summaryrefslogtreecommitdiff
path: root/include/linux/clk.h
blob: 1dcee6d701e439f35effd86ca3ee3b47a9839bd0 (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
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
/* SPDX-License-Identifier: GPL-2.0-only */
/*
 *  linux/include/linux/clk.h
 *
 *  Copyright (C) 2004 ARM Limited.
 *  Written by Deep Blue Solutions Limited.
 *  Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
 */
#ifndef __LINUX_CLK_H
#define __LINUX_CLK_H

#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/notifier.h>

struct device;
struct clk;
struct device_node;
struct of_phandle_args;

/**
 * DOC: clk notifier callback types
 *
 * PRE_RATE_CHANGE - called immediately before the clk rate is changed,
 *     to indicate that the rate change will proceed.  Drivers must
 *     immediately terminate any operations that will be affected by the
 *     rate change.  Callbacks may either return NOTIFY_DONE, NOTIFY_OK,
 *     NOTIFY_STOP or NOTIFY_BAD.
 *
 * ABORT_RATE_CHANGE: called if the rate change failed for some reason
 *     after PRE_RATE_CHANGE.  In this case, all registered notifiers on
 *     the clk will be called with ABORT_RATE_CHANGE. Callbacks must
 *     always return NOTIFY_DONE or NOTIFY_OK.
 *
 * POST_RATE_CHANGE - called after the clk rate change has successfully
 *     completed.  Callbacks must always return NOTIFY_DONE or NOTIFY_OK.
 *
 */
#define PRE_RATE_CHANGE			BIT(0)
#define POST_RATE_CHANGE		BIT(1)
#define ABORT_RATE_CHANGE		BIT(2)

/**
 * struct clk_notifier - associate a clk with a notifier
 * @clk: struct clk * to associate the notifier with
 * @notifier_head: a blocking_notifier_head for this clk
 * @node: linked list pointers
 *
 * A list of struct clk_notifier is maintained by the notifier code.
 * An entry is created whenever code registers the first notifier on a
 * particular @clk.  Future notifiers on that @clk are added to the
 * @notifier_head.
 */
struct clk_notifier {
	struct clk			*clk;
	struct srcu_notifier_head	notifier_head;
	struct list_head		node;
};

/**
 * struct clk_notifier_data - rate data to pass to the notifier callback
 * @clk: struct clk * being changed
 * @old_rate: previous rate of this clk
 * @new_rate: new rate of this clk
 *
 * For a pre-notifier, old_rate is the clk's rate before this rate
 * change, and new_rate is what the rate will be in the future.  For a
 * post-notifier, old_rate and new_rate are both set to the clk's
 * current rate (this was done to optimize the implementation).
 */
struct clk_notifier_data {
	struct clk		*clk;
	unsigned long		old_rate;
	unsigned long		new_rate;
};

/**
 * struct clk_bulk_data - Data used for bulk clk operations.
 *
 * @id: clock consumer ID
 * @clk: struct clk * to store the associated clock
 *
 * The CLK APIs provide a series of clk_bulk_() API calls as
 * a convenience to consumers which require multiple clks.  This
 * structure is used to manage data for these calls.
 */
struct clk_bulk_data {
	const char		*id;
	struct clk		*clk;
};

#ifdef CONFIG_COMMON_CLK

/**
 * clk_notifier_register - register a clock rate-change notifier callback
 * @clk: clock whose rate we are interested in
 * @nb: notifier block with callback function pointer
 *
 * ProTip: debugging across notifier chains can be frustrating. Make sure that
 * your notifier callback function prints a nice big warning in case of
 * failure.
 */
int clk_notifier_register(struct clk *clk, struct notifier_block *nb);

/**
 * clk_notifier_unregister - unregister a clock rate-change notifier callback
 * @clk: clock whose rate we are no longer interested in
 * @nb: notifier block which will be unregistered
 */
int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb);

/**
 * devm_clk_notifier_register - register a managed rate-change notifier callback
 * @dev: device for clock "consumer"
 * @clk: clock whose rate we are interested in
 * @nb: notifier block with callback function pointer
 *
 * Returns 0 on success, -EERROR otherwise
 */
int devm_clk_notifier_register(struct device *dev, struct clk *clk,
			       struct notifier_block *nb);

/**
 * clk_get_accuracy - obtain the clock accuracy in ppb (parts per billion)
 *		      for a clock source.
 * @clk: clock source
 *
 * This gets the clock source accuracy expressed in ppb.
 * A perfect clock returns 0.
 */
long clk_get_accuracy(struct clk *clk);

/**
 * clk_set_phase - adjust the phase shift of a clock signal
 * @clk: clock signal source
 * @degrees: number of degrees the signal is shifted
 *
 * Shifts the phase of a clock signal by the specified degrees. Returns 0 on
 * success, -EERROR otherwise.
 */
int clk_set_phase(struct clk *clk, int degrees);

