aboutsummaryrefslogtreecommitdiff
path: root/drivers/acpi/battery.c
blob: fbf1aceda8b8ab915a7d2476d78db2b6e2b94e68 (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
/*
 *  battery.c - ACPI Battery Driver (Revision: 2.0)
 *
 *  Copyright (C) 2007 Alexey Starikovskiy <astarikovskiy@suse.de>
 *  Copyright (C) 2004-2007 Vladimir Lebedev <vladimir.p.lebedev@intel.com>
 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  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.,
 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/jiffies.h>
#include <linux/async.h>
#include <linux/dmi.h>
#include <linux/slab.h>
#include <linux/suspend.h>
#include <asm/unaligned.h>

#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>
#include <linux/power_supply.h>

#define PREFIX "ACPI: "

#define ACPI_BATTERY_VALUE_UNKNOWN 0xFFFFFFFF

#define ACPI_BATTERY_CLASS		"battery"
#define ACPI_BATTERY_DEVICE_NAME	"Battery"
#define ACPI_BATTERY_NOTIFY_STATUS	0x80
#define ACPI_BATTERY_NOTIFY_INFO	0x81
#define ACPI_BATTERY_NOTIFY_THRESHOLD   0x82

/* Battery power unit: 0 means mW, 1 means mA */
#define ACPI_BATTERY_POWER_UNIT_MA	1

#define _COMPONENT		ACPI_BATTERY_COMPONENT

ACPI_MODULE_NAME("battery");

MODULE_AUTHOR("Paul Diefenbaugh");
MODULE_AUTHOR("Alexey Starikovskiy <astarikovskiy@suse.de>");
MODULE_DESCRIPTION("ACPI Battery Driver");
MODULE_LICENSE("GPL");

static unsigned int cache_time = 1000;
module_param(cache_time, uint, 0644);
MODULE_PARM_DESC(cache_time, "cache time in milliseconds");

static const struct acpi_device_id battery_device_ids[] = {
	{"PNP0C0A", 0},
	{"", 0},
};

MODULE_DEVICE_TABLE(acpi, battery_device_ids);

enum {
	ACPI_BATTERY_ALARM_PRESENT,
	ACPI_BATTERY_XINFO_PRESENT,
	ACPI_BATTERY_QUIRK_PERCENTAGE_CAPACITY,
	/* On Lenovo Thinkpad models from 2010 and 2011, the power unit
	   switches between mWh and mAh depending on whether the system
	   is running on battery or not.  When mAh is the unit, most
	   reported values are incorrect and need to be adjusted by
	   10000/design_voltage.  Verified on x201, t410, t410s, and x220.
	   Pre-2010 and 2012 models appear to always report in mWh and
	   are thus unaffected (tested with t42, t61, t500, x200, x300,
	   and x230).  Also, in mid-2012 Lenovo issued a BIOS update for
	   the 2011 models that fixes the issue (tested on x220 with a
	   post-1.29 BIOS), but as of Nov. 2012, no such update is
	   available for the 2010 models.  */
	ACPI_BATTERY_QUIRK_THINKPAD_MAH,
};

struct acpi_battery {
	struct mutex lock;
	struct mutex sysfs_lock;
	struct power_supply bat;
	struct acpi_device *device;
	struct notifier_block pm_nb;
	unsigned long update_time;
	int revision;
	int rate_now;
	int capacity_now;
	int voltage_now;
	int design_capacity;
	int full_charge_capacity;
	int technology;
	int design_voltage;
	int design_capacity_warning;
	int design_capacity_low;
	int cycle_count;
	int measurement_accuracy;
	int max_sampling_time;
	int min_sampling_time;
	int max_averaging_interval;
	int min_averaging_interval;
	int capacity_granularity_1;
	int capacity_granularity_2;
	int alarm;
	char model_number[32];
	char serial_number[32];
	char type[32];
	char oem_info[32];
	int state;
	int power_unit;
	unsigned long flags;
};

