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  * You should have received a copy of the GNU General Public License along
17  * with this program; if not, write to the Free Software Foundation, Inc.,
18  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
19  */
20 
21 #include <linux/init.h>
22 #include <linux/module.h>
23 #include <linux/kernel.h>
24 #include <linux/err.h>
25 #include <linux/power_supply.h>
26 #include <linux/i2c.h>
27 #include <linux/slab.h>
28 #include <linux/interrupt.h>
29 #include <linux/gpio/consumer.h>
30 #include <linux/of.h>
31 #include <linux/stat.h>
32 
33 #include <linux/power/sbs-battery.h>
34 
35 enum {
36 	REG_MANUFACTURER_DATA,
37 	REG_TEMPERATURE,
38 	REG_VOLTAGE,
39 	REG_CURRENT,
40 	REG_CAPACITY,
41 	REG_TIME_TO_EMPTY,
42 	REG_TIME_TO_FULL,
43 	REG_STATUS,
44 	REG_CAPACITY_LEVEL,
45 	REG_CYCLE_COUNT,
46 	REG_SERIAL_NUMBER,
47 	REG_REMAINING_CAPACITY,
48 	REG_REMAINING_CAPACITY_CHARGE,
49 	REG_FULL_CHARGE_CAPACITY,
50 	REG_FULL_CHARGE_CAPACITY_CHARGE,
51 	REG_DESIGN_CAPACITY,
52 	REG_DESIGN_CAPACITY_CHARGE,
53 	REG_DESIGN_VOLTAGE_MIN,
54 	REG_DESIGN_VOLTAGE_MAX,
55 	REG_MANUFACTURER,
56 	REG_MODEL_NAME,
57 };
58 
59 /* Battery Mode defines */
60 #define BATTERY_MODE_OFFSET		0x03
61 #define BATTERY_MODE_MASK		0x8000
62 enum sbs_battery_mode {
63 	BATTERY_MODE_AMPS,
64 	BATTERY_MODE_WATTS
65 };
66 
67 /* manufacturer access defines */
68 #define MANUFACTURER_ACCESS_STATUS	0x0006
69 #define MANUFACTURER_ACCESS_SLEEP	0x0011
70 
71 /* battery status value bits */
72 #define BATTERY_INITIALIZED		0x80
73 #define BATTERY_DISCHARGING		0x40
74 #define BATTERY_FULL_CHARGED		0x20
75 #define BATTERY_FULL_DISCHARGED		0x10
76 
77 /* min_value and max_value are only valid for numerical data */
78 #define SBS_DATA(_psp, _addr, _min_value, _max_value) { \
79 	.psp = _psp, \
80 	.addr = _addr, \
81 	.min_value = _min_value, \
82 	.max_value = _max_value, \
83 }
84 
85 static const struct chip_data {
86 	enum power_supply_property psp;
87 	u8 addr;
88 	int min_value;
89 	int max_value;
90 } sbs_data[] = {
91 	[REG_MANUFACTURER_DATA] =
92 		SBS_DATA(POWER_SUPPLY_PROP_PRESENT, 0x00, 0, 65535),
93 	[REG_TEMPERATURE] =
94 		SBS_DATA(POWER_SUPPLY_PROP_TEMP, 0x08, 0, 65535),
95 	[REG_VOLTAGE] =
96 		SBS_DATA(POWER_SUPPLY_PROP_VOLTAGE_NOW, 0x09, 0, 20000),
97 	[REG_CURRENT] =
98 		SBS_DATA(POWER_SUPPLY_PROP_CURRENT_NOW, 0x0A, -32768, 32767),
99 	[REG_CAPACITY] =
100 		SBS_DATA(POWER_SUPPLY_PROP_CAPACITY, 0x0D, 0, 100),
101 	[REG_REMAINING_CAPACITY] =
102 		SBS_DATA(POWER_SUPPLY_PROP_ENERGY_NOW, 0x0F, 0, 65535),
103 	[REG_REMAINING_CAPACITY_CHARGE] =
104 		SBS_DATA(POWER_SUPPLY_PROP_CHARGE_NOW, 0x0F, 0, 65535),
105 	[REG_FULL_CHARGE_CAPACITY] =
106 		SBS_DATA(POWER_SUPPLY_PROP_ENERGY_FULL, 0x10, 0, 65535),
107 	[REG_FULL_CHARGE_CAPACITY_CHARGE] =
108 		SBS_DATA(POWER_SUPPLY_PROP_CHARGE_FULL, 0x10, 0, 65535),
109 	[REG_TIME_TO_EMPTY] =
110 		SBS_DATA(POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG, 0x12, 0, 65535),
111 	[REG_TIME_TO_FULL] =
112 		SBS_DATA(POWER_SUPPLY_PROP_TIME_TO_FULL_AVG, 0x13, 0, 65535),
113 	[REG_STATUS] =
114 		SBS_DATA(POWER_SUPPLY_PROP_STATUS, 0x16, 0, 65535),
115 	[REG_CAPACITY_LEVEL] =
116 		SBS_DATA(POWER_SUPPLY_PROP_CAPACITY_LEVEL, 0x16, 0, 65535),
