aboutsummaryrefslogtreecommitdiff
path: root/drivers/power/sbs-battery.c
blob: 3960f0b2afe97200ff8c8e95312de66b36060f0e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
/*
 * Gas Gauge driver for SBS Compliant Batteries
 *
 * Copyright (c) 2010, NVIDIA Corporation.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/power_supply.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/gpio.h>

#include <linux/power/sbs-battery.h>

enum {
	REG_MANUFACTURER_DATA,
	REG_TEMPERATURE,
	REG_VOLTAGE,
	REG_CURRENT,
	REG_CAPACITY,
	REG_TIME_TO_EMPTY,
	REG_TIME_TO_FULL,
	REG_STATUS,
	REG_CYCLE_COUNT,
	REG_SERIAL_NUMBER,
	REG_REMAINING_CAPACITY,
	REG_REMAINING_CAPACITY_CHARGE,
	REG_FULL_CHARGE_CAPACITY,
	REG_FULL_CHARGE_CAPACITY_CHARGE,
	REG_DESIGN_CAPACITY,
	REG_DESIGN_CAPACITY_CHARGE,
	REG_DESIGN_VOLTAGE,
};

/* Battery Mode defines */
#define BATTERY_MODE_OFFSET		0x03
#define BATTERY_MODE_MASK		0x8000
enum sbs_battery_mode {
	BATTERY_MODE_AMPS,
	BATTERY_MODE_WATTS
};

/* manufacturer access defines */
#define MANUFACTURER_ACCESS_STATUS	0x0006
#define MANUFACTURER_ACCESS_SLEEP	0x0011

/* battery status value bits */
#define BATTERY_DISCHARGING		0x40
#define BATTERY_FULL_CHARGED		0x20
#define BATTERY_FULL_DISCHARGED		0x10

#define SBS_DATA(_psp, _addr, _min_value, _max_value) { \
	.psp = _psp, \
	.addr = _addr, \
	.min_value = _min_value, \
	.max_value = _max_value, \
}

static const struct chip_data {
	enum power_supply_property psp;
	u8 addr;
	int min_value;
	int max_value;
} sbs_data[] = {
	[REG_MANUFACTURER_DATA] =
		SBS_DATA(POWER_SUPPLY_PROP_PRESENT, 0x00, 0, 65535),
	[REG_TEMPERATURE] =
		SBS_DATA(POWER_SUPPLY_PROP_TEMP, 0x08, 0, 65535),
	[REG_VOLTAGE] =
		SBS_DATA(POWER_SUPPLY_PROP_VOLTAGE_NOW, 0x09, 0, 20000),
	[REG_CURRENT] =
		SBS_DATA(POWER_SUPPLY_PROP_CURRENT_NOW, 0x0A, -32768, 32767),
	[REG_CAPACITY] =
		SBS_DATA(POWER_SUPPLY_PROP_CAPACITY, 0x0D, 0, 100),
	[REG_REMAINING_CAPACITY] =
		SBS_DATA(POWER_SUPPLY_PROP_ENERGY_NOW, 0x0F, 0, 65535),
	[REG_REMAINING_CAPACITY_CHARGE] =
		SBS_DATA(POWER_SUPPLY_PROP_CHARGE_NOW, 0x0F, 0, 65535),
	[REG_FULL_CHARGE_CAPACITY] =
		SBS_DATA(POWER_SUPPLY_PROP_ENERGY_FULL, 0x10, 0, 65535),
	[REG_FULL_CHARGE_CAPACITY_CHARGE] =
		SBS_DATA(POWER_SUPPLY_PROP_CHARGE_FULL, 0x10, 0, 65535),
	[REG_TIME_TO_EMPTY] =
		SBS_DATA(POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG, 0x12, 0, 65535),
	[REG_TIME_TO_FULL] =
		SBS_DATA(POWER_SUPPLY_PROP_TIME_TO_FULL_AVG, 0x13, 0, 65535),
	[REG_STATUS] =
		SBS_DATA(POWER_SUPPLY_PROP_STATUS, 0x16, 0, 65535),
	[REG_CYCLE_COUNT] =
		SBS_DATA(POWER_SUPPLY_PROP_CYCLE_COUNT, 0x17, 0, 65535),
	[REG_DESIGN_CAPACITY] =
		SBS_DATA(POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN, 0x18, 0, 65535),
	[REG_DESIGN_CAPACITY_CHARGE] =
		SBS_DATA(POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN, 0x18, 0, 65535),
	[REG_DESIGN_VOLTAGE] =
		SBS_DATA(POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN, 0x19, 0, 65535),
	[REG_SERIAL_NUMBER] =
		SBS_DATA(POWER_SUPPLY_PROP_SERIAL_NUMBER, 0x1C, 0, 65535),
};

