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