117 	[REG_CYCLE_COUNT] =
118 		SBS_DATA(POWER_SUPPLY_PROP_CYCLE_COUNT, 0x17, 0, 65535),
119 	[REG_DESIGN_CAPACITY] =
120 		SBS_DATA(POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN, 0x18, 0, 65535),
121 	[REG_DESIGN_CAPACITY_CHARGE] =
122 		SBS_DATA(POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN, 0x18, 0, 65535),
123 	[REG_DESIGN_VOLTAGE_MIN] =
124 		SBS_DATA(POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN, 0x19, 0, 65535),
125 	[REG_DESIGN_VOLTAGE_MAX] =
126 		SBS_DATA(POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN, 0x19, 0, 65535),
127 	[REG_SERIAL_NUMBER] =
128 		SBS_DATA(POWER_SUPPLY_PROP_SERIAL_NUMBER, 0x1C, 0, 65535),
129 	/* Properties of type `const char *' */
130 	[REG_MANUFACTURER] =
131 		SBS_DATA(POWER_SUPPLY_PROP_MANUFACTURER, 0x20, 0, 65535),
132 	[REG_MODEL_NAME] =
133 		SBS_DATA(POWER_SUPPLY_PROP_MODEL_NAME, 0x21, 0, 65535)
134 };
135 
136 static enum power_supply_property sbs_properties[] = {
137 	POWER_SUPPLY_PROP_STATUS,
138 	POWER_SUPPLY_PROP_CAPACITY_LEVEL,
139 	POWER_SUPPLY_PROP_HEALTH,
140 	POWER_SUPPLY_PROP_PRESENT,
141 	POWER_SUPPLY_PROP_TECHNOLOGY,
142 	POWER_SUPPLY_PROP_CYCLE_COUNT,
143 	POWER_SUPPLY_PROP_VOLTAGE_NOW,
144 	POWER_SUPPLY_PROP_CURRENT_NOW,
145 	POWER_SUPPLY_PROP_CAPACITY,
146 	POWER_SUPPLY_PROP_TEMP,
147 	POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
148 	POWER_SUPPLY_PROP_TIME_TO_FULL_AVG,
149 	POWER_SUPPLY_PROP_SERIAL_NUMBER,
150 	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
151 	POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
152 	POWER_SUPPLY_PROP_ENERGY_NOW,
153 	POWER_SUPPLY_PROP_ENERGY_FULL,
154 	POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN,
155 	POWER_SUPPLY_PROP_CHARGE_NOW,
156 	POWER_SUPPLY_PROP_CHARGE_FULL,
157 	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
158 	/* Properties of type `const char *' */
159 	POWER_SUPPLY_PROP_MANUFACTURER,
160 	POWER_SUPPLY_PROP_MODEL_NAME
161 };
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 };
176 
177 static char model_name[I2C_SMBUS_BLOCK_MAX + 1];
178 static char manufacturer[I2C_SMBUS_BLOCK_MAX + 1];
179 static bool force_load;
180 
181 static int sbs_read_word_data(struct i2c_client *client, u8 address)
182 {
183 	struct sbs_info *chip = i2c_get_clientdata(client);
184 	s32 ret = 0;
185 	int retries = 1;
186 
187 	retries = chip->i2c_retry_count;
188 
189 	while (retries > 0) {
190 		ret = i2c_smbus_read_word_data(client, address);
191 		if (ret >= 0)
192 			break;
193 		retries--;
194 	}
195 
196 	if (ret < 0) {
197 		dev_dbg(&client->dev,
198 			"%s: i2c read at address 0x%x failed\n",
199 			__func__, address);
200 		return ret;
201 	}
202 
203 	return ret;
204 }
205 
206 static int sbs_read_string_data(struct i2c_client *client, u8 address,
207 				char *values)
208 {
209 	struct sbs_info *chip = i2c_get_clientdata(client);
210 	s32 ret = 0, block_length = 0;
211 	int retries_length = 1, retries_block = 1;
212 	u8 block_buffer[I2C_SMBUS_BLOCK_MAX + 1];
213 
214 	retries_length = chip->i2c_retry_count;
215 	retries_block = chip->i2c_retry_count;
216 
217 	/* Adapter needs to support these two functions */
218 	if (!i2c_check_functionality(client->adapter,
219 				     I2C_FUNC_SMBUS_BYTE_DATA |
