summaryrefslogtreecommitdiff
path: root/drivers/pwm/core.c
blob: d70f793ce4b38dd7bfb20c0d44392b018ab784ea (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
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Generic pwmlib implementation
 *
 * Copyright (C) 2011 Sascha Hauer <s.hauer@pengutronix.de>
 * Copyright (C) 2011-2012 Avionic Design GmbH
 */

#include <linux/acpi.h>
#include <linux/module.h>
#include <linux/idr.h>
#include <linux/of.h>
#include <linux/pwm.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>

#include <dt-bindings/pwm/pwm.h>

#define CREATE_TRACE_POINTS
#include <trace/events/pwm.h>

/* protects access to pwm_chips */
static DEFINE_MUTEX(pwm_lock);

static DEFINE_IDR(pwm_chips);

static void pwm_apply_debug(struct pwm_device *pwm,
			    const struct pwm_state *state)
{
	struct pwm_state *last = &pwm->last;
	struct pwm_chip *chip = pwm->chip;
	struct pwm_state s1 = { 0 }, s2 = { 0 };
	int err;

	if (!IS_ENABLED(CONFIG_PWM_DEBUG))
		return;

	/* No reasonable diagnosis possible without .get_state() */
	if (!chip->ops->get_state)
		return;

	/*
	 * *state was just applied. Read out the hardware state and do some
	 * checks.
	 */

	err = chip->ops->get_state(chip, pwm, &s1);
	trace_pwm_get(pwm, &s1, err);
	if (err)
		/* If that failed there isn't much to debug */
		return;

	/*
	 * The lowlevel driver either ignored .polarity (which is a bug) or as
	 * best effort inverted .polarity and fixed .duty_cycle respectively.
	 * Undo this inversion and fixup for further tests.
	 */
	if (s1.enabled && s1.polarity != state->polarity) {
		s2.polarity = state->polarity;
		s2.duty_cycle = s1.period - s1.duty_cycle;
		s2.period = s1.period;
		s2.enabled = s1.enabled;
	} else {
		s2 = s1;
	}

	if (s2.polarity != state->polarity &&
	    state->duty_cycle < state->period)
		dev_warn(pwmchip_parent(chip), ".apply ignored .polarity\n");

	if (state->enabled &&
	    last->polarity == state->polarity &&
	    last->period > s2.period &&
	    last->period <= state->period)
		dev_warn(pwmchip_parent(chip),
			 ".apply didn't pick the best available period (requested: %llu, applied: %llu, possible: %llu)\n",
			 state->period, s2.period, last->period);

	if (state->enabled && state->period < s2.period)
		dev_warn(pwmchip_parent(chip),
			 ".apply is supposed to round down period (requested: %llu, applied: %llu)\n",
			 state->period, s2.period);

	if (state->enabled &&
	    last->polarity == state->polarity &&
	    last->period == s2.period &&
	    last->duty_cycle > s2.duty_cycle &&
	    last->duty_cycle <= state->duty_cycle)
		dev_warn(pwmchip_parent(chip),
			 ".apply didn't pick the best available duty cycle (requested: %llu/%llu, applied: %llu/%llu, possible: %llu/%llu)\n",
			 state->duty_cycle, state->period,
			 s2.duty_cycle, s2.period,
			 last->duty_cycle, last->period);

	if (state->enabled && state->duty_cycle < s2.duty_cycle)
		dev_warn(pwmchip_parent(chip),
			 ".apply is supposed to round down duty_cycle (requested: %llu/%llu, applied: %llu/%llu)\n",
			 state->duty_cycle, state->period,
			 s2.duty_cycle, s2.period);

	if (!state->enabled && s2.enabled && s2.duty_cycle > 0)
		dev_warn(pwmchip_parent(chip),
			 "requested disabled, but yielded enabled with duty > 0\n");

	/* reapply the state that the driver reported being configured. */
	err = chip->ops->apply(chip, pwm, &s1);
	trace_pwm_apply(pwm, &s1, err);
	if (err) {
		*last = s1;
		dev_err(pwmchip_parent(chip), "failed to reapply current setting\n");
		return;
	}

