1 /*
2  * Gas Gauge driver for SBS Compliant Batteries
3  *
4  * Copyright (c) 2010, NVIDIA Corporation.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
14  * more details.
15  */
16 
17 #include <linux/delay.h>
18 #include <linux/err.h>
19 #include <linux/gpio/consumer.h>
20 #include <linux/i2c.h>
21 #include <linux/init.h>
22 #include <linux/interrupt.h>
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/of.h>
26 #include <linux/power/sbs-battery.h>
27 #include <linux/power_supply.h>
28 #include <linux/slab.h>
29 #include <linux/stat.h>
30 
31 enum {
32 	REG_MANUFACTURER_DATA,
33 	REG_TEMPERATURE,
34 	REG_VOLTAGE,
35 	REG_CURRENT,
36 	REG_CAPACITY,
37 	REG_TIME_TO_EMPTY,
38 	REG_TIME_TO_FULL,
39 	REG_STATUS,
40 	REG_CAPACITY_LEVEL,
41 	REG_CYCLE_COUNT,
42 	REG_SERIAL_NUMBER,
43 	REG_REMAINING_CAPACITY,
44 	REG_REMAINING_CAPACITY_CHARGE,
45 	REG_FULL_CHARGE_CAPACITY,
46 	REG_FULL_CHARGE_CAPACITY_CHARGE,
47 	REG_DESIGN_CAPACITY,
48 	REG_DESIGN_CAPACITY_CHARGE,
49 	REG_DESIGN_VOLTAGE_MIN,
50 	REG_DESIGN_VOLTAGE_MAX,
51 	REG_MANUFACTURER,
52 	REG_MODEL_NAME,
53 };
54 
55 /* Battery Mode defines */
56 #define BATTERY_MODE_OFFSET		0x03
57 #define BATTERY_MODE_MASK		0x8000
58 enum sbs_battery_mode {
59 	BATTERY_MODE_AMPS = 0,
60 	BATTERY_MODE_WATTS = 0x8000
61 };
62 
63 /* manufacturer access defines */
64 #define MANUFACTURER_ACCESS_STATUS	0x0006
65 #define MANUFACTURER_ACCESS_SLEEP	0x0011
66 
67 /* battery status value bits */
68 #define BATTERY_INITIALIZED		0x80
69 #define BATTERY_DISCHARGING		0x40
70 #define BATTERY_FULL_CHARGED		0x20
71 #define BATTERY_FULL_DISCHARGED		0x10
72 
73 /* min_value and max_value are only valid for numerical data */
74 #define SBS_DATA(_psp, _addr, _min_value, _max_value) { \
75 	.psp = _psp, \
76 	.addr = _addr, \
77 	.min_value = _min_value, \
78 	.max_value = _max_value, \
79 }
80 
81 static const struct chip_data {
82 	enum power_supply_property psp;
83 	u8 addr;
84 	int min_value;
85 	int max_value;
86 } sbs_data[] = {
87 	[REG_MANUFACTURER_DATA] =
88 		SBS_DATA(POWER_SUPPLY_PROP_PRESENT, 0x00, 0, 65535),
89 	[REG_TEMPERATURE] =
90 		SBS_DATA(POWER_SUPPLY_PROP_TEMP, 0x08, 0, 65535),
91 	[REG_VOLTAGE] =
92 		SBS_DATA(POWER_SUPPLY_PROP_VOLTAGE_NOW, 0x09, 0, 20000),
93 	[REG_CURRENT] =
94 		SBS_DATA(POWER_SUPPLY_PROP_CURRENT_NOW, 0x0A, -32768, 32767),
95 	[REG_CAPACITY] =
96 		SBS_DATA(POWER_SUPPLY_PROP_CAPACITY, 0x0D, 0, 100),
97 	[REG_REMAINING_CAPACITY] =
98 		SBS_DATA(POWER_SUPPLY_PROP_ENERGY_NOW, 0x0F, 0, 65535),
99 	[REG_REMAINING_CAPACITY_CHARGE] =
100 		SBS_DATA(POWER_SUPPLY_PROP_CHARGE_NOW, 0x0F, 0, 65535),
101 	[REG_FULL_CHARGE_CAPACITY] =
102 		SBS_DATA(POWER_SUPPLY_PROP_ENERGY_FULL, 0x10, 0, 65535),
103 	[REG_FULL_CHARGE_CAPACITY_CHARGE] =
104 		SBS_DATA(POWER_SUPPLY_PROP_CHARGE_FULL, 0x10, 0, 65535),
105 	[REG_TIME_TO_EMPTY] =
106 		SBS_DATA(POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG, 0x12, 0, 65535),
107 	[REG_TIME_TO_FULL] =
108 		SBS_DATA(POWER_SUPPLY_PROP_TIME_TO_FULL_AVG, 0x13, 0, 65535),
109 	[REG_STATUS] =
110 		SBS_DATA(POWER_SUPPLY_PROP_STATUS, 0x16, 0, 65535),
111 	[REG_CAPACITY_LEVEL] =
112 		SBS_DATA(POWER_SUPPLY_PROP_CAPACITY_LEVEL, 0x16, 0, 65535),
113 	[REG_CYCLE_COUNT] =
