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/of_device.h>
27 #include <linux/power/sbs-battery.h>
28 #include <linux/power_supply.h>
29 #include <linux/slab.h>
30 #include <linux/stat.h>
31 
32 enum {
33 	REG_MANUFACTURER_DATA,
34 	REG_TEMPERATURE,
35 	REG_VOLTAGE,
36 	REG_CURRENT,
37 	REG_CAPACITY,
38 	REG_TIME_TO_EMPTY,
39 	REG_TIME_TO_FULL,
40 	REG_STATUS,
41 	REG_CAPACITY_LEVEL,
42 	REG_CYCLE_COUNT,
43 	REG_SERIAL_NUMBER,
44 	REG_REMAINING_CAPACITY,
45 	REG_REMAINING_CAPACITY_CHARGE,
46 	REG_FULL_CHARGE_CAPACITY,
47 	REG_FULL_CHARGE_CAPACITY_CHARGE,
48 	REG_DESIGN_CAPACITY,
49 	REG_DESIGN_CAPACITY_CHARGE,
50 	REG_DESIGN_VOLTAGE_MIN,
51 	REG_DESIGN_VOLTAGE_MAX,
52 	REG_MANUFACTURER,
53 	REG_MODEL_NAME,
54 };
55 
56 /* Battery Mode defines */
57 #define BATTERY_MODE_OFFSET		0x03
58 #define BATTERY_MODE_MASK		0x8000
59 enum sbs_battery_mode {
60 	BATTERY_MODE_AMPS = 0,
61 	BATTERY_MODE_WATTS = 0x8000
62 };
63 
64 /* manufacturer access defines */
65 #define MANUFACTURER_ACCESS_STATUS	0x0006
66 #define MANUFACTURER_ACCESS_SLEEP	0x0011
67 
68 /* battery status value bits */
69 #define BATTERY_INITIALIZED		0x80
70 #define BATTERY_DISCHARGING		0x40
71 #define BATTERY_FULL_CHARGED		0x20
72 #define BATTERY_FULL_DISCHARGED		0x10
73 
74 /* min_value and max_value are only valid for numerical data */
75 #define SBS_DATA(_psp, _addr, _min_value, _max_value) { \
76 	.psp = _psp, \
77 	.addr = _addr, \
78 	.min_value = _min_value, \
79 	.max_value = _max_value, \
80 }
81 
82 static const struct chip_data {
83 	enum power_supply_property psp;
84 	u8 addr;
85 	int min_value;
86 	int max_value;
87 } sbs_data[] = {
88 	[REG_MANUFACTURER_DATA] =
89 		SBS_DATA(POWER_SUPPLY_PROP_PRESENT, 0x00, 0, 65535),
90 	[REG_TEMPERATURE] =
91 		SBS_DATA(POWER_SUPPLY_PROP_TEMP, 0x08, 0, 65535),
92 	[REG_VOLTAGE] =
93 		SBS_DATA(POWER_SUPPLY_PROP_VOLTAGE_NOW, 0x09, 0, 20000),
94 	[REG_CURRENT] =
95 		SBS_DATA(POWER_SUPPLY_PROP_CURRENT_NOW, 0x0A, -32768, 32767),
96 	[REG_CAPACITY] =
97 		SBS_DATA(POWER_SUPPLY_PROP_CAPACITY, 0x0D, 0, 100),
98 	[REG_REMAINING_CAPACITY] =
99 		SBS_DATA(POWER_SUPPLY_PROP_ENERGY_NOW, 0x0F, 0, 65535),
100 	[REG_REMAINING_CAPACITY_CHARGE] =
101 		SBS_DATA(POWER_SUPPLY_PROP_CHARGE_NOW, 0x0F, 0, 65535),
102 	[REG_FULL_CHARGE_CAPACITY] =
103 		SBS_DATA(POWER_SUPPLY_PROP_ENERGY_FULL, 0x10, 0, 65535),
104 	[REG_FULL_CHARGE_CAPACITY_CHARGE] =
105 		SBS_DATA(POWER_SUPPLY_PROP_CHARGE_FULL, 0x10, 0, 65535),
106 	[REG_TIME_TO_EMPTY] =
107 		SBS_DATA(POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG, 0x12, 0, 65535),
108 	[REG_TIME_TO_FULL] =
109 		SBS_DATA(POWER_SUPPLY_PROP_TIME_TO_FULL_AVG, 0x13, 0, 65535),
110 	[REG_STATUS] =
111 		SBS_DATA(POWER_SUPPLY_PROP_STATUS, 0x16, 0, 65535),
112 	[REG_CAPACITY_LEVEL] =
113 		SBS_DATA(POWER_SUPPLY_PROP_CAPACITY_LEVEL, 0x16, 0, 65535),
114 	[REG_CYCLE_COUNT] =
115 		SBS_DATA(POWER_SUPPLY_PROP_CYCLE_COUNT, 0x17, 0, 65535),
116 	[REG_DESIGN_CAPACITY] =
117 		SBS_DATA(POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN, 0x18, 0, 65535),
118 	[REG_DESIGN_CAPACITY_CHARGE] =
119 		SBS_DATA(POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN, 0x18, 0, 65535),
120 	[REG_DESIGN_VOLTAGE_MIN] =
121 		SBS_DATA(POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN, 0x19, 0, 65535),
122 	[REG_DESIGN_VOLTAGE_MAX] =