	*last = (struct pwm_state){ 0 };
	err = chip->ops->get_state(chip, pwm, last);
	trace_pwm_get(pwm, last, err);
	if (err)
		return;

	/* reapplication of the current state should give an exact match */
	if (s1.enabled != last->enabled ||
	    s1.polarity != last->polarity ||
	    (s1.enabled && s1.period != last->period) ||
	    (s1.enabled && s1.duty_cycle != last->duty_cycle)) {
		dev_err(pwmchip_parent(chip),
			".apply is not idempotent (ena=%d pol=%d %llu/%llu) -> (ena=%d pol=%d %llu/%llu)\n",
			s1.enabled, s1.polarity, s1.duty_cycle, s1.period,
			last->enabled, last->polarity, last->duty_cycle,
			last->period);
	}
}

/**
 * __pwm_apply() - atomically apply a new state to a PWM device
 * @pwm: PWM device
 * @state: new state to apply
 */
static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state)
{
	struct pwm_chip *chip;
	int err;

	if (!pwm || !state || !state->period ||
	    state->duty_cycle > state->period)
		return -EINVAL;

	chip = pwm->chip;

	if (state->period == pwm->state.period &&
	    state->duty_cycle == pwm->state.duty_cycle &&
	    state->polarity == pwm->state.polarity &&
	    state->enabled == pwm->state.enabled &&
	    state->usage_power == pwm->state.usage_power)
		return 0;

	err = chip->ops->apply(chip, pwm, state);
	trace_pwm_apply(pwm, state, err);
	if (err)
		return err;

	pwm->state = *state;

	/*
	 * only do this after pwm->state was applied as some
	 * implementations of .get_state depend on this
	 */
	pwm_apply_debug(pwm, state);

	return 0;
}

/**
 * pwm_apply_might_sleep() - atomically apply a new state to a PWM device
 * Cannot be used in atomic context.
 * @pwm: PWM device
 * @state: new state to apply
 */
int pwm_apply_might_sleep(struct pwm_device *pwm, const struct pwm_state *state)
{
	int err;

	/*
	 * Some lowlevel driver's implementations of .apply() make use of
	 * mutexes, also with some drivers only returning when the new
	 * configuration is active calling pwm_apply_might_sleep() from atomic context
	 * is a bad idea. So make it explicit that calling this function might
	 * sleep.
	 */
	might_sleep();

	if (IS_ENABLED(CONFIG_PWM_DEBUG) && pwm->chip->atomic) {
		/*
		 * Catch any drivers that have been marked as atomic but
		 * that will sleep anyway.
		 */
		non_block_start();
		err = __pwm_apply(pwm, state);
		non_block_end();
	} else {
		err = __pwm_apply(pwm, state);
	}

	return err;
}
EXPORT_SYMBOL_GPL(pwm_apply_might_sleep);

/**
 * pwm_apply_atomic() - apply a new state to a PWM device from atomic context
 * Not all PWM devices support this function, check with pwm_might_sleep().
 * @pwm: PWM device
 * @state: new state to apply
 */
int pwm_apply_atomic(struct pwm_device *pwm, const struct pwm_state *state)
{
	WARN_ONCE(!pwm->chip->atomic,
		  "sleeping PWM driver used in atomic context\n");

	return __pwm_apply(pwm, state);
}
EXPORT_SYMBOL_GPL(pwm_apply_atomic);

/**
 * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
 * @pwm: PWM device
 *
 * This function will adjust the PWM config to the PWM arguments provided
 * by the DT or PWM lookup table. This is particularly useful to adapt
 * the bootloader config to the Linux one.
 */
int pwm_adjust_config(struct pwm_device *pwm)
{
	struct pwm_state state;
	struct pwm_args pargs;

	pwm_get_args(pwm, &pargs);
	pwm_get_state(pwm, &state);

	/*
	 * If the current period is zero it means that either the PWM driver
	 * does not support initial state retrieval or the PWM has not yet
	 * been configured.
	 *
	 * In either case, we setup the new period and polarity, and assign a
	 * duty cycle of 0.
	 */
	if (!state.period) {
		state.duty_cycle = 0;
		state.period = pargs.period;
		state.polarity = pargs.polarity;

		return pwm_apply_might_sleep(pwm, &state);
	}

	/*
	 * Adjust the PWM duty cycle/period based on the period value provided
	 * in PWM args.
	 */
	if (pargs.period != state.period) {
		u64 dutycycle = (u64)state.duty_cycle * pargs.period;

		do_div(dutycycle, state.period);
		state.duty_cycle = dutycycle;
		state.period = pargs.period;
	}