#define to_acpi_battery(x) container_of(x, struct acpi_battery, bat)

static inline int acpi_battery_present(struct acpi_battery *battery)
{
	return battery->device->status.battery_present;
}

static int acpi_battery_technology(struct acpi_battery *battery)
{
	if (!strcasecmp("NiCd", battery->type))
		return POWER_SUPPLY_TECHNOLOGY_NiCd;
	if (!strcasecmp("NiMH", battery->type))
		return POWER_SUPPLY_TECHNOLOGY_NiMH;
	if (!strcasecmp("LION", battery->type))
		return POWER_SUPPLY_TECHNOLOGY_LION;
	if (!strncasecmp("LI-ION", battery->type, 6))
		return POWER_SUPPLY_TECHNOLOGY_LION;
	if (!strcasecmp("LiP", battery->type))
		return POWER_SUPPLY_TECHNOLOGY_LIPO;
	return POWER_SUPPLY_TECHNOLOGY_UNKNOWN;
}

static int acpi_battery_get_state(struct acpi_battery *battery);

static int acpi_battery_is_charged(struct acpi_battery *battery)
{
	/* either charging or discharging */
	if (battery->state != 0)
		return 0;

	/* battery not reporting charge */
	if (battery->capacity_now == ACPI_BATTERY_VALUE_UNKNOWN ||
	    battery->capacity_now == 0)
		return 0;

	/* good batteries update full_charge as the batteries degrade */
	if (battery->full_charge_capacity == battery->capacity_now)
		return 1;

	/* fallback to using design values for broken batteries */
	if (battery->design_capacity == battery->capacity_now)
		return 1;

	/* we don't do any sort of metric based on percentages */
	return 0;
}

static int acpi_battery_get_property(struct power_supply *psy,
				     enum power_supply_property psp,
				     union power_supply_propval *val)
{
	int ret = 0;
	struct acpi_battery *battery = to_acpi_battery(psy);

	if (acpi_battery_present(battery)) {
		/* run battery update only if it is present */
		acpi_battery_get_state(battery);
	} else if (psp != POWER_SUPPLY_PROP_PRESENT)
		return -ENODEV;
	switch (psp) {
	case POWER_SUPPLY_PROP_STATUS:
		if (battery->state & 0x01)
			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
		else if (battery->state & 0x02)
			val->intval = POWER_SUPPLY_STATUS_CHARGING;
		else if (acpi_battery_is_charged(battery))
			val->intval = POWER_SUPPLY_STATUS_FULL;
		else
			val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
		break;
	case POWER_SUPPLY_PROP_PRESENT:
		val->intval = acpi_battery_present(battery);
		break;
	case POWER_SUPPLY_PROP_TECHNOLOGY:
		val->intval = acpi_battery_technology(battery);
		break;
	case POWER_SUPPLY_PROP_CYCLE_COUNT:
		val->intval = battery->cycle_count;
		break;
	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
		if (battery->design_voltage == ACPI_BATTERY_VALUE_UNKNOWN)
			ret = -ENODEV;
		else
			val->intval = battery->design_voltage * 1000;
		break;
	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
		if (battery->voltage_now == ACPI_BATTERY_VALUE_UNKNOWN)
			ret = -ENODEV;
		else
			val->intval = battery->voltage_now * 1000;
		break;
	case POWER_SUPPLY_PROP_CURRENT_NOW:
	case POWER_SUPPLY_PROP_POWER_NOW:
		if (battery->rate_now == ACPI_BATTERY_VALUE_UNKNOWN)
			ret = -ENODEV;
		else
			val->intval = battery->rate_now * 1000;
		break;
	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
	case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
		if (battery->design_capacity == ACPI_BATTERY_VALUE_UNKNOWN)
			ret = -ENODEV;
		else
			val->intval = battery->design_capacity * 1000;
		break;
	case POWER_SUPPLY_PROP_CHARGE_FULL:
	case POWER_SUPPLY_PROP_ENERGY_FULL:
		if (battery->full_charge_capacity == ACPI_BATTERY_VALUE_UNKNOWN)
			ret = -ENODEV;
		else
			val->intval = battery->full_charge_capacity * 1000;
		break;
	case POWER_SUPPLY_PROP_CHARGE_NOW:
	case POWER_SUPPLY_PROP_ENERGY_NOW:
		if (battery->capacity_now == ACPI_BATTERY_VALUE_UNKNOWN)
			ret = -ENODEV;
		else
			val->intval = battery->capacity_now * 1000;
		break;
	case POWER_SUPPLY_PROP_CAPACITY:
		if (battery->capacity_now && battery->full_charge_capacity)
			val->intval = battery->capacity_now * 100/
					battery->full_charge_capacity;
		else
			val->intval = 0;
		break;
	case POWER_SUPPLY_PROP_MODEL_NAME:
		val->strval = battery->model_number;
		break;
	case POWER_SUPPLY_PROP_MANUFACTURER:
		val->strval = battery->oem_info;
		break;
	case POWER_SUPPLY_PROP_SERIAL_NUMBER:
		val->strval = battery->serial_number;
		break;
	default:
		ret = -EINVAL;
	}
	return ret;
}