123 		SBS_DATA(POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN, 0x19, 0, 65535),
124 	[REG_SERIAL_NUMBER] =
125 		SBS_DATA(POWER_SUPPLY_PROP_SERIAL_NUMBER, 0x1C, 0, 65535),
126 	/* Properties of type `const char *' */
127 	[REG_MANUFACTURER] =
128 		SBS_DATA(POWER_SUPPLY_PROP_MANUFACTURER, 0x20, 0, 65535),
129 	[REG_MODEL_NAME] =
130 		SBS_DATA(POWER_SUPPLY_PROP_MODEL_NAME, 0x21, 0, 65535)
131 };
132 
133 static enum power_supply_property sbs_properties[] = {
134 	POWER_SUPPLY_PROP_STATUS,
135 	POWER_SUPPLY_PROP_CAPACITY_LEVEL,
136 	POWER_SUPPLY_PROP_HEALTH,
137 	POWER_SUPPLY_PROP_PRESENT,
138 	POWER_SUPPLY_PROP_TECHNOLOGY,
139 	POWER_SUPPLY_PROP_CYCLE_COUNT,
140 	POWER_SUPPLY_PROP_VOLTAGE_NOW,
141 	POWER_SUPPLY_PROP_CURRENT_NOW,
142 	POWER_SUPPLY_PROP_CAPACITY,
143 	POWER_SUPPLY_PROP_TEMP,
144 	POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
145 	POWER_SUPPLY_PROP_TIME_TO_FULL_AVG,
146 	POWER_SUPPLY_PROP_SERIAL_NUMBER,
147 	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
148 	POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
149 	POWER_SUPPLY_PROP_ENERGY_NOW,
150 	POWER_SUPPLY_PROP_ENERGY_FULL,
151 	POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN,
152 	POWER_SUPPLY_PROP_CHARGE_NOW,
153 	POWER_SUPPLY_PROP_CHARGE_FULL,
154 	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
155 	/* Properties of type `const char *' */
156 	POWER_SUPPLY_PROP_MANUFACTURER,
157 	POWER_SUPPLY_PROP_MODEL_NAME
158 };
159 
160 /* Supports special manufacturer commands from TI BQ20Z75 IC. */
161 #define SBS_FLAGS_TI_BQ20Z75		BIT(0)
162 
163 struct sbs_info {
164 	struct i2c_client		*client;
165 	struct power_supply		*power_supply;
166 	bool				is_present;
167 	struct gpio_desc		*gpio_detect;
168 	bool				enable_detection;
169 	int				last_state;
170 	int				poll_time;
171 	u32				i2c_retry_count;
172 	u32				poll_retry_count;
173 	struct delayed_work		work;
174 	struct mutex			mode_lock;
175 	u32				flags;
176 };
177 
178 static char model_name[I2C_SMBUS_BLOCK_MAX + 1];
179 static char manufacturer[I2C_SMBUS_BLOCK_MAX + 1];
180 static bool force_load;
181 
182 static int sbs_read_word_data(struct i2c_client *client, u8 address)
183 {
184 	struct sbs_info *chip = i2c_get_clientdata(client);
185 	int retries = chip->i2c_retry_count;
186 	s32 ret = 0;
187 
188 	while (retries > 0) {
189 		ret = i2c_smbus_read_word_data(client, address);
190 		if (ret >= 0)
191 			break;
192 		retries--;
193 	}
194 
195 	if (ret < 0) {
196 		dev_dbg(&client->dev,
197 			"%s: i2c read at address 0x%x failed\n",
198 			__func__, address);
199 		return ret;
200 	}
201 
202 	return ret;
203 }
204 
205 static int sbs_read_string_data(struct i2c_client *client, u8 address,
206 				char *values)
207 {
208 	struct sbs_info *chip = i2c_get_clientdata(client);
209 	s32 ret = 0, block_length = 0;
210 	int retries_length, retries_block;
211 	u8 block_buffer[I2C_SMBUS_BLOCK_MAX + 1];
212 
213 	retries_length = chip->i2c_retry_count;
214 	retries_block = chip->i2c_retry_count;
215 
216 	/* Adapter needs to support these two functions */
217 	if (!i2c_check_functionality(client->adapter,
218 				     I2C_FUNC_SMBUS_BYTE_DATA |
219 				     I2C_FUNC_SMBUS_I2C_BLOCK)){
220 		return -ENODEV;
221 	}
222 
223 	/* Get the length of block data */