114 		SBS_DATA(POWER_SUPPLY_PROP_CYCLE_COUNT, 0x17, 0, 65535),
115 	[REG_DESIGN_CAPACITY] =
116 		SBS_DATA(POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN, 0x18, 0, 65535),
117 	[REG_DESIGN_CAPACITY_CHARGE] =
118 		SBS_DATA(POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN, 0x18, 0, 65535),
119 	[REG_DESIGN_VOLTAGE_MIN] =
120 		SBS_DATA(POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN, 0x19, 0, 65535),
121 	[REG_DESIGN_VOLTAGE_MAX] =
122 		SBS_DATA(POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN, 0x19, 0, 65535),
123 	[REG_SERIAL_NUMBER] =
124 		SBS_DATA(POWER_SUPPLY_PROP_SERIAL_NUMBER, 0x1C, 0, 65535),
125 	/* Properties of type `const char *' */
126 	[REG_MANUFACTURER] =
127 		SBS_DATA(POWER_SUPPLY_PROP_MANUFACTURER, 0x20, 0, 65535),
128 	[REG_MODEL_NAME] =
129 		SBS_DATA(POWER_SUPPLY_PROP_MODEL_NAME, 0x21, 0, 65535)
130 };
131 
132 static enum power_supply_property sbs_properties[] = {
133 	POWER_SUPPLY_PROP_STATUS,
134 	POWER_SUPPLY_PROP_CAPACITY_LEVEL,
135 	POWER_SUPPLY_PROP_HEALTH,
136 	POWER_SUPPLY_PROP_PRESENT,
137 	POWER_SUPPLY_PROP_TECHNOLOGY,
138 	POWER_SUPPLY_PROP_CYCLE_COUNT,
139 	POWER_SUPPLY_PROP_VOLTAGE_NOW,
140 	POWER_SUPPLY_PROP_CURRENT_NOW,
141 	POWER_SUPPLY_PROP_CAPACITY,
142 	POWER_SUPPLY_PROP_TEMP,
143 	POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
144 	POWER_SUPPLY_PROP_TIME_TO_FULL_AVG,
145 	POWER_SUPPLY_PROP_SERIAL_NUMBER,
146 	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
147 	POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
148 	POWER_SUPPLY_PROP_ENERGY_NOW,
149 	POWER_SUPPLY_PROP_ENERGY_FULL,
150 	POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN,
151 	POWER_SUPPLY_PROP_CHARGE_NOW,
152 	POWER_SUPPLY_PROP_CHARGE_FULL,
153 	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
154 	/* Properties of type `const char *' */
155 	POWER_SUPPLY_PROP_MANUFACTURER,
156 	POWER_SUPPLY_PROP_MODEL_NAME
157 };
158 
159 struct sbs_info {
160 	struct i2c_client		*client;
161 	struct power_supply		*power_supply;
162 	bool				is_present;
163 	struct gpio_desc		*gpio_detect;
164 	bool				enable_detection;
165 	int				last_state;
166 	int				poll_time;
167 	u32				i2c_retry_count;
168 	u32				poll_retry_count;
169 	struct delayed_work		work;
170 	struct mutex			mode_lock;
171 };
172 
173 static char model_name[I2C_SMBUS_BLOCK_MAX + 1];
174 static char manufacturer[I2C_SMBUS_BLOCK_MAX + 1];
175 static bool force_load;
176 
177 static int sbs_read_word_data(struct i2c_client *client, u8 address)
178 {
179 	struct sbs_info *chip = i2c_get_clientdata(client);
180 	int retries = chip->i2c_retry_count;
181 	s32 ret = 0;
182 
183 	while (retries > 0) {
184 		ret = i2c_smbus_read_word_data(client, address);
185 		if (ret >= 0)
186 			break;
187 		retries--;
188 	}
189 
190 	if (ret < 0) {
191 		dev_dbg(&client->dev,
192 			"%s: i2c read at address 0x%x failed\n",
193 			__func__, address);
194 		return ret;
195 	}
196 
197 	return ret;
198 }
199 
200 static int sbs_read_string_data(struct i2c_client *client, u8 address,
201 				char *values)
202 {
203 	struct sbs_info *chip = i2c_get_clientdata(client);
204 	s32 ret = 0, block_length = 0;
205 	int retries_length, retries_block;
