2 * BQ27x00 battery driver
4 * Copyright (C) 2008 Rodolfo Giometti <giometti@linux.it>
5 * Copyright (C) 2008 Eurotech S.p.A. <info@eurotech.it>
7 * Based on a previous work by Copyright (C) 2008 Texas Instruments, Inc.
9 * This package is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
13 * THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
18 #include <linux/module.h>
19 #include <linux/param.h>
20 #include <linux/jiffies.h>
21 #include <linux/workqueue.h>
22 #include <linux/delay.h>
23 #include <linux/platform_device.h>
24 #include <linux/power_supply.h>
25 #include <linux/idr.h>
26 #include <linux/i2c.h>
27 #include <asm/unaligned.h>
29 #define DRIVER_VERSION "1.1.0"
31 #define BQ27x00_REG_TEMP 0x06
32 #define BQ27x00_REG_VOLT 0x08
33 #define BQ27x00_REG_AI 0x14
34 #define BQ27x00_REG_FLAGS 0x0A
36 #define BQ27000_REG_RSOC 0x0B /* Relative State-of-Charge */
38 #define BQ27500_REG_SOC 0x2c
40 /* If the system has several batteries we need a different name for each
43 static DEFINE_IDR(battery_id);
44 static DEFINE_MUTEX(battery_mutex);
46 struct bq27x00_device_info;
47 struct bq27x00_access_methods {
48 int (*read)(u8 reg, int *rt_value, int b_single,
49 struct bq27x00_device_info *di);
52 enum bq27x00_chip { BQ27000, BQ27500 };
54 struct bq27x00_device_info {
57 struct bq27x00_access_methods *bus;
58 struct power_supply bat;
59 enum bq27x00_chip chip;
61 struct i2c_client *client;
64 static enum power_supply_property bq27x00_battery_props[] = {
65 POWER_SUPPLY_PROP_PRESENT,
66 POWER_SUPPLY_PROP_VOLTAGE_NOW,
67 POWER_SUPPLY_PROP_CURRENT_NOW,
68 POWER_SUPPLY_PROP_CAPACITY,
69 POWER_SUPPLY_PROP_TEMP,
73 * Common code for BQ27x00 devices
76 static int bq27x00_read(u8 reg, int *rt_value, int b_single,
77 struct bq27x00_device_info *di)
79 return di->bus->read(reg, rt_value, b_single, di);
83 * Return the battery temperature in tenths of degree Celsius
84 * Or < 0 if something fails.
86 static int bq27x00_battery_temperature(struct bq27x00_device_info *di)
91 ret = bq27x00_read(BQ27x00_REG_TEMP, &temp, 0, di);
93 dev_err(di->dev, "error reading temperature\n");
97 if (di->chip == BQ27500)
100 return ((temp >> 2) - 273) * 10;
104 * Return the battery Voltage in milivolts
105 * Or < 0 if something fails.
107 static int bq27x00_battery_voltage(struct bq27x00_device_info *di)
112 ret = bq27x00_read(BQ27x00_REG_VOLT, &volt, 0, di);
114 dev_err(di->dev, "error reading voltage\n");
122 * Return the battery average current
123 * Note that current can be negative signed as well
124 * Or 0 if something fails.
126 static int bq27x00_battery_current(struct bq27x00_device_info *di)
132 ret = bq27x00_read(BQ27x00_REG_AI, &curr, 0, di);
134 dev_err(di->dev, "error reading current\n");
138 if (di->chip == BQ27500) {
139 /* bq27500 returns signed value */
140 curr = (int)(s16)curr;
142 ret = bq27x00_read(BQ27x00_REG_FLAGS, &flags, 0, di);
144 dev_err(di->dev, "error reading flags\n");
147 if ((flags & (1 << 7)) != 0) {
148 dev_dbg(di->dev, "negative current!\n");
157 * Return the battery Relative State-of-Charge
158 * Or < 0 if something fails.