224 	while (retries_length > 0) {
225 		ret = i2c_smbus_read_byte_data(client, address);
226 		if (ret >= 0)
227 			break;
228 		retries_length--;
229 	}
230 
231 	if (ret < 0) {
232 		dev_dbg(&client->dev,
233 			"%s: i2c read at address 0x%x failed\n",
234 			__func__, address);
235 		return ret;
236 	}
237 
238 	/* block_length does not include NULL terminator */
239 	block_length = ret;
240 	if (block_length > I2C_SMBUS_BLOCK_MAX) {
241 		dev_err(&client->dev,
242 			"%s: Returned block_length is longer than 0x%x\n",
243 			__func__, I2C_SMBUS_BLOCK_MAX);
244 		return -EINVAL;
245 	}
246 
247 	/* Get the block data */
248 	while (retries_block > 0) {
249 		ret = i2c_smbus_read_i2c_block_data(
250 				client, address,
251 				block_length + 1, block_buffer);
252 		if (ret >= 0)
253 			break;
254 		retries_block--;
255 	}
256 
257 	if (ret < 0) {
258 		dev_dbg(&client->dev,
259 			"%s: i2c read at address 0x%x failed\n",
260 			__func__, address);
261 		return ret;
262 	}
263 
264 	/* block_buffer[0] == block_length */
265 	memcpy(values, block_buffer + 1, block_length);
266 	values[block_length] = '\0';
267 
268 	return ret;
269 }
270 
271 static int sbs_write_word_data(struct i2c_client *client, u8 address,
272 	u16 value)
273 {
274 	struct sbs_info *chip = i2c_get_clientdata(client);
275 	int retries = chip->i2c_retry_count;
276 	s32 ret = 0;
277 
278 	while (retries > 0) {
279 		ret = i2c_smbus_write_word_data(client, address, value);
280 		if (ret >= 0)
281 			break;
282 		retries--;
283 	}
284 
285 	if (ret < 0) {
286 		dev_dbg(&client->dev,
287 			"%s: i2c write to address 0x%x failed\n",
288 			__func__, address);
289 		return ret;
290 	}
291 
292 	return 0;
293 }
294 
295 static int sbs_status_correct(struct i2c_client *client, int *intval)
296 {
297 	int ret;
298 
299 	ret = sbs_read_word_data(client, sbs_data[REG_CURRENT].addr);
300 	if (ret < 0)
301 		return ret;
302 
303 	ret = (s16)ret;
304 
305 	/* Not drawing current means full (cannot be not charging) */
306 	if (ret == 0)
307 		*intval = POWER_SUPPLY_STATUS_FULL;
308 
309 	if (*intval == POWER_SUPPLY_STATUS_FULL) {
310 		/* Drawing or providing current when full */
311 		if (ret > 0)
312 			*intval = POWER_SUPPLY_STATUS_CHARGING;
313 		else if (ret < 0)
314 			*intval = POWER_SUPPLY_STATUS_DISCHARGING;
315 	}
316 
317 	return 0;
318 }
319 
320 static int sbs_get_battery_presence_and_health(
321 	struct i2c_client *client, enum power_supply_property psp,
322 	union power_supply_propval *val)
323 {
324 	int ret;
325 
326 	if (psp == POWER_SUPPLY_PROP_PRESENT) {
327 		/* Dummy command; if it succeeds, battery is present. */
328 		ret = sbs_read_word_data(client, sbs_data[REG_STATUS].addr);
329 		if (ret < 0)
330 			val->intval = 0; /* battery disconnected */
331 		else
332 			val->intval = 1; /* battery present */
333 	} else { /* POWER_SUPPLY_PROP_HEALTH */
334 		/* SBS spec doesn't have a general health command. */
335 		val->intval = POWER_SUPPLY_HEALTH_UNKNOWN;
336 	}
337 
338 	return 0;
339 }
340 
341 static int sbs_get_ti_battery_presence_and_health(
342 	struct i2c_client *client, enum power_supply_property psp,
343 	union power_supply_propval *val)
344 {
345 	s32 ret;
346 
347 	/*
348 	 * Write to ManufacturerAccess with ManufacturerAccess command
349 	 * and then read the status.
