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/kernel.h>
12 #include <linux/module.h>
13 #include <linux/of_device.h>
14 #include <linux/types.h>
15 #include <linux/errno.h>
16 #include <linux/swab.h>
17 #include <linux/i2c.h>
18 #include <linux/delay.h>
19 #include <linux/power_supply.h>
20 #include <linux/slab.h>
21 
22 #define I16_MSB(x)			((x >> 8) & 0xFF)
23 #define I16_LSB(x)			(x & 0xFF)
24 
25 #define LTC294X_WORK_DELAY		10	/* Update delay in seconds */
26 
27 #define LTC294X_MAX_VALUE		0xFFFF
28 #define LTC294X_MID_SUPPLY		0x7FFF
29 
30 #define LTC2941_MAX_PRESCALER_EXP	7
31 #define LTC2943_MAX_PRESCALER_EXP	6
32 
33 enum ltc294x_reg {
34 	LTC294X_REG_STATUS		= 0x00,
35 	LTC294X_REG_CONTROL		= 0x01,
36 	LTC294X_REG_ACC_CHARGE_MSB	= 0x02,
37 	LTC294X_REG_ACC_CHARGE_LSB	= 0x03,
38 	LTC294X_REG_CHARGE_THR_HIGH_MSB	= 0x04,
39 	LTC294X_REG_CHARGE_THR_HIGH_LSB	= 0x05,
40 	LTC294X_REG_CHARGE_THR_LOW_MSB	= 0x06,
41 	LTC294X_REG_CHARGE_THR_LOW_LSB	= 0x07,
42 	LTC294X_REG_VOLTAGE_MSB		= 0x08,
43 	LTC294X_REG_VOLTAGE_LSB		= 0x09,
44 	LTC2942_REG_TEMPERATURE_MSB	= 0x0C,
45 	LTC2942_REG_TEMPERATURE_LSB	= 0x0D,
46 	LTC2943_REG_CURRENT_MSB		= 0x0E,
47 	LTC2943_REG_CURRENT_LSB		= 0x0F,
48 	LTC2943_REG_TEMPERATURE_MSB	= 0x14,
49 	LTC2943_REG_TEMPERATURE_LSB	= 0x15,
50 };
51 
52 enum ltc294x_id {
53 	LTC2941_ID,
54 	LTC2942_ID,
55 	LTC2943_ID,
56 	LTC2944_ID,
57 };
58 
59 #define LTC2941_REG_STATUS_CHIP_ID	BIT(7)
60 
61 #define LTC2942_REG_CONTROL_MODE_SCAN	(BIT(7) | BIT(6))
62 #define LTC2943_REG_CONTROL_MODE_SCAN	BIT(7)
63 #define LTC294X_REG_CONTROL_PRESCALER_MASK	(BIT(5) | BIT(4) | BIT(3))
64 #define LTC294X_REG_CONTROL_SHUTDOWN_MASK	(BIT(0))
65 #define LTC294X_REG_CONTROL_PRESCALER_SET(x) \
66 	((x << 3) & LTC294X_REG_CONTROL_PRESCALER_MASK)
67 #define LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED	0
68 #define LTC294X_REG_CONTROL_ADC_DISABLE(x)	((x) & ~(BIT(7) | BIT(6)))
69 
70 struct ltc294x_info {
71 	struct i2c_client *client;	/* I2C Client pointer */
72 	struct power_supply *supply;	/* Supply pointer */
73 	struct power_supply_desc supply_desc;	/* Supply description */
74 	struct delayed_work work;	/* Work scheduler */
75 	enum ltc294x_id id;		/* Chip type */
76 	int charge;	/* Last charge register content */
77 	int r_sense;	/* mOhm */
78 	int Qlsb;	/* nAh */
79 };
80 
81 static inline int convert_bin_to_uAh(
82 	const struct ltc294x_info *info, int Q)
83 {
84 	return ((Q * (info->Qlsb / 10))) / 100;
85 }
86 
87 static inline int convert_uAh_to_bin(
88 	const struct ltc294x_info *info, int uAh)
89 {
90 	int Q;
91 
92 	Q = (uAh * 100) / (info->Qlsb/10);
93 	return (Q < LTC294X_MAX_VALUE) ? Q : LTC294X_MAX_VALUE;
94 }
95 
96 static int ltc294x_read_regs(struct i2c_client *client,
97 	enum ltc294x_reg reg, u8 *buf, int num_regs)
98 {
99 	int ret;
100 	struct i2c_msg msgs[2] = { };
101 	u8 reg_start = reg;
102 
103 	msgs[0].addr	= client->addr;
104 	msgs[0].len	= 1;
105 	msgs[0].buf	= &reg_start;
106 
107 	msgs[1].addr	= client->addr;
108 	msgs[1].len	= num_regs;
109 	msgs[1].buf	= buf;
110 	msgs[1].flags	= I2C_M_RD;
111 
112 	ret = i2c_transfer(client->adapter, &msgs[0], 2);
