1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * I2C client/driver for the Linear Technology LTC2941, LTC2942, LTC2943
4 * and LTC2944 Battery Gas Gauge IC
5 *
6 * Copyright (C) 2014 Topic Embedded Systems
7 *
8 * Author: Auryn Verwegen
9 * Author: Mike Looijmans
10 */
11#include <linux/devm-helpers.h>
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/of.h>
15#include <linux/types.h>
16#include <linux/errno.h>
17#include <linux/swab.h>
18#include <linux/i2c.h>
19#include <linux/delay.h>
20#include <linux/power_supply.h>
21#include <linux/slab.h>
22
23#define I16_MSB(x) ((x >> 8) & 0xFF)
24#define I16_LSB(x) (x & 0xFF)
25
26#define LTC294X_WORK_DELAY 10 /* Update delay in seconds */
27
28#define LTC294X_MAX_VALUE 0xFFFF
29#define LTC294X_MID_SUPPLY 0x7FFF
30
31#define LTC2941_MAX_PRESCALER_EXP 7
32#define LTC2943_MAX_PRESCALER_EXP 6
33
34enum ltc294x_reg {
35 LTC294X_REG_STATUS = 0x00,
36 LTC294X_REG_CONTROL = 0x01,
37 LTC294X_REG_ACC_CHARGE_MSB = 0x02,
38 LTC294X_REG_ACC_CHARGE_LSB = 0x03,
39 LTC294X_REG_CHARGE_THR_HIGH_MSB = 0x04,
40 LTC294X_REG_CHARGE_THR_HIGH_LSB = 0x05,
41 LTC294X_REG_CHARGE_THR_LOW_MSB = 0x06,
42 LTC294X_REG_CHARGE_THR_LOW_LSB = 0x07,
43 LTC294X_REG_VOLTAGE_MSB = 0x08,
44 LTC294X_REG_VOLTAGE_LSB = 0x09,
45 LTC2942_REG_TEMPERATURE_MSB = 0x0C,
46 LTC2942_REG_TEMPERATURE_LSB = 0x0D,
47 LTC2943_REG_CURRENT_MSB = 0x0E,
48 LTC2943_REG_CURRENT_LSB = 0x0F,
49 LTC2943_REG_TEMPERATURE_MSB = 0x14,
50 LTC2943_REG_TEMPERATURE_LSB = 0x15,
51};
52
53enum ltc294x_id {
54 LTC2941_ID,
55 LTC2942_ID,
56 LTC2943_ID,
57 LTC2944_ID,
58};
59
60#define LTC2941_REG_STATUS_CHIP_ID BIT(7)
61
62#define LTC2942_REG_CONTROL_MODE_SCAN (BIT(7) | BIT(6))
63#define LTC2943_REG_CONTROL_MODE_SCAN BIT(7)
64#define LTC294X_REG_CONTROL_PRESCALER_MASK (BIT(5) | BIT(4) | BIT(3))
65#define LTC294X_REG_CONTROL_SHUTDOWN_MASK (BIT(0))
66#define LTC294X_REG_CONTROL_PRESCALER_SET(x) \
67 ((x << 3) & LTC294X_REG_CONTROL_PRESCALER_MASK)
68#define LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED 0
69#define LTC294X_REG_CONTROL_ADC_DISABLE(x) ((x) & ~(BIT(7) | BIT(6)))
70
71struct ltc294x_info {
72 struct i2c_client *client; /* I2C Client pointer */
73 struct power_supply *supply; /* Supply pointer */
74 struct power_supply_desc supply_desc; /* Supply description */
75 struct delayed_work work; /* Work scheduler */
76 enum ltc294x_id id; /* Chip type */
77 int charge; /* Last charge register content */
78 int r_sense; /* mOhm */
79 int Qlsb; /* nAh */
80};
81
82static inline int convert_bin_to_uAh(
83 const struct ltc294x_info *info, int Q)
84{
85 return ((Q * (info->Qlsb / 10))) / 100;
86}
87
88static inline int convert_uAh_to_bin(
89 const struct ltc294x_info *info, int uAh)
90{
91 int Q;
92
93 Q = (uAh * 100) / (info->Qlsb/10);
94 return (Q < LTC294X_MAX_VALUE) ? Q : LTC294X_MAX_VALUE;
95}
96
97static int ltc294x_read_regs(struct i2c_client *client,
98 enum ltc294x_reg reg, u8 *buf, int num_regs)
99{
100 int ret;
101 struct i2c_msg msgs[2] = { };
102 u8 reg_start = reg;
103
104 msgs[0].addr = client->addr;
105 msgs[0].len = 1;
106 msgs[0].buf = &reg_start;
107
108 msgs[1].addr = client->addr;
109 msgs[1].len = num_regs;
110 msgs[1].buf = buf;