	/*
	 * If the polarity changed, we should also change the duty cycle.
	 */
	if (pargs.polarity != state.polarity) {
		state.polarity = pargs.polarity;
		state.duty_cycle = state.period - state.duty_cycle;
	}

	return pwm_apply_might_sleep(pwm, &state);
}
EXPORT_SYMBOL_GPL(pwm_adjust_config);

/**
 * pwm_capture() - capture and report a PWM signal
 * @pwm: PWM device
 * @result: structure to fill with capture result
 * @timeout: time to wait, in milliseconds, before giving up on capture
 *
 * Returns: 0 on success or a negative error code on failure.
 */
int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
		unsigned long timeout)
{
	int err;

	if (!pwm || !pwm->chip->ops)
		return -EINVAL;

	if (!pwm->chip->ops->capture)
		return -ENOSYS;

	mutex_lock(&pwm_lock);
	err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
	mutex_unlock(&pwm_lock);

	return err;
}
EXPORT_SYMBOL_GPL(pwm_capture);

static struct pwm_chip *pwmchip_find_by_name(const char *name)
{
	struct pwm_chip *chip;
	unsigned long id, tmp;

	if (!name)
		return NULL;

	mutex_lock(&pwm_lock);

	idr_for_each_entry_ul(&pwm_chips, chip, tmp, id) {
		const char *chip_name = dev_name(pwmchip_parent(chip));

		if (chip_name && strcmp(chip_name, name) == 0) {
			mutex_unlock(&pwm_lock);
			return chip;
		}
	}

	mutex_unlock(&pwm_lock);

	return NULL;
}

static int pwm_device_request(struct pwm_device *pwm, const char *label)
{
	int err;
	struct pwm_chip *chip = pwm->chip;
	const struct pwm_ops *ops = chip->ops;

	if (test_bit(PWMF_REQUESTED, &pwm->flags))
		return -EBUSY;

	if (!try_module_get(chip->owner))
		return -ENODEV;

	if (ops->request) {
		err = ops->request(chip, pwm);
		if (err) {
			module_put(chip->owner);
			return err;
		}
	}

	if (ops->get_state) {
		/*
		 * Zero-initialize state because most drivers are unaware of
		 * .usage_power. The other members of state are supposed to be
		 * set by lowlevel drivers. We still initialize the whole
		 * structure for simplicity even though this might paper over
		 * faulty implementations of .get_state().
		 */
		struct pwm_state state = { 0, };

		err = ops->get_state(chip, pwm, &state);
		trace_pwm_get(pwm, &state, err);

		if (!err)
			pwm->state = state;

		if (IS_ENABLED(CONFIG_PWM_DEBUG))
			pwm->last = pwm->state;
	}

	set_bit(PWMF_REQUESTED, &pwm->flags);
	pwm->label = label;

	return 0;
}

/**
 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
 * @chip: PWM chip
 * @index: per-chip index of the PWM to request
 * @label: a literal description string of this PWM
 *
 * Returns: A pointer to the PWM device at the given index of the given PWM
 * chip. A negative error code is returned if the index is not valid for the
 * specified PWM chip or if the PWM device cannot be requested.
 */
struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
					 unsigned int index,
					 const char *label)
{
	struct pwm_device *pwm;
	int err;

	if (!chip || index >= chip->npwm)
		return ERR_PTR(-EINVAL);

	mutex_lock(&pwm_lock);
	pwm = &chip->pwms[index];

	err = pwm_device_request(pwm, label);
	if (err < 0)
		pwm = ERR_PTR(err);

	mutex_unlock(&pwm_lock);
	return pwm;
}
EXPORT_SYMBOL_GPL(pwm_request_from_chip);


struct pwm_device *
of_pwm_xlate_with_flags(struct pwm_chip *chip, const struct of_phandle_args *args)
{
	struct pwm_device *pwm;