220 				     I2C_FUNC_SMBUS_I2C_BLOCK)){
221 		return -ENODEV;
222 	}
223 
224 	/* Get the length of block data */
225 	while (retries_length > 0) {
226 		ret = i2c_smbus_read_byte_data(client, address);
227 		if (ret >= 0)
228 			break;
229 		retries_length--;
230 	}
231 
232 	if (ret < 0) {
233 		dev_dbg(&client->dev,
234 			"%s: i2c read at address 0x%x failed\n",
235 			__func__, address);
236 		return ret;
237 	}
238 
239 	/* block_length does not include NULL terminator */
240 	block_length = ret;
241 	if (block_length > I2C_SMBUS_BLOCK_MAX) {
242 		dev_err(&client->dev,
243 			"%s: Returned block_length is longer than 0x%x\n",
244 			__func__, I2C_SMBUS_BLOCK_MAX);
245 		return -EINVAL;
246 	}
247 
248 	/* Get the block data */
249 	while (retries_block > 0) {
250 		ret = i2c_smbus_read_i2c_block_data(
251 				client, address,
252 				block_length + 1, block_buffer);
253 		if (ret >= 0)
254 			break;
255 		retries_block--;
256 	}
257 
258 	if (ret < 0) {
259 		dev_dbg(&client->dev,
260 			"%s: i2c read at address 0x%x failed\n",
261 			__func__, address);
262 		return ret;
263 	}
264 
265 	/* block_buffer[0] == block_length */
266 	memcpy(values, block_buffer + 1, block_length);
267 	values[block_length] = '\0';
268 
269 	return ret;
270 }
271 
272 static int sbs_write_word_data(struct i2c_client *client, u8 address,
273 	u16 value)
274 {
275 	struct sbs_info *chip = i2c_get_clientdata(client);
276 	s32 ret = 0;
277 	int retries = 1;
278 
279 	retries = chip->i2c_retry_count;
280 
281 	while (retries > 0) {
282 		ret = i2c_smbus_write_word_data(client, address, value);
283 		if (ret >= 0)
284 			break;
285 		retries--;
286 	}
287 
288 	if (ret < 0) {
289 		dev_dbg(&client->dev,
290 			"%s: i2c write to address 0x%x failed\n",
291 			__func__, address);
292 		return ret;
293 	}
294 
295 	return 0;
296 }
297 
298 static int sbs_status_correct(struct i2c_client *client, int *intval)
299 {
300 	int ret;
301 
302 	ret = sbs_read_word_data(client, sbs_data[REG_CURRENT].addr);
303 	if (ret < 0)
304 		return ret;
305 
306 	ret = (s16)ret;
307 
308 	/* Not drawing current means full (cannot be not charging) */
309 	if (ret == 0)
310 		*intval = POWER_SUPPLY_STATUS_FULL;
311 
312 	if (*intval == POWER_SUPPLY_STATUS_FULL) {
313 		/* Drawing or providing current when full */
314 		if (ret > 0)
315 			*intval = POWER_SUPPLY_STATUS_CHARGING;
316 		else if (ret < 0)
317 			*intval = POWER_SUPPLY_STATUS_DISCHARGING;
318 	}
319 
320 	return 0;
321 }
322 
323 static int sbs_get_battery_presence_and_health(
324 	struct i2c_client *client, enum power_supply_property psp,
325 	union power_supply_propval *val)
326 {
327 	s32 ret;
328 	struct sbs_info *chip = i2c_get_clientdata(client);
329 
330 	if (psp == POWER_SUPPLY_PROP_PRESENT && chip->gpio_detect) {
331 		ret = gpiod_get_value_cansleep(chip->gpio_detect);
332 		if (ret < 0)
333 			return ret;
334 		val->intval = ret;
335 		chip->is_present = val->intval;
336 		return ret;
337 	}
338 
339 	/*
340 	 * Write to ManufacturerAccess with ManufacturerAccess command
341 	 * and then read the status. Do not check for error on the write
342 	 * since not all batteries implement write access to this command,
343 	 * while others mandate it.