static enum power_supply_property charge_battery_props[] = {
	POWER_SUPPLY_PROP_STATUS,
	POWER_SUPPLY_PROP_PRESENT,
	POWER_SUPPLY_PROP_TECHNOLOGY,
	POWER_SUPPLY_PROP_CYCLE_COUNT,
	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
	POWER_SUPPLY_PROP_VOLTAGE_NOW,
	POWER_SUPPLY_PROP_CURRENT_NOW,
	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
	POWER_SUPPLY_PROP_CHARGE_FULL,
	POWER_SUPPLY_PROP_CHARGE_NOW,
	POWER_SUPPLY_PROP_CAPACITY,
	POWER_SUPPLY_PROP_MODEL_NAME,
	POWER_SUPPLY_PROP_MANUFACTURER,
	POWER_SUPPLY_PROP_SERIAL_NUMBER,
};

static enum power_supply_property energy_battery_props[] = {
	POWER_SUPPLY_PROP_STATUS,
	POWER_SUPPLY_PROP_PRESENT,
	POWER_SUPPLY_PROP_TECHNOLOGY,
	POWER_SUPPLY_PROP_CYCLE_COUNT,
	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
	POWER_SUPPLY_PROP_VOLTAGE_NOW,
	POWER_SUPPLY_PROP_POWER_NOW,
	POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN,
	POWER_SUPPLY_PROP_ENERGY_FULL,
	POWER_SUPPLY_PROP_ENERGY_NOW,
	POWER_SUPPLY_PROP_CAPACITY,
	POWER_SUPPLY_PROP_MODEL_NAME,
	POWER_SUPPLY_PROP_MANUFACTURER,
	POWER_SUPPLY_PROP_SERIAL_NUMBER,
};

/* --------------------------------------------------------------------------
                               Battery Management
   -------------------------------------------------------------------------- */
struct acpi_offsets {
	size_t offset;		/* offset inside struct acpi_sbs_battery */
	u8 mode;		/* int or string? */
};

static struct acpi_offsets state_offsets[] = {
	{offsetof(struct acpi_battery, state), 0},
	{offsetof(struct acpi_battery, rate_now), 0},
	{offsetof(struct acpi_battery, capacity_now), 0},
	{offsetof(struct acpi_battery, voltage_now), 0},
};