	/* period in the second cell and flags in the third cell are optional */
	if (args->args_count < 1)
		return ERR_PTR(-EINVAL);

	pwm = pwm_request_from_chip(chip, args->args[0], NULL);
	if (IS_ERR(pwm))
		return pwm;

	if (args->args_count > 1)
		pwm->args.period = args->args[1];

	pwm->args.polarity = PWM_POLARITY_NORMAL;
	if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
		pwm->args.polarity = PWM_POLARITY_INVERSED;

	return pwm;
}
EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);

struct pwm_device *
of_pwm_single_xlate(struct pwm_chip *chip, const struct of_phandle_args *args)
{
	struct pwm_device *pwm;

	pwm = pwm_request_from_chip(chip, 0, NULL);
	if (IS_ERR(pwm))
		return pwm;

	if (args->args_count > 1)
		pwm->args.period = args->args[0];

	pwm->args.polarity = PWM_POLARITY_NORMAL;
	if (args->args_count > 1 && args->args[1] & PWM_POLARITY_INVERTED)
		pwm->args.polarity = PWM_POLARITY_INVERSED;

	return pwm;
}
EXPORT_SYMBOL_GPL(of_pwm_single_xlate);

#define PWMCHIP_ALIGN ARCH_DMA_MINALIGN

static void *pwmchip_priv(struct pwm_chip *chip)
{
	return (void *)chip + ALIGN(sizeof(*chip), PWMCHIP_ALIGN);
}

/* This is the counterpart to pwmchip_alloc() */
void pwmchip_put(struct pwm_chip *chip)
{
	kfree(chip);
}
EXPORT_SYMBOL_GPL(pwmchip_put);

struct pwm_chip *pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv)
{
	struct pwm_chip *chip;
	size_t alloc_size;

	alloc_size = size_add(ALIGN(sizeof(*chip), PWMCHIP_ALIGN), sizeof_priv);

	chip = kzalloc(alloc_size, GFP_KERNEL);
	if (!chip)
		return ERR_PTR(-ENOMEM);

	chip->dev = parent;
	chip->npwm = npwm;

	pwmchip_set_drvdata(chip, pwmchip_priv(chip));

	return chip;
}
EXPORT_SYMBOL_GPL(pwmchip_alloc);

static void devm_pwmchip_put(void *data)
{
	struct pwm_chip *chip = data;

	pwmchip_put(chip);
}

struct pwm_chip *devm_pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv)
{
	struct pwm_chip *chip;
	int ret;

	chip = pwmchip_alloc(parent, npwm, sizeof_priv);
	if (IS_ERR(chip))
		return chip;

	ret = devm_add_action_or_reset(parent, devm_pwmchip_put, chip);
	if (ret)
		return ERR_PTR(ret);

	return chip;
}
EXPORT_SYMBOL_GPL(devm_pwmchip_alloc);

static void of_pwmchip_add(struct pwm_chip *chip)
{
	if (!pwmchip_parent(chip) || !pwmchip_parent(chip)->of_node)
		return;

	if (!chip->of_xlate)
		chip->of_xlate = of_pwm_xlate_with_flags;

	of_node_get(pwmchip_parent(chip)->of_node);
}

static void of_pwmchip_remove(struct pwm_chip *chip)
{
	if (pwmchip_parent(chip))
		of_node_put(pwmchip_parent(chip)->of_node);
}

static bool pwm_ops_check(const struct pwm_chip *chip)
{
	const struct pwm_ops *ops = chip->ops;

	if (!ops->apply)
		return false;

	if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state)
		dev_warn(pwmchip_parent(chip),
			 "Please implement the .get_state() callback\n");

	return true;
}

/**
 * __pwmchip_add() - register a new PWM chip
 * @chip: the PWM chip to add
 * @owner: reference to the module providing the chip.
 *
 * Register a new PWM chip. @owner is supposed to be THIS_MODULE, use the
 * pwmchip_add wrapper to do this right.
 *
 * Returns: 0 on success or a negative error code on failure.
 */
int __pwmchip_add(struct pwm_chip *chip, struct module *owner)
{
	unsigned int i;
	int ret;