206 	u8 block_buffer[I2C_SMBUS_BLOCK_MAX + 1];
207 
208 	retries_length = chip->i2c_retry_count;
209 	retries_block = chip->i2c_retry_count;
210 
211 	/* Adapter needs to support these two functions */
212 	if (!i2c_check_functionality(client->adapter,
213 				     I2C_FUNC_SMBUS_BYTE_DATA |
214 				     I2C_FUNC_SMBUS_I2C_BLOCK)){
215 		return -ENODEV;
216 	}
217 
218 	/* Get the length of block data */
219 	while (retries_length > 0) {
220 		ret = i2c_smbus_read_byte_data(client, address);
221 		if (ret >= 0)
222 			break;
223 		retries_length--;
224 	}
225 
226 	if (ret < 0) {
227 		dev_dbg(&client->dev,
228 			"%s: i2c read at address 0x%x failed\n",
229 			__func__, address);
230 		return ret;
231 	}
232 
233 	/* block_length does not include NULL terminator */
234 	block_length = ret;
235 	if (block_length > I2C_SMBUS_BLOCK_MAX) {
236 		dev_err(&client->dev,
237 			"%s: Returned block_length is longer than 0x%x\n",
238 			__func__, I2C_SMBUS_BLOCK_MAX);
239 		return -EINVAL;
240 	}
241 
242 	/* Get the block data */
243 	while (retries_block > 0) {
244 		ret = i2c_smbus_read_i2c_block_data(
245 				client, address,
246 				block_length + 1, block_buffer);
247 		if (ret >= 0)
248 			break;
249 		retries_block--;
250 	}
251 
252 	if (ret < 0) {
253 		dev_dbg(&client->dev,
254 			"%s: i2c read at address 0x%x failed\n",
255 			__func__, address);
256 		return ret;
257 	}
258 
259 	/* block_buffer[0] == block_length */
260 	memcpy(values, block_buffer + 1, block_length);
261 	values[block_length] = '\0';
262 
263 	return ret;
264 }
265 
266 static int sbs_write_word_data(struct i2c_client *client, u8 address,
267 	u16 value)
268 {
269 	struct sbs_info *chip = i2c_get_clientdata(client);
270 	int retries = chip->i2c_retry_count;
271 	s32 ret = 0;
272 
273 	while (retries > 0) {
274 		ret = i2c_smbus_write_word_data(client, address, value);
275 		if (ret >= 0)
276 			break;
277 		retries--;
278 	}
279 
280 	if (ret < 0) {
281 		dev_dbg(&client->dev,
282 			"%s: i2c write to address 0x%x failed\n",
283 			__func__, address);
284 		return ret;
285 	}
286 
287 	return 0;
288 }
289 
290 static int sbs_status_correct(struct i2c_client *client, int *intval)
291 {
292 	int ret;
293 
294 	ret = sbs_read_word_data(client, sbs_data[REG_CURRENT].addr);
295 	if (ret < 0)
296 		return ret;
297 
298 	ret = (s16)ret;
299 
300 	/* Not drawing current means full (cannot be not charging) */
301 	if (ret == 0)
302 		*intval = POWER_SUPPLY_STATUS_FULL;
303 
304 	if (*intval == POWER_SUPPLY_STATUS_FULL) {
305 		/* Drawing or providing current when full */
306 		if (ret > 0)
307 			*intval = POWER_SUPPLY_STATUS_CHARGING;
308 		else if (ret < 0)
309 			*intval = POWER_SUPPLY_STATUS_DISCHARGING;
310 	}
311 
312 	return 0;
313 }
314 
315 static int sbs_get_battery_presence_and_health(
316 	struct i2c_client *client, enum power_supply_property psp,
317 	union power_supply_propval *val)
318 {
319 	s32 ret;
320 
321 	/*
322 	 * Write to ManufacturerAccess with ManufacturerAccess command
323 	 * and then read the status. Do not check for error on the write
324 	 * since not all batteries implement write access to this command,
325 	 * while others mandate it.
