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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 | * | |
9b9ade6b YV |
8 | * DS2786 added by Yulia Vilensky <vilensky@compulab.co.il> |
9 | * | |
bfdb46ce RM |
10 | * This program is free software; you can redistribute it and/or modify |
11 | * it under the terms of the GNU General Public License version 2 as | |
12 | * published by the Free Software Foundation. | |
13 | * | |
14 | */ | |
15 | ||
16 | #include <linux/kernel.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/types.h> | |
19 | #include <linux/errno.h> | |
20 | #include <linux/swab.h> | |
21 | #include <linux/i2c.h> | |
22 | #include <linux/idr.h> | |
23 | #include <linux/power_supply.h> | |
5a0e3ad6 | 24 | #include <linux/slab.h> |
9b9ade6b | 25 | #include <linux/ds2782_battery.h> |
bfdb46ce RM |
26 | |
27 | #define DS2782_REG_RARC 0x06 /* Remaining active relative capacity */ | |
28 | ||
9b9ade6b YV |
29 | #define DS278x_REG_VOLT_MSB 0x0c |
30 | #define DS278x_REG_TEMP_MSB 0x0a | |
31 | #define DS278x_REG_CURRENT_MSB 0x0e | |
bfdb46ce RM |
32 | |
33 | /* EEPROM Block */ | |
34 | #define DS2782_REG_RSNSP 0x69 /* Sense resistor value */ | |
35 | ||
36 | /* Current unit measurement in uA for a 1 milli-ohm sense resistor */ | |
37 | #define DS2782_CURRENT_UNITS 1563 | |
38 | ||
9b9ade6b YV |
39 | #define DS2786_REG_RARC 0x02 /* Remaining active relative capacity */ |
40 | ||
41 | #define DS2786_CURRENT_UNITS 25 | |
42 | ||
43 | struct ds278x_info; | |
44 | ||
45 | struct ds278x_battery_ops { | |
46 | int (*get_current)(struct ds278x_info *info, int *current_uA); | |
47 | int (*get_voltage)(struct ds278x_info *info, int *voltage_uA); | |
48 | int (*get_capacity)(struct ds278x_info *info, int *capacity_uA); | |
49 | ||
50 | }; | |
51 | ||
52 | #define to_ds278x_info(x) container_of(x, struct ds278x_info, battery) | |
bfdb46ce | 53 | |
9b9ade6b | 54 | struct ds278x_info { |
bfdb46ce RM |
55 | struct i2c_client *client; |
56 | struct power_supply battery; | |
9b9ade6b | 57 | struct ds278x_battery_ops *ops; |
bfdb46ce | 58 | int id; |
9b9ade6b | 59 | int rsns; |
bfdb46ce RM |
60 | }; |
61 | ||
62 | static DEFINE_IDR(battery_id); | |
63 | static DEFINE_MUTEX(battery_lock); | |
64 | ||
9b9ade6b | 65 | static inline int ds278x_read_reg(struct ds278x_info *info, int reg, u8 *val) |
bfdb46ce RM |
66 | { |
67 | int ret; | |
68 | ||
69 | ret = i2c_smbus_read_byte_data(info->client, reg); | |
70 | if (ret < 0) { | |
71 | dev_err(&info->client->dev, "register read failed\n"); | |
72 | return ret; | |
73 | } | |
74 | ||
75 | *val = ret; | |
76 | return 0; | |
77 | } | |
78 | ||
9b9ade6b | 79 | static inline int ds278x_read_reg16(struct ds278x_info *info, int reg_msb, |
bfdb46ce RM |
80 | s16 *val) |
81 | { | |
82 | int ret; | |
83 | ||
84 | ret = swab16(i2c_smbus_read_word_data(info->client, reg_msb)); | |
85 | if (ret < 0) { | |
86 | dev_err(&info->client->dev, "register read failed\n"); | |
87 | return ret; | |
88 | } | |
89 | ||
90 | *val = ret; | |
91 | return 0; | |
92 | } | |
93 | ||
9b9ade6b | 94 | static int ds278x_get_temp(struct ds278x_info *info, int *temp) |
bfdb46ce RM |
95 | { |
96 | s16 raw; | |
97 | int err; | |
98 | ||
99 | /* | |
100 | * Temperature is measured in units of 0.125 degrees celcius, the | |
101 | * power_supply class measures temperature in tenths of degrees | |
102 | * celsius. The temperature value is stored as a 10 bit number, plus | |
103 | * sign in the upper bits of a 16 bit register. | |