350 	 */
351 	ret = sbs_write_word_data(client, sbs_data[REG_MANUFACTURER_DATA].addr,
352 				  MANUFACTURER_ACCESS_STATUS);
353 	if (ret < 0) {
354 		if (psp == POWER_SUPPLY_PROP_PRESENT)
355 			val->intval = 0; /* battery removed */
356 		return ret;
357 	}
358 
359 	ret = sbs_read_word_data(client, sbs_data[REG_MANUFACTURER_DATA].addr);
360 	if (ret < 0) {
361 		if (psp == POWER_SUPPLY_PROP_PRESENT)
362 			val->intval = 0; /* battery removed */
363 		return ret;
364 	}
365 
366 	if (ret < sbs_data[REG_MANUFACTURER_DATA].min_value ||
367 	    ret > sbs_data[REG_MANUFACTURER_DATA].max_value) {
368 		val->intval = 0;
369 		return 0;
370 	}
371 
372 	/* Mask the upper nibble of 2nd byte and
373 	 * lower byte of response then
374 	 * shift the result by 8 to get status*/
375 	ret &= 0x0F00;
376 	ret >>= 8;
377 	if (psp == POWER_SUPPLY_PROP_PRESENT) {
378 		if (ret == 0x0F)
379 			/* battery removed */
380 			val->intval = 0;
381 		else
382 			val->intval = 1;
383 	} else if (psp == POWER_SUPPLY_PROP_HEALTH) {
384 		if (ret == 0x09)
385 			val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
386 		else if (ret == 0x0B)
387 			val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
388 		else if (ret == 0x0C)
389 			val->intval = POWER_SUPPLY_HEALTH_DEAD;
390 		else
391 			val->intval = POWER_SUPPLY_HEALTH_GOOD;
392 	}
393 
394 	return 0;
395 }
396 
397 static int sbs_get_battery_property(struct i2c_client *client,
398 	int reg_offset, enum power_supply_property psp,
399 	union power_supply_propval *val)
400 {
401 	struct sbs_info *chip = i2c_get_clientdata(client);
402 	s32 ret;
403 
404 	ret = sbs_read_word_data(client, sbs_data[reg_offset].addr);
405 	if (ret < 0)
406 		return ret;
407 
408 	/* returned values are 16 bit */
409 	if (sbs_data[reg_offset].min_value < 0)
410 		ret = (s16)ret;
411 
412 	if (ret >= sbs_data[reg_offset].min_value &&
413 	    ret <= sbs_data[reg_offset].max_value) {
414 		val->intval = ret;
415 		if (psp == POWER_SUPPLY_PROP_CAPACITY_LEVEL) {
416 			if (!(ret & BATTERY_INITIALIZED))
417 				val->intval =
418 					POWER_SUPPLY_CAPACITY_LEVEL_UNKNOWN;
419 			else if (ret & BATTERY_FULL_CHARGED)
420 				val->intval =
421 					POWER_SUPPLY_CAPACITY_LEVEL_FULL;
422 			else if (ret & BATTERY_FULL_DISCHARGED)
423 				val->intval =
424 					POWER_SUPPLY_CAPACITY_LEVEL_CRITICAL;
425 			else
426 				val->intval =
427 					POWER_SUPPLY_CAPACITY_LEVEL_NORMAL;
428 			return 0;
429 		} else if (psp != POWER_SUPPLY_PROP_STATUS) {
430 			return 0;
431 		}
432 
433 		if (ret & BATTERY_FULL_CHARGED)
434 			val->intval = POWER_SUPPLY_STATUS_FULL;
435 		else if (ret & BATTERY_DISCHARGING)
436 			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
437 		else
438 			val->intval = POWER_SUPPLY_STATUS_CHARGING;
439 
440 		sbs_status_correct(client, &val->intval);
441 
442 		if (chip->poll_time == 0)
443 			chip->last_state = val->intval;
444 		else if (chip->last_state != val->intval) {
445 			cancel_delayed_work_sync(&chip->work);
446 			power_supply_changed(chip->power_supply);
447 			chip->poll_time = 0;
448 		}
449 	} else {
450 		if (psp == POWER_SUPPLY_PROP_STATUS)
451 			val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
452 		else if (psp == POWER_SUPPLY_PROP_CAPACITY)
453 			/* sbs spec says that this can be >100 %
454 			 * even if max value is 100 %
455 			 */
456 			val->intval = min(ret, 100);
457 		else
458 			val->intval = 0;
459 	}
460 
461 	return 0;
462 }
463 
464 static int sbs_get_battery_string_property(struct i2c_client *client,
465 	int reg_offset, enum power_supply_property psp, char *val)
466 {
467 	s32 ret;
468 
469 	ret = sbs_read_string_data(client, sbs_data[reg_offset].addr, val);
470 
471 	if (ret < 0)
472 		return ret;
473 
474 	return 0;
475 }
476 
477 static void  sbs_unit_adjustment(struct i2c_client *client,
478 	enum power_supply_property psp, union power_supply_propval *val)
479 {
480 #define BASE_UNIT_CONVERSION		1000
481 #define BATTERY_MODE_CAP_MULT_WATT	(10 * BASE_UNIT_CONVERSION)
482 #define TIME_UNIT_CONVERSION		60
483 #define TEMP_KELVIN_TO_CELSIUS		2731
484 	switch (psp) {
485 	case POWER_SUPPLY_PROP_ENERGY_NOW:
486 	case POWER_SUPPLY_PROP_ENERGY_FULL:
487 	case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
488 		/* sbs provides energy in units of 10mWh.