326 	 */
327 	sbs_write_word_data(client, sbs_data[REG_MANUFACTURER_DATA].addr,
328 			    MANUFACTURER_ACCESS_STATUS);
329 
330 	ret = sbs_read_word_data(client, sbs_data[REG_MANUFACTURER_DATA].addr);
331 	if (ret < 0) {
332 		if (psp == POWER_SUPPLY_PROP_PRESENT)
333 			val->intval = 0; /* battery removed */
334 		return ret;
335 	}
336 
337 	if (ret < sbs_data[REG_MANUFACTURER_DATA].min_value ||
338 	    ret > sbs_data[REG_MANUFACTURER_DATA].max_value) {
339 		val->intval = 0;
340 		return 0;
341 	}
342 
343 	/* Mask the upper nibble of 2nd byte and
344 	 * lower byte of response then
345 	 * shift the result by 8 to get status*/
346 	ret &= 0x0F00;
347 	ret >>= 8;
348 	if (psp == POWER_SUPPLY_PROP_PRESENT) {
349 		if (ret == 0x0F)
350 			/* battery removed */
351 			val->intval = 0;
352 		else
353 			val->intval = 1;
354 	} else if (psp == POWER_SUPPLY_PROP_HEALTH) {
355 		if (ret == 0x09)
356 			val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
357 		else if (ret == 0x0B)
358 			val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
359 		else if (ret == 0x0C)
360 			val->intval = POWER_SUPPLY_HEALTH_DEAD;
361 		else
362 			val->intval = POWER_SUPPLY_HEALTH_GOOD;
363 	}
364 
365 	return 0;
366 }
367 
368 static int sbs_get_battery_property(struct i2c_client *client,
369 	int reg_offset, enum power_supply_property psp,
370 	union power_supply_propval *val)
371 {
372 	struct sbs_info *chip = i2c_get_clientdata(client);
373 	s32 ret;
374 
375 	ret = sbs_read_word_data(client, sbs_data[reg_offset].addr);
376 	if (ret < 0)
377 		return ret;
378 
379 	/* returned values are 16 bit */
380 	if (sbs_data[reg_offset].min_value < 0)
381 		ret = (s16)ret;
382 
383 	if (ret >= sbs_data[reg_offset].min_value &&
384 	    ret <= sbs_data[reg_offset].max_value) {
385 		val->intval = ret;
386 		if (psp == POWER_SUPPLY_PROP_CAPACITY_LEVEL) {
387 			if (!(ret & BATTERY_INITIALIZED))
388 				val->intval =
389 					POWER_SUPPLY_CAPACITY_LEVEL_UNKNOWN;
390 			else if (ret & BATTERY_FULL_CHARGED)
391 				val->intval =
392 					POWER_SUPPLY_CAPACITY_LEVEL_FULL;
393 			else if (ret & BATTERY_FULL_DISCHARGED)
394 				val->intval =
395 					POWER_SUPPLY_CAPACITY_LEVEL_CRITICAL;
396 			else
397 				val->intval =
398 					POWER_SUPPLY_CAPACITY_LEVEL_NORMAL;
399 			return 0;
400 		} else if (psp != POWER_SUPPLY_PROP_STATUS) {
401 			return 0;
402 		}
403 
404 		if (ret & BATTERY_FULL_CHARGED)
405 			val->intval = POWER_SUPPLY_STATUS_FULL;
406 		else if (ret & BATTERY_DISCHARGING)
407 			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
408 		else
409 			val->intval = POWER_SUPPLY_STATUS_CHARGING;
410 
411 		sbs_status_correct(client, &val->intval);
412 
413 		if (chip->poll_time == 0)
414 			chip->last_state = val->intval;
415 		else if (chip->last_state != val->intval) {
416 			cancel_delayed_work_sync(&chip->work);
417 			power_supply_changed(chip->power_supply);
418 			chip->poll_time = 0;
419 		}
420 	} else {
421 		if (psp == POWER_SUPPLY_PROP_STATUS)
422 			val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
423 		else if (psp == POWER_SUPPLY_PROP_CAPACITY)
424 			/* sbs spec says that this can be >100 %
425 			 * even if max value is 100 %
426 			 */
427 			val->intval = min(ret, 100);
428 		else
429 			val->intval = 0;
430 	}
431 
432 	return 0;
433 }
434 
435 static int sbs_get_battery_string_property(struct i2c_client *client,
436 	int reg_offset, enum power_supply_property psp, char *val)
437 {
438 	s32 ret;
439 
440 	ret = sbs_read_string_data(client, sbs_data[reg_offset].addr, val);
441 
442 	if (ret < 0)
443 		return ret;
444 
445 	return 0;
446 }
447 
448 static void  sbs_unit_adjustment(struct i2c_client *client,
449 	enum power_supply_property psp, union power_supply_propval *val)
450 {
451 #define BASE_UNIT_CONVERSION		1000
452 #define BATTERY_MODE_CAP_MULT_WATT	(10 * BASE_UNIT_CONVERSION)
453 #define TIME_UNIT_CONVERSION		60
454 #define TEMP_KELVIN_TO_CELSIUS		2731
455 	switch (psp) {
456 	case POWER_SUPPLY_PROP_ENERGY_NOW:
457 	case POWER_SUPPLY_PROP_ENERGY_FULL:
458 	case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
459 		/* sbs provides energy in units of 10mWh.
