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085bc24d ML |
1 | /* |
2 | * I2C client/driver for the Linear Technology LTC2941 and LTC2943 | |
3 | * Battery Gas Gauge IC | |
4 | * | |
5 | * Copyright (C) 2014 Topic Embedded Systems | |
6 | * | |
7 | * Author: Auryn Verwegen | |
8 | * Author: Mike Looijmans | |
9 | */ | |
10 | #include <linux/kernel.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/types.h> | |
13 | #include <linux/errno.h> | |
14 | #include <linux/swab.h> | |
15 | #include <linux/i2c.h> | |
16 | #include <linux/delay.h> | |
085bc24d ML |
17 | #include <linux/power_supply.h> |
18 | #include <linux/slab.h> | |
19 | ||
20 | #define I16_MSB(x) ((x >> 8) & 0xFF) | |
21 | #define I16_LSB(x) (x & 0xFF) | |
22 | ||
23 | #define LTC294X_WORK_DELAY 10 /* Update delay in seconds */ | |
24 | ||
25 | #define LTC294X_MAX_VALUE 0xFFFF | |
26 | #define LTC294X_MID_SUPPLY 0x7FFF | |
27 | ||
28 | #define LTC2941_MAX_PRESCALER_EXP 7 | |
29 | #define LTC2943_MAX_PRESCALER_EXP 6 | |
30 | ||
31 | enum ltc294x_reg { | |
32 | LTC294X_REG_STATUS = 0x00, | |
33 | LTC294X_REG_CONTROL = 0x01, | |
34 | LTC294X_REG_ACC_CHARGE_MSB = 0x02, | |
35 | LTC294X_REG_ACC_CHARGE_LSB = 0x03, | |
36 | LTC294X_REG_THRESH_HIGH_MSB = 0x04, | |
37 | LTC294X_REG_THRESH_HIGH_LSB = 0x05, | |
38 | LTC294X_REG_THRESH_LOW_MSB = 0x06, | |
39 | LTC294X_REG_THRESH_LOW_LSB = 0x07, | |
40 | LTC294X_REG_VOLTAGE_MSB = 0x08, | |
41 | LTC294X_REG_VOLTAGE_LSB = 0x09, | |
42 | LTC294X_REG_CURRENT_MSB = 0x0E, | |
43 | LTC294X_REG_CURRENT_LSB = 0x0F, | |
44 | LTC294X_REG_TEMPERATURE_MSB = 0x14, | |
45 | LTC294X_REG_TEMPERATURE_LSB = 0x15, | |
46 | }; | |
47 | ||
48 | #define LTC2943_REG_CONTROL_MODE_MASK (BIT(7) | BIT(6)) | |
49 | #define LTC2943_REG_CONTROL_MODE_SCAN BIT(7) | |
50 | #define LTC294X_REG_CONTROL_PRESCALER_MASK (BIT(5) | BIT(4) | BIT(3)) | |
51 | #define LTC294X_REG_CONTROL_SHUTDOWN_MASK (BIT(0)) | |
52 | #define LTC294X_REG_CONTROL_PRESCALER_SET(x) \ | |
53 | ((x << 3) & LTC294X_REG_CONTROL_PRESCALER_MASK) | |
54 | #define LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED 0 | |
55 | ||
56 | #define LTC2941_NUM_REGS 0x08 | |
57 | #define LTC2943_NUM_REGS 0x18 | |
58 | ||
59 | struct ltc294x_info { | |
60 | struct i2c_client *client; /* I2C Client pointer */ | |
297d716f KK |
61 | struct power_supply *supply; /* Supply pointer */ |
62 | struct power_supply_desc supply_desc; /* Supply description */ | |
085bc24d ML |
63 | struct delayed_work work; /* Work scheduler */ |
64 | int num_regs; /* Number of registers (chip type) */ | |
085bc24d ML |
65 | int charge; /* Last charge register content */ |
66 | int r_sense; /* mOhm */ | |
67 | int Qlsb; /* nAh */ | |
68 | }; | |
69 | ||
085bc24d ML |
70 | static inline int convert_bin_to_uAh( |
71 | const struct ltc294x_info *info, int Q) | |
72 | { | |
73 | return ((Q * (info->Qlsb / 10))) / 100; | |
74 | } | |
75 | ||
76 | static inline int convert_uAh_to_bin( | |
77 | const struct ltc294x_info *info, int uAh) | |
78 | { | |
79 | int Q; | |
80 | ||
81 | Q = (uAh * 100) / (info->Qlsb/10); | |