/**
 * clk_get_phase - return the phase shift of a clock signal
 * @clk: clock signal source
 *
 * Returns the phase shift of a clock node in degrees, otherwise returns
 * -EERROR.
 */
int clk_get_phase(struct clk *clk);

/**
 * clk_set_duty_cycle - adjust the duty cycle ratio of a clock signal
 * @clk: clock signal source
 * @num: numerator of the duty cycle ratio to be applied
 * @den: denominator of the duty cycle ratio to be applied
 *
 * Adjust the duty cycle of a clock signal by the specified ratio. Returns 0 on
 * success, -EERROR otherwise.
 */
int clk_set_duty_cycle(struct clk *clk, unsigned int num, unsigned int den);

/**
 * clk_get_scaled_duty_cycle - return the duty cycle ratio of a clock signal
 * @clk: clock signal source
 * @scale: scaling factor to be applied to represent the ratio as an integer
 *
 * Returns the duty cycle ratio multiplied by the scale provided, otherwise
 * returns -EERROR.
 */
int clk_get_scaled_duty_cycle(struct clk *clk, unsigned int scale);

/**
 * clk_is_match - check if two clk's point to the same hardware clock
 * @p: clk compared against q
 * @q: clk compared against p
 *
 * Returns true if the two struct clk pointers both point to the same hardware
 * clock node. Put differently, returns true if @p and @q
 * share the same &struct clk_core object.
 *
 * Returns false otherwise. Note that two NULL clks are treated as matching.
 */
bool clk_is_match(const struct clk *p, const struct clk *q);

/**
 * clk_rate_exclusive_get - get exclusivity over the rate control of a
 *                          producer
 * @clk: clock source
 *
 * This function allows drivers to get exclusive control over the rate of a
 * provider. It prevents any other consumer to execute, even indirectly,
 * opereation which could alter the rate of the provider or cause glitches
 *
 * If exlusivity is claimed more than once on clock, even by the same driver,
 * the rate effectively gets locked as exclusivity can't be preempted.
 *
 * Must not be called from within atomic context.
 *
 * Returns success (0) or negative errno.
 */
int clk_rate_exclusive_get(struct clk *clk);

/**
 * devm_clk_rate_exclusive_get - devm variant of clk_rate_exclusive_get
 * @dev: device the exclusivity is bound to
 * @clk: clock source
 *
 * Calls clk_rate_exclusive_get() on @clk and registers a devm cleanup handler
 * on @dev to call clk_rate_exclusive_put().
 *
 * Must not be called from within atomic context.
 */
int devm_clk_rate_exclusive_get(struct device *dev, struct clk *clk);

/**
 * clk_rate_exclusive_put - release exclusivity over the rate control of a
 *                          producer
 * @clk: clock source
 *
 * This function allows drivers to release the exclusivity it previously got
 * from clk_rate_exclusive_get()
 *
 * The caller must balance the number of clk_rate_exclusive_get() and
 * clk_rate_exclusive_put() calls.
 *
 * Must not be called from within atomic context.
 */
void clk_rate_exclusive_put(struct clk *clk);

#else

static inline int clk_notifier_register(struct clk *clk,
					struct notifier_block *nb)
{
	return -ENOTSUPP;
}

static inline int clk_notifier_unregister(struct clk *clk,
					  struct notifier_block *nb)
{
	return -ENOTSUPP;
}

static inline int devm_clk_notifier_register(struct device *dev,
					     struct clk *clk,
					     struct notifier_block *nb)
{
	return -ENOTSUPP;
}

static inline long clk_get_accuracy(struct clk *clk)
{
	return -ENOTSUPP;
}

static inline long clk_set_phase(struct clk *clk, int phase)
{
	return -ENOTSUPP;
}

static inline long clk_get_phase(struct clk *clk)
{
	return -ENOTSUPP;
}

static inline int clk_set_duty_cycle(struct clk *clk, unsigned int num,
				     unsigned int den)
{
	return -ENOTSUPP;
}

static inline unsigned int clk_get_scaled_duty_cycle(struct clk *clk,
						     unsigned int scale)
{
	return 0;
}

static inline bool clk_is_match(const struct clk *p, const struct clk *q)
{
	return p == q;
}

static inline int clk_rate_exclusive_get(struct clk *clk)
{
	return 0;
}

static inline int devm_clk_rate_exclusive_get(struct device *dev, struct clk *clk)
{
	return 0;
}

static inline void clk_rate_exclusive_put(struct clk *clk) {}

#endif

#ifdef CONFIG_HAVE_CLK_PREPARE
/**
 * clk_prepare - prepare a clock source
 * @clk: clock source
 *
 * This prepares the clock source for use.
 *
 * Must not be called from within atomic context.
 */
int clk_prepare(struct clk *clk);
int __must_check clk_bulk_prepare(int num_clks,
				  const struct clk_bulk_data *clks);