104 | */ | |
9b9ade6b | 105 | err = ds278x_read_reg16(info, DS278x_REG_TEMP_MSB, &raw); |
bfdb46ce RM |
106 | if (err) |
107 | return err; | |
108 | *temp = ((raw / 32) * 125) / 100; | |
109 | return 0; | |
110 | } | |
111 | ||
9b9ade6b | 112 | static int ds2782_get_current(struct ds278x_info *info, int *current_uA) |
bfdb46ce RM |
113 | { |
114 | int sense_res; | |
115 | int err; | |
116 | u8 sense_res_raw; | |
117 | s16 raw; | |
118 | ||
119 | /* | |
120 | * The units of measurement for current are dependent on the value of | |
121 | * the sense resistor. | |
122 | */ | |
9b9ade6b | 123 | err = ds278x_read_reg(info, DS2782_REG_RSNSP, &sense_res_raw); |
bfdb46ce RM |
124 | if (err) |
125 | return err; | |
126 | if (sense_res_raw == 0) { | |
127 | dev_err(&info->client->dev, "sense resistor value is 0\n"); | |
128 | return -ENXIO; | |
129 | } | |
130 | sense_res = 1000 / sense_res_raw; | |
131 | ||
132 | dev_dbg(&info->client->dev, "sense resistor = %d milli-ohms\n", | |
133 | sense_res); | |
9b9ade6b | 134 | err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw); |
bfdb46ce RM |
135 | if (err) |
136 | return err; | |
137 | *current_uA = raw * (DS2782_CURRENT_UNITS / sense_res); | |
138 | return 0; | |
139 | } | |
140 | ||
9b9ade6b | 141 | static int ds2782_get_voltage(struct ds278x_info *info, int *voltage_uA) |
bfdb46ce RM |
142 | { |
143 | s16 raw; | |
144 | int err; | |
145 | ||
146 | /* | |
147 | * Voltage is measured in units of 4.88mV. The voltage is stored as | |
148 | * a 10-bit number plus sign, in the upper bits of a 16-bit register | |
149 | */ | |
9b9ade6b | 150 | err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw); |
bfdb46ce RM |
151 | if (err) |
152 | return err; | |
153 | *voltage_uA = (raw / 32) * 4800; | |
154 | return 0; | |
155 | } | |
156 | ||
9b9ade6b | 157 | static int ds2782_get_capacity(struct ds278x_info *info, int *capacity) |
bfdb46ce RM |
158 | { |
159 | int err; | |
160 | u8 raw; | |
161 | ||
9b9ade6b | 162 | err = ds278x_read_reg(info, DS2782_REG_RARC, &raw); |
bfdb46ce RM |
163 | if (err) |
164 | return err; | |
165 | *capacity = raw; | |
166 | return raw; | |
167 | } | |
168 | ||
9b9ade6b YV |
169 | static int ds2786_get_current(struct ds278x_info *info, int *current_uA) |
170 | { | |
171 | int err; | |
172 | s16 raw; | |
173 | ||
174 | err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw); | |
175 | if (err) | |
176 | return err; | |
177 | *current_uA = (raw / 16) * (DS2786_CURRENT_UNITS / info->rsns); | |
178 | return 0; | |
179 | } | |
180 | ||
181 | static int ds2786_get_voltage(struct ds278x_info *info, int *voltage_uA) | |
182 | { | |
183 | s16 raw; | |
184 | int err; | |
185 | ||
186 | /* | |
187 | * Voltage is measured in units of 1.22mV. The voltage is stored as | |
188 | * a 10-bit number plus sign, in the upper bits of a 16-bit register | |
189 | */ | |
190 | err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw); | |
191 | if (err) | |
192 | return err; | |
193 | *voltage_uA = (raw / 8) * 1220; | |
194 | return 0; | |
195 | } | |
196 | ||
197 | static int ds2786_get_capacity(struct ds278x_info *info, int *capacity) | |
198 | { | |
199 | int err; | |
200 | u8 raw; | |
201 | ||
202 | err = ds278x_read_reg(info, DS2786_REG_RARC, &raw); | |
203 | if (err) | |
204 | return err; | |
205 | /* Relative capacity is displayed with resolution 0.5 % */ | |
206 | *capacity = raw/2 ; | |
207 | return 0; | |
208 | } | |
209 | ||
210 | static int ds278x_get_status(struct ds278x_info *info, int *status) | |