	if (!chip || !pwmchip_parent(chip) || !chip->ops || !chip->npwm)
		return -EINVAL;

	if (!pwm_ops_check(chip))
		return -EINVAL;

	chip->owner = owner;

	chip->pwms = kcalloc(chip->npwm, sizeof(*chip->pwms), GFP_KERNEL);
	if (!chip->pwms)
		return -ENOMEM;

	mutex_lock(&pwm_lock);

	ret = idr_alloc(&pwm_chips, chip, 0, 0, GFP_KERNEL);
	if (ret < 0) {
		mutex_unlock(&pwm_lock);
		kfree(chip->pwms);
		return ret;
	}

	chip->id = ret;

	for (i = 0; i < chip->npwm; i++) {
		struct pwm_device *pwm = &chip->pwms[i];

		pwm->chip = chip;
		pwm->hwpwm = i;
	}

	mutex_unlock(&pwm_lock);

	if (IS_ENABLED(CONFIG_OF))
		of_pwmchip_add(chip);

	pwmchip_sysfs_export(chip);

	return 0;
}
EXPORT_SYMBOL_GPL(__pwmchip_add);

/**
 * pwmchip_remove() - remove a PWM chip
 * @chip: the PWM chip to remove
 *
 * Removes a PWM chip.
 */
void pwmchip_remove(struct pwm_chip *chip)
{
	pwmchip_sysfs_unexport(chip);

	if (IS_ENABLED(CONFIG_OF))
		of_pwmchip_remove(chip);

	mutex_lock(&pwm_lock);

	idr_remove(&pwm_chips, chip->id);

	mutex_unlock(&pwm_lock);

	kfree(chip->pwms);
}
EXPORT_SYMBOL_GPL(pwmchip_remove);

static void devm_pwmchip_remove(void *data)
{
	struct pwm_chip *chip = data;

	pwmchip_remove(chip);
}

int __devm_pwmchip_add(struct device *dev, struct pwm_chip *chip, struct module *owner)
{
	int ret;

	ret = __pwmchip_add(chip, owner);
	if (ret)
		return ret;

	return devm_add_action_or_reset(dev, devm_pwmchip_remove, chip);
}
EXPORT_SYMBOL_GPL(__devm_pwmchip_add);

static struct device_link *pwm_device_link_add(struct device *dev,
					       struct pwm_device *pwm)
{
	struct device_link *dl;

	if (!dev) {
		/*
		 * No device for the PWM consumer has been provided. It may
		 * impact the PM sequence ordering: the PWM supplier may get
		 * suspended before the consumer.
		 */
		dev_warn(pwmchip_parent(pwm->chip),
			 "No consumer device specified to create a link to\n");
		return NULL;
	}

	dl = device_link_add(dev, pwmchip_parent(pwm->chip), DL_FLAG_AUTOREMOVE_CONSUMER);
	if (!dl) {
		dev_err(dev, "failed to create device link to %s\n",
			dev_name(pwmchip_parent(pwm->chip)));
		return ERR_PTR(-EINVAL);
	}

	return dl;
}

static struct pwm_chip *fwnode_to_pwmchip(struct fwnode_handle *fwnode)
{
	struct pwm_chip *chip;
	unsigned long id, tmp;

	mutex_lock(&pwm_lock);

	idr_for_each_entry_ul(&pwm_chips, chip, tmp, id)
		if (pwmchip_parent(chip) && device_match_fwnode(pwmchip_parent(chip), fwnode)) {
			mutex_unlock(&pwm_lock);
			return chip;
		}

	mutex_unlock(&pwm_lock);

	return ERR_PTR(-EPROBE_DEFER);
}

/**
 * of_pwm_get() - request a PWM via the PWM framework
 * @dev: device for PWM consumer
 * @np: device node to get the PWM from
 * @con_id: consumer name
 *
 * Returns the PWM device parsed from the phandle and index specified in the
 * "pwms" property of a device tree node or a negative error-code on failure.
 * Values parsed from the device tree are stored in the returned PWM device
 * object.
 *
 * If con_id is NULL, the first PWM device listed in the "pwms" property will
 * be requested. Otherwise the "pwm-names" property is used to do a reverse
 * lookup of the PWM index. This also means that the "pwm-names" property
 * becomes mandatory for devices that look up the PWM device via the con_id
 * parameter.
 *
 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
 * error code on failure.
 */
static struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
				     const char *con_id)
{
	struct pwm_device *pwm = NULL;
	struct of_phandle_args args;
	struct device_link *dl;
	struct pwm_chip *chip;
	int index = 0;
	int err;