344 	 */
345 	sbs_write_word_data(client, sbs_data[REG_MANUFACTURER_DATA].addr,
346 			    MANUFACTURER_ACCESS_STATUS);
347 
348 	ret = sbs_read_word_data(client, sbs_data[REG_MANUFACTURER_DATA].addr);
349 	if (ret < 0) {
350 		if (psp == POWER_SUPPLY_PROP_PRESENT)
351 			val->intval = 0; /* battery removed */
352 		return ret;
353 	}
354 
355 	if (ret < sbs_data[REG_MANUFACTURER_DATA].min_value ||
356 	    ret > sbs_data[REG_MANUFACTURER_DATA].max_value) {
357 		val->intval = 0;
358 		return 0;
359 	}
360 
361 	/* Mask the upper nibble of 2nd byte and
362 	 * lower byte of response then
363 	 * shift the result by 8 to get status*/
364 	ret &= 0x0F00;
365 	ret >>= 8;
366 	if (psp == POWER_SUPPLY_PROP_PRESENT) {
367 		if (ret == 0x0F)
368 			/* battery removed */
369 			val->intval = 0;
370 		else
371 			val->intval = 1;
372 	} else if (psp == POWER_SUPPLY_PROP_HEALTH) {
373 		if (ret == 0x09)
374 			val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
375 		else if (ret == 0x0B)
376 			val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
377 		else if (ret == 0x0C)
378 			val->intval = POWER_SUPPLY_HEALTH_DEAD;
379 		else
380 			val->intval = POWER_SUPPLY_HEALTH_GOOD;
381 	}
382 
383 	return 0;
384 }
385 
386 static int sbs_get_battery_property(struct i2c_client *client,
387 	int reg_offset, enum power_supply_property psp,
388 	union power_supply_propval *val)
389 {
390 	struct sbs_info *chip = i2c_get_clientdata(client);
391 	s32 ret;
392 
393 	ret = sbs_read_word_data(client, sbs_data[reg_offset].addr);
394 	if (ret < 0)
395 		return ret;
396 
397 	/* returned values are 16 bit */
398 	if (sbs_data[reg_offset].min_value < 0)
399 		ret = (s16)ret;
400 
401 	if (ret >= sbs_data[reg_offset].min_value &&
402 	    ret <= sbs_data[reg_offset].max_value) {
403 		val->intval = ret;
404 		if (psp == POWER_SUPPLY_PROP_CAPACITY_LEVEL) {
405 			if (!(ret & BATTERY_INITIALIZED))
406 				val->intval =
407 					POWER_SUPPLY_CAPACITY_LEVEL_UNKNOWN;
408 			else if (ret & BATTERY_FULL_CHARGED)
409 				val->intval =
410 					POWER_SUPPLY_CAPACITY_LEVEL_FULL;
411 			else if (ret & BATTERY_FULL_DISCHARGED)
412 				val->intval =
413 					POWER_SUPPLY_CAPACITY_LEVEL_CRITICAL;
414 			else
415 				val->intval =
416 					POWER_SUPPLY_CAPACITY_LEVEL_NORMAL;
417 			return 0;
418 		} else if (psp != POWER_SUPPLY_PROP_STATUS) {
419 			return 0;
420 		}
421 
422 		if (ret & BATTERY_FULL_CHARGED)
423 			val->intval = POWER_SUPPLY_STATUS_FULL;
424 		else if (ret & BATTERY_DISCHARGING)
425 			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
426 		else
427 			val->intval = POWER_SUPPLY_STATUS_CHARGING;
428 
429 		sbs_status_correct(client, &val->intval);
430 
431 		if (chip->poll_time == 0)
432 			chip->last_state = val->intval;
433 		else if (chip->last_state != val->intval) {
434 			cancel_delayed_work_sync(&chip->work);
435 			power_supply_changed(chip->power_supply);
436 			chip->poll_time = 0;
437 		}
438 	} else {
439 		if (psp == POWER_SUPPLY_PROP_STATUS)
440 			val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
441 		else if (psp == POWER_SUPPLY_PROP_CAPACITY)
442 			/* sbs spec says that this can be >100 %
443 			 * even if max value is 100 %
444 			 */
445 			val->intval = min(ret, 100);
446 		else
447 			val->intval = 0;
448 	}
449 
450 	return 0;
451 }
452 
453 static int sbs_get_battery_string_property(struct i2c_client *client,
454 	int reg_offset, enum power_supply_property psp, char *val)
455 {
456 	s32 ret;
457 
458 	ret = sbs_read_string_data(client, sbs_data[reg_offset].addr, val);
459 
460 	if (ret < 0)
461 		return ret;
462 
463 	return 0;
464 }
465 
466 static void  sbs_unit_adjustment(struct i2c_client *client,
467 	enum power_supply_property psp, union power_supply_propval *val)
468 {
469 #define BASE_UNIT_CONVERSION		1000
470 #define BATTERY_MODE_CAP_MULT_WATT	(10 * BASE_UNIT_CONVERSION)
471 #define TIME_UNIT_CONVERSION		60
472 #define TEMP_KELVIN_TO_CELSIUS		2731
473 	switch (psp) {
474 	case POWER_SUPPLY_PROP_ENERGY_NOW:
475 	case POWER_SUPPLY_PROP_ENERGY_FULL:
476 	case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
477 		/* sbs provides energy in units of 10mWh.