82 | return (Q < LTC294X_MAX_VALUE) ? Q : LTC294X_MAX_VALUE; | |
83 | } | |
84 | ||
85 | static int ltc294x_read_regs(struct i2c_client *client, | |
86 | enum ltc294x_reg reg, u8 *buf, int num_regs) | |
87 | { | |
88 | int ret; | |
89 | struct i2c_msg msgs[2] = { }; | |
90 | u8 reg_start = reg; | |
91 | ||
92 | msgs[0].addr = client->addr; | |
93 | msgs[0].len = 1; | |
94 | msgs[0].buf = ®_start; | |
95 | ||
96 | msgs[1].addr = client->addr; | |
97 | msgs[1].len = num_regs; | |
98 | msgs[1].buf = buf; | |
99 | msgs[1].flags = I2C_M_RD; | |
100 | ||
101 | ret = i2c_transfer(client->adapter, &msgs[0], 2); | |
102 | if (ret < 0) { | |
103 | dev_err(&client->dev, "ltc2941 read_reg failed!\n"); | |
104 | return ret; | |
105 | } | |
106 | ||
107 | dev_dbg(&client->dev, "%s (%#x, %d) -> %#x\n", | |
108 | __func__, reg, num_regs, *buf); | |
109 | ||
110 | return 0; | |
111 | } | |
112 | ||
113 | static int ltc294x_write_regs(struct i2c_client *client, | |
114 | enum ltc294x_reg reg, const u8 *buf, int num_regs) | |
115 | { | |
116 | int ret; | |
117 | u8 reg_start = reg; | |
118 | ||
119 | ret = i2c_smbus_write_i2c_block_data(client, reg_start, num_regs, buf); | |
120 | if (ret < 0) { | |
121 | dev_err(&client->dev, "ltc2941 write_reg failed!\n"); | |
122 | return ret; | |
123 | } | |
124 | ||
125 | dev_dbg(&client->dev, "%s (%#x, %d) -> %#x\n", | |
126 | __func__, reg, num_regs, *buf); | |
127 | ||
128 | return 0; | |
129 | } | |
130 | ||
131 | static int ltc294x_reset(const struct ltc294x_info *info, int prescaler_exp) | |
132 | { | |
133 | int ret; | |
134 | u8 value; | |
135 | u8 control; | |
136 | ||
137 | /* Read status and control registers */ | |
138 | ret = ltc294x_read_regs(info->client, LTC294X_REG_CONTROL, &value, 1); | |
139 | if (ret < 0) { | |
140 | dev_err(&info->client->dev, | |
141 | "Could not read registers from device\n"); | |
142 | goto error_exit; | |
143 | } | |
144 | ||
145 | control = LTC294X_REG_CONTROL_PRESCALER_SET(prescaler_exp) | | |
146 | LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED; | |
147 | /* Put the 2943 into "monitor" mode, so it measures every 10 sec */ | |
148 | if (info->num_regs == LTC2943_NUM_REGS) | |
149 | control |= LTC2943_REG_CONTROL_MODE_SCAN; | |
150 | ||
151 | if (value != control) { | |
152 | ret = ltc294x_write_regs(info->client, | |
153 | LTC294X_REG_CONTROL, &control, 1); | |
154 | if (ret < 0) { | |
155 | dev_err(&info->client->dev, | |
156 | "Could not write register\n"); | |
157 | goto error_exit; | |
158 | } | |
159 | } | |
160 | ||
161 | return 0; | |
162 | ||
163 | error_exit: | |
164 | return ret; | |
165 | } | |
166 | ||
167 | static int ltc294x_read_charge_register(const struct ltc294x_info *info) | |
168 | { | |
169 | int ret; | |
170 | u8 datar[2]; | |
171 | ||
172 | ret = ltc294x_read_regs(info->client, | |
173 | LTC294X_REG_ACC_CHARGE_MSB, &datar[0], 2); | |
174 | if (ret < 0) | |
175 | return ret; | |
176 | return (datar[0] << 8) + datar[1]; | |
177 | } | |
178 | ||
179 | static int ltc294x_get_charge_now(const struct ltc294x_info *info, int *val) | |