/**
 * clk_is_enabled_when_prepared - indicate if preparing a clock also enables it.
 * @clk: clock source
 *
 * Returns true if clk_prepare() implicitly enables the clock, effectively
 * making clk_enable()/clk_disable() no-ops, false otherwise.
 *
 * This is of interest mainly to the power management code where actually
 * disabling the clock also requires unpreparing it to have any material
 * effect.
 *
 * Regardless of the value returned here, the caller must always invoke
 * clk_enable() or clk_prepare_enable()  and counterparts for usage counts
 * to be right.
 */
bool clk_is_enabled_when_prepared(struct clk *clk);
#else
static inline int clk_prepare(struct clk *clk)
{
	might_sleep();
	return 0;
}

static inline int __must_check
clk_bulk_prepare(int num_clks, const struct clk_bulk_data *clks)
{
	might_sleep();
	return 0;
}

static inline bool clk_is_enabled_when_prepared(struct clk *clk)
{
	return false;
}
#endif

/**
 * clk_unprepare - undo preparation of a clock source
 * @clk: clock source
 *
 * This undoes a previously prepared clock.  The caller must balance
 * the number of prepare and unprepare calls.
 *
 * Must not be called from within atomic context.
 */
#ifdef CONFIG_HAVE_CLK_PREPARE
void clk_unprepare(struct clk *clk);
void clk_bulk_unprepare(int num_clks, const struct clk_bulk_data *clks);
#else
static inline void clk_unprepare(struct clk *clk)
{
	might_sleep();
}
static inline void clk_bulk_unprepare(int num_clks,
				      const struct clk_bulk_data *clks)
{
	might_sleep();
}
#endif

#ifdef CONFIG_HAVE_CLK
/**
 * clk_get - lookup and obtain a reference to a clock producer.
 * @dev: device for clock "consumer"
 * @id: clock consumer ID
 *
 * Returns a struct clk corresponding to the clock producer, or
 * valid IS_ERR() condition containing errno.  The implementation
 * uses @dev and @id to determine the clock consumer, and thereby
 * the clock producer.  (IOW, @id may be identical strings, but
 * clk_get may return different clock producers depending on @dev.)
 *
 * Drivers must assume that the clock source is not enabled.
 *
 * clk_get should not be called from within interrupt context.
 */
struct clk *clk_get(struct device *dev, const char *id);

/**
 * clk_bulk_get - lookup and obtain a number of references to clock producer.
 * @dev: device for clock "consumer"
 * @num_clks: the number of clk_bulk_data
 * @clks: the clk_bulk_data table of consumer
 *
 * This helper function allows drivers to get several clk consumers in one
 * operation. If any of the clk cannot be acquired then any clks
 * that were obtained will be freed before returning to the caller.
 *
 * Returns 0 if all clocks specified in clk_bulk_data table are obtained
 * successfully, or valid IS_ERR() condition containing errno.
 * The implementation uses @dev and @clk_bulk_data.id to determine the
 * clock consumer, and thereby the clock producer.
 * The clock returned is stored in each @clk_bulk_data.clk field.
 *
 * Drivers must assume that the clock source is not enabled.
 *
 * clk_bulk_get should not be called from within interrupt context.
 */
int __must_check clk_bulk_get(struct device *dev, int num_clks,
			      struct clk_bulk_data *clks);
/**
 * clk_bulk_get_all - lookup and obtain all available references to clock
 *		      producer.
 * @dev: device for clock "consumer"
 * @clks: pointer to the clk_bulk_data table of consumer
 *
 * This helper function allows drivers to get all clk consumers in one
 * operation. If any of the clk cannot be acquired then any clks
 * that were obtained will be freed before returning to the caller.
 *
 * Returns a positive value for the number of clocks obtained while the
 * clock references are stored in the clk_bulk_data table in @clks field.
 * Returns 0 if there're none and a negative value if something failed.
 *
 * Drivers must assume that the clock source is not enabled.
 *
 * clk_bulk_get should not be called from within interrupt context.
 */
int __must_check clk_bulk_get_all(struct device *dev,
				  struct clk_bulk_data **clks);