static struct acpi_offsets info_offsets[] = {
	{offsetof(struct acpi_battery, power_unit), 0},
	{offsetof(struct acpi_battery, design_capacity), 0},
	{offsetof(struct acpi_battery, full_charge_capacity), 0},
	{offsetof(struct acpi_battery, technology), 0},
	{offsetof(struct acpi_battery, design_voltage), 0},
	{offsetof(struct acpi_battery, design_capacity_warning), 0},
	{offsetof(struct acpi_battery, design_capacity_low), 0},
	{offsetof(struct acpi_battery, capacity_granularity_1), 0},
	{offsetof(struct acpi_battery, capacity_granularity_2), 0},
	{offsetof(struct acpi_battery, model_number), 1},
	{offsetof(struct acpi_battery, serial_number), 1},
	{offsetof(struct acpi_battery, type), 1},
	{offsetof(struct acpi_battery, oem_info), 1},
};

static struct acpi_offsets extended_info_offsets[] = {
	{offsetof(struct acpi_battery, revision), 0},
	{offsetof(struct acpi_battery, power_unit), 0},
	{offsetof(struct acpi_battery, design_capacity), 0},
	{offsetof(struct acpi_battery, full_charge_capacity), 0},
	{offsetof(struct acpi_battery, technology), 0},
	{offsetof(struct acpi_battery, design_voltage), 0},
	{offsetof(struct acpi_battery, design_capacity_warning), 0},
	{offsetof(struct acpi_battery, design_capacity_low), 0},
	{offsetof(struct acpi_battery, cycle_count), 0},
	{offsetof(struct acpi_battery, measurement_accuracy), 0},
	{offsetof(struct acpi_battery, max_sampling_time), 0},
	{offsetof(struct acpi_battery, min_sampling_time), 0},
	{offsetof(struct acpi_battery, max_averaging_interval), 0},
	{offsetof(struct acpi_battery, min_averaging_interval), 0},
	{offsetof(struct acpi_battery, capacity_granularity_1), 0},
	{offsetof(struct acpi_battery, capacity_granularity_2), 0},
	{offsetof(struct acpi_battery, model_number), 1},
	{offsetof(struct acpi_battery, serial_number), 1},
	{offsetof(struct acpi_battery, type), 1},
	{offsetof(struct acpi_battery, oem_info), 1},
};

static int extract_package(struct acpi_battery *battery,
			   union acpi_object *package,
			   struct acpi_offsets *offsets, int num)
{
	int i;
	union acpi_object *element;
	if (package->type != ACPI_TYPE_PACKAGE)
		return -EFAULT;
	for (i = 0; i < num; ++i) {
		if (package->package.count <= i)
			return -EFAULT;
		element = &package->package.elements[i];
		if (offsets[i].mode) {
			u8 *ptr = (u8 *)battery + offsets[i].offset;
			if (element->type == ACPI_TYPE_STRING ||
			    element->type == ACPI_TYPE_BUFFER)
				strncpy(ptr, element->string.pointer, 32);
			else if (element->type == ACPI_TYPE_INTEGER) {
				strncpy(ptr, (u8 *)&element->integer.value,
					sizeof(u64));
				ptr[sizeof(u64)] = 0;
			} else
				*ptr = 0; /* don't have value */
		} else {
			int *x = (int *)((u8 *)battery + offsets[i].offset);
			*x = (element->type == ACPI_TYPE_INTEGER) ?
				element->integer.value : -1;
		}
	}
	return 0;
}

static int acpi_battery_get_status(struct acpi_battery *battery)
{
	if (acpi_bus_get_status(battery->device)) {
		ACPI_EXCEPTION((AE_INFO, AE_ERROR, "Evaluating _STA"));
		return -ENODEV;
	}
	return 0;
}

static int acpi_battery_get_info(struct acpi_battery *battery)
{
	int result = -EFAULT;
	acpi_status status = 0;
	char *name = test_bit(ACPI_BATTERY_XINFO_PRESENT, &battery->flags) ?
			"_BIX" : "_BIF";