static enum power_supply_property sbs_properties[] = {
	POWER_SUPPLY_PROP_STATUS,
	POWER_SUPPLY_PROP_HEALTH,
	POWER_SUPPLY_PROP_PRESENT,
	POWER_SUPPLY_PROP_TECHNOLOGY,
	POWER_SUPPLY_PROP_CYCLE_COUNT,
	POWER_SUPPLY_PROP_VOLTAGE_NOW,
	POWER_SUPPLY_PROP_CURRENT_NOW,
	POWER_SUPPLY_PROP_CAPACITY,
	POWER_SUPPLY_PROP_TEMP,
	POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
	POWER_SUPPLY_PROP_TIME_TO_FULL_AVG,
	POWER_SUPPLY_PROP_SERIAL_NUMBER,
	POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
	POWER_SUPPLY_PROP_ENERGY_NOW,
	POWER_SUPPLY_PROP_ENERGY_FULL,
	POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN,
	POWER_SUPPLY_PROP_CHARGE_NOW,
	POWER_SUPPLY_PROP_CHARGE_FULL,
	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
};

struct sbs_info {
	struct i2c_client		*client;
	struct power_supply		power_supply;
	struct sbs_platform_data	*pdata;
	bool				is_present;
	bool				gpio_detect;
	bool				enable_detection;
	int				irq;
	int				last_state;
	int				poll_time;
	struct delayed_work		work;
	int				ignore_changes;
};

static int sbs_read_word_data(struct i2c_client *client, u8 address)
{
	struct sbs_info *chip = i2c_get_clientdata(client);
	s32 ret = 0;
	int retries = 1;

	if (chip->pdata)
		retries = max(chip->pdata->i2c_retry_count + 1, 1);

	while (retries > 0) {
		ret = i2c_smbus_read_word_data(client, address);
		if (ret >= 0)
			break;
		retries--;
	}

	if (ret < 0) {
		dev_dbg(&client->dev,
			"%s: i2c read at address 0x%x failed\n",
			__func__, address);
		return ret;
	}

	return le16_to_cpu(ret);
}

static int sbs_write_word_data(struct i2c_client *client, u8 address,
	u16 value)
{
	struct sbs_info *chip = i2c_get_clientdata(client);
	s32 ret = 0;
	int retries = 1;

	if (chip->pdata)
		retries = max(chip->pdata->i2c_retry_count + 1, 1);

	while (retries > 0) {
		ret = i2c_smbus_write_word_data(client, address,
			le16_to_cpu(value));
		if (ret >= 0)
			break;
		retries--;
	}

	if (ret < 0) {
		dev_dbg(&client->dev,
			"%s: i2c write to address 0x%x failed\n",
			__func__, address);
		return ret;
	}

	return 0;
}

static int sbs_get_battery_presence_and_health(
	struct i2c_client *client, enum power_supply_property psp,
	union power_supply_propval *val)
{
	s32 ret;
	struct sbs_info *chip = i2c_get_clientdata(client);

	if (psp == POWER_SUPPLY_PROP_PRESENT &&
		chip->gpio_detect) {
		ret = gpio_get_value(chip->pdata->battery_detect);
		if (ret == chip->pdata->battery_detect_present)
			val->intval = 1;
		else
			val->intval = 0;
		chip->is_present = val->intval;
		return ret;
	}

