1 /*
2 * BQ27x00 battery driver
3 *
4 * Copyright (C) 2008 Rodolfo Giometti <giometti@linux.it>
5 * Copyright (C) 2008 Eurotech S.p.A. <info@eurotech.it>
6 *
7 * Based on a previous work by Copyright (C) 2008 Texas Instruments, Inc.
8 *
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.
12 *
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.
16 *
17 */
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>
28
29 #define DRIVER_VERSION "1.0.0"
30
31 #define BQ27x00_REG_TEMP 0x06
32 #define BQ27x00_REG_VOLT 0x08
33 #define BQ27x00_REG_RSOC 0x0B /* Relative State-of-Charge */
34 #define BQ27x00_REG_AI 0x14
35 #define BQ27x00_REG_FLAGS 0x0A
36
37 /* If the system has several batteries we need a different name for each
38 * of them...
39 */
40 static DEFINE_IDR(battery_id);
41 static DEFINE_MUTEX(battery_mutex);
42
43 struct bq27x00_device_info;
44 struct bq27x00_access_methods {
45 int (*read)(u8 reg, int *rt_value, int b_single,
46 struct bq27x00_device_info *di);
47 };
48
49 struct bq27x00_device_info {
50 struct device *dev;
51 int id;
52 int voltage_uV;
53 int current_uA;
54 int temp_C;
55 int charge_rsoc;
56 struct bq27x00_access_methods *bus;
57 struct power_supply bat;
58
59 struct i2c_client *client;
60 };
61
62 static enum power_supply_property bq27x00_battery_props[] = {
63 POWER_SUPPLY_PROP_PRESENT,
64 POWER_SUPPLY_PROP_VOLTAGE_NOW,
65 POWER_SUPPLY_PROP_CURRENT_NOW,
66 POWER_SUPPLY_PROP_CAPACITY,
67 POWER_SUPPLY_PROP_TEMP,
68 };
69
70 /*
71 * Common code for BQ27x00 devices
72 */
73
74 static int bq27x00_read(u8 reg, int *rt_value, int b_single,
75 struct bq27x00_device_info *di)
76 {
77 int ret;
78
79 ret = di->bus->read(reg, rt_value, b_single, di);
80 *rt_value = be16_to_cpu(*rt_value);
81
82 return ret;
83 }
84
85 /*
86 * Return the battery temperature in Celsius degrees
87 * Or < 0 if something fails.
88 */
89 static int bq27x00_battery_temperature(struct bq27x00_device_info *di)
90 {
91 int ret;
92 int temp = 0;
93
94 ret = bq27x00_read(BQ27x00_REG_TEMP, &temp, 0, di);
95 if (ret) {
96 dev_err(di->dev, "error reading temperature\n");
97 return ret;
98 }
99
100 return (temp >> 2) - 273;
101 }
102
103 /*
104 * Return the battery Voltage in milivolts
105 * Or < 0 if something fails.
106 */
107 static int bq27x00_battery_voltage(struct bq27x00_device_info *di)
108 {
109 int ret;
110 int volt = 0;
111
112 ret = bq27x00_read(BQ27x00_REG_VOLT, &volt, 0, di);
113 if (ret) {
114 dev_err(di->dev, "error reading voltage\n");
115 return ret;
116 }
117
118 return volt;
119 }
120
121 /*
122 * Return the battery average current
123 * Note that current can be negative signed as well
124 * Or 0 if something fails.
125 */
126 static int bq27x00_battery_current(struct bq27x00_device_info *di)
127 {
128 int ret;
129 int curr = 0;
130 int flags = 0;
131
132 ret = bq27x00_read(BQ27x00_REG_AI, &curr, 0, di);
133 if (ret) {
134 dev_err(di->dev, "error reading current\n");
135 return 0;
136 }
137 ret = bq27x00_read(BQ27x00_REG_FLAGS, &flags, 0, di);
138 if (ret < 0) {
139 dev_err(di->dev, "error reading flags\n");
140 return 0;
141 }
142 if ((flags & (1 << 7)) != 0) {
143 dev_dbg(di->dev, "negative current!\n");
144 return -curr;
145 }
146 return curr;
147 }
148
149 /*
150 * Return the battery Relative State-of-Charge
151 * Or < 0 if something fails.