478 		 * Convert to µWh
479 		 */
480 		val->intval *= BATTERY_MODE_CAP_MULT_WATT;
481 		break;
482 
483 	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
484 	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
485 	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
486 	case POWER_SUPPLY_PROP_CURRENT_NOW:
487 	case POWER_SUPPLY_PROP_CHARGE_NOW:
488 	case POWER_SUPPLY_PROP_CHARGE_FULL:
489 	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
490 		val->intval *= BASE_UNIT_CONVERSION;
491 		break;
492 
493 	case POWER_SUPPLY_PROP_TEMP:
494 		/* sbs provides battery temperature in 0.1K
495 		 * so convert it to 0.1°C
496 		 */
497 		val->intval -= TEMP_KELVIN_TO_CELSIUS;
498 		break;
499 
500 	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
501 	case POWER_SUPPLY_PROP_TIME_TO_FULL_AVG:
502 		/* sbs provides time to empty and time to full in minutes.
503 		 * Convert to seconds
504 		 */
505 		val->intval *= TIME_UNIT_CONVERSION;
506 		break;
507 
508 	default:
509 		dev_dbg(&client->dev,
510 			"%s: no need for unit conversion %d\n", __func__, psp);
511 	}
512 }
513 
514 static enum sbs_battery_mode sbs_set_battery_mode(struct i2c_client *client,
515 	enum sbs_battery_mode mode)
516 {
517 	int ret, original_val;
518 
519 	original_val = sbs_read_word_data(client, BATTERY_MODE_OFFSET);
520 	if (original_val < 0)
521 		return original_val;
522 
523 	if ((original_val & BATTERY_MODE_MASK) == mode)
524 		return mode;
525 
526 	if (mode == BATTERY_MODE_AMPS)
527 		ret = original_val & ~BATTERY_MODE_MASK;
528 	else
529 		ret = original_val | BATTERY_MODE_MASK;
530 
531 	ret = sbs_write_word_data(client, BATTERY_MODE_OFFSET, ret);
532 	if (ret < 0)
533 		return ret;
534 
535 	return original_val & BATTERY_MODE_MASK;
536 }
537 
538 static int sbs_get_battery_capacity(struct i2c_client *client,
539 	int reg_offset, enum power_supply_property psp,
540 	union power_supply_propval *val)
541 {
542 	s32 ret;
543 	enum sbs_battery_mode mode = BATTERY_MODE_WATTS;
544 
545 	if (power_supply_is_amp_property(psp))
546 		mode = BATTERY_MODE_AMPS;
547 
548 	mode = sbs_set_battery_mode(client, mode);
549 	if (mode < 0)
550 		return mode;
551 
552 	ret = sbs_read_word_data(client, sbs_data[reg_offset].addr);
553 	if (ret < 0)
554 		return ret;
555 
556 	val->intval = ret;
557 
558 	ret = sbs_set_battery_mode(client, mode);
559 	if (ret < 0)
560 		return ret;
561 
562 	return 0;
563 }
564 
565 static char sbs_serial[5];
566 static int sbs_get_battery_serial_number(struct i2c_client *client,
567 	union power_supply_propval *val)
568 {
569 	int ret;
570 
571 	ret = sbs_read_word_data(client, sbs_data[REG_SERIAL_NUMBER].addr);
572 	if (ret < 0)
573 		return ret;
574 
575 	ret = sprintf(sbs_serial, "%04x", ret);
576 	val->strval = sbs_serial;
577 
578 	return 0;
579 }
580 
581 static int sbs_get_property_index(struct i2c_client *client,
582 	enum power_supply_property psp)
583 {
584 	int count;
585 	for (count = 0; count < ARRAY_SIZE(sbs_data); count++)
586 		if (psp == sbs_data[count].psp)
587 			return count;
588 
589 	dev_warn(&client->dev,
590 		"%s: Invalid Property - %d\n", __func__, psp);
591 
592 	return -EINVAL;
593 }
594 
595 static int sbs_get_property(struct power_supply *psy,
596 	enum power_supply_property psp,
597 	union power_supply_propval *val)
598 {
599 	int ret = 0;
600 	struct sbs_info *chip = power_supply_get_drvdata(psy);
601 	struct i2c_client *client = chip->client;
602 
603 	switch (psp) {
604 	case POWER_SUPPLY_PROP_PRESENT:
605 	case POWER_SUPPLY_PROP_HEALTH:
606 		ret = sbs_get_battery_presence_and_health(client, psp, val);
607 		if (psp == POWER_SUPPLY_PROP_PRESENT)
608 			return 0;
609 		break;
610 
611 	case POWER_SUPPLY_PROP_TECHNOLOGY:
612 		val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
613 		goto done; /* don't trigger power_supply_changed()! */
614 
615 	case POWER_SUPPLY_PROP_ENERGY_NOW:
616 	case POWER_SUPPLY_PROP_ENERGY_FULL:
617 	case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
618 	case POWER_SUPPLY_PROP_CHARGE_NOW:
619 	case POWER_SUPPLY_PROP_CHARGE_FULL:
620 	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
621 		ret = sbs_get_property_index(client, psp);
622 		if (ret < 0)
623 			break;
624 
625 		/* sbs_get_battery_capacity() will change the battery mode
626 		 * temporarily to read the requested attribute. Ensure we stay
627 		 * in the desired mode for the duration of the attribute read.