160 static int bq27x00_battery_rsoc(struct bq27x00_device_info *di)
165 if (di->chip == BQ27500)
166 ret = bq27x00_read(BQ27500_REG_SOC, &rsoc, 0, di);
168 ret = bq27x00_read(BQ27000_REG_RSOC, &rsoc, 1, di);
170 dev_err(di->dev, "error reading relative State-of-Charge\n");
177 #define to_bq27x00_device_info(x) container_of((x), \
178 struct bq27x00_device_info, bat);
180 static int bq27x00_battery_get_property(struct power_supply *psy,
181 enum power_supply_property psp,
182 union power_supply_propval *val)
184 struct bq27x00_device_info *di = to_bq27x00_device_info(psy);
187 case POWER_SUPPLY_PROP_VOLTAGE_NOW:
188 case POWER_SUPPLY_PROP_PRESENT:
189 val->intval = bq27x00_battery_voltage(di);
190 if (psp == POWER_SUPPLY_PROP_PRESENT)
191 val->intval = val->intval <= 0 ? 0 : 1;
193 case POWER_SUPPLY_PROP_CURRENT_NOW:
194 val->intval = bq27x00_battery_current(di);
196 case POWER_SUPPLY_PROP_CAPACITY:
197 val->intval = bq27x00_battery_rsoc(di);
199 case POWER_SUPPLY_PROP_TEMP:
200 val->intval = bq27x00_battery_temperature(di);
209 static void bq27x00_powersupply_init(struct bq27x00_device_info *di)
211 di->bat.type = POWER_SUPPLY_TYPE_BATTERY;
212 di->bat.properties = bq27x00_battery_props;
213 di->bat.num_properties = ARRAY_SIZE(bq27x00_battery_props);
214 di->bat.get_property = bq27x00_battery_get_property;
215 di->bat.external_power_changed = NULL;
222 static int bq27x00_read_i2c(u8 reg, int *rt_value, int b_single,
223 struct bq27x00_device_info *di)
225 struct i2c_client *client = di->client;
226 struct i2c_msg msg[1];
227 unsigned char data[2];
230 if (!client->adapter)
233 msg->addr = client->addr;
239 err = i2c_transfer(client->adapter, msg, 1);
247 msg->flags = I2C_M_RD;
248 err = i2c_transfer(client->adapter, msg, 1);
251 *rt_value = get_unaligned_le16(data);
261 static int bq27x00_battery_probe(struct i2c_client *client,
262 const struct i2c_device_id *id)
265 struct bq27x00_device_info *di;
266 struct bq27x00_access_methods *bus;
270 /* Get new ID for the new battery device */
271 retval = idr_pre_get(&battery_id, GFP_KERNEL);
274 mutex_lock(&battery_mutex);
275 retval = idr_get_new(&battery_id, client, &num);
276 mutex_unlock(&battery_mutex);
280 name = kasprintf(GFP_KERNEL, "%s-%d", id->name, num);
282 dev_err(&client->dev, "failed to allocate device name\n");
287 di = kzalloc(sizeof(*di), GFP_KERNEL);
289 dev_err(&client->dev, "failed to allocate device info data\n");
294 di->chip = id->driver_data;
296 bus = kzalloc(sizeof(*bus), GFP_KERNEL);
298 dev_err(&client->dev, "failed to allocate access method "
304 i2c_set_clientdata(client, di);
305 di->dev = &client->dev;
307 bus->read = &bq27x00_read_i2c;
311 bq27x00_powersupply_init(di);
313 retval = power_supply_register(&client->dev, &di->bat);
315 dev_err(&client->dev, "failed to register battery\n");
319 dev_info(&client->dev, "support ver. %s enabled\n", DRIVER_VERSION);
330 mutex_lock(&battery_mutex);
331 idr_remove(&battery_id, num);
332 mutex_unlock(&battery_mutex);
337 static int bq27x00_battery_remove(struct i2c_client *client)
339 struct bq27x00_device_info *di = i2c_get_clientdata(client);
341 power_supply_unregister(&di->bat);
345 mutex_lock(&battery_mutex);
346 idr_remove(&battery_id, di->id);
347 mutex_unlock(&battery_mutex);
358 static const struct i2c_device_id bq27x00_id[] = {
359 { "bq27200", BQ27000 }, /* bq27200 is same as bq27000, but with i2c */
360 { "bq27500", BQ27500 },
364 static struct i2c_driver bq27x00_battery_driver = {
366 .name = "bq27x00-battery",
368 .probe = bq27x00_battery_probe,
369 .remove = bq27x00_battery_remove,
370 .id_table = bq27x00_id,
373 static int __init bq27x00_battery_init(void)
377 ret = i2c_add_driver(&bq27x00_battery_driver);
379 printk(KERN_ERR "Unable to register BQ27x00 driver\n");
383 module_init(bq27x00_battery_init);
385 static void __exit bq27x00_battery_exit(void)
387 i2c_del_driver(&bq27x00_battery_driver);
389 module_exit(bq27x00_battery_exit);
391 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
392 MODULE_DESCRIPTION("BQ27x00 battery monitor driver");
393 MODULE_LICENSE("GPL");