aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/power/bq27x00_battery.c
blob: 62bb98124e26e0b273de974e9ee357ce875dcf87 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
/*
 * BQ27x00 battery driver
 *
 * Copyright (C) 2008 Rodolfo Giometti <giometti@linux.it>
 * Copyright (C) 2008 Eurotech S.p.A. <info@eurotech.it>
 *
 * 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.
 *
 */
#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 <asm/unaligned.h>

#define DRIVER_VERSION			"1.0.0"

#define BQ27x00_REG_TEMP		0x06
#define BQ27x00_REG_VOLT		0x08
#define BQ27x00_REG_RSOC		0x0B /* Relative State-of-Charge */
#define BQ27x00_REG_AI			0x14
#define BQ27x00_REG_FLAGS		0x0A

/* 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);

struct bq27x00_device_info;
struct bq27x00_access_methods {
	int (*read)(u8 reg, int *rt_value, int b_single,
		struct bq27x00_device_info *di);
};

struct bq27x00_device_info {
	struct device 		*dev;
	int			id;
	int			voltage_uV;
	int			current_uA;
	int			temp_C;
	int			charge_rsoc;
	struct bq27x00_access_methods	*bus;
	struct power_supply	bat;

	struct i2c_client	*client;
};

static enum power_supply_property bq27x00_battery_props[] = {
	POWER_SUPPLY_PROP_PRESENT,
	POWER_SUPPLY_PROP_VOLTAGE_NOW,
	POWER_SUPPLY_PROP_CURRENT_NOW,
	POWER_SUPPLY_PROP_CAPACITY,
	POWER_SUPPLY_PROP_TEMP,
};

/*
 * Common code for BQ27x00 devices
 */

static int bq27x00_read(u8 reg, int *rt_value, int b_single,
			struct bq27x00_device_info *di)
{
	int ret;

	ret = di->bus->read(reg, rt_value, b_single, di);
	*rt_value = be16_to_cpu(*rt_value);

	return ret;
}

/*
 * Return the battery temperature in Celsius degrees
 * Or < 0 if something fails.
 */
static int bq27x00_battery_temperature(struct bq27x00_device_info *di)
{
	int ret;
	int temp = 0;

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

	return (temp >> 2) - 273;
}

/*
 * Return the battery Voltage in milivolts
 * Or < 0 if something fails.
 */
static int bq27x00_battery_voltage(struct bq27x00_device_info *di)
{
	int ret;
	int volt = 0;

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

	return volt;
}

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

	ret = bq27x00_read(BQ27x00_REG_AI, &curr, 0, di);
	if (ret) {
		dev_err(di->dev, "error reading current\n");
		return 0;
	}
	ret = bq27x00_read(BQ27x00_REG_FLAGS, &flags, 0, di);
	if (ret < 0) {
		dev_err(di->dev, "error reading flags\n");
		return 0;
	}
	if ((flags & (1 << 7)) != 0) {
		dev_dbg(di->dev, "negative current!\n");
		return -curr;
	}
	return curr;
}

/*
 * Return the battery Relative State-of-Charge
 * Or < 0 if something fails.
 */
static int bq27x00_battery_rsoc(struct bq27x00_device_info *di)
{
	int ret;
	int rsoc = 0;

	ret = bq27x00_read(BQ27x00_REG_RSOC, &rsoc, 1, di);
	if (ret) {
		dev_err(di->dev, "error reading relative State-of-Charge\n");
		return ret;
	}

	return rsoc >> 8;
}

#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)
{
	struct bq27x00_device_info *di = to_bq27x00_device_info(psy);

	switch (psp) {
	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
	case POWER_SUPPLY_PROP_PRESENT:
		val->intval = bq27x00_battery_voltage(di);
		if (psp == POWER_SUPPLY_PROP_PRESENT)
			val->intval = val->intval <= 0 ? 0 : 1;
		break;
	case POWER_SUPPLY_PROP_CURRENT_NOW:
		val->intval = bq27x00_battery_current(di);
		break;
	case POWER_SUPPLY_PROP_CAPACITY:
		val->intval = bq27x00_battery_rsoc(di);
		break;
	case POWER_SUPPLY_PROP_TEMP:
		val->intval = bq27x00_battery_temperature(di);
		break;
	default:
		return -EINVAL;
	}

	return 0;
}

static void bq27x00_powersupply_init(struct bq27x00_device_info *di)
{
	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 = NULL;
}

/*
 * BQ27200 specific code
 */

static int bq27200_read(u8 reg, int *rt_value, int b_single,
			struct bq27x00_device_info *di)
{
	struct i2c_client *client = di->client;
	struct i2c_msg msg[1];
	unsigned char data[2];
	int err;

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

	msg->addr = client->addr;
	msg->flags = 0;
	msg->len = 1;
	msg->buf = data;

	data[0] = reg;
	err = i2c_transfer(client->adapter, msg, 1);

	if (err >= 0) {
		if (!b_single)
			msg->len = 2;
		else
			msg->len = 1;

		msg->flags = I2C_M_RD;
		err = i2c_transfer(client->adapter, msg, 1);
		if (err >= 0) {
			if (!b_single)
				*rt_value = get_unaligned_be16(data);
			else
				*rt_value = data[0];

			return 0;
		}
	}
	return err;
}

static int bq27200_battery_probe(struct i2c_client *client,
				 const struct i2c_device_id *id)
{
	char *name;
	struct bq27x00_device_info *di;
	struct bq27x00_access_methods *bus;
	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, "bq27200-%d", 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;

	bus = kzalloc(sizeof(*bus), GFP_KERNEL);
	if (!bus) {
		dev_err(&client->dev, "failed to allocate access method "
					"data\n");
		retval = -ENOMEM;
		goto batt_failed_3;
	}

	i2c_set_clientdata(client, di);
	di->dev = &client->dev;
	di->bat.name = name;
	bus->read = &bq27200_read;
	di->bus = bus;
	di->client = client;

	bq27x00_powersupply_init(di);

	retval = power_supply_register(&client->dev, &di->bat);
	if (retval) {
		dev_err(&client->dev, "failed to register battery\n");
		goto batt_failed_4;
	}

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

	return 0;

batt_failed_4:
	kfree(bus);
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 bq27200_battery_remove(struct i2c_client *client)
{
	struct bq27x00_device_info *di = i2c_get_clientdata(client);

	power_supply_unregister(&di->bat);

	kfree(di->bat.name);

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

	kfree(di);

	return 0;
}

/*
 * Module stuff
 */

static const struct i2c_device_id bq27200_id[] = {
	{ "bq27200", 0 },
	{},
};

static struct i2c_driver bq27200_battery_driver = {
	.driver = {
		.name = "bq27200-battery",
	},
	.probe = bq27200_battery_probe,
	.remove = bq27200_battery_remove,
	.id_table = bq27200_id,
};

static int __init bq27x00_battery_init(void)
{
	int ret;

	ret = i2c_add_driver(&bq27200_battery_driver);
	if (ret)
		printk(KERN_ERR "Unable to register BQ27200 driver\n");

	return ret;
}
module_init(bq27x00_battery_init);

static void __exit bq27x00_battery_exit(void)
{
	i2c_del_driver(&bq27200_battery_driver);
}
module_exit(bq27x00_battery_exit);

MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
MODULE_DESCRIPTION("BQ27x00 battery monitor driver");
MODULE_LICENSE("GPL");