	if (con_id) {
		index = of_property_match_string(np, "pwm-names", con_id);
		if (index < 0)
			return ERR_PTR(index);
	}

	err = of_parse_phandle_with_args(np, "pwms", "#pwm-cells", index,
					 &args);
	if (err) {
		pr_err("%s(): can't parse \"pwms\" property\n", __func__);
		return ERR_PTR(err);
	}

	chip = fwnode_to_pwmchip(of_fwnode_handle(args.np));
	if (IS_ERR(chip)) {
		if (PTR_ERR(chip) != -EPROBE_DEFER)
			pr_err("%s(): PWM chip not found\n", __func__);

		pwm = ERR_CAST(chip);
		goto put;
	}

	pwm = chip->of_xlate(chip, &args);
	if (IS_ERR(pwm))
		goto put;

	dl = pwm_device_link_add(dev, pwm);
	if (IS_ERR(dl)) {
		/* of_xlate ended up calling pwm_request_from_chip() */
		pwm_put(pwm);
		pwm = ERR_CAST(dl);
		goto put;
	}

	/*
	 * If a consumer name was not given, try to look it up from the
	 * "pwm-names" property if it exists. Otherwise use the name of
	 * the user device node.
	 */
	if (!con_id) {
		err = of_property_read_string_index(np, "pwm-names", index,
						    &con_id);
		if (err < 0)
			con_id = np->name;
	}

	pwm->label = con_id;

put:
	of_node_put(args.np);

	return pwm;
}

/**
 * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI
 * @fwnode: firmware node to get the "pwms" property from
 *
 * Returns the PWM device parsed from the fwnode and index specified in the
 * "pwms" property or a negative error-code on failure.
 * Values parsed from the device tree are stored in the returned PWM device
 * object.
 *
 * This is analogous to of_pwm_get() except con_id is not yet supported.
 * ACPI entries must look like
 * Package () {"pwms", Package ()
 *     { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}}
 *
 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
 * error code on failure.
 */
static struct pwm_device *acpi_pwm_get(const struct fwnode_handle *fwnode)
{
	struct pwm_device *pwm;
	struct fwnode_reference_args args;
	struct pwm_chip *chip;
	int ret;

	memset(&args, 0, sizeof(args));

	ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args);
	if (ret < 0)
		return ERR_PTR(ret);

	if (args.nargs < 2)
		return ERR_PTR(-EPROTO);

	chip = fwnode_to_pwmchip(args.fwnode);
	if (IS_ERR(chip))
		return ERR_CAST(chip);

	pwm = pwm_request_from_chip(chip, args.args[0], NULL);
	if (IS_ERR(pwm))
		return pwm;

	pwm->args.period = args.args[1];
	pwm->args.polarity = PWM_POLARITY_NORMAL;

	if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED)
		pwm->args.polarity = PWM_POLARITY_INVERSED;

	return pwm;
}

static DEFINE_MUTEX(pwm_lookup_lock);
static LIST_HEAD(pwm_lookup_list);

/**
 * pwm_add_table() - register PWM device consumers
 * @table: array of consumers to register
 * @num: number of consumers in table
 */
void pwm_add_table(struct pwm_lookup *table, size_t num)
{
	mutex_lock(&pwm_lookup_lock);

	while (num--) {
		list_add_tail(&table->list, &pwm_lookup_list);
		table++;
	}

	mutex_unlock(&pwm_lookup_lock);
}

/**
 * pwm_remove_table() - unregister PWM device consumers
 * @table: array of consumers to unregister
 * @num: number of consumers in table
 */
void pwm_remove_table(struct pwm_lookup *table, size_t num)
{
	mutex_lock(&pwm_lookup_lock);