bfdb46ce RM |
211 | { |
212 | int err; | |
213 | int current_uA; | |
214 | int capacity; | |
215 | ||
9b9ade6b | 216 | err = info->ops->get_current(info, ¤t_uA); |
bfdb46ce RM |
217 | if (err) |
218 | return err; | |
219 | ||
9b9ade6b | 220 | err = info->ops->get_capacity(info, &capacity); |
bfdb46ce RM |
221 | if (err) |
222 | return err; | |
223 | ||
224 | if (capacity == 100) | |
225 | *status = POWER_SUPPLY_STATUS_FULL; | |
226 | else if (current_uA == 0) | |
227 | *status = POWER_SUPPLY_STATUS_NOT_CHARGING; | |
228 | else if (current_uA < 0) | |
229 | *status = POWER_SUPPLY_STATUS_DISCHARGING; | |
230 | else | |
231 | *status = POWER_SUPPLY_STATUS_CHARGING; | |
232 | ||
233 | return 0; | |
234 | } | |
235 | ||
9b9ade6b | 236 | static int ds278x_battery_get_property(struct power_supply *psy, |
bfdb46ce RM |
237 | enum power_supply_property prop, |
238 | union power_supply_propval *val) | |
239 | { | |
9b9ade6b | 240 | struct ds278x_info *info = to_ds278x_info(psy); |
bfdb46ce RM |
241 | int ret; |
242 | ||
243 | switch (prop) { | |
244 | case POWER_SUPPLY_PROP_STATUS: | |
9b9ade6b | 245 | ret = ds278x_get_status(info, &val->intval); |
bfdb46ce RM |
246 | break; |
247 | ||
248 | case POWER_SUPPLY_PROP_CAPACITY: | |
9b9ade6b | 249 | ret = info->ops->get_capacity(info, &val->intval); |
bfdb46ce RM |
250 | break; |
251 | ||
252 | case POWER_SUPPLY_PROP_VOLTAGE_NOW: | |
9b9ade6b | 253 | ret = info->ops->get_voltage(info, &val->intval); |
bfdb46ce RM |
254 | break; |
255 | ||
256 | case POWER_SUPPLY_PROP_CURRENT_NOW: | |
9b9ade6b | 257 | ret = info->ops->get_current(info, &val->intval); |
bfdb46ce RM |
258 | break; |
259 | ||
260 | case POWER_SUPPLY_PROP_TEMP: | |
9b9ade6b | 261 | ret = ds278x_get_temp(info, &val->intval); |
bfdb46ce RM |
262 | break; |
263 | ||
264 | default: | |
265 | ret = -EINVAL; | |
266 | } | |
267 | ||
268 | return ret; | |
269 | } | |
270 | ||
9b9ade6b | 271 | static enum power_supply_property ds278x_battery_props[] = { |
bfdb46ce RM |
272 | POWER_SUPPLY_PROP_STATUS, |
273 | POWER_SUPPLY_PROP_CAPACITY, | |
274 | POWER_SUPPLY_PROP_VOLTAGE_NOW, | |
275 | POWER_SUPPLY_PROP_CURRENT_NOW, | |
276 | POWER_SUPPLY_PROP_TEMP, | |
277 | }; | |
278 | ||
9b9ade6b | 279 | static void ds278x_power_supply_init(struct power_supply *battery) |
bfdb46ce RM |
280 | { |
281 | battery->type = POWER_SUPPLY_TYPE_BATTERY; | |
9b9ade6b YV |
282 | battery->properties = ds278x_battery_props; |
283 | battery->num_properties = ARRAY_SIZE(ds278x_battery_props); | |
284 | battery->get_property = ds278x_battery_get_property; | |
bfdb46ce RM |
285 | battery->external_power_changed = NULL; |
286 | } | |
287 | ||
9b9ade6b | 288 | static int ds278x_battery_remove(struct i2c_client *client) |
bfdb46ce | 289 | { |
9b9ade6b | 290 | struct ds278x_info *info = i2c_get_clientdata(client); |
bfdb46ce RM |
291 | |
292 | power_supply_unregister(&info->battery); | |
293 | kfree(info->battery.name); | |
294 | ||
295 | mutex_lock(&battery_lock); | |
296 | idr_remove(&battery_id, info->id); | |
297 | mutex_unlock(&battery_lock); | |
298 | ||
bfdb46ce RM |
299 | kfree(info); |
300 | return 0; | |
301 | } | |
302 | ||
9b9ade6b YV |
303 | static struct ds278x_battery_ops ds278x_ops[] = { |
304 | [0] = { | |
305 | .get_current = ds2782_get_current, | |
306 | .get_voltage = ds2782_get_voltage, | |
307 | .get_capacity = ds2782_get_capacity, | |
308 | }, | |
309 | [1] = { | |
310 | .get_current = ds2786_get_current, | |
311 | .get_voltage = ds2786_get_voltage, | |