460 		 * Convert to µWh
461 		 */
462 		val->intval *= BATTERY_MODE_CAP_MULT_WATT;
463 		break;
464 
465 	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
466 	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
467 	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
468 	case POWER_SUPPLY_PROP_CURRENT_NOW:
469 	case POWER_SUPPLY_PROP_CHARGE_NOW:
470 	case POWER_SUPPLY_PROP_CHARGE_FULL:
471 	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
472 		val->intval *= BASE_UNIT_CONVERSION;
473 		break;
474 
475 	case POWER_SUPPLY_PROP_TEMP:
476 		/* sbs provides battery temperature in 0.1K
477 		 * so convert it to 0.1°C
478 		 */
479 		val->intval -= TEMP_KELVIN_TO_CELSIUS;
480 		break;
481 
482 	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
483 	case POWER_SUPPLY_PROP_TIME_TO_FULL_AVG:
484 		/* sbs provides time to empty and time to full in minutes.
485 		 * Convert to seconds
486 		 */
487 		val->intval *= TIME_UNIT_CONVERSION;
488 		break;
489 
490 	default:
491 		dev_dbg(&client->dev,
492 			"%s: no need for unit conversion %d\n", __func__, psp);
493 	}
494 }
495 
496 static enum sbs_battery_mode sbs_set_battery_mode(struct i2c_client *client,
497 	enum sbs_battery_mode mode)
498 {
499 	int ret, original_val;
500 
501 	original_val = sbs_read_word_data(client, BATTERY_MODE_OFFSET);
502 	if (original_val < 0)
503 		return original_val;
504 
505 	if ((original_val & BATTERY_MODE_MASK) == mode)
506 		return mode;
507 
508 	if (mode == BATTERY_MODE_AMPS)
509 		ret = original_val & ~BATTERY_MODE_MASK;
510 	else
511 		ret = original_val | BATTERY_MODE_MASK;
512 
513 	ret = sbs_write_word_data(client, BATTERY_MODE_OFFSET, ret);
514 	if (ret < 0)
515 		return ret;
516 
517 	usleep_range(1000, 2000);
518 
519 	return original_val & BATTERY_MODE_MASK;
520 }
521 
522 static int sbs_get_battery_capacity(struct i2c_client *client,
523 	int reg_offset, enum power_supply_property psp,
524 	union power_supply_propval *val)
525 {
526 	s32 ret;
527 	enum sbs_battery_mode mode = BATTERY_MODE_WATTS;
528 
529 	if (power_supply_is_amp_property(psp))
530 		mode = BATTERY_MODE_AMPS;
531 
532 	mode = sbs_set_battery_mode(client, mode);
533 	if (mode < 0)
534 		return mode;
535 
536 	ret = sbs_read_word_data(client, sbs_data[reg_offset].addr);
537 	if (ret < 0)
538 		return ret;
539 
540 	val->intval = ret;
541 
542 	ret = sbs_set_battery_mode(client, mode);
543 	if (ret < 0)
544 		return ret;
545 
546 	return 0;
547 }
548 
549 static char sbs_serial[5];
550 static int sbs_get_battery_serial_number(struct i2c_client *client,
551 	union power_supply_propval *val)
552 {
553 	int ret;
554 
555 	ret = sbs_read_word_data(client, sbs_data[REG_SERIAL_NUMBER].addr);
556 	if (ret < 0)
557 		return ret;
558 
559 	sprintf(sbs_serial, "%04x", ret);
560 	val->strval = sbs_serial;
561 
562 	return 0;
563 }
564 
565 static int sbs_get_property_index(struct i2c_client *client,
566 	enum power_supply_property psp)
567 {
568 	int count;
569 	for (count = 0; count < ARRAY_SIZE(sbs_data); count++)
570 		if (psp == sbs_data[count].psp)
571 			return count;
572 
573 	dev_warn(&client->dev,
574 		"%s: Invalid Property - %d\n", __func__, psp);
575 
576 	return -EINVAL;
577 }
578 
579 static int sbs_get_property(struct power_supply *psy,
580 	enum power_supply_property psp,
581 	union power_supply_propval *val)
582 {
583 	int ret = 0;
584 	struct sbs_info *chip = power_supply_get_drvdata(psy);
585 	struct i2c_client *client = chip->client;
586 
587 	if (chip->gpio_detect) {
588 		ret = gpiod_get_value_cansleep(chip->gpio_detect);
589 		if (ret < 0)
590 			return ret;
591 		if (psp == POWER_SUPPLY_PROP_PRESENT) {
592 			val->intval = ret;
593 			chip->is_present = val->intval;
594 			return 0;
595 		}
596 		if (ret == 0)
597 			return -ENODATA;
598 	}
599 
600 	switch (psp) {
601 	case POWER_SUPPLY_PROP_PRESENT:
602 	case POWER_SUPPLY_PROP_HEALTH:
603 		ret = sbs_get_battery_presence_and_health(client, psp, val);