489 		 * Convert to µWh
490 		 */
491 		val->intval *= BATTERY_MODE_CAP_MULT_WATT;
492 		break;
493 
494 	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
495 	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
496 	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
497 	case POWER_SUPPLY_PROP_CURRENT_NOW:
498 	case POWER_SUPPLY_PROP_CHARGE_NOW:
499 	case POWER_SUPPLY_PROP_CHARGE_FULL:
500 	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
501 		val->intval *= BASE_UNIT_CONVERSION;
502 		break;
503 
504 	case POWER_SUPPLY_PROP_TEMP:
505 		/* sbs provides battery temperature in 0.1K
506 		 * so convert it to 0.1°C
507 		 */
508 		val->intval -= TEMP_KELVIN_TO_CELSIUS;
509 		break;
510 
511 	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
512 	case POWER_SUPPLY_PROP_TIME_TO_FULL_AVG:
513 		/* sbs provides time to empty and time to full in minutes.
514 		 * Convert to seconds
515 		 */
516 		val->intval *= TIME_UNIT_CONVERSION;
517 		break;
518 
519 	default:
520 		dev_dbg(&client->dev,
521 			"%s: no need for unit conversion %d\n", __func__, psp);
522 	}
523 }
524 
525 static enum sbs_battery_mode sbs_set_battery_mode(struct i2c_client *client,
526 	enum sbs_battery_mode mode)
527 {
528 	int ret, original_val;
529 
530 	original_val = sbs_read_word_data(client, BATTERY_MODE_OFFSET);
531 	if (original_val < 0)
532 		return original_val;
533 
534 	if ((original_val & BATTERY_MODE_MASK) == mode)
535 		return mode;
536 
537 	if (mode == BATTERY_MODE_AMPS)
538 		ret = original_val & ~BATTERY_MODE_MASK;
539 	else
540 		ret = original_val | BATTERY_MODE_MASK;
541 
542 	ret = sbs_write_word_data(client, BATTERY_MODE_OFFSET, ret);
543 	if (ret < 0)
544 		return ret;
545 
546 	usleep_range(1000, 2000);
547 
548 	return original_val & BATTERY_MODE_MASK;
549 }
550 
551 static int sbs_get_battery_capacity(struct i2c_client *client,
552 	int reg_offset, enum power_supply_property psp,
553 	union power_supply_propval *val)
554 {
555 	s32 ret;
556 	enum sbs_battery_mode mode = BATTERY_MODE_WATTS;
557 
558 	if (power_supply_is_amp_property(psp))
559 		mode = BATTERY_MODE_AMPS;
560 
561 	mode = sbs_set_battery_mode(client, mode);
562 	if (mode < 0)
563 		return mode;
564 
565 	ret = sbs_read_word_data(client, sbs_data[reg_offset].addr);
566 	if (ret < 0)
567 		return ret;
568 
569 	val->intval = ret;
570 
571 	ret = sbs_set_battery_mode(client, mode);
572 	if (ret < 0)
573 		return ret;
574 
575 	return 0;
576 }
577 
578 static char sbs_serial[5];
579 static int sbs_get_battery_serial_number(struct i2c_client *client,
580 	union power_supply_propval *val)
581 {
582 	int ret;
583 
584 	ret = sbs_read_word_data(client, sbs_data[REG_SERIAL_NUMBER].addr);
585 	if (ret < 0)
586 		return ret;
587 
588 	sprintf(sbs_serial, "%04x", ret);
589 	val->strval = sbs_serial;
590 
591 	return 0;
592 }
593 
594 static int sbs_get_property_index(struct i2c_client *client,
595 	enum power_supply_property psp)
596 {
597 	int count;
598 	for (count = 0; count < ARRAY_SIZE(sbs_data); count++)
599 		if (psp == sbs_data[count].psp)
600 			return count;
601 
602 	dev_warn(&client->dev,
603 		"%s: Invalid Property - %d\n", __func__, psp);
604 
605 	return -EINVAL;
606 }
607 
608 static int sbs_get_property(struct power_supply *psy,
609 	enum power_supply_property psp,
610 	union power_supply_propval *val)
611 {
612 	int ret = 0;
613 	struct sbs_info *chip = power_supply_get_drvdata(psy);
614 	struct i2c_client *client = chip->client;
615 
616 	if (chip->gpio_detect) {
617 		ret = gpiod_get_value_cansleep(chip->gpio_detect);
618 		if (ret < 0)
619 			return ret;
620 		if (psp == POWER_SUPPLY_PROP_PRESENT) {
621 			val->intval = ret;
622 			chip->is_present = val->intval;
623 			return 0;
624 		}
625 		if (ret == 0)
626 			return -ENODATA;
627 	}
628 
629 	switch (psp) {
630 	case POWER_SUPPLY_PROP_PRESENT:
631 	case POWER_SUPPLY_PROP_HEALTH:
632 		if (client->flags & SBS_FLAGS_TI_BQ20Z75)
633 			ret = sbs_get_ti_battery_presence_and_health(client,