180 | { | |
181 | int value = ltc294x_read_charge_register(info); | |
182 | ||
183 | if (value < 0) | |
184 | return value; | |
185 | /* When r_sense < 0, this counts up when the battery discharges */ | |
186 | if (info->Qlsb < 0) | |
187 | value -= 0xFFFF; | |
188 | *val = convert_bin_to_uAh(info, value); | |
189 | return 0; | |
190 | } | |
191 | ||
192 | static int ltc294x_set_charge_now(const struct ltc294x_info *info, int val) | |
193 | { | |
194 | int ret; | |
195 | u8 dataw[2]; | |
196 | u8 ctrl_reg; | |
197 | s32 value; | |
198 | ||
199 | value = convert_uAh_to_bin(info, val); | |
200 | /* Direction depends on how sense+/- were connected */ | |
201 | if (info->Qlsb < 0) | |
202 | value += 0xFFFF; | |
203 | if ((value < 0) || (value > 0xFFFF)) /* input validation */ | |
204 | return -EINVAL; | |
205 | ||
206 | /* Read control register */ | |
207 | ret = ltc294x_read_regs(info->client, | |
208 | LTC294X_REG_CONTROL, &ctrl_reg, 1); | |
209 | if (ret < 0) | |
210 | return ret; | |
211 | /* Disable analog section */ | |
212 | ctrl_reg |= LTC294X_REG_CONTROL_SHUTDOWN_MASK; | |
213 | ret = ltc294x_write_regs(info->client, | |
214 | LTC294X_REG_CONTROL, &ctrl_reg, 1); | |
215 | if (ret < 0) | |
216 | return ret; | |
217 | /* Set new charge value */ | |
218 | dataw[0] = I16_MSB(value); | |
219 | dataw[1] = I16_LSB(value); | |
220 | ret = ltc294x_write_regs(info->client, | |
221 | LTC294X_REG_ACC_CHARGE_MSB, &dataw[0], 2); | |
222 | if (ret < 0) | |
223 | goto error_exit; | |
224 | /* Enable analog section */ | |
225 | error_exit: | |
226 | ctrl_reg &= ~LTC294X_REG_CONTROL_SHUTDOWN_MASK; | |
227 | ret = ltc294x_write_regs(info->client, | |
228 | LTC294X_REG_CONTROL, &ctrl_reg, 1); | |
229 | ||
230 | return ret < 0 ? ret : 0; | |
231 | } | |
232 | ||
233 | static int ltc294x_get_charge_counter( | |
234 | const struct ltc294x_info *info, int *val) | |
235 | { | |
236 | int value = ltc294x_read_charge_register(info); | |
237 | ||
238 | if (value < 0) | |
239 | return value; | |
240 | value -= LTC294X_MID_SUPPLY; | |
241 | *val = convert_bin_to_uAh(info, value); | |
242 | return 0; | |
243 | } | |
244 | ||
245 | static int ltc294x_get_voltage(const struct ltc294x_info *info, int *val) | |
246 | { | |
247 | int ret; | |
248 | u8 datar[2]; | |
249 | u32 value; | |
250 | ||
251 | ret = ltc294x_read_regs(info->client, | |
252 | LTC294X_REG_VOLTAGE_MSB, &datar[0], 2); | |
253 | value = (datar[0] << 8) | datar[1]; | |
254 | *val = ((value * 23600) / 0xFFFF) * 1000; /* in uV */ | |
255 | return ret; | |
256 | } | |
257 | ||
258 | static int ltc294x_get_current(const struct ltc294x_info *info, int *val) | |
259 | { | |
260 | int ret; | |
261 | u8 datar[2]; | |
262 | s32 value; | |
263 | ||
264 | ret = ltc294x_read_regs(info->client, | |
265 | LTC294X_REG_CURRENT_MSB, &datar[0], 2); | |
266 | value = (datar[0] << 8) | datar[1]; | |
267 | value -= 0x7FFF; | |
268 | /* Value is in range -32k..+32k, r_sense is usually 10..50 mOhm, | |
269 | * the formula below keeps everything in s32 range while preserving | |