604 		if (psp == POWER_SUPPLY_PROP_PRESENT)
605 			return 0;
606 		break;
607 
608 	case POWER_SUPPLY_PROP_TECHNOLOGY:
609 		val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
610 		goto done; /* don't trigger power_supply_changed()! */
611 
612 	case POWER_SUPPLY_PROP_ENERGY_NOW:
613 	case POWER_SUPPLY_PROP_ENERGY_FULL:
614 	case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
615 	case POWER_SUPPLY_PROP_CHARGE_NOW:
616 	case POWER_SUPPLY_PROP_CHARGE_FULL:
617 	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
618 		ret = sbs_get_property_index(client, psp);
619 		if (ret < 0)
620 			break;
621 
622 		/* sbs_get_battery_capacity() will change the battery mode
623 		 * temporarily to read the requested attribute. Ensure we stay
624 		 * in the desired mode for the duration of the attribute read.
625 		 */
626 		mutex_lock(&chip->mode_lock);
627 		ret = sbs_get_battery_capacity(client, ret, psp, val);
628 		mutex_unlock(&chip->mode_lock);
629 		break;
630 
631 	case POWER_SUPPLY_PROP_SERIAL_NUMBER:
632 		ret = sbs_get_battery_serial_number(client, val);
633 		break;
634 
635 	case POWER_SUPPLY_PROP_STATUS:
636 	case POWER_SUPPLY_PROP_CAPACITY_LEVEL:
637 	case POWER_SUPPLY_PROP_CYCLE_COUNT:
638 	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
639 	case POWER_SUPPLY_PROP_CURRENT_NOW:
640 	case POWER_SUPPLY_PROP_TEMP:
641 	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
642 	case POWER_SUPPLY_PROP_TIME_TO_FULL_AVG:
643 	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
644 	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
645 	case POWER_SUPPLY_PROP_CAPACITY:
646 		ret = sbs_get_property_index(client, psp);
647 		if (ret < 0)
648 			break;
649 
650 		ret = sbs_get_battery_property(client, ret, psp, val);
651 		break;
652 
653 	case POWER_SUPPLY_PROP_MODEL_NAME:
654 		ret = sbs_get_property_index(client, psp);
655 		if (ret < 0)
656 			break;
657 
658 		ret = sbs_get_battery_string_property(client, ret, psp,
659 						      model_name);
660 		val->strval = model_name;
661 		break;
662 
663 	case POWER_SUPPLY_PROP_MANUFACTURER:
664 		ret = sbs_get_property_index(client, psp);
665 		if (ret < 0)
666 			break;
667 
668 		ret = sbs_get_battery_string_property(client, ret, psp,
669 						      manufacturer);
670 		val->strval = manufacturer;
671 		break;
672 
673 	default:
674 		dev_err(&client->dev,
675 			"%s: INVALID property\n", __func__);
676 		return -EINVAL;
677 	}
678 
679 	if (!chip->enable_detection)
680 		goto done;
681 
682 	if (!chip->gpio_detect &&
683 		chip->is_present != (ret >= 0)) {
684 		chip->is_present = (ret >= 0);
685 		power_supply_changed(chip->power_supply);
686 	}
687 
688 done:
689 	if (!ret) {
690 		/* Convert units to match requirements for power supply class */
691 		sbs_unit_adjustment(client, psp, val);
692 	}
693 
694 	dev_dbg(&client->dev,
695 		"%s: property = %d, value = %x\n", __func__, psp, val->intval);
696 
697 	if (ret && chip->is_present)
698 		return ret;
699 
700 	/* battery not present, so return NODATA for properties */
701 	if (ret)
702 		return -ENODATA;
703 
704 	return 0;
705 }
706 
707 static void sbs_supply_changed(struct sbs_info *chip)
708 {
709 	struct power_supply *battery = chip->power_supply;
710 	int ret;
711 
712 	ret = gpiod_get_value_cansleep(chip->gpio_detect);
713 	if (ret < 0)
714 		return;
715 	chip->is_present = ret;
716 	power_supply_changed(battery);
717 }
718 
719 static irqreturn_t sbs_irq(int irq, void *devid)
720 {
721 	sbs_supply_changed(devid);
722 	return IRQ_HANDLED;
723 }
724 
725 static void sbs_alert(struct i2c_client *client, enum i2c_alert_protocol prot,
726 	unsigned int data)
727 {
728 	sbs_supply_changed(i2c_get_clientdata(client));
729 }
730 
731 static void sbs_external_power_changed(struct power_supply *psy)
732 {
733 	struct sbs_info *chip = power_supply_get_drvdata(psy);
734 
735 	/* cancel outstanding work */