/**
 * clk_bulk_get_optional - lookup and obtain a number of references to clock producer
 * @dev: device for clock "consumer"
 * @num_clks: the number of clk_bulk_data
 * @clks: the clk_bulk_data table of consumer
 *
 * Behaves the same as clk_bulk_get() except where there is no clock producer.
 * In this case, instead of returning -ENOENT, the function returns 0 and
 * NULL for a clk for which a clock producer could not be determined.
 */
int __must_check clk_bulk_get_optional(struct device *dev, int num_clks,
				       struct clk_bulk_data *clks);
/**
 * devm_clk_bulk_get - managed get multiple clk consumers
 * @dev: device for clock "consumer"
 * @num_clks: the number of clk_bulk_data
 * @clks: the clk_bulk_data table of consumer
 *
 * Return 0 on success, an errno on failure.
 *
 * This helper function allows drivers to get several clk
 * consumers in one operation with management, the clks will
 * automatically be freed when the device is unbound.
 */
int __must_check devm_clk_bulk_get(struct device *dev, int num_clks,
				   struct clk_bulk_data *clks);
/**
 * devm_clk_bulk_get_optional - managed get multiple optional consumer clocks
 * @dev: device for clock "consumer"
 * @num_clks: the number of clk_bulk_data
 * @clks: pointer to the clk_bulk_data table of consumer
 *
 * Behaves the same as devm_clk_bulk_get() except where there is no clock
 * producer.  In this case, instead of returning -ENOENT, the function returns
 * NULL for given clk. It is assumed all clocks in clk_bulk_data are optional.
 *
 * Returns 0 if all clocks specified in clk_bulk_data table are obtained
 * successfully or for any clk there was no clk provider available, otherwise
 * returns valid IS_ERR() condition containing errno.
 * The implementation uses @dev and @clk_bulk_data.id to determine the
 * clock consumer, and thereby the clock producer.
 * The clock returned is stored in each @clk_bulk_data.clk field.
 *
 * Drivers must assume that the clock source is not enabled.
 *
 * clk_bulk_get should not be called from within interrupt context.
 */
int __must_check devm_clk_bulk_get_optional(struct device *dev, int num_clks,
					    struct clk_bulk_data *clks);
/**
 * devm_clk_bulk_get_all - managed get multiple clk consumers
 * @dev: device for clock "consumer"
 * @clks: pointer to the clk_bulk_data table of consumer
 *
 * Returns a positive value for the number of clocks obtained while the
 * clock references are stored in the clk_bulk_data table in @clks field.
 * Returns 0 if there're none and a negative value if something failed.
 *
 * This helper function allows drivers to get several clk
 * consumers in one operation with management, the clks will
 * automatically be freed when the device is unbound.
 */

int __must_check devm_clk_bulk_get_all(struct device *dev,
				       struct clk_bulk_data **clks);

/**
 * devm_clk_bulk_get_all_enabled - Get and enable all clocks of the consumer (managed)
 * @dev: device for clock "consumer"
 * @clks: pointer to the clk_bulk_data table of consumer
 *
 * Returns a positive value for the number of clocks obtained while the
 * clock references are stored in the clk_bulk_data table in @clks field.
 * Returns 0 if there're none and a negative value if something failed.
 *
 * This helper function allows drivers to get all clocks of the
 * consumer and enables them in one operation with management.
 * The clks will automatically be disabled and freed when the device
 * is unbound.
 */

int __must_check devm_clk_bulk_get_all_enabled(struct device *dev,
					       struct clk_bulk_data **clks);

/**
 * devm_clk_get - lookup and obtain a managed reference to a clock producer.
 * @dev: device for clock "consumer"
 * @id: clock consumer ID
 *
 * Context: May sleep.
 *
 * Return: a struct clk corresponding to the clock producer, or
 * valid IS_ERR() condition containing errno.  The implementation
 * uses @dev and @id to determine the clock consumer, and thereby
 * the clock producer.  (IOW, @id may be identical strings, but
 * clk_get may return different clock producers depending on @dev.)
 *
 * Drivers must assume that the clock source is neither prepared nor
 * enabled.
 *
 * The clock will automatically be freed when the device is unbound
 * from the bus.
 */
struct clk *devm_clk_get(struct device *dev, const char *id);

/**
 * devm_clk_get_prepared - devm_clk_get() + clk_prepare()
 * @dev: device for clock "consumer"
 * @id: clock consumer ID
 *
 * Context: May sleep.
 *
 * Return: a struct clk corresponding to the clock producer, or
 * valid IS_ERR() condition containing errno.  The implementation
 * uses @dev and @id to determine the clock consumer, and thereby
 * the clock producer.  (IOW, @id may be identical strings, but
 * clk_get may return different clock producers depending on @dev.)
 *
 * The returned clk (if valid) is prepared. Drivers must however assume
 * that the clock is not enabled.
 *
 * The clock will automatically be unprepared and freed when the device
 * is unbound from the bus.
 */
struct clk *devm_clk_get_prepared(struct device *dev, const char *id);

/**
 * devm_clk_get_enabled - devm_clk_get() + clk_prepare_enable()
 * @dev: device for clock "consumer"
 * @id: clock consumer ID
 *
 * Context: May sleep.
 *
 * Return: a struct clk corresponding to the clock producer, or
 * valid IS_ERR() condition containing errno.  The implementation
 * uses @dev and @id to determine the clock consumer, and thereby
 * the clock producer.  (IOW, @id may be identical strings, but
 * clk_get may return different clock producers depending on @dev.)
 *
 * The returned clk (if valid) is prepared and enabled.
 *
 * The clock will automatically be disabled, unprepared and freed
 * when the device is unbound from the bus.
 */
struct clk *devm_clk_get_enabled(struct device *dev, const char *id);