113 	if (ret < 0) {
114 		dev_err(&client->dev, "ltc2941 read_reg failed!\n");
115 		return ret;
116 	}
117 
118 	dev_dbg(&client->dev, "%s (%#x, %d) -> %#x\n",
119 		__func__, reg, num_regs, *buf);
120 
121 	return 0;
122 }
123 
124 static int ltc294x_write_regs(struct i2c_client *client,
125 	enum ltc294x_reg reg, const u8 *buf, int num_regs)
126 {
127 	int ret;
128 	u8 reg_start = reg;
129 
130 	ret = i2c_smbus_write_i2c_block_data(client, reg_start, num_regs, buf);
131 	if (ret < 0) {
132 		dev_err(&client->dev, "ltc2941 write_reg failed!\n");
133 		return ret;
134 	}
135 
136 	dev_dbg(&client->dev, "%s (%#x, %d) -> %#x\n",
137 		__func__, reg, num_regs, *buf);
138 
139 	return 0;
140 }
141 
142 static int ltc294x_reset(const struct ltc294x_info *info, int prescaler_exp)
143 {
144 	int ret;
145 	u8 value;
146 	u8 control;
147 
148 	/* Read status and control registers */
149 	ret = ltc294x_read_regs(info->client, LTC294X_REG_CONTROL, &value, 1);
150 	if (ret < 0) {
151 		dev_err(&info->client->dev,
152 			"Could not read registers from device\n");
153 		goto error_exit;
154 	}
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(info->client,
173 			LTC294X_REG_CONTROL, &control, 1);
174 		if (ret < 0) {
175 			dev_err(&info->client->dev,
176 				"Could not write register\n");
177 			goto error_exit;
178 		}
179 	}
180 
181 	return 0;
182 
183 error_exit:
184 	return ret;
185 }
186 
187 static int ltc294x_read_charge_register(const struct ltc294x_info *info,
188 					enum ltc294x_reg reg)
189  {
190 	int ret;
191 	u8 datar[2];
192 
193 	ret = ltc294x_read_regs(info->client, reg, &datar[0], 2);
194 	if (ret < 0)
195 		return ret;
196 	return (datar[0] << 8) + datar[1];
197 }
198 
199 static int ltc294x_get_charge(const struct ltc294x_info *info,
200 				enum ltc294x_reg reg, int *val)
201 {
202 	int value = ltc294x_read_charge_register(info, reg);
203 
204 	if (value < 0)
205 		return value;
206 	/* When r_sense < 0, this counts up when the battery discharges */
207 	if (info->Qlsb < 0)
208 		value -= 0xFFFF;
209 	*val = convert_bin_to_uAh(info, value);
210 	return 0;
211 }
212 
213 static int ltc294x_set_charge_now(const struct ltc294x_info *info, int val)
214 {
215 	int ret;
216 	u8 dataw[2];
217 	u8 ctrl_reg;
218 	s32 value;
219 
220 	value = convert_uAh_to_bin(info, val);
221 	/* Direction depends on how sense+/- were connected */
222 	if (info->Qlsb < 0)
223 		value += 0xFFFF;
224 	if ((value < 0) || (value > 0xFFFF)) /* input validation */
225 		return -EINVAL;
226 
227 	/* Read control register */
228 	ret = ltc294x_read_regs(info->client,
229 		LTC294X_REG_CONTROL, &ctrl_reg, 1);
230 	if (ret < 0)
231 		return ret;
232 	/* Disable analog section */
233 	ctrl_reg |= LTC294X_REG_CONTROL_SHUTDOWN_MASK;
234 	ret = ltc294x_write_regs(info->client,
235 		LTC294X_REG_CONTROL, &ctrl_reg, 1);
236 	if (ret < 0)
237 		return ret;
238 	/* Set new charge value */
239 	dataw[0] = I16_MSB(value);
240 	dataw[1] = I16_LSB(value);
241 	ret = ltc294x_write_regs(info->client,
242 		LTC294X_REG_ACC_CHARGE_MSB, &dataw[0], 2);
243 	if (ret < 0)
244 		goto error_exit;
245 	/* Enable analog section */