111 msgs[1].flags = I2C_M_RD;
112
113 ret = i2c_transfer(adap: client->adapter, msgs: &msgs[0], num: 2);
114 if (ret < 0) {
115 dev_err(&client->dev, "ltc2941 read_reg(0x%x[%d]) failed: %pe\n",
116 reg, num_regs, ERR_PTR(ret));
117 return ret;
118 }
119
120 dev_dbg(&client->dev, "%s (%#x, %d) -> %#x\n",
121 __func__, reg, num_regs, *buf);
122
123 return 0;
124}
125
126static int ltc294x_write_regs(struct i2c_client *client,
127 enum ltc294x_reg reg, const u8 *buf, int num_regs)
128{
129 int ret;
130 u8 reg_start = reg;
131
132 ret = i2c_smbus_write_i2c_block_data(client, command: reg_start, length: num_regs, values: buf);
133 if (ret < 0) {
134 dev_err(&client->dev, "ltc2941 write_reg(0x%x[%d]) failed: %pe\n",
135 reg, num_regs, ERR_PTR(ret));
136 return ret;
137 }
138
139 dev_dbg(&client->dev, "%s (%#x, %d) -> %#x\n",
140 __func__, reg, num_regs, *buf);
141
142 return 0;
143}
144
145static int ltc294x_reset(const struct ltc294x_info *info, int prescaler_exp)
146{
147 int ret;
148 u8 value;
149 u8 control;
150
151 /* Read status and control registers */
152 ret = ltc294x_read_regs(client: info->client, reg: LTC294X_REG_CONTROL, buf: &value, num_regs: 1);
153 if (ret < 0)
154 return ret;
155
156 control = LTC294X_REG_CONTROL_PRESCALER_SET(prescaler_exp) |
157 LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED;
158 /* Put device into "monitor" mode */
159 switch (info->id) {
160 case LTC2942_ID: /* 2942 measures every 2 sec */
161 control |= LTC2942_REG_CONTROL_MODE_SCAN;
162 break;
163 case LTC2943_ID:
164 case LTC2944_ID: /* 2943 and 2944 measure every 10 sec */
165 control |= LTC2943_REG_CONTROL_MODE_SCAN;
166 break;
167 default:
168 break;
169 }
170
171 if (value != control) {
172 ret = ltc294x_write_regs(client: info->client,
173 reg: LTC294X_REG_CONTROL, buf: &control, num_regs: 1);
174 if (ret < 0)
175 return ret;
176 }
177
178 return 0;
179}
180
181static int ltc294x_read_charge_register(const struct ltc294x_info *info,
182 enum ltc294x_reg reg)
183 {
184 int ret;
185 u8 datar[2];
186
187 ret = ltc294x_read_regs(client: info->client, reg, buf: &datar[0], num_regs: 2);
188 if (ret < 0)
189 return ret;
190 return (datar[0] << 8) + datar[1];
191}
192
193static int ltc294x_get_charge(const struct ltc294x_info *info,
194 enum ltc294x_reg reg, int *val)
195{
196 int value = ltc294x_read_charge_register(info, reg);
197
198 if (value < 0)
199 return value;
200 /* When r_sense < 0, this counts up when the battery discharges */
201 if (info->Qlsb < 0)
202 value -= 0xFFFF;
203 *val = convert_bin_to_uAh(info, Q: value);
204 return 0;
205}
206
207static int ltc294x_set_charge_now(const struct ltc294x_info *info, int val)
208{
209 int ret;
210 u8 dataw[2];
211 u8 ctrl_reg;
212 s32 value;
213
214 value = convert_uAh_to_bin(info, uAh: val);
215 /* Direction depends on how sense+/- were connected */
216 if (info->Qlsb < 0)
217 value += 0xFFFF;
218 if ((value < 0) || (value > 0xFFFF)) /* input validation */
219 return -EINVAL;
220
221 /* Read control register */
222 ret = ltc294x_read_regs(client: info->client,
223 reg: LTC294X_REG_CONTROL, buf: &ctrl_reg, num_regs: 1);
224 if (ret < 0)
225 return ret;
226 /* Disable analog section */