736 	cancel_delayed_work_sync(&chip->work);
737 
738 	schedule_delayed_work(&chip->work, HZ);
739 	chip->poll_time = chip->poll_retry_count;
740 }
741 
742 static void sbs_delayed_work(struct work_struct *work)
743 {
744 	struct sbs_info *chip;
745 	s32 ret;
746 
747 	chip = container_of(work, struct sbs_info, work.work);
748 
749 	ret = sbs_read_word_data(chip->client, sbs_data[REG_STATUS].addr);
750 	/* if the read failed, give up on this work */
751 	if (ret < 0) {
752 		chip->poll_time = 0;
753 		return;
754 	}
755 
756 	if (ret & BATTERY_FULL_CHARGED)
757 		ret = POWER_SUPPLY_STATUS_FULL;
758 	else if (ret & BATTERY_DISCHARGING)
759 		ret = POWER_SUPPLY_STATUS_DISCHARGING;
760 	else
761 		ret = POWER_SUPPLY_STATUS_CHARGING;
762 
763 	sbs_status_correct(chip->client, &ret);
764 
765 	if (chip->last_state != ret) {
766 		chip->poll_time = 0;
767 		power_supply_changed(chip->power_supply);
768 		return;
769 	}
770 	if (chip->poll_time > 0) {
771 		schedule_delayed_work(&chip->work, HZ);
772 		chip->poll_time--;
773 		return;
774 	}
775 }
776 
777 static const struct power_supply_desc sbs_default_desc = {
778 	.type = POWER_SUPPLY_TYPE_BATTERY,
779 	.properties = sbs_properties,
780 	.num_properties = ARRAY_SIZE(sbs_properties),
781 	.get_property = sbs_get_property,
782 	.external_power_changed = sbs_external_power_changed,
783 };
784 
785 static int sbs_probe(struct i2c_client *client,
786 	const struct i2c_device_id *id)
787 {
788 	struct sbs_info *chip;
789 	struct power_supply_desc *sbs_desc;
790 	struct sbs_platform_data *pdata = client->dev.platform_data;
791 	struct power_supply_config psy_cfg = {};
792 	int rc;
793 	int irq;
794 
795 	sbs_desc = devm_kmemdup(&client->dev, &sbs_default_desc,
796 			sizeof(*sbs_desc), GFP_KERNEL);
797 	if (!sbs_desc)
798 		return -ENOMEM;
799 
800 	sbs_desc->name = devm_kasprintf(&client->dev, GFP_KERNEL, "sbs-%s",
801 			dev_name(&client->dev));
802 	if (!sbs_desc->name)
803 		return -ENOMEM;
804 
805 	chip = devm_kzalloc(&client->dev, sizeof(struct sbs_info), GFP_KERNEL);
806 	if (!chip)
807 		return -ENOMEM;
808 
809 	chip->client = client;
810 	chip->enable_detection = false;
811 	psy_cfg.of_node = client->dev.of_node;
812 	psy_cfg.drv_data = chip;
813 	chip->last_state = POWER_SUPPLY_STATUS_UNKNOWN;
814 	mutex_init(&chip->mode_lock);
815 
816 	/* use pdata if available, fall back to DT properties,
817 	 * or hardcoded defaults if not
818 	 */
819 	rc = of_property_read_u32(client->dev.of_node, "sbs,i2c-retry-count",
820 				  &chip->i2c_retry_count);
821 	if (rc)
822 		chip->i2c_retry_count = 0;
823 
824 	rc = of_property_read_u32(client->dev.of_node, "sbs,poll-retry-count",
825 				  &chip->poll_retry_count);
826 	if (rc)
827 		chip->poll_retry_count = 0;
828 
829 	if (pdata) {
830 		chip->poll_retry_count = pdata->poll_retry_count;
831 		chip->i2c_retry_count  = pdata->i2c_retry_count;
832 	}
833 	chip->i2c_retry_count = chip->i2c_retry_count + 1;
834 
835 	chip->gpio_detect = devm_gpiod_get_optional(&client->dev,
836 			"sbs,battery-detect", GPIOD_IN);
837 	if (IS_ERR(chip->gpio_detect)) {
838 		dev_err(&client->dev, "Failed to get gpio: %ld\n",
839 			PTR_ERR(chip->gpio_detect));
840 		return PTR_ERR(chip->gpio_detect);
841 	}
842 
843 	i2c_set_clientdata(client, chip);
844 
845 	if (!chip->gpio_detect)
846 		goto skip_gpio;
847 
848 	irq = gpiod_to_irq(chip->gpio_detect);
849 	if (irq <= 0) {
850 		dev_warn(&client->dev, "Failed to get gpio as irq: %d\n", irq);
851 		goto skip_gpio;
852 	}
853 
854 	rc = devm_request_threaded_irq(&client->dev, irq, NULL, sbs_irq,
855 		IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
856 		dev_name(&client->dev), chip);
857 	if (rc) {
858 		dev_warn(&client->dev, "Failed to request irq: %d\n", rc);
859 		goto skip_gpio;
860 	}
861 
862 skip_gpio:
863 	/*
864 	 * Before we register, we might need to make sure we can actually talk
865 	 * to the battery.