	while (num--) {
		list_del(&table->list);
		table++;
	}

	mutex_unlock(&pwm_lookup_lock);
}

/**
 * pwm_get() - look up and request a PWM device
 * @dev: device for PWM consumer
 * @con_id: consumer name
 *
 * Lookup is first attempted using DT. If the device was not instantiated from
 * a device tree, a PWM chip and a relative index is looked up via a table
 * supplied by board setup code (see pwm_add_table()).
 *
 * Once a PWM chip has been found the specified PWM device will be requested
 * and is ready to be used.
 *
 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
 * error code on failure.
 */
struct pwm_device *pwm_get(struct device *dev, const char *con_id)
{
	const struct fwnode_handle *fwnode = dev ? dev_fwnode(dev) : NULL;
	const char *dev_id = dev ? dev_name(dev) : NULL;
	struct pwm_device *pwm;
	struct pwm_chip *chip;
	struct device_link *dl;
	unsigned int best = 0;
	struct pwm_lookup *p, *chosen = NULL;
	unsigned int match;
	int err;

	/* look up via DT first */
	if (is_of_node(fwnode))
		return of_pwm_get(dev, to_of_node(fwnode), con_id);

	/* then lookup via ACPI */
	if (is_acpi_node(fwnode)) {
		pwm = acpi_pwm_get(fwnode);
		if (!IS_ERR(pwm) || PTR_ERR(pwm) != -ENOENT)
			return pwm;
	}

	/*
	 * We look up the provider in the static table typically provided by
	 * board setup code. We first try to lookup the consumer device by
	 * name. If the consumer device was passed in as NULL or if no match
	 * was found, we try to find the consumer by directly looking it up
	 * by name.
	 *
	 * If a match is found, the provider PWM chip is looked up by name
	 * and a PWM device is requested using the PWM device per-chip index.
	 *
	 * The lookup algorithm was shamelessly taken from the clock
	 * framework:
	 *
	 * We do slightly fuzzy matching here:
	 *  An entry with a NULL ID is assumed to be a wildcard.
	 *  If an entry has a device ID, it must match
	 *  If an entry has a connection ID, it must match
	 * Then we take the most specific entry - with the following order
	 * of precedence: dev+con > dev only > con only.
	 */
	mutex_lock(&pwm_lookup_lock);

	list_for_each_entry(p, &pwm_lookup_list, list) {
		match = 0;

		if (p->dev_id) {
			if (!dev_id || strcmp(p->dev_id, dev_id))
				continue;

			match += 2;
		}

		if (p->con_id) {
			if (!con_id || strcmp(p->con_id, con_id))
				continue;

			match += 1;
		}

		if (match > best) {
			chosen = p;

			if (match != 3)
				best = match;
			else
				break;
		}
	}

	mutex_unlock(&pwm_lookup_lock);

	if (!chosen)
		return ERR_PTR(-ENODEV);

	chip = pwmchip_find_by_name(chosen->provider);

	/*
	 * If the lookup entry specifies a module, load the module and retry
	 * the PWM chip lookup. This can be used to work around driver load
	 * ordering issues if driver's can't be made to properly support the
	 * deferred probe mechanism.
	 */
	if (!chip && chosen->module) {
		err = request_module(chosen->module);
		if (err == 0)
			chip = pwmchip_find_by_name(chosen->provider);
	}

	if (!chip)
		return ERR_PTR(-EPROBE_DEFER);

	pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
	if (IS_ERR(pwm))
		return pwm;

	dl = pwm_device_link_add(dev, pwm);
	if (IS_ERR(dl)) {
		pwm_put(pwm);
		return ERR_CAST(dl);
	}

	pwm->args.period = chosen->period;
	pwm->args.polarity = chosen->polarity;

	return pwm;
}
EXPORT_SYMBOL_GPL(pwm_get);