312 | .get_capacity = ds2786_get_capacity, | |
313 | } | |
314 | }; | |
315 | ||
316 | static int ds278x_battery_probe(struct i2c_client *client, | |
bfdb46ce RM |
317 | const struct i2c_device_id *id) |
318 | { | |
9b9ade6b YV |
319 | struct ds278x_platform_data *pdata = client->dev.platform_data; |
320 | struct ds278x_info *info; | |
bfdb46ce RM |
321 | int ret; |
322 | int num; | |
323 | ||
9b9ade6b YV |
324 | /* |
325 | * ds2786 should have the sense resistor value set | |
326 | * in the platform data | |
327 | */ | |
328 | if (id->driver_data == 1 && !pdata) { | |
329 | dev_err(&client->dev, "missing platform data for ds2786\n"); | |
330 | return -EINVAL; | |
331 | } | |
332 | ||
bfdb46ce RM |
333 | /* Get an ID for this battery */ |
334 | ret = idr_pre_get(&battery_id, GFP_KERNEL); | |
335 | if (ret == 0) { | |
336 | ret = -ENOMEM; | |
337 | goto fail_id; | |
338 | } | |
339 | ||
340 | mutex_lock(&battery_lock); | |
341 | ret = idr_get_new(&battery_id, client, &num); | |
342 | mutex_unlock(&battery_lock); | |
343 | if (ret < 0) | |
344 | goto fail_id; | |
345 | ||
346 | info = kzalloc(sizeof(*info), GFP_KERNEL); | |
347 | if (!info) { | |
348 | ret = -ENOMEM; | |
349 | goto fail_info; | |
350 | } | |
351 | ||
9b9ade6b | 352 | info->battery.name = kasprintf(GFP_KERNEL, "%s-%d", client->name, num); |
bfdb46ce RM |
353 | if (!info->battery.name) { |
354 | ret = -ENOMEM; | |
355 | goto fail_name; | |
356 | } | |
357 | ||
9b9ade6b YV |
358 | if (id->driver_data == 1) |
359 | info->rsns = pdata->rsns; | |
360 | ||
bfdb46ce RM |
361 | i2c_set_clientdata(client, info); |
362 | info->client = client; | |
9b9ade6b YV |
363 | info->id = num; |
364 | info->ops = &ds278x_ops[id->driver_data]; | |
365 | ds278x_power_supply_init(&info->battery); | |
bfdb46ce RM |
366 | |
367 | ret = power_supply_register(&client->dev, &info->battery); | |
368 | if (ret) { | |
369 | dev_err(&client->dev, "failed to register battery\n"); | |
370 | goto fail_register; | |
371 | } | |
372 | ||
373 | return 0; | |
374 | ||
375 | fail_register: | |
376 | kfree(info->battery.name); | |
377 | fail_name: | |
bfdb46ce RM |
378 | kfree(info); |
379 | fail_info: | |
380 | mutex_lock(&battery_lock); | |
381 | idr_remove(&battery_id, num); | |
382 | mutex_unlock(&battery_lock); | |
383 | fail_id: | |
384 | return ret; | |
385 | } | |
386 | ||
9b9ade6b | 387 | static const struct i2c_device_id ds278x_id[] = { |
bfdb46ce | 388 | {"ds2782", 0}, |
9b9ade6b | 389 | {"ds2786", 1}, |
bfdb46ce RM |
390 | {}, |
391 | }; | |
392 | ||
9b9ade6b | 393 | static struct i2c_driver ds278x_battery_driver = { |
bfdb46ce RM |
394 | .driver = { |
395 | .name = "ds2782-battery", | |
396 | }, | |
9b9ade6b YV |
397 | .probe = ds278x_battery_probe, |
398 | .remove = ds278x_battery_remove, | |
399 | .id_table = ds278x_id, | |
bfdb46ce RM |
400 | }; |
401 | ||
9b9ade6b | 402 | static int __init ds278x_init(void) |
bfdb46ce | 403 | { |
9b9ade6b | 404 | return i2c_add_driver(&ds278x_battery_driver); |
bfdb46ce | 405 | } |
9b9ade6b | 406 | module_init(ds278x_init); |
bfdb46ce | 407 | |
9b9ade6b | 408 | static void __exit ds278x_exit(void) |
bfdb46ce | 409 | { |
9b9ade6b | 410 | i2c_del_driver(&ds278x_battery_driver); |
bfdb46ce | 411 | } |
9b9ade6b | 412 | module_exit(ds278x_exit); |
bfdb46ce RM |
413 | |
414 | MODULE_AUTHOR("Ryan Mallon <ryan@bluewatersys.com>"); | |
415 | MODULE_DESCRIPTION("Maxim/Dallas DS2782 Stand-Alone Fuel Gauage IC driver"); | |
416 | MODULE_LICENSE("GPL"); |