152 */
153 static int bq27x00_battery_rsoc(struct bq27x00_device_info *di)
154 {
155 int ret;
156 int rsoc = 0;
157
158 ret = bq27x00_read(BQ27x00_REG_RSOC, &rsoc, 1, di);
159 if (ret) {
160 dev_err(di->dev, "error reading relative State-of-Charge\n");
161 return ret;
162 }
163
164 return rsoc >> 8;
165 }
166
167 #define to_bq27x00_device_info(x) container_of((x), \
168 struct bq27x00_device_info, bat);
169
170 static int bq27x00_battery_get_property(struct power_supply *psy,
171 enum power_supply_property psp,
172 union power_supply_propval *val)
173 {
174 struct bq27x00_device_info *di = to_bq27x00_device_info(psy);
175
176 switch (psp) {
177 case POWER_SUPPLY_PROP_VOLTAGE_NOW:
178 case POWER_SUPPLY_PROP_PRESENT:
179 val->intval = bq27x00_battery_voltage(di);
180 if (psp == POWER_SUPPLY_PROP_PRESENT)
181 val->intval = val->intval <= 0 ? 0 : 1;
182 break;
183 case POWER_SUPPLY_PROP_CURRENT_NOW:
184 val->intval = bq27x00_battery_current(di);
185 break;
186 case POWER_SUPPLY_PROP_CAPACITY:
187 val->intval = bq27x00_battery_rsoc(di);
188 break;
189 case POWER_SUPPLY_PROP_TEMP:
190 val->intval = bq27x00_battery_temperature(di);
191 break;
192 default:
193 return -EINVAL;
194 }
195
196 return 0;
197 }
198
199 static void bq27x00_powersupply_init(struct bq27x00_device_info *di)
200 {
201 di->bat.type = POWER_SUPPLY_TYPE_BATTERY;
202 di->bat.properties = bq27x00_battery_props;
203 di->bat.num_properties = ARRAY_SIZE(bq27x00_battery_props);
204 di->bat.get_property = bq27x00_battery_get_property;
205 di->bat.external_power_changed = NULL;
206 }
207
208 /*
209 * BQ27200 specific code
210 */
211
212 static int bq27200_read(u8 reg, int *rt_value, int b_single,
213 struct bq27x00_device_info *di)
214 {
215 struct i2c_client *client = di->client;
216 struct i2c_msg msg[1];
217 unsigned char data[2];
218 int err;
219
220 if (!client->adapter)
221 return -ENODEV;
222
223 msg->addr = client->addr;
224 msg->flags = 0;
225 msg->len = 1;
226 msg->buf = data;
227
228 data[0] = reg;
229 err = i2c_transfer(client->adapter, msg, 1);
230
231 if (err >= 0) {
232 if (!b_single)
233 msg->len = 2;
234 else
235 msg->len = 1;
236
237 msg->flags = I2C_M_RD;
238 err = i2c_transfer(client->adapter, msg, 1);
239 if (err >= 0) {
240 if (!b_single)
241 *rt_value = get_unaligned_be16(data);
242 else
243 *rt_value = data[0];
244
245 return 0;
246 }
247 }
248 return err;
249 }
250
251 static int bq27200_battery_probe(struct i2c_client *client,
252 const struct i2c_device_id *id)
253 {
254 char *name;
255 struct bq27x00_device_info *di;
256 struct bq27x00_access_methods *bus;
257 int num;
258 int retval = 0;
259
260 /* Get new ID for the new battery device */
261 retval = idr_pre_get(&battery_id, GFP_KERNEL);
262 if (retval == 0)
263 return -ENOMEM;
264 mutex_lock(&battery_mutex);
265 retval = idr_get_new(&battery_id, client, &num);
266 mutex_unlock(&battery_mutex);
267 if (retval < 0)
268 return retval;
269
270 name = kasprintf(GFP_KERNEL, "bq27200-%d", num);
271 if (!name) {
272 dev_err(&client->dev, "failed to allocate device name\n");
273 retval = -ENOMEM;
274 goto batt_failed_1;
275 }
276
277 di = kzalloc(sizeof(*di), GFP_KERNEL);
278 if (!di) {
279 dev_err(&client->dev, "failed to allocate device info data\n");
280 retval = -ENOMEM;
281 goto batt_failed_2;
282 }
283 di->id = num;
284
285 bus = kzalloc(sizeof(*bus), GFP_KERNEL);
286 if (!bus) {
287 dev_err(&client->dev, "failed to allocate access method "
288 "data\n");
289 retval = -ENOMEM;
290 goto batt_failed_3;
291 }
292
293 i2c_set_clientdata(client, di);
294 di->dev = &client->dev;
295 di->bat.name = name;
296 bus->read = &bq27200_read;
297 di->bus = bus;
298 di->client = client;
299
300 bq27x00_powersupply_init(di);
301
302 retval = power_supply_register(&client->dev, &di->bat);
303 if (retval) {
304 dev_err(&client->dev, "failed to register battery\n");
305 goto batt_failed_4;
306 }
307
308 dev_info(&client->dev, "support ver. %s enabled\n", DRIVER_VERSION);
309
310 return 0;
311
312 batt_failed_4:
313 kfree(bus);
314 batt_failed_3:
315 kfree(di);
316 batt_failed_2:
317 kfree(name);
318 batt_failed_1:
319 mutex_lock(&battery_mutex);
320 idr_remove(&battery_id, num);
321 mutex_unlock(&battery_mutex);
322
323 return retval;
324 }
325
326 static int bq27200_battery_remove(struct i2c_client *client)
327 {
328 struct bq27x00_device_info *di = i2c_get_clientdata(client);
329
330 power_supply_unregister(&di->bat);
331
332 kfree(di->bat.name);
333
334 mutex_lock(&battery_mutex);
335 idr_remove(&battery_id, di->id);
336 mutex_unlock(&battery_mutex);
337
338 kfree(di);
339
340 return 0;
341 }
342
343 /*
344 * Module stuff
345 */
346
347 static const struct i2c_device_id bq27200_id[] = {
348 { "bq27200", 0 },
349 {},
350 };
351
352 static struct i2c_driver bq27200_battery_driver = {
353 .driver = {
354 .name = "bq27200-battery",
355 },
356 .probe = bq27200_battery_probe,
357 .remove = bq27200_battery_remove,
358 .id_table = bq27200_id,
359 };
360
361 static int __init bq27x00_battery_init(void)
362 {
363 int ret;
364
365 ret = i2c_add_driver(&bq27200_battery_driver);
366 if (ret)
367 printk(KERN_ERR "Unable to register BQ27200 driver\n");
368
369 return ret;
370 }
371 module_init(bq27x00_battery_init);
372
373 static void __exit bq27x00_battery_exit(void)
374 {
375 i2c_del_driver(&bq27200_battery_driver);
376 }
377 module_exit(bq27x00_battery_exit);
378
379 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
380 MODULE_DESCRIPTION("BQ27x00 battery monitor driver");
381 MODULE_LICENSE("GPL");
382
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