/**
 * pwm_put() - release a PWM device
 * @pwm: PWM device
 */
void pwm_put(struct pwm_device *pwm)
{
	if (!pwm)
		return;

	mutex_lock(&pwm_lock);

	if (!test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
		pr_warn("PWM device already freed\n");
		goto out;
	}

	if (pwm->chip->ops->free)
		pwm->chip->ops->free(pwm->chip, pwm);

	pwm->label = NULL;

	module_put(pwm->chip->owner);
out:
	mutex_unlock(&pwm_lock);
}
EXPORT_SYMBOL_GPL(pwm_put);

static void devm_pwm_release(void *pwm)
{
	pwm_put(pwm);
}

/**
 * devm_pwm_get() - resource managed pwm_get()
 * @dev: device for PWM consumer
 * @con_id: consumer name
 *
 * This function performs like pwm_get() but the acquired PWM device will
 * automatically be released on driver detach.
 *
 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
 * error code on failure.
 */
struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
{
	struct pwm_device *pwm;
	int ret;

	pwm = pwm_get(dev, con_id);
	if (IS_ERR(pwm))
		return pwm;

	ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
	if (ret)
		return ERR_PTR(ret);

	return pwm;
}
EXPORT_SYMBOL_GPL(devm_pwm_get);

/**
 * devm_fwnode_pwm_get() - request a resource managed PWM from firmware node
 * @dev: device for PWM consumer
 * @fwnode: firmware node to get the PWM from
 * @con_id: consumer name
 *
 * Returns the PWM device parsed from the firmware node. See of_pwm_get() and
 * acpi_pwm_get() for a detailed description.
 *
 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
 * error code on failure.
 */
struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
				       struct fwnode_handle *fwnode,
				       const char *con_id)
{
	struct pwm_device *pwm = ERR_PTR(-ENODEV);
	int ret;

	if (is_of_node(fwnode))
		pwm = of_pwm_get(dev, to_of_node(fwnode), con_id);
	else if (is_acpi_node(fwnode))
		pwm = acpi_pwm_get(fwnode);
	if (IS_ERR(pwm))
		return pwm;

	ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
	if (ret)
		return ERR_PTR(ret);

	return pwm;
}
EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get);

#ifdef CONFIG_DEBUG_FS
static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
{
	unsigned int i;

	for (i = 0; i < chip->npwm; i++) {
		struct pwm_device *pwm = &chip->pwms[i];
		struct pwm_state state;

		pwm_get_state(pwm, &state);

		seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);

		if (test_bit(PWMF_REQUESTED, &pwm->flags))
			seq_puts(s, " requested");

		if (state.enabled)
			seq_puts(s, " enabled");

		seq_printf(s, " period: %llu ns", state.period);
		seq_printf(s, " duty: %llu ns", state.duty_cycle);
		seq_printf(s, " polarity: %s",
			   state.polarity ? "inverse" : "normal");

		if (state.usage_power)
			seq_puts(s, " usage_power");

		seq_puts(s, "\n");
	}
}

static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
{
	unsigned long id = *pos;
	void *ret;

	mutex_lock(&pwm_lock);
	s->private = "";

	ret = idr_get_next_ul(&pwm_chips, &id);
	*pos = id;
	return ret;
}

static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
	unsigned long id = *pos + 1;
	void *ret;

	s->private = "\n";

	ret = idr_get_next_ul(&pwm_chips, &id);
	*pos = id;
	return ret;
}

static void pwm_seq_stop(struct seq_file *s, void *v)
{
	mutex_unlock(&pwm_lock);
}

static int pwm_seq_show(struct seq_file *s, void *v)
{
	struct pwm_chip *chip = v;

	seq_printf(s, "%s%d: %s/%s, %d PWM device%s\n",
		   (char *)s->private, chip->id,
		   pwmchip_parent(chip)->bus ? pwmchip_parent(chip)->bus->name : "no-bus",
		   dev_name(pwmchip_parent(chip)), chip->npwm,
		   (chip->npwm != 1) ? "s" : "");

	pwm_dbg_show(chip, s);

	return 0;
}

static const struct seq_operations pwm_debugfs_sops = {
	.start = pwm_seq_start,
	.next = pwm_seq_next,
	.stop = pwm_seq_stop,
	.show = pwm_seq_show,
};

DEFINE_SEQ_ATTRIBUTE(pwm_debugfs);

static int __init pwm_debugfs_init(void)
{
	debugfs_create_file("pwm", 0444, NULL, NULL, &pwm_debugfs_fops);

	return 0;
}
subsys_initcall(pwm_debugfs_init);
#endif /* CONFIG_DEBUG_FS */