/**
 * devm_clk_get_optional - lookup and obtain a managed reference to an optional
 *			   clock producer.
 * @dev: device for clock "consumer"
 * @id: clock consumer ID
 *
 * Context: May sleep.
 *
 * Return: a struct clk corresponding to the clock producer, or
 * valid IS_ERR() condition containing errno.  The implementation
 * uses @dev and @id to determine the clock consumer, and thereby
 * the clock producer.  If no such clk is found, it returns NULL
 * which serves as a dummy clk.  That's the only difference compared
 * to devm_clk_get().
 *
 * Drivers must assume that the clock source is neither prepared nor
 * enabled.
 *
 * The clock will automatically be freed when the device is unbound
 * from the bus.
 */
struct clk *devm_clk_get_optional(struct device *dev, const char *id);

/**
 * devm_clk_get_optional_prepared - devm_clk_get_optional() + clk_prepare()
 * @dev: device for clock "consumer"
 * @id: clock consumer ID
 *
 * Context: May sleep.
 *
 * Return: a struct clk corresponding to the clock producer, or
 * valid IS_ERR() condition containing errno.  The implementation
 * uses @dev and @id to determine the clock consumer, and thereby
 * the clock producer.  If no such clk is found, it returns NULL
 * which serves as a dummy clk.  That's the only difference compared
 * to devm_clk_get_prepared().
 *
 * The returned clk (if valid) is prepared. Drivers must however
 * assume that the clock is not enabled.
 *
 * The clock will automatically be unprepared and freed when the
 * device is unbound from the bus.
 */
struct clk *devm_clk_get_optional_prepared(struct device *dev, const char *id);

/**
 * devm_clk_get_optional_enabled - devm_clk_get_optional() +
 *                                 clk_prepare_enable()
 * @dev: device for clock "consumer"
 * @id: clock consumer ID
 *
 * Context: May sleep.
 *
 * Return: a struct clk corresponding to the clock producer, or
 * valid IS_ERR() condition containing errno.  The implementation
 * uses @dev and @id to determine the clock consumer, and thereby
 * the clock producer.  If no such clk is found, it returns NULL
 * which serves as a dummy clk.  That's the only difference compared
 * to devm_clk_get_enabled().
 *
 * The returned clk (if valid) is prepared and enabled.
 *
 * The clock will automatically be disabled, unprepared and freed
 * when the device is unbound from the bus.
 */
struct clk *devm_clk_get_optional_enabled(struct device *dev, const char *id);

/**
 * devm_clk_get_optional_enabled_with_rate - devm_clk_get_optional() +
 *                                           clk_set_rate() +
 *                                           clk_prepare_enable()
 * @dev: device for clock "consumer"
 * @id: clock consumer ID
 * @rate: new clock rate
 *
 * Context: May sleep.
 *
 * Return: a struct clk corresponding to the clock producer, or
 * valid IS_ERR() condition containing errno.  The implementation
 * uses @dev and @id to determine the clock consumer, and thereby
 * the clock producer.  If no such clk is found, it returns NULL
 * which serves as a dummy clk.  That's the only difference compared
 * to devm_clk_get_enabled().
 *
 * The returned clk (if valid) is prepared and enabled and rate was set.
 *
 * The clock will automatically be disabled, unprepared and freed
 * when the device is unbound from the bus.
 */
struct clk *devm_clk_get_optional_enabled_with_rate(struct device *dev,
						    const char *id,
						    unsigned long rate);

/**
 * devm_get_clk_from_child - lookup and obtain a managed reference to a
 *			     clock producer from child node.
 * @dev: device for clock "consumer"
 * @np: pointer to clock consumer node
 * @con_id: clock consumer ID
 *
 * This function parses the clocks, and uses them to look up the
 * struct clk from the registered list of clock providers by using
 * @np and @con_id
 *
 * The clock will automatically be freed when the device is unbound
 * from the bus.
 */
struct clk *devm_get_clk_from_child(struct device *dev,
				    struct device_node *np, const char *con_id);

/**
 * clk_enable - inform the system when the clock source should be running.
 * @clk: clock source
 *
 * If the clock can not be enabled/disabled, this should return success.
 *
 * May be called from atomic contexts.
 *
 * Returns success (0) or negative errno.
 */
int clk_enable(struct clk *clk);

/**
 * clk_bulk_enable - inform the system when the set of clks should be running.
 * @num_clks: the number of clk_bulk_data
 * @clks: the clk_bulk_data table of consumer
 *
 * May be called from atomic contexts.
 *
 * Returns success (0) or negative errno.
 */
int __must_check clk_bulk_enable(int num_clks,
				 const struct clk_bulk_data *clks);