628 		 */
629 		mutex_lock(&chip->mode_lock);
630 		ret = sbs_get_battery_capacity(client, ret, psp, val);
631 		mutex_unlock(&chip->mode_lock);
632 		break;
633 
634 	case POWER_SUPPLY_PROP_SERIAL_NUMBER:
635 		ret = sbs_get_battery_serial_number(client, val);
636 		break;
637 
638 	case POWER_SUPPLY_PROP_STATUS:
639 	case POWER_SUPPLY_PROP_CAPACITY_LEVEL:
640 	case POWER_SUPPLY_PROP_CYCLE_COUNT:
641 	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
642 	case POWER_SUPPLY_PROP_CURRENT_NOW:
643 	case POWER_SUPPLY_PROP_TEMP:
644 	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
645 	case POWER_SUPPLY_PROP_TIME_TO_FULL_AVG:
646 	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
647 	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
648 	case POWER_SUPPLY_PROP_CAPACITY:
649 		ret = sbs_get_property_index(client, psp);
650 		if (ret < 0)
651 			break;
652 
653 		ret = sbs_get_battery_property(client, ret, psp, val);
654 		break;
655 
656 	case POWER_SUPPLY_PROP_MODEL_NAME:
657 		ret = sbs_get_property_index(client, psp);
658 		if (ret < 0)
659 			break;
660 
661 		ret = sbs_get_battery_string_property(client, ret, psp,
662 						      model_name);
663 		val->strval = model_name;
664 		break;
665 
666 	case POWER_SUPPLY_PROP_MANUFACTURER:
667 		ret = sbs_get_property_index(client, psp);
668 		if (ret < 0)
669 			break;
670 
671 		ret = sbs_get_battery_string_property(client, ret, psp,
672 						      manufacturer);
673 		val->strval = manufacturer;
674 		break;
675 
676 	default:
677 		dev_err(&client->dev,
678 			"%s: INVALID property\n", __func__);
679 		return -EINVAL;
680 	}
681 
682 	if (!chip->enable_detection)
683 		goto done;
684 
685 	if (!chip->gpio_detect &&
686 		chip->is_present != (ret >= 0)) {
687 		chip->is_present = (ret >= 0);
688 		power_supply_changed(chip->power_supply);
689 	}
690 
691 done:
692 	if (!ret) {
693 		/* Convert units to match requirements for power supply class */
694 		sbs_unit_adjustment(client, psp, val);
695 	}
696 
697 	dev_dbg(&client->dev,
698 		"%s: property = %d, value = %x\n", __func__, psp, val->intval);
699 
700 	if (ret && chip->is_present)
701 		return ret;
702 
703 	/* battery not present, so return NODATA for properties */
704 	if (ret)
705 		return -ENODATA;
706 
707 	return 0;
708 }
709 
710 static void sbs_supply_changed(struct sbs_info *chip)
711 {
712 	struct power_supply *battery = chip->power_supply;
713 	int ret;
714 
715 	ret = gpiod_get_value_cansleep(chip->gpio_detect);
716 	if (ret < 0)
717 		return;
718 	chip->is_present = ret;
719 	power_supply_changed(battery);
720 }
721 
722 static irqreturn_t sbs_irq(int irq, void *devid)
723 {
724 	sbs_supply_changed(devid);
725 	return IRQ_HANDLED;
726 }
727 
728 static void sbs_alert(struct i2c_client *client, enum i2c_alert_protocol prot,
729 	unsigned int data)
730 {
731 	sbs_supply_changed(i2c_get_clientdata(client));
732 }
733 
734 static void sbs_external_power_changed(struct power_supply *psy)
735 {
736 	struct sbs_info *chip = power_supply_get_drvdata(psy);
737 
738 	/* cancel outstanding work */
739 	cancel_delayed_work_sync(&chip->work);
740 
741 	schedule_delayed_work(&chip->work, HZ);
742 	chip->poll_time = chip->poll_retry_count;
743 }
744 
745 static void sbs_delayed_work(struct work_struct *work)
746 {
747 	struct sbs_info *chip;
748 	s32 ret;
749 
750 	chip = container_of(work, struct sbs_info, work.work);
751 
752 	ret = sbs_read_word_data(chip->client, sbs_data[REG_STATUS].addr);