227 ctrl_reg |= LTC294X_REG_CONTROL_SHUTDOWN_MASK;
228 ret = ltc294x_write_regs(client: info->client,
229 reg: LTC294X_REG_CONTROL, buf: &ctrl_reg, num_regs: 1);
230 if (ret < 0)
231 return ret;
232 /* Set new charge value */
233 dataw[0] = I16_MSB(value);
234 dataw[1] = I16_LSB(value);
235 ret = ltc294x_write_regs(client: info->client,
236 reg: LTC294X_REG_ACC_CHARGE_MSB, buf: &dataw[0], num_regs: 2);
237 if (ret < 0)
238 goto error_exit;
239 /* Enable analog section */
240error_exit:
241 ctrl_reg &= ~LTC294X_REG_CONTROL_SHUTDOWN_MASK;
242 ret = ltc294x_write_regs(client: info->client,
243 reg: LTC294X_REG_CONTROL, buf: &ctrl_reg, num_regs: 1);
244
245 return ret < 0 ? ret : 0;
246}
247
248static int ltc294x_set_charge_thr(const struct ltc294x_info *info,
249 enum ltc294x_reg reg, int val)
250{
251 u8 dataw[2];
252 s32 value;
253
254 value = convert_uAh_to_bin(info, uAh: val);
255 /* Direction depends on how sense+/- were connected */
256 if (info->Qlsb < 0)
257 value += 0xFFFF;
258 if ((value < 0) || (value > 0xFFFF)) /* input validation */
259 return -EINVAL;
260
261 /* Set new charge value */
262 dataw[0] = I16_MSB(value);
263 dataw[1] = I16_LSB(value);
264 return ltc294x_write_regs(client: info->client, reg, buf: &dataw[0], num_regs: 2);
265}
266
267static int ltc294x_get_charge_counter(
268 const struct ltc294x_info *info, int *val)
269{
270 int value = ltc294x_read_charge_register(info, reg: LTC294X_REG_ACC_CHARGE_MSB);
271
272 if (value < 0)
273 return value;
274 value -= LTC294X_MID_SUPPLY;
275 *val = convert_bin_to_uAh(info, Q: value);
276 return 0;
277}
278
279static int ltc294x_get_voltage(const struct ltc294x_info *info, int *val)
280{
281 int ret;
282 u8 datar[2];
283 u32 value;
284
285 ret = ltc294x_read_regs(client: info->client,
286 reg: LTC294X_REG_VOLTAGE_MSB, buf: &datar[0], num_regs: 2);
287 value = (datar[0] << 8) | datar[1];
288 switch (info->id) {
289 case LTC2943_ID:
290 value *= 23600 * 2;
291 value /= 0xFFFF;
292 value *= 1000 / 2;
293 break;
294 case LTC2944_ID:
295 value *= 70800 / 5*4;
296 value /= 0xFFFF;
297 value *= 1000 * 5/4;
298 break;
299 default:
300 value *= 6000 * 10;
301 value /= 0xFFFF;
302 value *= 1000 / 10;
303 break;
304 }
305 *val = value;
306 return ret;
307}
308
309static int ltc294x_get_current(const struct ltc294x_info *info, int *val)
310{
311 int ret;
312 u8 datar[2];
313 s32 value;
314
315 ret = ltc294x_read_regs(client: info->client,
316 reg: LTC2943_REG_CURRENT_MSB, buf: &datar[0], num_regs: 2);
317 value = (datar[0] << 8) | datar[1];
318 value -= 0x7FFF;
319 if (info->id == LTC2944_ID)
320 value *= 64000;
321 else
322 value *= 60000;
323 /* Value is in range -32k..+32k, r_sense is usually 10..50 mOhm,
324 * the formula below keeps everything in s32 range while preserving
325 * enough digits */
326 *val = 1000 * (value / (info->r_sense * 0x7FFF)); /* in uA */
327 return ret;
328}
329
330static int ltc294x_get_temperature(const struct ltc294x_info *info, int *val)
331{
332 enum ltc294x_reg reg;
333 int ret;
334 u8 datar[2];
335 u32 value;
336
337 if (info->id == LTC2942_ID) {
338 reg = LTC2942_REG_TEMPERATURE_MSB;
339 value = 6000; /* Full-scale is 600 Kelvin */
340 } else {