	/* Write to ManufacturerAccess with
	 * ManufacturerAccess command and then
	 * read the status */
	ret = sbs_write_word_data(client, sbs_data[REG_MANUFACTURER_DATA].addr,
					MANUFACTURER_ACCESS_STATUS);
	if (ret < 0) {
		if (psp == POWER_SUPPLY_PROP_PRESENT)
			val->intval = 0; /* battery removed */
		return ret;
	}

	ret = sbs_read_word_data(client, sbs_data[REG_MANUFACTURER_DATA].addr);
	if (ret < 0)
		return ret;

	if (ret < sbs_data[REG_MANUFACTURER_DATA].min_value ||
	    ret > sbs_data[REG_MANUFACTURER_DATA].max_value) {
		val->intval = 0;
		return 0;
	}

	/* Mask the upper nibble of 2nd byte and
	 * lower byte of response then
	 * shift the result by 8 to get status*/
	ret &= 0x0F00;
	ret >>= 8;
	if (psp == POWER_SUPPLY_PROP_PRESENT) {
		if (ret == 0x0F)
			/* battery removed */
			val->intval = 0;
		else
			val->intval = 1;
	} else if (psp == POWER_SUPPLY_PROP_HEALTH) {
		if (ret == 0x09)
			val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
		else if (ret == 0x0B)
			val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
		else if (ret == 0x0C)
			val->intval = POWER_SUPPLY_HEALTH_DEAD;
		else
			val->intval = POWER_SUPPLY_HEALTH_GOOD;
	}

	return 0;
}

static int sbs_get_battery_property(struct i2c_client *client,
	int reg_offset, enum power_supply_property psp,
	union power_supply_propval *val)
{
	struct sbs_info *chip = i2c_get_clientdata(client);
	s32 ret;

	ret = sbs_read_word_data(client, sbs_data[reg_offset].addr);
	if (ret < 0)
		return ret;

	/* returned values are 16 bit */
	if (sbs_data[reg_offset].min_value < 0)
		ret = (s16)ret;

	if (ret >= sbs_data[reg_offset].min_value &&
	    ret <= sbs_data[reg_offset].max_value) {
		val->intval = ret;
		if (psp != POWER_SUPPLY_PROP_STATUS)
			return 0;

		if (ret & BATTERY_FULL_CHARGED)
			val->intval = POWER_SUPPLY_STATUS_FULL;
		else if (ret & BATTERY_FULL_DISCHARGED)
			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
		else if (ret & BATTERY_DISCHARGING)
			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
		else
			val->intval = POWER_SUPPLY_STATUS_CHARGING;

		if (chip->poll_time == 0)
			chip->last_state = val->intval;
		else if (chip->last_state != val->intval) {
			cancel_delayed_work_sync(&chip->work);
			power_supply_changed(&chip->power_supply);
			chip->poll_time = 0;
		}
	} else {
		if (psp == POWER_SUPPLY_PROP_STATUS)
			val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
		else
			val->intval = 0;
	}

	return 0;
}

static void  sbs_unit_adjustment(struct i2c_client *client,
	enum power_supply_property psp, union power_supply_propval *val)
{
#define BASE_UNIT_CONVERSION		1000
#define BATTERY_MODE_CAP_MULT_WATT	(10 * BASE_UNIT_CONVERSION)
#define TIME_UNIT_CONVERSION		60
#define TEMP_KELVIN_TO_CELSIUS		2731
	switch (psp) {
	case POWER_SUPPLY_PROP_ENERGY_NOW:
	case POWER_SUPPLY_PROP_ENERGY_FULL:
	case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
		/* sbs provides energy in units of 10mWh.
		 * Convert to µWh
		 */
		val->intval *= BATTERY_MODE_CAP_MULT_WATT;
		break;