/**
 * clk_disable - inform the system when the clock source is no longer required.
 * @clk: clock source
 *
 * Inform the system that a clock source is no longer required by
 * a driver and may be shut down.
 *
 * May be called from atomic contexts.
 *
 * Implementation detail: if the clock source is shared between
 * multiple drivers, clk_enable() calls must be balanced by the
 * same number of clk_disable() calls for the clock source to be
 * disabled.
 */
void clk_disable(struct clk *clk);

/**
 * clk_bulk_disable - inform the system when the set of clks is no
 *		      longer required.
 * @num_clks: the number of clk_bulk_data
 * @clks: the clk_bulk_data table of consumer
 *
 * Inform the system that a set of clks is no longer required by
 * a driver and may be shut down.
 *
 * May be called from atomic contexts.
 *
 * Implementation detail: if the set of clks is shared between
 * multiple drivers, clk_bulk_enable() calls must be balanced by the
 * same number of clk_bulk_disable() calls for the clock source to be
 * disabled.
 */
void clk_bulk_disable(int num_clks, const struct clk_bulk_data *clks);

/**
 * clk_get_rate - obtain the current clock rate (in Hz) for a clock source.
 *		  This is only valid once the clock source has been enabled.
 * @clk: clock source
 */
unsigned long clk_get_rate(struct clk *clk);

/**
 * clk_put	- "free" the clock source
 * @clk: clock source
 *
 * Note: drivers must ensure that all clk_enable calls made on this
 * clock source are balanced by clk_disable calls prior to calling
 * this function.
 *
 * clk_put should not be called from within interrupt context.
 */
void clk_put(struct clk *clk);

/**
 * clk_bulk_put	- "free" the clock source
 * @num_clks: the number of clk_bulk_data
 * @clks: the clk_bulk_data table of consumer
 *
 * Note: drivers must ensure that all clk_bulk_enable calls made on this
 * clock source are balanced by clk_bulk_disable calls prior to calling
 * this function.
 *
 * clk_bulk_put should not be called from within interrupt context.
 */
void clk_bulk_put(int num_clks, struct clk_bulk_data *clks);

/**
 * clk_bulk_put_all - "free" all the clock source
 * @num_clks: the number of clk_bulk_data
 * @clks: the clk_bulk_data table of consumer
 *
 * Note: drivers must ensure that all clk_bulk_enable calls made on this
 * clock source are balanced by clk_bulk_disable calls prior to calling
 * this function.
 *
 * clk_bulk_put_all should not be called from within interrupt context.
 */
void clk_bulk_put_all(int num_clks, struct clk_bulk_data *clks);

/**
 * devm_clk_put	- "free" a managed clock source
 * @dev: device used to acquire the clock
 * @clk: clock source acquired with devm_clk_get()
 *
 * Note: drivers must ensure that all clk_enable calls made on this
 * clock source are balanced by clk_disable calls prior to calling
 * this function.
 *
 * clk_put should not be called from within interrupt context.
 */
void devm_clk_put(struct device *dev, struct clk *clk);

/*
 * The remaining APIs are optional for machine class support.
 */


/**
 * clk_round_rate - adjust a rate to the exact rate a clock can provide
 * @clk: clock source
 * @rate: desired clock rate in Hz
 *
 * This answers the question "if I were to pass @rate to clk_set_rate(),
 * what clock rate would I end up with?" without changing the hardware
 * in any way.  In other words:
 *
 *   rate = clk_round_rate(clk, r);
 *
 * and:
 *
 *   clk_set_rate(clk, r);
 *   rate = clk_get_rate(clk);
 *
 * are equivalent except the former does not modify the clock hardware
 * in any way.
 *
 * Returns rounded clock rate in Hz, or negative errno.
 */
long clk_round_rate(struct clk *clk, unsigned long rate);

/**
 * clk_set_rate - set the clock rate for a clock source
 * @clk: clock source
 * @rate: desired clock rate in Hz
 *
 * Updating the rate starts at the top-most affected clock and then
 * walks the tree down to the bottom-most clock that needs updating.
 *
 * Returns success (0) or negative errno.
 */
int clk_set_rate(struct clk *clk, unsigned long rate);

/**
 * clk_set_rate_exclusive- set the clock rate and claim exclusivity over
 *                         clock source
 * @clk: clock source
 * @rate: desired clock rate in Hz
 *
 * This helper function allows drivers to atomically set the rate of a producer
 * and claim exclusivity over the rate control of the producer.
 *
 * It is essentially a combination of clk_set_rate() and
 * clk_rate_exclusite_get(). Caller must balance this call with a call to
 * clk_rate_exclusive_put()
 *
 * Returns success (0) or negative errno.
 */
int clk_set_rate_exclusive(struct clk *clk, unsigned long rate);