341 reg = LTC2943_REG_TEMPERATURE_MSB;
342 value = 5100; /* Full-scale is 510 Kelvin */
343 }
344 ret = ltc294x_read_regs(client: info->client, reg, buf: &datar[0], num_regs: 2);
345 value *= (datar[0] << 8) | datar[1];
346 /* Convert to tenths of degree Celsius */
347 *val = value / 0xFFFF - 2722;
348 return ret;
349}
350
351static int ltc294x_get_property(struct power_supply *psy,
352 enum power_supply_property prop,
353 union power_supply_propval *val)
354{
355 struct ltc294x_info *info = power_supply_get_drvdata(psy);
356
357 switch (prop) {
358 case POWER_SUPPLY_PROP_CHARGE_FULL:
359 return ltc294x_get_charge(info, reg: LTC294X_REG_CHARGE_THR_HIGH_MSB,
360 val: &val->intval);
361 case POWER_SUPPLY_PROP_CHARGE_EMPTY:
362 return ltc294x_get_charge(info, reg: LTC294X_REG_CHARGE_THR_LOW_MSB,
363 val: &val->intval);
364 case POWER_SUPPLY_PROP_CHARGE_NOW:
365 return ltc294x_get_charge(info, reg: LTC294X_REG_ACC_CHARGE_MSB,
366 val: &val->intval);
367 case POWER_SUPPLY_PROP_CHARGE_COUNTER:
368 return ltc294x_get_charge_counter(info, val: &val->intval);
369 case POWER_SUPPLY_PROP_VOLTAGE_NOW:
370 return ltc294x_get_voltage(info, val: &val->intval);
371 case POWER_SUPPLY_PROP_CURRENT_NOW:
372 return ltc294x_get_current(info, val: &val->intval);
373 case POWER_SUPPLY_PROP_TEMP:
374 return ltc294x_get_temperature(info, val: &val->intval);
375 default:
376 return -EINVAL;
377 }
378}
379
380static int ltc294x_set_property(struct power_supply *psy,
381 enum power_supply_property psp,
382 const union power_supply_propval *val)
383{
384 struct ltc294x_info *info = power_supply_get_drvdata(psy);
385
386 switch (psp) {
387 case POWER_SUPPLY_PROP_CHARGE_FULL:
388 return ltc294x_set_charge_thr(info,
389 reg: LTC294X_REG_CHARGE_THR_HIGH_MSB, val: val->intval);
390 case POWER_SUPPLY_PROP_CHARGE_EMPTY:
391 return ltc294x_set_charge_thr(info,
392 reg: LTC294X_REG_CHARGE_THR_LOW_MSB, val: val->intval);
393 case POWER_SUPPLY_PROP_CHARGE_NOW:
394 return ltc294x_set_charge_now(info, val: val->intval);
395 default:
396 return -EPERM;
397 }
398}
399
400static int ltc294x_property_is_writeable(
401 struct power_supply *psy, enum power_supply_property psp)
402{
403 switch (psp) {
404 case POWER_SUPPLY_PROP_CHARGE_FULL:
405 case POWER_SUPPLY_PROP_CHARGE_EMPTY:
406 case POWER_SUPPLY_PROP_CHARGE_NOW:
407 return 1;
408 default:
409 return 0;
410 }
411}
412
413static void ltc294x_update(struct ltc294x_info *info)
414{
415 int charge = ltc294x_read_charge_register(info, reg: LTC294X_REG_ACC_CHARGE_MSB);
416
417 if (charge != info->charge) {
418 info->charge = charge;
419 power_supply_changed(psy: info->supply);
420 }
421}
422
423static void ltc294x_work(struct work_struct *work)
424{
425 struct ltc294x_info *info;
426
427 info = container_of(work, struct ltc294x_info, work.work);
428 ltc294x_update(info);
429 schedule_delayed_work(dwork: &info->work, LTC294X_WORK_DELAY * HZ);
430}
431
432static enum power_supply_property ltc294x_properties[] = {
433 POWER_SUPPLY_PROP_CHARGE_COUNTER,
434 POWER_SUPPLY_PROP_CHARGE_FULL,
435 POWER_SUPPLY_PROP_CHARGE_EMPTY,
436 POWER_SUPPLY_PROP_CHARGE_NOW,
437 POWER_SUPPLY_PROP_VOLTAGE_NOW,
438 POWER_SUPPLY_PROP_TEMP,