	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
	case POWER_SUPPLY_PROP_CURRENT_NOW:
	case POWER_SUPPLY_PROP_CHARGE_NOW:
	case POWER_SUPPLY_PROP_CHARGE_FULL:
	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
		val->intval *= BASE_UNIT_CONVERSION;
		break;

	case POWER_SUPPLY_PROP_TEMP:
		/* sbs provides battery temperature in 0.1K
		 * so convert it to 0.1°C
		 */
		val->intval -= TEMP_KELVIN_TO_CELSIUS;
		break;

	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
	case POWER_SUPPLY_PROP_TIME_TO_FULL_AVG:
		/* sbs provides time to empty and time to full in minutes.
		 * Convert to seconds
		 */
		val->intval *= TIME_UNIT_CONVERSION;
		break;

	default:
		dev_dbg(&client->dev,
			"%s: no need for unit conversion %d\n", __func__, psp);
	}
}

static enum sbs_battery_mode sbs_set_battery_mode(struct i2c_client *client,
	enum sbs_battery_mode mode)
{
	int ret, original_val;

	original_val = sbs_read_word_data(client, BATTERY_MODE_OFFSET);
	if (original_val < 0)
		return original_val;

	if ((original_val & BATTERY_MODE_MASK) == mode)
		return mode;

	if (mode == BATTERY_MODE_AMPS)
		ret = original_val & ~BATTERY_MODE_MASK;
	else
		ret = original_val | BATTERY_MODE_MASK;

	ret = sbs_write_word_data(client, BATTERY_MODE_OFFSET, ret);
	if (ret < 0)
		return ret;

	return original_val & BATTERY_MODE_MASK;
}

static int sbs_get_battery_capacity(struct i2c_client *client,
	int reg_offset, enum power_supply_property psp,
	union power_supply_propval *val)
{
	s32 ret;
	enum sbs_battery_mode mode = BATTERY_MODE_WATTS;

	if (power_supply_is_amp_property(psp))
		mode = BATTERY_MODE_AMPS;

	mode = sbs_set_battery_mode(client, mode);
	if (mode < 0)
		return mode;

	ret = sbs_read_word_data(client, sbs_data[reg_offset].addr);
	if (ret < 0)
		return ret;

	if (psp == POWER_SUPPLY_PROP_CAPACITY) {
		/* sbs spec says that this can be >100 %
		* even if max value is 100 % */
		val->intval = min(ret, 100);
	} else
		val->intval = ret;

	ret = sbs_set_battery_mode(client, mode);
	if (ret < 0)
		return ret;

	return 0;
}

static char sbs_serial[5];
static int sbs_get_battery_serial_number(struct i2c_client *client,
	union power_supply_propval *val)
{
	int ret;

	ret = sbs_read_word_data(client, sbs_data[REG_SERIAL_NUMBER].addr);
	if (ret < 0)
		return ret;

	ret = sprintf(sbs_serial, "%04x", ret);
	val->strval = sbs_serial;

	return 0;
}

static int sbs_get_property_index(struct i2c_client *client,
	enum power_supply_property psp)
{
	int count;
	for (count = 0; count < ARRAY_SIZE(sbs_data); count++)
		if (psp == sbs_data[count].psp)
			return count;

	dev_warn(&client->dev,
		"%s: Invalid Property - %d\n", __func__, psp);

	return -EINVAL;
}

static int sbs_get_property(struct power_supply *psy,
	enum power_supply_property psp,
	union power_supply_propval *val)
{
	int ret = 0;
	struct sbs_info *chip = container_of(psy,
				struct sbs_info, power_supply);
	struct i2c_client *client = chip->client;

	switch (psp) {
	case POWER_SUPPLY_PROP_PRESENT:
	case POWER_SUPPLY_PROP_HEALTH:
		ret = sbs_get_battery_presence_and_health(client, psp, val);
		if (psp == POWER_SUPPLY_PROP_PRESENT)
			return 0;
		break;