634 								     psp, val);
635 		else
636 			ret = sbs_get_battery_presence_and_health(client, psp,
637 								  val);
638 		if (psp == POWER_SUPPLY_PROP_PRESENT)
639 			return 0;
640 		break;
641 
642 	case POWER_SUPPLY_PROP_TECHNOLOGY:
643 		val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
644 		goto done; /* don't trigger power_supply_changed()! */
645 
646 	case POWER_SUPPLY_PROP_ENERGY_NOW:
647 	case POWER_SUPPLY_PROP_ENERGY_FULL:
648 	case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
649 	case POWER_SUPPLY_PROP_CHARGE_NOW:
650 	case POWER_SUPPLY_PROP_CHARGE_FULL:
651 	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
652 		ret = sbs_get_property_index(client, psp);
653 		if (ret < 0)
654 			break;
655 
656 		/* sbs_get_battery_capacity() will change the battery mode
657 		 * temporarily to read the requested attribute. Ensure we stay
658 		 * in the desired mode for the duration of the attribute read.
659 		 */
660 		mutex_lock(&chip->mode_lock);
661 		ret = sbs_get_battery_capacity(client, ret, psp, val);
662 		mutex_unlock(&chip->mode_lock);
663 		break;
664 
665 	case POWER_SUPPLY_PROP_SERIAL_NUMBER:
666 		ret = sbs_get_battery_serial_number(client, val);
667 		break;
668 
669 	case POWER_SUPPLY_PROP_STATUS:
670 	case POWER_SUPPLY_PROP_CAPACITY_LEVEL:
671 	case POWER_SUPPLY_PROP_CYCLE_COUNT:
672 	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
673 	case POWER_SUPPLY_PROP_CURRENT_NOW:
674 	case POWER_SUPPLY_PROP_TEMP:
675 	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
676 	case POWER_SUPPLY_PROP_TIME_TO_FULL_AVG:
677 	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
678 	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
679 	case POWER_SUPPLY_PROP_CAPACITY:
680 		ret = sbs_get_property_index(client, psp);
681 		if (ret < 0)
682 			break;
683 
684 		ret = sbs_get_battery_property(client, ret, psp, val);
685 		break;
686 
687 	case POWER_SUPPLY_PROP_MODEL_NAME:
688 		ret = sbs_get_property_index(client, psp);
689 		if (ret < 0)
690 			break;
691 
692 		ret = sbs_get_battery_string_property(client, ret, psp,
693 						      model_name);
694 		val->strval = model_name;
695 		break;
696 
697 	case POWER_SUPPLY_PROP_MANUFACTURER:
698 		ret = sbs_get_property_index(client, psp);
699 		if (ret < 0)
700 			break;
701 
702 		ret = sbs_get_battery_string_property(client, ret, psp,
703 						      manufacturer);
704 		val->strval = manufacturer;
705 		break;
706 
707 	default:
708 		dev_err(&client->dev,
709 			"%s: INVALID property\n", __func__);
710 		return -EINVAL;
711 	}
712 
713 	if (!chip->enable_detection)
714 		goto done;
715 
716 	if (!chip->gpio_detect &&
717 		chip->is_present != (ret >= 0)) {
718 		chip->is_present = (ret >= 0);
719 		power_supply_changed(chip->power_supply);
720 	}
721 
722 done:
723 	if (!ret) {
724 		/* Convert units to match requirements for power supply class */
725 		sbs_unit_adjustment(client, psp, val);
726 	}
727 
728 	dev_dbg(&client->dev,
729 		"%s: property = %d, value = %x\n", __func__, psp, val->intval);
730 
731 	if (ret && chip->is_present)
732 		return ret;
733 
734 	/* battery not present, so return NODATA for properties */
735 	if (ret)
736 		return -ENODATA;
737 
738 	return 0;
739 }
740 
741 static void sbs_supply_changed(struct sbs_info *chip)
742 {
743 	struct power_supply *battery = chip->power_supply;
744 	int ret;
745 
746 	ret = gpiod_get_value_cansleep(chip->gpio_detect);
747 	if (ret < 0)
748 		return;
749 	chip->is_present = ret;
750 	power_supply_changed(battery);
751 }
752 
753 static irqreturn_t sbs_irq(int irq, void *devid)
754 {
755 	sbs_supply_changed(devid);
756 	return IRQ_HANDLED;
757 }
758 
759 static void sbs_alert(struct i2c_client *client, enum i2c_alert_protocol prot,
760 	unsigned int data)
761 {
762 	sbs_supply_changed(i2c_get_clientdata(client));
763 }
764 
765 static void sbs_external_power_changed(struct power_supply *psy)
766 {
767 	struct sbs_info *chip = power_supply_get_drvdata(psy);
768 
769 	/* cancel outstanding work */