439 POWER_SUPPLY_PROP_CURRENT_NOW,
440};
441
442static int ltc294x_i2c_probe(struct i2c_client *client)
443{
444 struct power_supply_config psy_cfg = {};
445 struct ltc294x_info *info;
446 struct device_node *np;
447 int ret;
448 u32 prescaler_exp;
449 s32 r_sense;
450 u8 status;
451
452 info = devm_kzalloc(dev: &client->dev, size: sizeof(*info), GFP_KERNEL);
453 if (info == NULL)
454 return -ENOMEM;
455
456 i2c_set_clientdata(client, data: info);
457
458 np = of_node_get(node: client->dev.of_node);
459
460 info->id = (enum ltc294x_id) (uintptr_t) of_device_get_match_data(
461 dev: &client->dev);
462 info->supply_desc.name = np->name;
463
464 /* r_sense can be negative, when sense+ is connected to the battery
465 * instead of the sense-. This results in reversed measurements. */
466 ret = of_property_read_u32(np, propname: "lltc,resistor-sense", out_value: &r_sense);
467 if (ret < 0)
468 return dev_err_probe(dev: &client->dev, err: ret,
469 fmt: "Could not find lltc,resistor-sense in devicetree\n");
470 info->r_sense = r_sense;
471
472 ret = of_property_read_u32(np, propname: "lltc,prescaler-exponent",
473 out_value: &prescaler_exp);
474 if (ret < 0) {
475 dev_warn(&client->dev,
476 "lltc,prescaler-exponent not in devicetree\n");
477 prescaler_exp = LTC2941_MAX_PRESCALER_EXP;
478 }
479
480 if (info->id == LTC2943_ID) {
481 if (prescaler_exp > LTC2943_MAX_PRESCALER_EXP)
482 prescaler_exp = LTC2943_MAX_PRESCALER_EXP;
483 info->Qlsb = ((340 * 50000) / r_sense) >>
484 (12 - 2*prescaler_exp);
485 } else {
486 if (prescaler_exp > LTC2941_MAX_PRESCALER_EXP)
487 prescaler_exp = LTC2941_MAX_PRESCALER_EXP;
488 info->Qlsb = ((85 * 50000) / r_sense) >>
489 (7 - prescaler_exp);
490 }
491
492 /* Read status register to check for LTC2942 */
493 if (info->id == LTC2941_ID || info->id == LTC2942_ID) {
494 ret = ltc294x_read_regs(client, reg: LTC294X_REG_STATUS, buf: &status, num_regs: 1);
495 if (ret < 0)
496 return dev_err_probe(dev: &client->dev, err: ret,
497 fmt: "Could not read status register\n");
498 if (status & LTC2941_REG_STATUS_CHIP_ID)
499 info->id = LTC2941_ID;
500 else
501 info->id = LTC2942_ID;
502 }
503
504 info->client = client;
505 info->supply_desc.type = POWER_SUPPLY_TYPE_BATTERY;
506 info->supply_desc.properties = ltc294x_properties;
507 switch (info->id) {
508 case LTC2944_ID:
509 case LTC2943_ID:
510 info->supply_desc.num_properties =
511 ARRAY_SIZE(ltc294x_properties);
512 break;
513 case LTC2942_ID:
514 info->supply_desc.num_properties =
515 ARRAY_SIZE(ltc294x_properties) - 1;
516 break;
517 case LTC2941_ID:
518 default:
519 info->supply_desc.num_properties =
520 ARRAY_SIZE(ltc294x_properties) - 3;
521 break;
522 }
523 info->supply_desc.get_property = ltc294x_get_property;
524 info->supply_desc.set_property = ltc294x_set_property;
525 info->supply_desc.property_is_writeable = ltc294x_property_is_writeable;
526 info->supply_desc.external_power_changed = NULL;
527
528 psy_cfg.drv_data = info;
529
530 ret = devm_delayed_work_autocancel(dev: &client->dev, w: &info->work,
531 worker: ltc294x_work);
532 if (ret)
533 return ret;
534
535 ret = ltc294x_reset(info, prescaler_exp);
536 if (ret < 0)
537 return dev_err_probe(dev: &client->dev, err: ret,