	case POWER_SUPPLY_PROP_TECHNOLOGY:
		val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
		goto done; /* don't trigger power_supply_changed()! */

	case POWER_SUPPLY_PROP_ENERGY_NOW:
	case POWER_SUPPLY_PROP_ENERGY_FULL:
	case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
	case POWER_SUPPLY_PROP_CHARGE_NOW:
	case POWER_SUPPLY_PROP_CHARGE_FULL:
	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
	case POWER_SUPPLY_PROP_CAPACITY:
		ret = sbs_get_property_index(client, psp);
		if (ret < 0)
			break;

		ret = sbs_get_battery_capacity(client, ret, psp, val);
		break;

	case POWER_SUPPLY_PROP_SERIAL_NUMBER:
		ret = sbs_get_battery_serial_number(client, val);
		break;

	case POWER_SUPPLY_PROP_STATUS:
	case POWER_SUPPLY_PROP_CYCLE_COUNT:
	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
	case POWER_SUPPLY_PROP_CURRENT_NOW:
	case POWER_SUPPLY_PROP_TEMP:
	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
	case POWER_SUPPLY_PROP_TIME_TO_FULL_AVG:
	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
		ret = sbs_get_property_index(client, psp);
		if (ret < 0)
			break;

		ret = sbs_get_battery_property(client, ret, psp, val);
		break;

	default:
		dev_err(&client->dev,
			"%s: INVALID property\n", __func__);
		return -EINVAL;
	}

	if (!chip->enable_detection)
		goto done;

	if (!chip->gpio_detect &&
		chip->is_present != (ret >= 0)) {
		chip->is_present = (ret >= 0);
		power_supply_changed(&chip->power_supply);
	}

done:
	if (!ret) {
		/* Convert units to match requirements for power supply class */
		sbs_unit_adjustment(client, psp, val);
	}

	dev_dbg(&client->dev,
		"%s: property = %d, value = %x\n", __func__, psp, val->intval);

	if (ret && chip->is_present)
		return ret;

	/* battery not present, so return NODATA for properties */
	if (ret)
		return -ENODATA;

	return 0;
}

static irqreturn_t sbs_irq(int irq, void *devid)
{
	struct power_supply *battery = devid;

	power_supply_changed(battery);

	return IRQ_HANDLED;
}

static void sbs_external_power_changed(struct power_supply *psy)
{
	struct sbs_info *chip;

	chip = container_of(psy, struct sbs_info, power_supply);

	if (chip->ignore_changes > 0) {
		chip->ignore_changes--;
		return;
	}

	/* cancel outstanding work */
	cancel_delayed_work_sync(&chip->work);

	schedule_delayed_work(&chip->work, HZ);
	chip->poll_time = chip->pdata->poll_retry_count;
}

static void sbs_delayed_work(struct work_struct *work)
{
	struct sbs_info *chip;
	s32 ret;

	chip = container_of(work, struct sbs_info, work.work);

	ret = sbs_read_word_data(chip->client, sbs_data[REG_STATUS].addr);
	/* if the read failed, give up on this work */
	if (ret < 0) {
		chip->poll_time = 0;
		return;
	}

	if (ret & BATTERY_FULL_CHARGED)
		ret = POWER_SUPPLY_STATUS_FULL;
	else if (ret & BATTERY_FULL_DISCHARGED)
		ret = POWER_SUPPLY_STATUS_NOT_CHARGING;
	else if (ret & BATTERY_DISCHARGING)
		ret = POWER_SUPPLY_STATUS_DISCHARGING;
	else
		ret = POWER_SUPPLY_STATUS_CHARGING;

	if (chip->last_state != ret) {
		chip->poll_time = 0;
		power_supply_changed(&chip->power_supply);
		return;
	}
	if (chip->poll_time > 0) {
		schedule_delayed_work(&chip->work, HZ);
		chip->poll_time--;
		return;
	}
}

#if defined(CONFIG_OF)