	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };

	if (!acpi_battery_present(battery))
		return 0;
	mutex_lock(&battery->lock);
	status = acpi_evaluate_object(battery->device->handle, name,
						NULL, &buffer);
	mutex_unlock(&battery->lock);

	if (ACPI_FAILURE(status)) {
		ACPI_EXCEPTION((AE_INFO, status, "Evaluating %s", name));
		return -ENODEV;
	}
	if (test_bit(ACPI_BATTERY_XINFO_PRESENT, &battery->flags))
		result = extract_package(battery, buffer.pointer,
				extended_info_offsets,
				ARRAY_SIZE(extended_info_offsets));
	else
		result = extract_package(battery, buffer.pointer,
				info_offsets, ARRAY_SIZE(info_offsets));
	kfree(buffer.pointer);
	if (test_bit(ACPI_BATTERY_QUIRK_PERCENTAGE_CAPACITY, &battery->flags))
		battery->full_charge_capacity = battery->design_capacity;
	if (test_bit(ACPI_BATTERY_QUIRK_THINKPAD_MAH, &battery->flags) &&
	    battery->power_unit && battery->design_voltage) {
		battery->design_capacity = battery->design_capacity *
		    10000 / battery->design_voltage;
		battery->full_charge_capacity = battery->full_charge_capacity *
		    10000 / battery->design_voltage;
		battery->design_capacity_warning =
		    battery->design_capacity_warning *
		    10000 / battery->design_voltage;
		/* Curiously, design_capacity_low, unlike the rest of them,
		   is correct.  */
		/* capacity_granularity_* equal 1 on the systems tested, so
		   it's impossible to tell if they would need an adjustment
		   or not if their values were higher.  */
	}
	return result;
}

static int acpi_battery_get_state(struct acpi_battery *battery)
{
	int result = 0;
	acpi_status status = 0;
	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };

	if (!acpi_battery_present(battery))
		return 0;

	if (battery->update_time &&
	    time_before(jiffies, battery->update_time +
			msecs_to_jiffies(cache_time)))
		return 0;

	mutex_lock(&battery->lock);
	status = acpi_evaluate_object(battery->device->handle, "_BST",
				      NULL, &buffer);
	mutex_unlock(&battery->lock);

	if (ACPI_FAILURE(status)) {
		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _BST"));
		return -ENODEV;
	}

	result = extract_package(battery, buffer.pointer,
				 state_offsets, ARRAY_SIZE(state_offsets));
	battery->update_time = jiffies;
	kfree(buffer.pointer);

	/* For buggy DSDTs that report negative 16-bit values for either
	 * charging or discharging current and/or report 0 as 65536
	 * due to bad math.
	 */
	if (battery->power_unit == ACPI_BATTERY_POWER_UNIT_MA &&
		battery->rate_now != ACPI_BATTERY_VALUE_UNKNOWN &&
		(s16)(battery->rate_now) < 0) {
		battery->rate_now = abs((s16)battery->rate_now);
		printk_once(KERN_WARNING FW_BUG "battery: (dis)charge rate"
			" invalid.\n");
	}

	if (test_bit(ACPI_BATTERY_QUIRK_PERCENTAGE_CAPACITY, &battery->flags)
	    && battery->capacity_now >= 0 && battery->capacity_now <= 100)
		battery->capacity_now = (battery->capacity_now *
				battery->full_charge_capacity) / 100;
	if (test_bit(ACPI_BATTERY_QUIRK_THINKPAD_MAH, &battery->flags) &&
	    battery->power_unit && battery->design_voltage) {
		battery->capacity_now = battery->capacity_now *
		    10000 / battery->design_voltage;
	}
	return result;
}

static int acpi_battery_set_alarm(struct acpi_battery *battery)
{
	acpi_status status = 0;

	if (!acpi_battery_present(battery) ||
	    !test_bit(ACPI_BATTERY_ALARM_PRESENT, &battery->flags))
		return -ENODEV;

	mutex_lock(&battery->lock);
	status = acpi_execute_simple_method(battery->device->handle, "_BTP",
					    battery->alarm);
	mutex_unlock(&battery->lock);

	if (ACPI_FAILURE(status))
		return -ENODEV;