753 	/* if the read failed, give up on this work */
754 	if (ret < 0) {
755 		chip->poll_time = 0;
756 		return;
757 	}
758 
759 	if (ret & BATTERY_FULL_CHARGED)
760 		ret = POWER_SUPPLY_STATUS_FULL;
761 	else if (ret & BATTERY_DISCHARGING)
762 		ret = POWER_SUPPLY_STATUS_DISCHARGING;
763 	else
764 		ret = POWER_SUPPLY_STATUS_CHARGING;
765 
766 	sbs_status_correct(chip->client, &ret);
767 
768 	if (chip->last_state != ret) {
769 		chip->poll_time = 0;
770 		power_supply_changed(chip->power_supply);
771 		return;
772 	}
773 	if (chip->poll_time > 0) {
774 		schedule_delayed_work(&chip->work, HZ);
775 		chip->poll_time--;
776 		return;
777 	}
778 }
779 
780 static const struct power_supply_desc sbs_default_desc = {
781 	.type = POWER_SUPPLY_TYPE_BATTERY,
782 	.properties = sbs_properties,
783 	.num_properties = ARRAY_SIZE(sbs_properties),
784 	.get_property = sbs_get_property,
785 	.external_power_changed = sbs_external_power_changed,
786 };
787 
788 static int sbs_probe(struct i2c_client *client,
789 	const struct i2c_device_id *id)
790 {
791 	struct sbs_info *chip;
792 	struct power_supply_desc *sbs_desc;
793 	struct sbs_platform_data *pdata = client->dev.platform_data;
794 	struct power_supply_config psy_cfg = {};
795 	int rc;
796 	int irq;
797 
798 	sbs_desc = devm_kmemdup(&client->dev, &sbs_default_desc,
799 			sizeof(*sbs_desc), GFP_KERNEL);
800 	if (!sbs_desc)
801 		return -ENOMEM;
802 
803 	sbs_desc->name = devm_kasprintf(&client->dev, GFP_KERNEL, "sbs-%s",
804 			dev_name(&client->dev));
805 	if (!sbs_desc->name)
806 		return -ENOMEM;
807 
808 	chip = devm_kzalloc(&client->dev, sizeof(struct sbs_info), GFP_KERNEL);
809 	if (!chip)
810 		return -ENOMEM;
811 
812 	chip->client = client;
813 	chip->enable_detection = false;
814 	psy_cfg.of_node = client->dev.of_node;
815 	psy_cfg.drv_data = chip;
816 	chip->last_state = POWER_SUPPLY_STATUS_UNKNOWN;
817 	mutex_init(&chip->mode_lock);
818 
819 	/* use pdata if available, fall back to DT properties,
820 	 * or hardcoded defaults if not
821 	 */
822 	rc = of_property_read_u32(client->dev.of_node, "sbs,i2c-retry-count",
823 				  &chip->i2c_retry_count);
824 	if (rc)
825 		chip->i2c_retry_count = 0;
826 
827 	rc = of_property_read_u32(client->dev.of_node, "sbs,poll-retry-count",
828 				  &chip->poll_retry_count);
829 	if (rc)
830 		chip->poll_retry_count = 0;
831 
832 	if (pdata) {
833 		chip->poll_retry_count = pdata->poll_retry_count;
834 		chip->i2c_retry_count  = pdata->i2c_retry_count;
835 	}
836 	chip->i2c_retry_count = chip->i2c_retry_count + 1;
837 
838 	chip->gpio_detect = devm_gpiod_get_optional(&client->dev,
839 			"sbs,battery-detect", GPIOD_IN);
840 	if (IS_ERR(chip->gpio_detect)) {
841 		dev_err(&client->dev, "Failed to get gpio: %ld\n",
842 			PTR_ERR(chip->gpio_detect));
843 		return PTR_ERR(chip->gpio_detect);
844 	}
845 
846 	i2c_set_clientdata(client, chip);
847 
848 	if (!chip->gpio_detect)
849 		goto skip_gpio;
850 
851 	irq = gpiod_to_irq(chip->gpio_detect);
852 	if (irq <= 0) {
853 		dev_warn(&client->dev, "Failed to get gpio as irq: %d\n", irq);
854 		goto skip_gpio;
855 	}
856 
857 	rc = devm_request_threaded_irq(&client->dev, irq, NULL, sbs_irq,
858 		IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
859 		dev_name(&client->dev), chip);
860 	if (rc) {
861 		dev_warn(&client->dev, "Failed to request irq: %d\n", rc);
862 		goto skip_gpio;
863 	}
864 
865 skip_gpio:
866 	/*
867 	 * Before we register, we might need to make sure we can actually talk
868 	 * to the battery.