#include <linux/of_device.h>
#include <linux/of_gpio.h>

static const struct of_device_id sbs_dt_ids[] = {
	{ .compatible = "sbs,sbs-battery" },
	{ .compatible = "ti,bq20z75" },
	{ }
};
MODULE_DEVICE_TABLE(of, sbs_dt_ids);

static struct sbs_platform_data *sbs_of_populate_pdata(
		struct i2c_client *client)
{
	struct device_node *of_node = client->dev.of_node;
	struct sbs_platform_data *pdata = client->dev.platform_data;
	enum of_gpio_flags gpio_flags;
	int rc;
	u32 prop;

	/* verify this driver matches this device */
	if (!of_node)
		return NULL;

	/* if platform data is set, honor it */
	if (pdata)
		return pdata;

	/* first make sure at least one property is set, otherwise
	 * it won't change behavior from running without pdata.
	 */
	if (!of_get_property(of_node, "sbs,i2c-retry-count", NULL) &&
		!of_get_property(of_node, "sbs,poll-retry-count", NULL) &&
		!of_get_property(of_node, "sbs,battery-detect-gpios", NULL))
		goto of_out;

	pdata = devm_kzalloc(&client->dev, sizeof(struct sbs_platform_data),
				GFP_KERNEL);
	if (!pdata)
		goto of_out;

	rc = of_property_read_u32(of_node, "sbs,i2c-retry-count", &prop);
	if (!rc)
		pdata->i2c_retry_count = prop;

	rc = of_property_read_u32(of_node, "sbs,poll-retry-count", &prop);
	if (!rc)
		pdata->poll_retry_count = prop;

	if (!of_get_property(of_node, "sbs,battery-detect-gpios", NULL)) {
		pdata->battery_detect = -1;
		goto of_out;
	}

	pdata->battery_detect = of_get_named_gpio_flags(of_node,
			"sbs,battery-detect-gpios", 0, &gpio_flags);

	if (gpio_flags & OF_GPIO_ACTIVE_LOW)
		pdata->battery_detect_present = 0;
	else
		pdata->battery_detect_present = 1;

of_out:
	return pdata;
}
#else
#define sbs_dt_ids NULL
static struct sbs_platform_data *sbs_of_populate_pdata(
	struct i2c_client *client)
{
	return client->dev.platform_data;
}
#endif

static int sbs_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
{
	struct sbs_info *chip;
	struct sbs_platform_data *pdata = client->dev.platform_data;
	int rc;
	int irq;
	char *name;

	name = kasprintf(GFP_KERNEL, "sbs-%s", dev_name(&client->dev));
	if (!name) {
		dev_err(&client->dev, "Failed to allocate device name\n");
		return -ENOMEM;
	}

	chip = kzalloc(sizeof(struct sbs_info), GFP_KERNEL);
	if (!chip) {
		rc = -ENOMEM;
		goto exit_free_name;
	}

	chip->client = client;
	chip->enable_detection = false;
	chip->gpio_detect = false;
	chip->power_supply.name = name;
	chip->power_supply.type = POWER_SUPPLY_TYPE_BATTERY;
	chip->power_supply.properties = sbs_properties;
	chip->power_supply.num_properties = ARRAY_SIZE(sbs_properties);
	chip->power_supply.get_property = sbs_get_property;
	/* ignore first notification of external change, it is generated
	 * from the power_supply_register call back
	 */
	chip->ignore_changes = 1;
	chip->last_state = POWER_SUPPLY_STATUS_UNKNOWN;
	chip->power_supply.external_power_changed = sbs_external_power_changed;

	pdata = sbs_of_populate_pdata(client);

	if (pdata) {
		chip->gpio_detect = gpio_is_valid(pdata->battery_detect);
		chip->pdata = pdata;
	}

	i2c_set_clientdata(client, chip);

	if (!chip->gpio_detect)
		goto skip_gpio;

	rc = gpio_request(pdata->battery_detect, dev_name(&client->dev));
	if (rc) {
		dev_warn(&client->dev, "Failed to request gpio: %d\n", rc);
		chip->gpio_detect = false;
		goto skip_gpio;
	}