	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Alarm set to %d\n", battery->alarm));
	return 0;
}

static int acpi_battery_init_alarm(struct acpi_battery *battery)
{
	/* See if alarms are supported, and if so, set default */
	if (!acpi_has_method(battery->device->handle, "_BTP")) {
		clear_bit(ACPI_BATTERY_ALARM_PRESENT, &battery->flags);
		return 0;
	}
	set_bit(ACPI_BATTERY_ALARM_PRESENT, &battery->flags);
	if (!battery->alarm)
		battery->alarm = battery->design_capacity_warning;
	return acpi_battery_set_alarm(battery);
}

static ssize_t acpi_battery_alarm_show(struct device *dev,
					struct device_attribute *attr,
					char *buf)
{
	struct acpi_battery *battery = to_acpi_battery(dev_get_drvdata(dev));
	return sprintf(buf, "%d\n", battery->alarm * 1000);
}

static ssize_t acpi_battery_alarm_store(struct device *dev,
					struct device_attribute *attr,
					const char *buf, size_t count)
{
	unsigned long x;
	struct acpi_battery *battery = to_acpi_battery(dev_get_drvdata(dev));
	if (sscanf(buf, "%ld\n", &x) == 1)
		battery->alarm = x/1000;
	if (acpi_battery_present(battery))
		acpi_battery_set_alarm(battery);
	return count;
}

static struct device_attribute alarm_attr = {
	.attr = {.name = "alarm", .mode = 0644},
	.show = acpi_battery_alarm_show,
	.store = acpi_battery_alarm_store,
};

static int sysfs_add_battery(struct acpi_battery *battery)
{
	int result;

	if (battery->power_unit == ACPI_BATTERY_POWER_UNIT_MA) {
		battery->bat.properties = charge_battery_props;
		battery->bat.num_properties =
			ARRAY_SIZE(charge_battery_props);
	} else {
		battery->bat.properties = energy_battery_props;
		battery->bat.num_properties =
			ARRAY_SIZE(energy_battery_props);
	}

	battery->bat.name = acpi_device_bid(battery->device);
	battery->bat.type = POWER_SUPPLY_TYPE_BATTERY;
	battery->bat.get_property = acpi_battery_get_property;

	result = power_supply_register(&battery->device->dev, &battery->bat);
	if (result)
		return result;
	return device_create_file(battery->bat.dev, &alarm_attr);
}

static void sysfs_remove_battery(struct acpi_battery *battery)
{
	mutex_lock(&battery->sysfs_lock);
	if (!battery->bat.dev) {
		mutex_unlock(&battery->sysfs_lock);
		return;
	}

	device_remove_file(battery->bat.dev, &alarm_attr);
	power_supply_unregister(&battery->bat);
	battery->bat.dev = NULL;
	mutex_unlock(&battery->sysfs_lock);
}

static void find_battery(const struct dmi_header *dm, void *private)
{
	struct acpi_battery *battery = (struct acpi_battery *)private;
	/* Note: the hardcoded offsets below have been extracted from
	   the source code of dmidecode.  */
	if (dm->type == DMI_ENTRY_PORTABLE_BATTERY && dm->length >= 8) {
		const u8 *dmi_data = (const u8 *)(dm + 1);
		int dmi_capacity = get_unaligned((const u16 *)(dmi_data + 6));
		if (dm->length >= 18)
			dmi_capacity *= dmi_data[17];
		if (battery->design_capacity * battery->design_voltage / 1000
		    != dmi_capacity &&
		    battery->design_capacity * 10 == dmi_capacity)
			set_bit(ACPI_BATTERY_QUIRK_THINKPAD_MAH,
				&battery->flags);
	}
}