/**
 * clk_has_parent - check if a clock is a possible parent for another
 * @clk: clock source
 * @parent: parent clock source
 *
 * This function can be used in drivers that need to check that a clock can be
 * the parent of another without actually changing the parent.
 *
 * Returns true if @parent is a possible parent for @clk, false otherwise.
 */
bool clk_has_parent(const struct clk *clk, const struct clk *parent);

/**
 * clk_set_rate_range - set a rate range for a clock source
 * @clk: clock source
 * @min: desired minimum clock rate in Hz, inclusive
 * @max: desired maximum clock rate in Hz, inclusive
 *
 * Returns success (0) or negative errno.
 */
int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max);

/**
 * clk_set_min_rate - set a minimum clock rate for a clock source
 * @clk: clock source
 * @rate: desired minimum clock rate in Hz, inclusive
 *
 * Returns success (0) or negative errno.
 */
int clk_set_min_rate(struct clk *clk, unsigned long rate);

/**
 * clk_set_max_rate - set a maximum clock rate for a clock source
 * @clk: clock source
 * @rate: desired maximum clock rate in Hz, inclusive
 *
 * Returns success (0) or negative errno.
 */
int clk_set_max_rate(struct clk *clk, unsigned long rate);

/**
 * clk_set_parent - set the parent clock source for this clock
 * @clk: clock source
 * @parent: parent clock source
 *
 * Returns success (0) or negative errno.
 */
int clk_set_parent(struct clk *clk, struct clk *parent);

/**
 * clk_get_parent - get the parent clock source for this clock
 * @clk: clock source
 *
 * Returns struct clk corresponding to parent clock source, or
 * valid IS_ERR() condition containing errno.
 */
struct clk *clk_get_parent(struct clk *clk);

/**
 * clk_get_sys - get a clock based upon the device name
 * @dev_id: device name
 * @con_id: connection ID
 *
 * Returns a struct clk corresponding to the clock producer, or
 * valid IS_ERR() condition containing errno.  The implementation
 * uses @dev_id and @con_id to determine the clock consumer, and
 * thereby the clock producer. In contrast to clk_get() this function
 * takes the device name instead of the device itself for identification.
 *
 * Drivers must assume that the clock source is not enabled.
 *
 * clk_get_sys should not be called from within interrupt context.
 */
struct clk *clk_get_sys(const char *dev_id, const char *con_id);

/**
 * clk_save_context - save clock context for poweroff
 *
 * Saves the context of the clock register for powerstates in which the
 * contents of the registers will be lost. Occurs deep within the suspend
 * code so locking is not necessary.
 */
int clk_save_context(void);

/**
 * clk_restore_context - restore clock context after poweroff
 *
 * This occurs with all clocks enabled. Occurs deep within the resume code
 * so locking is not necessary.
 */
void clk_restore_context(void);

#else /* !CONFIG_HAVE_CLK */

static inline struct clk *clk_get(struct device *dev, const char *id)
{
	return NULL;
}

static inline int __must_check clk_bulk_get(struct device *dev, int num_clks,
					    struct clk_bulk_data *clks)
{
	return 0;
}

static inline int __must_check clk_bulk_get_optional(struct device *dev,
				int num_clks, struct clk_bulk_data *clks)
{
	return 0;
}

static inline int __must_check clk_bulk_get_all(struct device *dev,
					 struct clk_bulk_data **clks)
{
	return 0;
}

static inline struct clk *devm_clk_get(struct device *dev, const char *id)
{
	return NULL;
}

static inline struct clk *devm_clk_get_prepared(struct device *dev,
						const char *id)
{
	return NULL;
}

static inline struct clk *devm_clk_get_enabled(struct device *dev,
					       const char *id)
{
	return NULL;
}

static inline struct clk *devm_clk_get_optional(struct device *dev,
						const char *id)
{
	return NULL;
}

static inline struct clk *devm_clk_get_optional_prepared(struct device *dev,
							 const char *id)
{
	return NULL;
}

static inline struct clk *devm_clk_get_optional_enabled(struct device *dev,
							const char *id)
{
	return NULL;
}

static inline struct clk *
devm_clk_get_optional_enabled_with_rate(struct device *dev, const char *id,
					unsigned long rate)
{
	return NULL;
}

static inline int __must_check devm_clk_bulk_get(struct device *dev, int num_clks,
						 struct clk_bulk_data *clks)
{
	return 0;
}

static inline int __must_check devm_clk_bulk_get_optional(struct device *dev,
				int num_clks, struct clk_bulk_data *clks)
{
	return 0;
}

static inline int __must_check devm_clk_bulk_get_all(struct device *dev,
						     struct clk_bulk_data **clks)
{

	return 0;
}

static inline int __must_check devm_clk_bulk_get_all_enabled(struct device *dev,
						struct clk_bulk_data **clks)
{
	return 0;
}