866 	 */
867 	if (!(force_load || chip->gpio_detect)) {
868 		rc = sbs_read_word_data(client, sbs_data[REG_STATUS].addr);
869 
870 		if (rc < 0) {
871 			dev_err(&client->dev, "%s: Failed to get device status\n",
872 				__func__);
873 			goto exit_psupply;
874 		}
875 	}
876 
877 	chip->power_supply = devm_power_supply_register(&client->dev, sbs_desc,
878 						   &psy_cfg);
879 	if (IS_ERR(chip->power_supply)) {
880 		dev_err(&client->dev,
881 			"%s: Failed to register power supply\n", __func__);
882 		rc = PTR_ERR(chip->power_supply);
883 		goto exit_psupply;
884 	}
885 
886 	dev_info(&client->dev,
887 		"%s: battery gas gauge device registered\n", client->name);
888 
889 	INIT_DELAYED_WORK(&chip->work, sbs_delayed_work);
890 
891 	chip->enable_detection = true;
892 
893 	return 0;
894 
895 exit_psupply:
896 	return rc;
897 }
898 
899 static int sbs_remove(struct i2c_client *client)
900 {
901 	struct sbs_info *chip = i2c_get_clientdata(client);
902 
903 	cancel_delayed_work_sync(&chip->work);
904 
905 	return 0;
906 }
907 
908 #if defined CONFIG_PM_SLEEP
909 
910 static int sbs_suspend(struct device *dev)
911 {
912 	struct i2c_client *client = to_i2c_client(dev);
913 	struct sbs_info *chip = i2c_get_clientdata(client);
914 
915 	if (chip->poll_time > 0)
916 		cancel_delayed_work_sync(&chip->work);
917 
918 	/*
919 	 * Write to manufacturer access with sleep command.
920 	 * Support is manufacturer dependend, so ignore errors.
921 	 */
922 	sbs_write_word_data(client, sbs_data[REG_MANUFACTURER_DATA].addr,
923 		MANUFACTURER_ACCESS_SLEEP);
924 
925 	return 0;
926 }
927 
928 static SIMPLE_DEV_PM_OPS(sbs_pm_ops, sbs_suspend, NULL);
929 #define SBS_PM_OPS (&sbs_pm_ops)
930 
931 #else
932 #define SBS_PM_OPS NULL
933 #endif
934 
935 static const struct i2c_device_id sbs_id[] = {
936 	{ "bq20z75", 0 },
937 	{ "sbs-battery", 1 },
938 	{}
939 };
940 MODULE_DEVICE_TABLE(i2c, sbs_id);
941 
942 static const struct of_device_id sbs_dt_ids[] = {
943 	{ .compatible = "sbs,sbs-battery" },
944 	{ .compatible = "ti,bq20z75" },
945 	{ }
946 };
947 MODULE_DEVICE_TABLE(of, sbs_dt_ids);
948 
949 static struct i2c_driver sbs_battery_driver = {
950 	.probe		= sbs_probe,
951 	.remove		= sbs_remove,
952 	.alert		= sbs_alert,
953 	.id_table	= sbs_id,
954 	.driver = {
955 		.name	= "sbs-battery",
956 		.of_match_table = sbs_dt_ids,
957 		.pm	= SBS_PM_OPS,
958 	},
959 };
960 module_i2c_driver(sbs_battery_driver);
961 
962 MODULE_DESCRIPTION("SBS battery monitor driver");
963 MODULE_LICENSE("GPL");
964 
965 module_param(force_load, bool, S_IRUSR | S_IRGRP | S_IROTH);
966 MODULE_PARM_DESC(force_load,
967 		 "Attempt to load the driver even if no battery is connected");
968