246 error_exit:
247 	ctrl_reg &= ~LTC294X_REG_CONTROL_SHUTDOWN_MASK;
248 	ret = ltc294x_write_regs(info->client,
249 		LTC294X_REG_CONTROL, &ctrl_reg, 1);
250 
251 	return ret < 0 ? ret : 0;
252 }
253 
254 static int ltc294x_set_charge_thr(const struct ltc294x_info *info,
255 					enum ltc294x_reg reg, int val)
256 {
257 	u8 dataw[2];
258 	s32 value;
259 
260 	value = convert_uAh_to_bin(info, val);
261 	/* Direction depends on how sense+/- were connected */
262 	if (info->Qlsb < 0)
263 		value += 0xFFFF;
264 	if ((value < 0) || (value > 0xFFFF)) /* input validation */
265 		return -EINVAL;
266 
267 	/* Set new charge value */
268 	dataw[0] = I16_MSB(value);
269 	dataw[1] = I16_LSB(value);
270 	return ltc294x_write_regs(info->client, reg, &dataw[0], 2);
271 }
272 
273 static int ltc294x_get_charge_counter(
274 	const struct ltc294x_info *info, int *val)
275 {
276 	int value = ltc294x_read_charge_register(info, LTC294X_REG_ACC_CHARGE_MSB);
277 
278 	if (value < 0)
279 		return value;
280 	value -= LTC294X_MID_SUPPLY;
281 	*val = convert_bin_to_uAh(info, value);
282 	return 0;
283 }
284 
285 static int ltc294x_get_voltage(const struct ltc294x_info *info, int *val)
286 {
287 	int ret;
288 	u8 datar[2];
289 	u32 value;
290 
291 	ret = ltc294x_read_regs(info->client,
292 		LTC294X_REG_VOLTAGE_MSB, &datar[0], 2);
293 	value = (datar[0] << 8) | datar[1];
294 	switch (info->id) {
295 	case LTC2943_ID:
296 		value *= 23600 * 2;
297 		value /= 0xFFFF;
298 		value *= 1000 / 2;
299 		break;
300 	case LTC2944_ID:
301 		value *= 70800 / 5*4;
302 		value /= 0xFFFF;
303 		value *= 1000 * 5/4;
304 		break;
305 	default:
306 		value *= 6000 * 10;
307 		value /= 0xFFFF;
308 		value *= 1000 / 10;
309 		break;
310 	}
311 	*val = value;
312 	return ret;
313 }
314 
315 static int ltc294x_get_current(const struct ltc294x_info *info, int *val)
316 {
317 	int ret;
318 	u8 datar[2];
319 	s32 value;
320 
321 	ret = ltc294x_read_regs(info->client,
322 		LTC2943_REG_CURRENT_MSB, &datar[0], 2);
323 	value = (datar[0] << 8) | datar[1];
324 	value -= 0x7FFF;
325 	if (info->id == LTC2944_ID)
326 		value *= 64000;
327 	else
328 		value *= 60000;
329 	/* Value is in range -32k..+32k, r_sense is usually 10..50 mOhm,
330 	 * the formula below keeps everything in s32 range while preserving
331 	 * enough digits */
332 	*val = 1000 * (value / (info->r_sense * 0x7FFF)); /* in uA */
333 	return ret;
334 }
335 
336 static int ltc294x_get_temperature(const struct ltc294x_info *info, int *val)
337 {
338 	enum ltc294x_reg reg;
339 	int ret;
340 	u8 datar[2];
341 	u32 value;
342 
343 	if (info->id == LTC2942_ID) {
344 		reg = LTC2942_REG_TEMPERATURE_MSB;
345 		value = 6000;	/* Full-scale is 600 Kelvin */
346 	} else {
347 		reg = LTC2943_REG_TEMPERATURE_MSB;
348 		value = 5100;	/* Full-scale is 510 Kelvin */
349 	}
350 	ret = ltc294x_read_regs(info->client, reg, &datar[0], 2);
351 	value *= (datar[0] << 8) | datar[1];
352 	/* Convert to tenths of degree Celsius */
353 	*val = value / 0xFFFF - 2722;
354 	return ret;
355 }
356 
357 static int ltc294x_get_property(struct power_supply *psy,
358 				enum power_supply_property prop,