static inline struct clk *devm_get_clk_from_child(struct device *dev,
				struct device_node *np, const char *con_id)
{
	return NULL;
}

static inline void clk_put(struct clk *clk) {}

static inline void clk_bulk_put(int num_clks, struct clk_bulk_data *clks) {}

static inline void clk_bulk_put_all(int num_clks, struct clk_bulk_data *clks) {}

static inline void devm_clk_put(struct device *dev, struct clk *clk) {}

static inline int clk_enable(struct clk *clk)
{
	return 0;
}

static inline int __must_check clk_bulk_enable(int num_clks,
					       const struct clk_bulk_data *clks)
{
	return 0;
}

static inline void clk_disable(struct clk *clk) {}


static inline void clk_bulk_disable(int num_clks,
				    const struct clk_bulk_data *clks) {}

static inline unsigned long clk_get_rate(struct clk *clk)
{
	return 0;
}

static inline int clk_set_rate(struct clk *clk, unsigned long rate)
{
	return 0;
}

static inline int clk_set_rate_exclusive(struct clk *clk, unsigned long rate)
{
	return 0;
}

static inline long clk_round_rate(struct clk *clk, unsigned long rate)
{
	return 0;
}

static inline bool clk_has_parent(struct clk *clk, struct clk *parent)
{
	return true;
}

static inline int clk_set_rate_range(struct clk *clk, unsigned long min,
				     unsigned long max)
{
	return 0;
}

static inline int clk_set_min_rate(struct clk *clk, unsigned long rate)
{
	return 0;
}

static inline int clk_set_max_rate(struct clk *clk, unsigned long rate)
{
	return 0;
}

static inline int clk_set_parent(struct clk *clk, struct clk *parent)
{
	return 0;
}

static inline struct clk *clk_get_parent(struct clk *clk)
{
	return NULL;
}

static inline struct clk *clk_get_sys(const char *dev_id, const char *con_id)
{
	return NULL;
}

static inline int clk_save_context(void)
{
	return 0;
}

static inline void clk_restore_context(void) {}

#endif

/* Deprecated. Use devm_clk_bulk_get_all_enabled() */
static inline int __must_check
devm_clk_bulk_get_all_enable(struct device *dev, struct clk_bulk_data **clks)
{
	int ret = devm_clk_bulk_get_all_enabled(dev, clks);

	return ret > 0 ? 0 : ret;
}

/* clk_prepare_enable helps cases using clk_enable in non-atomic context. */
static inline int clk_prepare_enable(struct clk *clk)
{
	int ret;

	ret = clk_prepare(clk);
	if (ret)
		return ret;
	ret = clk_enable(clk);
	if (ret)
		clk_unprepare(clk);

	return ret;
}

/* clk_disable_unprepare helps cases using clk_disable in non-atomic context. */
static inline void clk_disable_unprepare(struct clk *clk)
{
	clk_disable(clk);
	clk_unprepare(clk);
}

static inline int __must_check
clk_bulk_prepare_enable(int num_clks, const struct clk_bulk_data *clks)
{
	int ret;

	ret = clk_bulk_prepare(num_clks, clks);
	if (ret)
		return ret;
	ret = clk_bulk_enable(num_clks, clks);
	if (ret)
		clk_bulk_unprepare(num_clks, clks);

	return ret;
}

static inline void clk_bulk_disable_unprepare(int num_clks,
					      const struct clk_bulk_data *clks)
{
	clk_bulk_disable(num_clks, clks);
	clk_bulk_unprepare(num_clks, clks);
}

/**
 * clk_drop_range - Reset any range set on that clock
 * @clk: clock source
 *
 * Returns success (0) or negative errno.
 */
static inline int clk_drop_range(struct clk *clk)
{
	return clk_set_rate_range(clk, 0, ULONG_MAX);
}

/**
 * clk_get_optional - lookup and obtain a reference to an optional clock
 *		      producer.
 * @dev: device for clock "consumer"
 * @id: clock consumer ID
 *
 * Behaves the same as clk_get() except where there is no clock producer. In
 * this case, instead of returning -ENOENT, the function returns NULL.
 */
static inline struct clk *clk_get_optional(struct device *dev, const char *id)
{
	struct clk *clk = clk_get(dev, id);

	if (clk == ERR_PTR(-ENOENT))
		return NULL;

	return clk;
}

#if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK)
struct clk *of_clk_get(struct device_node *np, int index);
struct clk *of_clk_get_by_name(struct device_node *np, const char *name);
struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec);
#else
static inline struct clk *of_clk_get(struct device_node *np, int index)
{
	return ERR_PTR(-ENOENT);
}
static inline struct clk *of_clk_get_by_name(struct device_node *np,
					     const char *name)
{
	return ERR_PTR(-ENOENT);
}
static inline struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
{
	return ERR_PTR(-ENOENT);
}
#endif

#endif