270 | * enough digits */ | |
271 | *val = 1000 * ((60000 * value) / (info->r_sense * 0x7FFF)); /* in uA */ | |
272 | return ret; | |
273 | } | |
274 | ||
275 | static int ltc294x_get_temperature(const struct ltc294x_info *info, int *val) | |
276 | { | |
277 | int ret; | |
278 | u8 datar[2]; | |
279 | u32 value; | |
280 | ||
281 | ret = ltc294x_read_regs(info->client, | |
282 | LTC294X_REG_TEMPERATURE_MSB, &datar[0], 2); | |
283 | value = (datar[0] << 8) | datar[1]; | |
284 | /* Full-scale is 510 Kelvin, convert to centidegrees */ | |
285 | *val = (((51000 * value) / 0xFFFF) - 27215); | |
286 | return ret; | |
287 | } | |
288 | ||
289 | static int ltc294x_get_property(struct power_supply *psy, | |
290 | enum power_supply_property prop, | |
291 | union power_supply_propval *val) | |
292 | { | |
297d716f | 293 | struct ltc294x_info *info = power_supply_get_drvdata(psy); |
085bc24d ML |
294 | |
295 | switch (prop) { | |
296 | case POWER_SUPPLY_PROP_CHARGE_NOW: | |
297 | return ltc294x_get_charge_now(info, &val->intval); | |
298 | case POWER_SUPPLY_PROP_CHARGE_COUNTER: | |
299 | return ltc294x_get_charge_counter(info, &val->intval); | |
300 | case POWER_SUPPLY_PROP_VOLTAGE_NOW: | |
301 | return ltc294x_get_voltage(info, &val->intval); | |
302 | case POWER_SUPPLY_PROP_CURRENT_NOW: | |
303 | return ltc294x_get_current(info, &val->intval); | |
304 | case POWER_SUPPLY_PROP_TEMP: | |
305 | return ltc294x_get_temperature(info, &val->intval); | |
306 | default: | |
307 | return -EINVAL; | |
308 | } | |
309 | } | |
310 | ||
311 | static int ltc294x_set_property(struct power_supply *psy, | |
312 | enum power_supply_property psp, | |
313 | const union power_supply_propval *val) | |
314 | { | |
297d716f | 315 | struct ltc294x_info *info = power_supply_get_drvdata(psy); |
085bc24d ML |
316 | |
317 | switch (psp) { | |
318 | case POWER_SUPPLY_PROP_CHARGE_NOW: | |
319 | return ltc294x_set_charge_now(info, val->intval); | |
320 | default: | |
321 | return -EPERM; | |
322 | } | |
323 | } | |
324 | ||
325 | static int ltc294x_property_is_writeable( | |
326 | struct power_supply *psy, enum power_supply_property psp) | |
327 | { | |
328 | switch (psp) { | |
329 | case POWER_SUPPLY_PROP_CHARGE_NOW: | |
330 | return 1; | |
331 | default: | |
332 | return 0; | |
333 | } | |
334 | } | |
335 | ||
336 | static void ltc294x_update(struct ltc294x_info *info) | |
337 | { | |
338 | int charge = ltc294x_read_charge_register(info); | |
339 | ||
340 | if (charge != info->charge) { | |
341 | info->charge = charge; | |
297d716f | 342 | power_supply_changed(info->supply); |
085bc24d ML |
343 | } |
344 | } | |
345 | ||
346 | static void ltc294x_work(struct work_struct *work) | |
347 | { | |
348 | struct ltc294x_info *info; | |
349 | ||
350 | info = container_of(work, struct ltc294x_info, work.work); | |
351 | ltc294x_update(info); | |
352 | schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ); | |
353 | } | |
354 | ||
355 | static enum power_supply_property ltc294x_properties[] = { | |
356 | POWER_SUPPLY_PROP_CHARGE_COUNTER, | |