869 	 */
870 	if (!(force_load || chip->gpio_detect)) {
871 		rc = sbs_read_word_data(client, sbs_data[REG_STATUS].addr);
872 
873 		if (rc < 0) {
874 			dev_err(&client->dev, "%s: Failed to get device status\n",
875 				__func__);
876 			goto exit_psupply;
877 		}
878 	}
879 
880 	chip->power_supply = devm_power_supply_register(&client->dev, sbs_desc,
881 						   &psy_cfg);
882 	if (IS_ERR(chip->power_supply)) {
883 		dev_err(&client->dev,
884 			"%s: Failed to register power supply\n", __func__);
885 		rc = PTR_ERR(chip->power_supply);
886 		goto exit_psupply;
887 	}
888 
889 	dev_info(&client->dev,
890 		"%s: battery gas gauge device registered\n", client->name);
891 
892 	INIT_DELAYED_WORK(&chip->work, sbs_delayed_work);
893 
894 	chip->enable_detection = true;
895 
896 	return 0;
897 
898 exit_psupply:
899 	return rc;
900 }
901 
902 static int sbs_remove(struct i2c_client *client)
903 {
904 	struct sbs_info *chip = i2c_get_clientdata(client);
905 
906 	cancel_delayed_work_sync(&chip->work);
907 
908 	return 0;
909 }
910 
911 #if defined CONFIG_PM_SLEEP
912 
913 static int sbs_suspend(struct device *dev)
914 {
915 	struct i2c_client *client = to_i2c_client(dev);
916 	struct sbs_info *chip = i2c_get_clientdata(client);
917 
918 	if (chip->poll_time > 0)
919 		cancel_delayed_work_sync(&chip->work);
920 
921 	/*
922 	 * Write to manufacturer access with sleep command.
923 	 * Support is manufacturer dependend, so ignore errors.
924 	 */
925 	sbs_write_word_data(client, sbs_data[REG_MANUFACTURER_DATA].addr,
926 		MANUFACTURER_ACCESS_SLEEP);
927 
928 	return 0;
929 }
930 
931 static SIMPLE_DEV_PM_OPS(sbs_pm_ops, sbs_suspend, NULL);
932 #define SBS_PM_OPS (&sbs_pm_ops)
933 
934 #else
935 #define SBS_PM_OPS NULL
936 #endif
937 
938 static const struct i2c_device_id sbs_id[] = {
939 	{ "bq20z75", 0 },
940 	{ "sbs-battery", 1 },
941 	{}
942 };
943 MODULE_DEVICE_TABLE(i2c, sbs_id);
944 
945 static const struct of_device_id sbs_dt_ids[] = {
946 	{ .compatible = "sbs,sbs-battery" },
947 	{ .compatible = "ti,bq20z75" },
948 	{ }
949 };
950 MODULE_DEVICE_TABLE(of, sbs_dt_ids);
951 
952 static struct i2c_driver sbs_battery_driver = {
953 	.probe		= sbs_probe,
954 	.remove		= sbs_remove,
955 	.alert		= sbs_alert,
956 	.id_table	= sbs_id,
957 	.driver = {
958 		.name	= "sbs-battery",
959 		.of_match_table = sbs_dt_ids,
960 		.pm	= SBS_PM_OPS,
961 	},
962 };
963 module_i2c_driver(sbs_battery_driver);
964 
965 MODULE_DESCRIPTION("SBS battery monitor driver");
966 MODULE_LICENSE("GPL");
967 
968 module_param(force_load, bool, S_IRUSR | S_IRGRP | S_IROTH);
969 MODULE_PARM_DESC(force_load,
970 		 "Attempt to load the driver even if no battery is connected");
971