[net-next-2.6.git] / drivers / power / ds2782_battery.c

/*
 * 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>
#include <linux/slab.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");
Commit	Line	Data
bfdb46ce RM	1	/*
	2	* I2C client/driver for the Maxim/Dallas DS2782 Stand-Alone Fuel Gauge IC
	3	*
	4	* Copyright (C) 2009 Bluewater Systems Ltd
	5	*
	6	* Author: Ryan Mallon <ryan@bluewatersys.com>
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*
	12	*/
	13
	14	#include <linux/kernel.h>
	15	#include <linux/module.h>
	16	#include <linux/types.h>
	17	#include <linux/errno.h>
	18	#include <linux/swab.h>
	19	#include <linux/i2c.h>
	20	#include <linux/idr.h>
	21	#include <linux/power_supply.h>
5a0e3ad6	22	#include <linux/slab.h>
bfdb46ce RM	23
	24	#define DS2782_REG_RARC 0x06 /* Remaining active relative capacity */
	25
	26	#define DS2782_REG_VOLT_MSB 0x0c
	27	#define DS2782_REG_TEMP_MSB 0x0a
	28	#define DS2782_REG_CURRENT_MSB 0x0e
	29
	30	/* EEPROM Block */
	31	#define DS2782_REG_RSNSP 0x69 /* Sense resistor value */
	32
	33	/* Current unit measurement in uA for a 1 milli-ohm sense resistor */
	34	#define DS2782_CURRENT_UNITS 1563
	35
	36	#define to_ds2782_info(x) container_of(x, struct ds2782_info, battery)
	37
	38	struct ds2782_info {
	39	struct i2c_client *client;
	40	struct power_supply battery;
	41	int id;
	42	};
	43
	44	static DEFINE_IDR(battery_id);
	45	static DEFINE_MUTEX(battery_lock);
	46
	47	static inline int ds2782_read_reg(struct ds2782_info info, int reg, u8 val)
	48	{
	49	int ret;
	50
	51	ret = i2c_smbus_read_byte_data(info->client, reg);
	52	if (ret < 0) {
	53	dev_err(&info->client->dev, "register read failed\n");
	54	return ret;
	55	}
	56
	57	*val = ret;
	58	return 0;
	59	}
	60
	61	static inline int ds2782_read_reg16(struct ds2782_info *info, int reg_msb,
	62	s16 *val)
	63	{
	64	int ret;
	65
	66	ret = swab16(i2c_smbus_read_word_data(info->client, reg_msb));
	67	if (ret < 0) {
	68	dev_err(&info->client->dev, "register read failed\n");
	69	return ret;
	70	}
	71
	72	*val = ret;
	73	return 0;
	74	}
	75
	76	static int ds2782_get_temp(struct ds2782_info info, int temp)
	77	{
	78	s16 raw;
	79	int err;
	80
	81	/*
	82	* Temperature is measured in units of 0.125 degrees celcius, the
	83	* power_supply class measures temperature in tenths of degrees
	84	* celsius. The temperature value is stored as a 10 bit number, plus
	85	* sign in the upper bits of a 16 bit register.
	86	*/
87	err = ds2782_read_reg16(info, DS2782_REG_TEMP_MSB, &raw);
88	if (err)
89	return err;
90	temp = ((raw / 32) 125) / 100;
91	return 0;
92	}
93
94	static int ds2782_get_current(struct ds2782_info info, int current_uA)
95	{
96	int sense_res;
97	int err;
98	u8 sense_res_raw;
99	s16 raw;
100
101	/*
102	* The units of measurement for current are dependent on the value of
103	* the sense resistor.
104	*/
105	err = ds2782_read_reg(info, DS2782_REG_RSNSP, &sense_res_raw);
106	if (err)
107	return err;
108	if (sense_res_raw == 0) {
109	dev_err(&info->client->dev, "sense resistor value is 0\n");
110	return -ENXIO;
111	}
112	sense_res = 1000 / sense_res_raw;
113
114	dev_dbg(&info->client->dev, "sense resistor = %d milli-ohms\n",
115	sense_res);
116	err = ds2782_read_reg16(info, DS2782_REG_CURRENT_MSB, &raw);
117	if (err)
118	return err;
119	current_uA = raw (DS2782_CURRENT_UNITS / sense_res);
120	return 0;
121	}
122
123	static int ds2782_get_voltage(struct ds2782_info info, int voltage_uA)
124	{
125	s16 raw;
126	int err;
127
128	/*
129	* Voltage is measured in units of 4.88mV. The voltage is stored as
130	* a 10-bit number plus sign, in the upper bits of a 16-bit register
131	*/
132	err = ds2782_read_reg16(info, DS2782_REG_VOLT_MSB, &raw);
133	if (err)
134	return err;
135	voltage_uA = (raw / 32) 4800;
136	return 0;
137	}
138
139	static int ds2782_get_capacity(struct ds2782_info info, int capacity)
140	{
141	int err;
142	u8 raw;
143
144	err = ds2782_read_reg(info, DS2782_REG_RARC, &raw);
145	if (err)
146	return err;
147	*capacity = raw;
148	return raw;
149	}
150
151	static int ds2782_get_status(struct ds2782_info info, int status)
152	{
153	int err;
154	int current_uA;
155	int capacity;
156
157	err = ds2782_get_current(info, &current_uA);
158	if (err)
159	return err;
160