	rc = gpio_direction_input(pdata->battery_detect);
	if (rc) {
		dev_warn(&client->dev, "Failed to get gpio as input: %d\n", rc);
		gpio_free(pdata->battery_detect);
		chip->gpio_detect = false;
		goto skip_gpio;
	}

	irq = gpio_to_irq(pdata->battery_detect);
	if (irq <= 0) {
		dev_warn(&client->dev, "Failed to get gpio as irq: %d\n", irq);
		gpio_free(pdata->battery_detect);
		chip->gpio_detect = false;
		goto skip_gpio;
	}

	rc = request_irq(irq, sbs_irq,
		IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
		dev_name(&client->dev), &chip->power_supply);
	if (rc) {
		dev_warn(&client->dev, "Failed to request irq: %d\n", rc);
		gpio_free(pdata->battery_detect);
		chip->gpio_detect = false;
		goto skip_gpio;
	}

	chip->irq = irq;

skip_gpio:
	/*
	 * Before we register, we need to make sure we can actually talk
	 * to the battery.
	 */
	rc = sbs_read_word_data(client, sbs_data[REG_STATUS].addr);
	if (rc < 0) {
		dev_err(&client->dev, "%s: Failed to get device status\n",
			__func__);
		goto exit_psupply;
	}

	rc = power_supply_register(&client->dev, &chip->power_supply);
	if (rc) {
		dev_err(&client->dev,
			"%s: Failed to register power supply\n", __func__);
		goto exit_psupply;
	}

	dev_info(&client->dev,
		"%s: battery gas gauge device registered\n", client->name);

	INIT_DELAYED_WORK(&chip->work, sbs_delayed_work);

	chip->enable_detection = true;

	return 0;

exit_psupply:
	if (chip->irq)
		free_irq(chip->irq, &chip->power_supply);
	if (chip->gpio_detect)
		gpio_free(pdata->battery_detect);

	kfree(chip);

exit_free_name:
	kfree(name);

	return rc;
}

static int sbs_remove(struct i2c_client *client)
{
	struct sbs_info *chip = i2c_get_clientdata(client);

	if (chip->irq)
		free_irq(chip->irq, &chip->power_supply);
	if (chip->gpio_detect)
		gpio_free(chip->pdata->battery_detect);

	power_supply_unregister(&chip->power_supply);

	cancel_delayed_work_sync(&chip->work);

	kfree(chip->power_supply.name);
	kfree(chip);
	chip = NULL;

	return 0;
}

#if defined CONFIG_PM
static int sbs_suspend(struct i2c_client *client,
	pm_message_t state)
{
	struct sbs_info *chip = i2c_get_clientdata(client);
	s32 ret;

	if (chip->poll_time > 0)
		cancel_delayed_work_sync(&chip->work);

	/* write to manufacturer access with sleep command */
	ret = sbs_write_word_data(client, sbs_data[REG_MANUFACTURER_DATA].addr,
		MANUFACTURER_ACCESS_SLEEP);
	if (chip->is_present && ret < 0)
		return ret;

	return 0;
}
#else
#define sbs_suspend		NULL
#endif
/* any smbus transaction will wake up sbs */
#define sbs_resume		NULL

static const struct i2c_device_id sbs_id[] = {
	{ "bq20z75", 0 },
	{ "sbs-battery", 1 },
	{}
};
MODULE_DEVICE_TABLE(i2c, sbs_id);

static struct i2c_driver sbs_battery_driver = {
	.probe		= sbs_probe,
	.remove		= sbs_remove,
	.suspend	= sbs_suspend,
	.resume		= sbs_resume,
	.id_table	= sbs_id,
	.driver = {
		.name	= "sbs-battery",
		.of_match_table = sbs_dt_ids,
	},
};
module_i2c_driver(sbs_battery_driver);

MODULE_DESCRIPTION("SBS battery monitor driver");
MODULE_LICENSE("GPL");