info, &capacity);

	if (err)

		return err;



	if (capacity == 100)

		*status = POWER_SUPPLY_STATUS_FULL;

	else if (current_uA == 0)

		*status = POWER_SUPPLY_STATUS_NOT_CHARGING;

	else if (current_uA < 0)

		*status = POWER_SUPPLY_STATUS_DISCHARGING;

	else

		*status = POWER_SUPPLY_STATUS_CHARGING;



	return 0;

}



static int ds2782_battery_get_property(struct power_supply *psy,

				       enum power_supply_property prop,

				       union power_supply_propval *val)

{

	struct ds2782_info *info = to_ds2782_info(psy);

	int ret;



	switch (prop) {

	case POWER_SUPPLY_PROP_STATUS:

		ret = ds2782_get_status(info, &val->intval);

		break;



	case POWER_SUPPLY_PROP_CAPACITY:

		ret = ds2782_get_capacity(info, &val->intval);

		break;



	case POWER_SUPPLY_PROP_VOLTAGE_NOW:

		ret = ds2782_get_voltage(info, &val->intval);

		break;



	case POWER_SUPPLY_PROP_CURRENT_NOW:

		ret = ds2782_get_current(info, &val->intval);

		break;



	case POWER_SUPPLY_PROP_TEMP:

		ret = ds2782_get_temp(info, &val->intval);

		break;



	default:

		ret = -EINVAL;

	}



	return ret;

}



static enum power_supply_property ds2782_battery_props[] = {

	POWER_SUPPLY_PROP_STATUS,

	POWER_SUPPLY_PROP_CAPACITY,

	POWER_SUPPLY_PROP_VOLTAGE_NOW,

	POWER_SUPPLY_PROP_CURRENT_NOW,

	POWER_SUPPLY_PROP_TEMP,

};



static void ds2782_power_supply_init(struct power_supply *battery)

{

	battery->type			= POWER_SUPPLY_TYPE_BATTERY;

	battery->properties		= ds2782_battery_props;

	battery->num_properties		= ARRAY_SIZE(ds2782_battery_props);

	battery->get_property		= ds2782_battery_get_property;

	battery->external_power_changed	= NULL;

}



static int ds2782_battery_remove(struct i2c_client *client)

{

	struct ds2782_info *info = i2c_get_clientdata(client);



	power_supply_unregister(&info->battery);

	kfree(info->battery.name);



	mutex_lock(&battery_lock);

	idr_remove(&battery_id, info->id);

	mutex_unlock(&battery_lock);



	i2c_set_clientdata(client, info);



	kfree(info);

	return 0;

}



static int ds2782_battery_probe(struct i2c_client *client,

				const struct i2c_device_id *id)

{

	struct ds2782_info *info;

	int ret;

	int num;



	/* Get an ID for this battery */

	ret = idr_pre_get(&battery_id, GFP_KERNEL);

	if (ret == 0) {

		ret = -ENOMEM;

		goto fail_id;

	}



	mutex_lock(&battery_lock);

	ret = idr_get_new(&battery_id, client, &num);

	mutex_unlock(&battery_lock);

	if (ret < 0)

		goto fail_id;



	info = kzalloc(sizeof(*info), GFP_KERNEL);

	if (!info) {

		ret = -ENOMEM;

		goto fail_info;

	}



	info->battery.name = kasprintf(GFP_KERNEL, "ds2782-%d", num);

	if (!info->battery.name) {

		ret = -ENOMEM;

		goto fail_name;

	}



	i2c_set_clientdata(client, info);

	info->client = client;

	ds2782_power_supply_init(&info->battery);



	ret = power_supply_register(&client->dev, &info->battery);

	if (ret) {

		dev_err(&client->dev, "failed to register battery\n");

		goto fail_register;

	}



	return 0;



fail_register:

	kfree(info->battery.name);

fail_name:

	i2c_set_clientdata(client, info);

	kfree(info);

fail_info:

	mutex_lock(&battery_lock);

	idr_remove(&battery_id, num);

	mutex_unlock(&battery_lock);

fail_id:

	return ret;

}



static const struct i2c_device_id ds2782_id[] = {

	{"ds2782", 0},

	{},

};



static struct i2c_driver ds2782_battery_driver = {

	.driver 	= {

		.name	= "ds2782-battery",

	},

	.probe		= ds2782_battery_probe,

	.remove		= ds2782_battery_remove,

	.id_table	= ds2782_id,

};



static int __init ds2782_init(void)

{

	return i2c_add_driver(&ds2782_battery_driver);

}

module_init(ds2782_init);



static void __exit ds2782_exit(void)

{

	i2c_del_driver(&ds2782_battery_driver);

}

module_exit(ds2782_exit);



MODULE_AUTHOR("Ryan Mallon <ryan@bluewatersys.com>");

MODULE_DESCRIPTION("Maxim/Dallas DS2782 Stand-Alone Fuel Gauage IC driver");

MODULE_LICENSE("GPL");