/*
 * According to the ACPI spec, some kinds of primary batteries can
 * report percentage battery remaining capacity directly to OS.
 * In this case, it reports the Last Full Charged Capacity == 100
 * and BatteryPresentRate == 0xFFFFFFFF.
 *
 * Now we found some battery reports percentage remaining capacity
 * even if it's rechargeable.
 * https://bugzilla.kernel.org/show_bug.cgi?id=15979
 *
 * Handle this correctly so that they won't break userspace.
 */
static void acpi_battery_quirks(struct acpi_battery *battery)
{
	if (test_bit(ACPI_BATTERY_QUIRK_PERCENTAGE_CAPACITY, &battery->flags))
		return;

	if (battery->full_charge_capacity == 100 &&
		battery->rate_now == ACPI_BATTERY_VALUE_UNKNOWN &&
		battery->capacity_now >= 0 && battery->capacity_now <= 100) {
		set_bit(ACPI_BATTERY_QUIRK_PERCENTAGE_CAPACITY, &battery->flags);
		battery->full_charge_capacity = battery->design_capacity;
		battery->capacity_now = (battery->capacity_now *
				battery->full_charge_capacity) / 100;
	}

	if (test_bit(ACPI_BATTERY_QUIRK_THINKPAD_MAH, &battery->flags))
		return;

	if (battery->power_unit && dmi_name_in_vendors("LENOVO")) {
		const char *s;
		s = dmi_get_system_info(DMI_PRODUCT_VERSION);
		if (s && !strnicmp(s, "ThinkPad", 8)) {
			dmi_walk(find_battery, battery);
			if (test_bit(ACPI_BATTERY_QUIRK_THINKPAD_MAH,
				     &battery->flags) &&
			    battery->design_voltage) {
				battery->design_capacity =
				    battery->design_capacity *
				    10000 / battery->design_voltage;
				battery->full_charge_capacity =
				    battery->full_charge_capacity *
				    10000 / battery->design_voltage;
				battery->design_capacity_warning =
				    battery->design_capacity_warning *
				    10000 / battery->design_voltage;
				battery->capacity_now = battery->capacity_now *
				    10000 / battery->design_voltage;
			}
		}
	}
}

static int acpi_battery_update(struct acpi_battery *battery)
{
	int result, old_present = acpi_battery_present(battery);
	result = acpi_battery_get_status(battery);
	if (result)
		return result;
	if (!acpi_battery_present(battery)) {
		sysfs_remove_battery(battery);
		battery->update_time = 0;
		return 0;
	}
	if (!battery->update_time ||
	    old_present != acpi_battery_present(battery)) {
		result = acpi_battery_get_info(battery);
		if (result)
			return result;
		acpi_battery_init_alarm(battery);
	}
	if (!battery->bat.dev) {
		result = sysfs_add_battery(battery);
		if (result)
			return result;
	}
	result = acpi_battery_get_state(battery);
	acpi_battery_quirks(battery);
	return result;
}

static void acpi_battery_refresh(struct acpi_battery *battery)
{
	int power_unit;

	if (!battery->bat.dev)
		return;

	power_unit = battery->power_unit;

	acpi_battery_get_info(battery);

	if (power_unit == battery->power_unit)
		return;

	/* The battery has changed its reporting units. */
	sysfs_remove_battery(battery);
	sysfs_add_battery(battery);
}

/* --------------------------------------------------------------------------
                                 Driver Interface
   -------------------------------------------------------------------------- */

static void acpi_battery_notify(struct acpi_device *device, u32 event)
{
	struct acpi_battery *battery = acpi_driver_data(device);
	struct device *old;

	if (!battery)
		return;
	old = battery->bat.dev;
	if (event == ACPI_BATTERY_NOTIFY_INFO)
		acpi_battery_refresh(battery);
	acpi_battery_update(battery);
	acpi_bus_generate_netlink_event(device->pnp.device_class,
					dev_name(&device->dev), event,
					acpi_battery_present(battery));
	/* acpi_battery_update could remove power_supply object */
	if (old && battery->bat.dev)
		power_supply_changed(&battery->bat);
}