161	err = ds2782_get_capacity(info, &capacity);
162	if (err)
163	return err;
164
165	if (capacity == 100)
166	*status = POWER_SUPPLY_STATUS_FULL;
167	else if (current_uA == 0)
168	*status = POWER_SUPPLY_STATUS_NOT_CHARGING;
169	else if (current_uA < 0)
170	*status = POWER_SUPPLY_STATUS_DISCHARGING;
171	else
172	*status = POWER_SUPPLY_STATUS_CHARGING;
173
174	return 0;
175	}
176
177	static int ds2782_battery_get_property(struct power_supply *psy,
178	enum power_supply_property prop,
179	union power_supply_propval *val)
180	{
181	struct ds2782_info *info = to_ds2782_info(psy);
182	int ret;
183
184	switch (prop) {
185	case POWER_SUPPLY_PROP_STATUS:
186	ret = ds2782_get_status(info, &val->intval);
187	break;
188
189	case POWER_SUPPLY_PROP_CAPACITY:
190	ret = ds2782_get_capacity(info, &val->intval);
191	break;
192
193	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
194	ret = ds2782_get_voltage(info, &val->intval);
195	break;
196
197	case POWER_SUPPLY_PROP_CURRENT_NOW:
198	ret = ds2782_get_current(info, &val->intval);
199	break;
200
201	case POWER_SUPPLY_PROP_TEMP:
202	ret = ds2782_get_temp(info, &val->intval);
203	break;
204
205	default:
206	ret = -EINVAL;
207	}
208
209	return ret;
210	}
211
212	static enum power_supply_property ds2782_battery_props[] = {
213	POWER_SUPPLY_PROP_STATUS,
214	POWER_SUPPLY_PROP_CAPACITY,
215	POWER_SUPPLY_PROP_VOLTAGE_NOW,
216	POWER_SUPPLY_PROP_CURRENT_NOW,
217	POWER_SUPPLY_PROP_TEMP,
218	};
219
220	static void ds2782_power_supply_init(struct power_supply *battery)
221	{
222	battery->type = POWER_SUPPLY_TYPE_BATTERY;
223	battery->properties = ds2782_battery_props;
224	battery->num_properties = ARRAY_SIZE(ds2782_battery_props);
225	battery->get_property = ds2782_battery_get_property;
226	battery->external_power_changed = NULL;
227	}
228
229	static int ds2782_battery_remove(struct i2c_client *client)
230	{
231	struct ds2782_info *info = i2c_get_clientdata(client);
232
233	power_supply_unregister(&info->battery);
234	kfree(info->battery.name);
235
236	mutex_lock(&battery_lock);
237	idr_remove(&battery_id, info->id);
238	mutex_unlock(&battery_lock);
239
240	i2c_set_clientdata(client, info);
241
242	kfree(info);
243	return 0;
244	}
245
246	static int ds2782_battery_probe(struct i2c_client *client,
247	const struct i2c_device_id *id)
248	{
249	struct ds2782_info *info;
250	int ret;
251	int num;
252
253	/* Get an ID for this battery */
254	ret = idr_pre_get(&battery_id, GFP_KERNEL);
255	if (ret == 0) {
256	ret = -ENOMEM;
257	goto fail_id;
258	}
259
260	mutex_lock(&battery_lock);
261	ret = idr_get_new(&battery_id, client, &num);
262	mutex_unlock(&battery_lock);
263	if (ret < 0)
264	goto fail_id;
265
266	info = kzalloc(sizeof(*info), GFP_KERNEL);
267	if (!info) {
268	ret = -ENOMEM;
269	goto fail_info;
270	}
271
272	info->battery.name = kasprintf(GFP_KERNEL, "ds2782-%d", num);
273	if (!info->battery.name) {
274	ret = -ENOMEM;
275	goto fail_name;
276	}
277
278	i2c_set_clientdata(client, info);
279	info->client = client;
280	ds2782_power_supply_init(&info->battery);
281
282	ret = power_supply_register(&client->dev, &info->battery);
283	if (ret) {
284	dev_err(&client->dev, "failed to register battery\n");
285	goto fail_register;
286	}
287
288	return 0;
289
290	fail_register:
291	kfree(info->battery.name);
292	fail_name:
293	i2c_set_clientdata(client, info);
294	kfree(info);
295	fail_info:
296	mutex_lock(&battery_lock);
297	idr_remove(&battery_id, num);
298	mutex_unlock(&battery_lock);
299	fail_id:
300	return ret;
301	}
302
303	static const struct i2c_device_id ds2782_id[] = {
304	{"ds2782", 0},
305	{},
306	};
307
308	static struct i2c_driver ds2782_battery_driver = {
309	.driver = {
310	.name = "ds2782-battery",
311	},
312	.probe = ds2782_battery_probe,
313	.remove = ds2782_battery_remove,
314	.id_table = ds2782_id,
315	};
316
317	static int __init ds2782_init(void)
318	{
319	return i2c_add_driver(&ds2782_battery_driver);
320	}
321	module_init(ds2782_init);
322
323	static void __exit ds2782_exit(void)
324	{
325	i2c_del_driver(&ds2782_battery_driver);
326	}
327	module_exit(ds2782_exit);
328
329	MODULE_AUTHOR("Ryan Mallon <ryan@bluewatersys.com>");
330	MODULE_DESCRIPTION("Maxim/Dallas DS2782 Stand-Alone Fuel Gauage IC driver");
331	MODULE_LICENSE("GPL");