770 	cancel_delayed_work_sync(&chip->work);
771 
772 	schedule_delayed_work(&chip->work, HZ);
773 	chip->poll_time = chip->poll_retry_count;
774 }
775 
776 static void sbs_delayed_work(struct work_struct *work)
777 {
778 	struct sbs_info *chip;
779 	s32 ret;
780 
781 	chip = container_of(work, struct sbs_info, work.work);
782 
783 	ret = sbs_read_word_data(chip->client, sbs_data[REG_STATUS].addr);
784 	/* if the read failed, give up on this work */
785 	if (ret < 0) {
786 		chip->poll_time = 0;
787 		return;
788 	}
789 
790 	if (ret & BATTERY_FULL_CHARGED)
791 		ret = POWER_SUPPLY_STATUS_FULL;
792 	else if (ret & BATTERY_DISCHARGING)
793 		ret = POWER_SUPPLY_STATUS_DISCHARGING;
794 	else
795 		ret = POWER_SUPPLY_STATUS_CHARGING;
796 
797 	sbs_status_correct(chip->client, &ret);
798 
799 	if (chip->last_state != ret) {
800 		chip->poll_time = 0;
801 		power_supply_changed(chip->power_supply);
802 		return;
803 	}
804 	if (chip->poll_time > 0) {
805 		schedule_delayed_work(&chip->work, HZ);
806 		chip->poll_time--;
807 		return;
808 	}
809 }
810 
811 static const struct power_supply_desc sbs_default_desc = {
812 	.type = POWER_SUPPLY_TYPE_BATTERY,
813 	.properties = sbs_properties,
814 	.num_properties = ARRAY_SIZE(sbs_properties),
815 	.get_property = sbs_get_property,
816 	.external_power_changed = sbs_external_power_changed,
817 };
818 
819 static int sbs_probe(struct i2c_client *client,
820 	const struct i2c_device_id *id)
821 {
822 	struct sbs_info *chip;
823 	struct power_supply_desc *sbs_desc;
824 	struct sbs_platform_data *pdata = client->dev.platform_data;
825 	struct power_supply_config psy_cfg = {};
826 	int rc;
827 	int irq;
828 
829 	sbs_desc = devm_kmemdup(&client->dev, &sbs_default_desc,
830 			sizeof(*sbs_desc), GFP_KERNEL);
831 	if (!sbs_desc)
832 		return -ENOMEM;
833 
834 	sbs_desc->name = devm_kasprintf(&client->dev, GFP_KERNEL, "sbs-%s",
835 			dev_name(&client->dev));
836 	if (!sbs_desc->name)
837 		return -ENOMEM;
838 
839 	chip = devm_kzalloc(&client->dev, sizeof(struct sbs_info), GFP_KERNEL);
840 	if (!chip)
841 		return -ENOMEM;
842 
843 	chip->flags = (u32)(uintptr_t)of_device_get_match_data(&client->dev);
844 	chip->client = client;
845 	chip->enable_detection = false;
846 	psy_cfg.of_node = client->dev.of_node;
847 	psy_cfg.drv_data = chip;
848 	chip->last_state = POWER_SUPPLY_STATUS_UNKNOWN;
849 	mutex_init(&chip->mode_lock);
850 
851 	/* use pdata if available, fall back to DT properties,
852 	 * or hardcoded defaults if not
853 	 */
854 	rc = of_property_read_u32(client->dev.of_node, "sbs,i2c-retry-count",
855 				  &chip->i2c_retry_count);
856 	if (rc)
857 		chip->i2c_retry_count = 0;
858 
859 	rc = of_property_read_u32(client->dev.of_node, "sbs,poll-retry-count",
860 				  &chip->poll_retry_count);
861 	if (rc)
862 		chip->poll_retry_count = 0;
863 
864 	if (pdata) {
865 		chip->poll_retry_count = pdata->poll_retry_count;
866 		chip->i2c_retry_count  = pdata->i2c_retry_count;
867 	}
868 	chip->i2c_retry_count = chip->i2c_retry_count + 1;
869 
870 	chip->gpio_detect = devm_gpiod_get_optional(&client->dev,
871 			"sbs,battery-detect", GPIOD_IN);
872 	if (IS_ERR(chip->gpio_detect)) {
873 		dev_err(&client->dev, "Failed to get gpio: %ld\n",
874 			PTR_ERR(chip->gpio_detect));
875 		return PTR_ERR(chip->gpio_detect);
876 	}
877 
878 	i2c_set_clientdata(client, chip);
879 
880 	if (!chip->gpio_detect)
881 		goto skip_gpio;
882 
883 	irq = gpiod_to_irq(chip->gpio_detect);
884 	if (irq <= 0) {
885 		dev_warn(&client->dev, "Failed to get gpio as irq: %d\n", irq);
886 		goto skip_gpio;
887 	}
888 
889 	rc = devm_request_threaded_irq(&client->dev, irq, NULL, sbs_irq,
890 		IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
891 		dev_name(&client->dev), chip);
892 	if (rc) {
893 		dev_warn(&client->dev, "Failed to request irq: %d\n", rc);
894 		goto skip_gpio;
895 	}
896 
897 skip_gpio:
898 	/*
899 	 * Before we register, we might need to make sure we can actually talk
900 	 * to the battery.