static int battery_notify(struct notifier_block *nb,
			       unsigned long mode, void *_unused)
{
	struct acpi_battery *battery = container_of(nb, struct acpi_battery,
						    pm_nb);
	switch (mode) {
	case PM_POST_HIBERNATION:
	case PM_POST_SUSPEND:
		if (battery->bat.dev) {
			sysfs_remove_battery(battery);
			sysfs_add_battery(battery);
		}
		break;
	}

	return 0;
}

static int acpi_battery_add(struct acpi_device *device)
{
	int result = 0;
	struct acpi_battery *battery = NULL;

	if (!device)
		return -EINVAL;
	battery = kzalloc(sizeof(struct acpi_battery), GFP_KERNEL);
	if (!battery)
		return -ENOMEM;
	battery->device = device;
	strcpy(acpi_device_name(device), ACPI_BATTERY_DEVICE_NAME);
	strcpy(acpi_device_class(device), ACPI_BATTERY_CLASS);
	device->driver_data = battery;
	mutex_init(&battery->lock);
	mutex_init(&battery->sysfs_lock);
	if (acpi_has_method(battery->device->handle, "_BIX"))
		set_bit(ACPI_BATTERY_XINFO_PRESENT, &battery->flags);
	result = acpi_battery_update(battery);
	if (result)
		goto fail;

	printk(KERN_INFO PREFIX "%s Slot [%s] (battery %s)\n",
		ACPI_BATTERY_DEVICE_NAME, acpi_device_bid(device),
		device->status.battery_present ? "present" : "absent");

	battery->pm_nb.notifier_call = battery_notify;
	register_pm_notifier(&battery->pm_nb);

	return result;

fail:
	sysfs_remove_battery(battery);
	mutex_destroy(&battery->lock);
	mutex_destroy(&battery->sysfs_lock);
	kfree(battery);
	return result;
}

static int acpi_battery_remove(struct acpi_device *device)
{
	struct acpi_battery *battery = NULL;

	if (!device || !acpi_driver_data(device))
		return -EINVAL;
	battery = acpi_driver_data(device);
	unregister_pm_notifier(&battery->pm_nb);
	sysfs_remove_battery(battery);
	mutex_destroy(&battery->lock);
	mutex_destroy(&battery->sysfs_lock);
	kfree(battery);
	return 0;
}

#ifdef CONFIG_PM_SLEEP
/* this is needed to learn about changes made in suspended state */
static int acpi_battery_resume(struct device *dev)
{
	struct acpi_battery *battery;

	if (!dev)
		return -EINVAL;

	battery = acpi_driver_data(to_acpi_device(dev));
	if (!battery)
		return -EINVAL;

	battery->update_time = 0;
	acpi_battery_update(battery);
	return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(acpi_battery_pm, NULL, acpi_battery_resume);

static struct acpi_driver acpi_battery_driver = {
	.name = "battery",
	.class = ACPI_BATTERY_CLASS,
	.ids = battery_device_ids,
	.flags = ACPI_DRIVER_ALL_NOTIFY_EVENTS,
	.ops = {
		.add = acpi_battery_add,
		.remove = acpi_battery_remove,
		.notify = acpi_battery_notify,
		},
	.drv.pm = &acpi_battery_pm,
};

static void __init acpi_battery_init_async(void *unused, async_cookie_t cookie)
{
	if (acpi_disabled)
		return;
	acpi_bus_register_driver(&acpi_battery_driver);
}

static int __init acpi_battery_init(void)
{
	async_schedule(acpi_battery_init_async, NULL);
	return 0;
}

static void __exit acpi_battery_exit(void)
{
	acpi_bus_unregister_driver(&acpi_battery_driver);
}

module_init(acpi_battery_init);
module_exit(acpi_battery_exit);