359 				union power_supply_propval *val)
360 {
361 	struct ltc294x_info *info = power_supply_get_drvdata(psy);
362 
363 	switch (prop) {
364 	case POWER_SUPPLY_PROP_CHARGE_FULL:
365 		return ltc294x_get_charge(info, LTC294X_REG_CHARGE_THR_HIGH_MSB,
366 						&val->intval);
367 	case POWER_SUPPLY_PROP_CHARGE_EMPTY:
368 		return ltc294x_get_charge(info, LTC294X_REG_CHARGE_THR_LOW_MSB,
369 						&val->intval);
370 	case POWER_SUPPLY_PROP_CHARGE_NOW:
371 		return ltc294x_get_charge(info, LTC294X_REG_ACC_CHARGE_MSB,
372 						&val->intval);
373 	case POWER_SUPPLY_PROP_CHARGE_COUNTER:
374 		return ltc294x_get_charge_counter(info, &val->intval);
375 	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
376 		return ltc294x_get_voltage(info, &val->intval);
377 	case POWER_SUPPLY_PROP_CURRENT_NOW:
378 		return ltc294x_get_current(info, &val->intval);
379 	case POWER_SUPPLY_PROP_TEMP:
380 		return ltc294x_get_temperature(info, &val->intval);
381 	default:
382 		return -EINVAL;
383 	}
384 }
385 
386 static int ltc294x_set_property(struct power_supply *psy,
387 	enum power_supply_property psp,
388 	const union power_supply_propval *val)
389 {
390 	struct ltc294x_info *info = power_supply_get_drvdata(psy);
391 
392 	switch (psp) {
393 	case POWER_SUPPLY_PROP_CHARGE_FULL:
394 		return ltc294x_set_charge_thr(info,
395 			LTC294X_REG_CHARGE_THR_HIGH_MSB, val->intval);
396 	case POWER_SUPPLY_PROP_CHARGE_EMPTY:
397 		return ltc294x_set_charge_thr(info,
398 			LTC294X_REG_CHARGE_THR_LOW_MSB, val->intval);
399 	case POWER_SUPPLY_PROP_CHARGE_NOW:
400 		return ltc294x_set_charge_now(info, val->intval);
401 	default:
402 		return -EPERM;
403 	}
404 }
405 
406 static int ltc294x_property_is_writeable(
407 	struct power_supply *psy, enum power_supply_property psp)
408 {
409 	switch (psp) {
410 	case POWER_SUPPLY_PROP_CHARGE_FULL:
411 	case POWER_SUPPLY_PROP_CHARGE_EMPTY:
412 	case POWER_SUPPLY_PROP_CHARGE_NOW:
413 		return 1;
414 	default:
415 		return 0;
416 	}
417 }
418 
419 static void ltc294x_update(struct ltc294x_info *info)
420 {
421 	int charge = ltc294x_read_charge_register(info, LTC294X_REG_ACC_CHARGE_MSB);
422 
423 	if (charge != info->charge) {
424 		info->charge = charge;
425 		power_supply_changed(info->supply);
426 	}
427 }
428 
429 static void ltc294x_work(struct work_struct *work)
430 {
431 	struct ltc294x_info *info;
432 
433 	info = container_of(work, struct ltc294x_info, work.work);
434 	ltc294x_update(info);
435 	schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
436 }
437 
438 static enum power_supply_property ltc294x_properties[] = {
439 	POWER_SUPPLY_PROP_CHARGE_COUNTER,
440 	POWER_SUPPLY_PROP_CHARGE_FULL,
441 	POWER_SUPPLY_PROP_CHARGE_EMPTY,
442 	POWER_SUPPLY_PROP_CHARGE_NOW,
443 	POWER_SUPPLY_PROP_VOLTAGE_NOW,
444 	POWER_SUPPLY_PROP_TEMP,
445 	POWER_SUPPLY_PROP_CURRENT_NOW,
446 };
447 
448 static int ltc294x_i2c_remove(struct i2c_client *client)
449 {
450 	struct ltc294x_info *info = i2c_get_clientdata(client);
451 
452 	cancel_delayed_work_sync(&info->work);
453 	power_supply_unregister(info->supply);
454 	return 0;
455 }
456 
457 static int ltc294x_i2c_probe(struct i2c_client *client,