901 	 */
902 	if (!(force_load || chip->gpio_detect)) {
903 		rc = sbs_read_word_data(client, sbs_data[REG_STATUS].addr);
904 
905 		if (rc < 0) {
906 			dev_err(&client->dev, "%s: Failed to get device status\n",
907 				__func__);
908 			goto exit_psupply;
909 		}
910 	}
911 
912 	chip->power_supply = devm_power_supply_register(&client->dev, sbs_desc,
913 						   &psy_cfg);
914 	if (IS_ERR(chip->power_supply)) {
915 		dev_err(&client->dev,
916 			"%s: Failed to register power supply\n", __func__);
917 		rc = PTR_ERR(chip->power_supply);
918 		goto exit_psupply;
919 	}
920 
921 	dev_info(&client->dev,
922 		"%s: battery gas gauge device registered\n", client->name);
923 
924 	INIT_DELAYED_WORK(&chip->work, sbs_delayed_work);
925 
926 	chip->enable_detection = true;
927 
928 	return 0;
929 
930 exit_psupply:
931 	return rc;
932 }
933 
934 static int sbs_remove(struct i2c_client *client)
935 {
936 	struct sbs_info *chip = i2c_get_clientdata(client);
937 
938 	cancel_delayed_work_sync(&chip->work);
939 
940 	return 0;
941 }
942 
943 #if defined CONFIG_PM_SLEEP
944 
945 static int sbs_suspend(struct device *dev)
946 {
947 	struct i2c_client *client = to_i2c_client(dev);
948 	struct sbs_info *chip = i2c_get_clientdata(client);
949 	int ret;
950 
951 	if (chip->poll_time > 0)
952 		cancel_delayed_work_sync(&chip->work);
953 
954 	if (chip->flags & SBS_FLAGS_TI_BQ20Z75) {
955 		/* Write to manufacturer access with sleep command. */
956 		ret = sbs_write_word_data(client,
957 					  sbs_data[REG_MANUFACTURER_DATA].addr,
958 					  MANUFACTURER_ACCESS_SLEEP);
959 		if (chip->is_present && ret < 0)
960 			return ret;
961 	}
962 
963 	return 0;
964 }
965 
966 static SIMPLE_DEV_PM_OPS(sbs_pm_ops, sbs_suspend, NULL);
967 #define SBS_PM_OPS (&sbs_pm_ops)
968 
969 #else
970 #define SBS_PM_OPS NULL
971 #endif
972 
973 static const struct i2c_device_id sbs_id[] = {
974 	{ "bq20z75", 0 },
975 	{ "sbs-battery", 1 },
976 	{}
977 };
978 MODULE_DEVICE_TABLE(i2c, sbs_id);
979 
980 static const struct of_device_id sbs_dt_ids[] = {
981 	{ .compatible = "sbs,sbs-battery" },
982 	{
983 		.compatible = "ti,bq20z75",
984 		.data = (void *)SBS_FLAGS_TI_BQ20Z75,
985 	},
986 	{ }
987 };
988 MODULE_DEVICE_TABLE(of, sbs_dt_ids);
989 
990 static struct i2c_driver sbs_battery_driver = {
991 	.probe		= sbs_probe,
992 	.remove		= sbs_remove,
993 	.alert		= sbs_alert,
994 	.id_table	= sbs_id,
995 	.driver = {
996 		.name	= "sbs-battery",
997 		.of_match_table = sbs_dt_ids,
998 		.pm	= SBS_PM_OPS,
999 	},
1000 };
1001 module_i2c_driver(sbs_battery_driver);
1002 
1003 MODULE_DESCRIPTION("SBS battery monitor driver");
1004 MODULE_LICENSE("GPL");
1005 
1006 module_param(force_load, bool, S_IRUSR | S_IRGRP | S_IROTH);
1007 MODULE_PARM_DESC(force_load,
1008 		 "Attempt to load the driver even if no battery is connected");
1009