538 fmt: "Communication with chip failed\n");
539
540 info->supply = devm_power_supply_register(parent: &client->dev,
541 desc: &info->supply_desc, cfg: &psy_cfg);
542 if (IS_ERR(ptr: info->supply))
543 return dev_err_probe(dev: &client->dev, err: PTR_ERR(ptr: info->supply),
544 fmt: "failed to register ltc2941\n");
545
546 schedule_delayed_work(dwork: &info->work, LTC294X_WORK_DELAY * HZ);
547
548 return 0;
549}
550
551static void ltc294x_i2c_shutdown(struct i2c_client *client)
552{
553 struct ltc294x_info *info = i2c_get_clientdata(client);
554 int ret;
555 u8 value;
556 u8 control;
557
558 /* The LTC2941 does not need any special handling */
559 if (info->id == LTC2941_ID)
560 return;
561
562 /* Read control register */
563 ret = ltc294x_read_regs(client: info->client, reg: LTC294X_REG_CONTROL, buf: &value, num_regs: 1);
564 if (ret < 0)
565 return;
566
567 /* Disable continuous ADC conversion as this drains the battery */
568 control = LTC294X_REG_CONTROL_ADC_DISABLE(value);
569 if (control != value)
570 ltc294x_write_regs(client: info->client, reg: LTC294X_REG_CONTROL,
571 buf: &control, num_regs: 1);
572}
573
574#ifdef CONFIG_PM_SLEEP
575
576static int ltc294x_suspend(struct device *dev)
577{
578 struct i2c_client *client = to_i2c_client(dev);
579 struct ltc294x_info *info = i2c_get_clientdata(client);
580
581 cancel_delayed_work(dwork: &info->work);
582 return 0;
583}
584
585static int ltc294x_resume(struct device *dev)
586{
587 struct i2c_client *client = to_i2c_client(dev);
588 struct ltc294x_info *info = i2c_get_clientdata(client);
589
590 schedule_delayed_work(dwork: &info->work, LTC294X_WORK_DELAY * HZ);
591 return 0;
592}
593
594static SIMPLE_DEV_PM_OPS(ltc294x_pm_ops, ltc294x_suspend, ltc294x_resume);
595#define LTC294X_PM_OPS (&ltc294x_pm_ops)
596
597#else
598#define LTC294X_PM_OPS NULL
599#endif /* CONFIG_PM_SLEEP */
600
601
602static const struct i2c_device_id ltc294x_i2c_id[] = {
603 { "ltc2941", LTC2941_ID, },
604 { "ltc2942", LTC2942_ID, },
605 { "ltc2943", LTC2943_ID, },
606 { "ltc2944", LTC2944_ID, },
607 { },
608};
609MODULE_DEVICE_TABLE(i2c, ltc294x_i2c_id);
610
611static const struct of_device_id ltc294x_i2c_of_match[] = {
612 {
613 .compatible = "lltc,ltc2941",
614 .data = (void *)LTC2941_ID,
615 },
616 {
617 .compatible = "lltc,ltc2942",
618 .data = (void *)LTC2942_ID,
619 },
620 {
621 .compatible = "lltc,ltc2943",
622 .data = (void *)LTC2943_ID,
623 },
624 {
625 .compatible = "lltc,ltc2944",
626 .data = (void *)LTC2944_ID,
627 },
628 { },
629};
630MODULE_DEVICE_TABLE(of, ltc294x_i2c_of_match);
631
632static struct i2c_driver ltc294x_driver = {
633 .driver = {
634 .name = "LTC2941",
635 .of_match_table = ltc294x_i2c_of_match,
636 .pm = LTC294X_PM_OPS,
637 },
638 .probe = ltc294x_i2c_probe,
639 .shutdown = ltc294x_i2c_shutdown,
640 .id_table = ltc294x_i2c_id,
641};
642module_i2c_driver(ltc294x_driver);
643
644MODULE_AUTHOR("Auryn Verwegen, Topic Embedded Systems");
645MODULE_AUTHOR("Mike Looijmans, Topic Embedded Products");
646MODULE_DESCRIPTION("LTC2941/LTC2942/LTC2943/LTC2944 Battery Gas Gauge IC driver");
647MODULE_LICENSE("GPL");
648

source code of linux/drivers/power/supply/ltc2941-battery-gauge.c