458 	const struct i2c_device_id *id)
459 {
460 	struct power_supply_config psy_cfg = {};
461 	struct ltc294x_info *info;
462 	struct device_node *np;
463 	int ret;
464 	u32 prescaler_exp;
465 	s32 r_sense;
466 	u8 status;
467 
468 	info = devm_kzalloc(&client->dev, sizeof(*info), GFP_KERNEL);
469 	if (info == NULL)
470 		return -ENOMEM;
471 
472 	i2c_set_clientdata(client, info);
473 
474 	np = of_node_get(client->dev.of_node);
475 
476 	info->id = (enum ltc294x_id)of_device_get_match_data(&client->dev);
477 	info->supply_desc.name = np->name;
478 
479 	/* r_sense can be negative, when sense+ is connected to the battery
480 	 * instead of the sense-. This results in reversed measurements. */
481 	ret = of_property_read_u32(np, "lltc,resistor-sense", &r_sense);
482 	if (ret < 0) {
483 		dev_err(&client->dev,
484 			"Could not find lltc,resistor-sense in devicetree\n");
485 		return ret;
486 	}
487 	info->r_sense = r_sense;
488 
489 	ret = of_property_read_u32(np, "lltc,prescaler-exponent",
490 		&prescaler_exp);
491 	if (ret < 0) {
492 		dev_warn(&client->dev,
493 			"lltc,prescaler-exponent not in devicetree\n");
494 		prescaler_exp = LTC2941_MAX_PRESCALER_EXP;
495 	}
496 
497 	if (info->id == LTC2943_ID) {
498 		if (prescaler_exp > LTC2943_MAX_PRESCALER_EXP)
499 			prescaler_exp = LTC2943_MAX_PRESCALER_EXP;
500 		info->Qlsb = ((340 * 50000) / r_sense) /
501 				(4096 / (1 << (2*prescaler_exp)));
502 	} else {
503 		if (prescaler_exp > LTC2941_MAX_PRESCALER_EXP)
504 			prescaler_exp = LTC2941_MAX_PRESCALER_EXP;
505 		info->Qlsb = ((85 * 50000) / r_sense) /
506 				(128 / (1 << prescaler_exp));
507 	}
508 
509 	/* Read status register to check for LTC2942 */
510 	if (info->id == LTC2941_ID || info->id == LTC2942_ID) {
511 		ret = ltc294x_read_regs(client, LTC294X_REG_STATUS, &status, 1);
512 		if (ret < 0) {
513 			dev_err(&client->dev,
514 				"Could not read status register\n");
515 			return ret;
516 		}
517 		if (status & LTC2941_REG_STATUS_CHIP_ID)
518 			info->id = LTC2941_ID;
519 		else
520 			info->id = LTC2942_ID;
521 	}
522 
523 	info->client = client;
524 	info->supply_desc.type = POWER_SUPPLY_TYPE_BATTERY;
525 	info->supply_desc.properties = ltc294x_properties;
526 	switch (info->id) {
527 	case LTC2944_ID:
528 	case LTC2943_ID:
529 		info->supply_desc.num_properties =
530 			ARRAY_SIZE(ltc294x_properties);
531 		break;
532 	case LTC2942_ID:
533 		info->supply_desc.num_properties =
534 			ARRAY_SIZE(ltc294x_properties) - 1;
535 		break;
536 	case LTC2941_ID:
537 	default:
538 		info->supply_desc.num_properties =
539 			ARRAY_SIZE(ltc294x_properties) - 3;
540 		break;
541 	}
542 	info->supply_desc.get_property = ltc294x_get_property;
543 	info->supply_desc.set_property = ltc294x_set_property;
544 	info->supply_desc.property_is_writeable = ltc294x_property_is_writeable;
545 	info->supply_desc.external_power_changed	= NULL;
546 
547 	psy_cfg.drv_data = info;
548 
549 	INIT_DELAYED_WORK(&info->work, ltc294x_work);
550 
551 	ret = ltc294x_reset(info, prescaler_exp);
552 	if (ret < 0) {
553 		dev_err(&client->dev, "Communication with chip failed\n");
554 		return ret;