357 | POWER_SUPPLY_PROP_CHARGE_NOW, | |
358 | POWER_SUPPLY_PROP_VOLTAGE_NOW, | |
359 | POWER_SUPPLY_PROP_CURRENT_NOW, | |
360 | POWER_SUPPLY_PROP_TEMP, | |
361 | }; | |
362 | ||
363 | static int ltc294x_i2c_remove(struct i2c_client *client) | |
364 | { | |
365 | struct ltc294x_info *info = i2c_get_clientdata(client); | |
366 | ||
367 | cancel_delayed_work(&info->work); | |
297d716f | 368 | power_supply_unregister(info->supply); |
085bc24d ML |
369 | return 0; |
370 | } | |
371 | ||
372 | static int ltc294x_i2c_probe(struct i2c_client *client, | |
373 | const struct i2c_device_id *id) | |
374 | { | |
297d716f | 375 | struct power_supply_config psy_cfg = {}; |
085bc24d ML |
376 | struct ltc294x_info *info; |
377 | int ret; | |
085bc24d ML |
378 | u32 prescaler_exp; |
379 | s32 r_sense; | |
380 | struct device_node *np; | |
381 | ||
085bc24d | 382 | info = devm_kzalloc(&client->dev, sizeof(*info), GFP_KERNEL); |
377b641a ML |
383 | if (info == NULL) |
384 | return -ENOMEM; | |
085bc24d ML |
385 | |
386 | i2c_set_clientdata(client, info); | |
387 | ||
085bc24d ML |
388 | np = of_node_get(client->dev.of_node); |
389 | ||
377b641a ML |
390 | info->num_regs = id->driver_data; |
391 | info->supply_desc.name = np->name; | |
392 | ||
085bc24d ML |
393 | /* r_sense can be negative, when sense+ is connected to the battery |
394 | * instead of the sense-. This results in reversed measurements. */ | |
395 | ret = of_property_read_u32(np, "lltc,resistor-sense", &r_sense); | |
396 | if (ret < 0) { | |
397 | dev_err(&client->dev, | |
398 | "Could not find lltc,resistor-sense in devicetree\n"); | |
377b641a | 399 | return ret; |
085bc24d ML |
400 | } |
401 | info->r_sense = r_sense; | |
402 | ||
403 | ret = of_property_read_u32(np, "lltc,prescaler-exponent", | |
404 | &prescaler_exp); | |
405 | if (ret < 0) { | |
406 | dev_warn(&client->dev, | |
407 | "lltc,prescaler-exponent not in devicetree\n"); | |
408 | prescaler_exp = LTC2941_MAX_PRESCALER_EXP; | |
409 | } | |
410 | ||
411 | if (info->num_regs == LTC2943_NUM_REGS) { | |
412 | if (prescaler_exp > LTC2943_MAX_PRESCALER_EXP) | |
413 | prescaler_exp = LTC2943_MAX_PRESCALER_EXP; | |
414 | info->Qlsb = ((340 * 50000) / r_sense) / | |
415 | (4096 / (1 << (2*prescaler_exp))); | |
416 | } else { | |
417 | if (prescaler_exp > LTC2941_MAX_PRESCALER_EXP) | |
418 | prescaler_exp = LTC2941_MAX_PRESCALER_EXP; | |
4bf828cf | 419 | info->Qlsb = ((85 * 50000) / r_sense) / |
085bc24d ML |
420 | (128 / (1 << prescaler_exp)); |
421 | } | |
422 | ||
423 | info->client = client; | |
297d716f KK |
424 | info->supply_desc.type = POWER_SUPPLY_TYPE_BATTERY; |
425 | info->supply_desc.properties = ltc294x_properties; | |
085bc24d | 426 | if (info->num_regs >= LTC294X_REG_TEMPERATURE_LSB) |
297d716f | 427 | info->supply_desc.num_properties = |
085bc24d ML |
428 | ARRAY_SIZE(ltc294x_properties); |
429 | else if (info->num_regs >= LTC294X_REG_CURRENT_LSB) | |
297d716f | 430 | info->supply_desc.num_properties = |
085bc24d ML |
431 | ARRAY_SIZE(ltc294x_properties) - 1; |