555 	}
556 
557 	info->supply = power_supply_register(&client->dev, &info->supply_desc,
558 					     &psy_cfg);
559 	if (IS_ERR(info->supply)) {
560 		dev_err(&client->dev, "failed to register ltc2941\n");
561 		return PTR_ERR(info->supply);
562 	} else {
563 		schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
564 	}
565 
566 	return 0;
567 }
568 
569 static void ltc294x_i2c_shutdown(struct i2c_client *client)
570 {
571 	struct ltc294x_info *info = i2c_get_clientdata(client);
572 	int ret;
573 	u8 value;
574 	u8 control;
575 
576 	/* The LTC2941 does not need any special handling */
577 	if (info->id == LTC2941_ID)
578 		return;
579 
580 	/* Read control register */
581 	ret = ltc294x_read_regs(info->client, LTC294X_REG_CONTROL, &value, 1);
582 	if (ret < 0)
583 		return;
584 
585 	/* Disable continuous ADC conversion as this drains the battery */
586 	control = LTC294X_REG_CONTROL_ADC_DISABLE(value);
587 	if (control != value)
588 		ltc294x_write_regs(info->client, LTC294X_REG_CONTROL,
589 			&control, 1);
590 }
591 
592 #ifdef CONFIG_PM_SLEEP
593 
594 static int ltc294x_suspend(struct device *dev)
595 {
596 	struct i2c_client *client = to_i2c_client(dev);
597 	struct ltc294x_info *info = i2c_get_clientdata(client);
598 
599 	cancel_delayed_work(&info->work);
600 	return 0;
601 }
602 
603 static int ltc294x_resume(struct device *dev)
604 {
605 	struct i2c_client *client = to_i2c_client(dev);
606 	struct ltc294x_info *info = i2c_get_clientdata(client);
607 
608 	schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
609 	return 0;
610 }
611 
612 static SIMPLE_DEV_PM_OPS(ltc294x_pm_ops, ltc294x_suspend, ltc294x_resume);
613 #define LTC294X_PM_OPS (&ltc294x_pm_ops)
614 
615 #else
616 #define LTC294X_PM_OPS NULL
617 #endif /* CONFIG_PM_SLEEP */
618 
619 
620 static const struct i2c_device_id ltc294x_i2c_id[] = {
621 	{ "ltc2941", LTC2941_ID, },
622 	{ "ltc2942", LTC2942_ID, },
623 	{ "ltc2943", LTC2943_ID, },
624 	{ "ltc2944", LTC2944_ID, },
625 	{ },
626 };
627 MODULE_DEVICE_TABLE(i2c, ltc294x_i2c_id);
628 
629 static const struct of_device_id ltc294x_i2c_of_match[] = {
630 	{
631 		.compatible = "lltc,ltc2941",
632 		.data = (void *)LTC2941_ID,
633 	},
634 	{
635 		.compatible = "lltc,ltc2942",
636 		.data = (void *)LTC2942_ID,
637 	},
638 	{
639 		.compatible = "lltc,ltc2943",
640 		.data = (void *)LTC2943_ID,
641 	},
642 	{
643 		.compatible = "lltc,ltc2944",
644 		.data = (void *)LTC2944_ID,
645 	},
646 	{ },
647 };
648 MODULE_DEVICE_TABLE(of, ltc294x_i2c_of_match);
649 
650 static struct i2c_driver ltc294x_driver = {
651 	.driver = {
652 		.name	= "LTC2941",
653 		.of_match_table = ltc294x_i2c_of_match,
654 		.pm	= LTC294X_PM_OPS,
655 	},
656 	.probe		= ltc294x_i2c_probe,
657 	.remove		= ltc294x_i2c_remove,
658 	.shutdown	= ltc294x_i2c_shutdown,
659 	.id_table	= ltc294x_i2c_id,
660 };
661 module_i2c_driver(ltc294x_driver);
662 
663 MODULE_AUTHOR("Auryn Verwegen, Topic Embedded Systems");
664 MODULE_AUTHOR("Mike Looijmans, Topic Embedded Products");
665 MODULE_DESCRIPTION("LTC2941/LTC2942/LTC2943/LTC2944 Battery Gas Gauge IC driver");
666 MODULE_LICENSE("GPL");
667