432 | else if (info->num_regs >= LTC294X_REG_VOLTAGE_LSB) | |
297d716f | 433 | info->supply_desc.num_properties = |
085bc24d ML |
434 | ARRAY_SIZE(ltc294x_properties) - 2; |
435 | else | |
297d716f | 436 | info->supply_desc.num_properties = |
085bc24d | 437 | ARRAY_SIZE(ltc294x_properties) - 3; |
297d716f KK |
438 | info->supply_desc.get_property = ltc294x_get_property; |
439 | info->supply_desc.set_property = ltc294x_set_property; | |
440 | info->supply_desc.property_is_writeable = ltc294x_property_is_writeable; | |
441 | info->supply_desc.external_power_changed = NULL; | |
442 | ||
443 | psy_cfg.drv_data = info; | |
085bc24d ML |
444 | |
445 | INIT_DELAYED_WORK(&info->work, ltc294x_work); | |
446 | ||
447 | ret = ltc294x_reset(info, prescaler_exp); | |
448 | if (ret < 0) { | |
449 | dev_err(&client->dev, "Communication with chip failed\n"); | |
377b641a | 450 | return ret; |
085bc24d ML |
451 | } |
452 | ||
297d716f KK |
453 | info->supply = power_supply_register(&client->dev, &info->supply_desc, |
454 | &psy_cfg); | |
455 | if (IS_ERR(info->supply)) { | |
085bc24d | 456 | dev_err(&client->dev, "failed to register ltc2941\n"); |
377b641a | 457 | return PTR_ERR(info->supply); |
085bc24d ML |
458 | } else { |
459 | schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ); | |
460 | } | |
461 | ||
462 | return 0; | |
085bc24d ML |
463 | } |
464 | ||
465 | #ifdef CONFIG_PM_SLEEP | |
466 | ||
467 | static int ltc294x_suspend(struct device *dev) | |
468 | { | |
469 | struct i2c_client *client = to_i2c_client(dev); | |
470 | struct ltc294x_info *info = i2c_get_clientdata(client); | |
471 | ||
472 | cancel_delayed_work(&info->work); | |
473 | return 0; | |
474 | } | |
475 | ||
476 | static int ltc294x_resume(struct device *dev) | |
477 | { | |
478 | struct i2c_client *client = to_i2c_client(dev); | |
479 | struct ltc294x_info *info = i2c_get_clientdata(client); | |
480 | ||
481 | schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ); | |
482 | return 0; | |
483 | } | |
484 | ||
485 | static SIMPLE_DEV_PM_OPS(ltc294x_pm_ops, ltc294x_suspend, ltc294x_resume); | |
486 | #define LTC294X_PM_OPS (<c294x_pm_ops) | |
487 | ||
488 | #else | |
489 | #define LTC294X_PM_OPS NULL | |
490 | #endif /* CONFIG_PM_SLEEP */ | |
491 | ||
492 | ||
493 | static const struct i2c_device_id ltc294x_i2c_id[] = { | |
494 | {"ltc2941", LTC2941_NUM_REGS}, | |
495 | {"ltc2943", LTC2943_NUM_REGS}, | |
496 | { }, | |
497 | }; | |
498 | MODULE_DEVICE_TABLE(i2c, ltc294x_i2c_id); | |
499 | ||
500 | static struct i2c_driver ltc294x_driver = { | |
501 | .driver = { | |
502 | .name = "LTC2941", | |
503 | .pm = LTC294X_PM_OPS, | |
504 | }, | |
505 | .probe = ltc294x_i2c_probe, | |
506 | .remove = ltc294x_i2c_remove, | |
507 | .id_table = ltc294x_i2c_id, | |
508 | }; | |
509 | module_i2c_driver(ltc294x_driver); | |
510 | ||
511 | MODULE_AUTHOR("Auryn Verwegen, Topic Embedded Systems"); | |
512 | MODULE_AUTHOR("Mike Looijmans, Topic Embedded Products"); | |
513 | MODULE_DESCRIPTION("LTC2941/LTC2943 Battery Gas Gauge IC driver"); | |
514 | MODULE_LICENSE("GPL"); |