aboutsummaryrefslogtreecommitdiffstatshomepage
path: root/include/media/v4l2-ctrls.h
blob: f40e2cbb21d344f99dc6bf2feef23422968804ad (plain) (blame)
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
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 *  V4L2 controls support header.
 *
 *  Copyright (C) 2010  Hans Verkuil <hverkuil@xs4all.nl>
 */

#ifndef _V4L2_CTRLS_H
#define _V4L2_CTRLS_H

#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/videodev2.h>
#include <media/media-request.h>

/*
 * Include the stateless codec compound control definitions.
 * This will move to the public headers once this API is fully stable.
 */
#include <media/mpeg2-ctrls.h>
#include <media/fwht-ctrls.h>
#include <media/h264-ctrls.h>
#include <media/vp8-ctrls.h>
#include <media/hevc-ctrls.h>

/* forward references */
struct file;
struct poll_table_struct;
struct v4l2_ctrl;
struct v4l2_ctrl_handler;
struct v4l2_ctrl_helper;
struct v4l2_fh;
struct v4l2_fwnode_device_properties;
struct v4l2_subdev;
struct v4l2_subscribed_event;
struct video_device;

/**
 * union v4l2_ctrl_ptr - A pointer to a control value.
 * @p_s32:			Pointer to a 32-bit signed value.
 * @p_s64:			Pointer to a 64-bit signed value.
 * @p_u8:			Pointer to a 8-bit unsigned value.
 * @p_u16:			Pointer to a 16-bit unsigned value.
 * @p_u32:			Pointer to a 32-bit unsigned value.
 * @p_char:			Pointer to a string.
 * @p_mpeg2_slice_params:	Pointer to a MPEG2 slice parameters structure.
 * @p_mpeg2_quantization:	Pointer to a MPEG2 quantization data structure.
 * @p_fwht_params:		Pointer to a FWHT stateless parameters structure.
 * @p_h264_sps:			Pointer to a struct v4l2_ctrl_h264_sps.
 * @p_h264_pps:			Pointer to a struct v4l2_ctrl_h264_pps.
 * @p_h264_scaling_matrix:	Pointer to a struct v4l2_ctrl_h264_scaling_matrix.
 * @p_h264_slice_params:	Pointer to a struct v4l2_ctrl_h264_slice_params.
 * @p_h264_decode_params:	Pointer to a struct v4l2_ctrl_h264_decode_params.
 * @p_vp8_frame_header:		Pointer to a VP8 frame header structure.
 * @p_hevc_sps:			Pointer to an HEVC sequence parameter set structure.
 * @p_hevc_pps:			Pointer to an HEVC picture parameter set structure.
 * @p_hevc_slice_params:	Pointer to an HEVC slice parameters structure.
 * @p_area:			Pointer to an area.
 * @p:				Pointer to a compound value.
 * @p_const:			Pointer to a constant compound value.
 */
union v4l2_ctrl_ptr {
	s32 *p_s32;
	s64 *p_s64;
	u8 *p_u8;
	u16 *p_u16;
	u32 *p_u32;
	char *p_char;
	struct v4l2_ctrl_mpeg2_slice_params *p_mpeg2_slice_params;
	struct v4l2_ctrl_mpeg2_quantization *p_mpeg2_quantization;
	struct v4l2_ctrl_fwht_params *p_fwht_params;
	struct v4l2_ctrl_h264_sps *p_h264_sps;
	struct v4l2_ctrl_h264_pps *p_h264_pps;
	struct v4l2_ctrl_h264_scaling_matrix *p_h264_scaling_matrix;
	struct v4l2_ctrl_h264_slice_params *p_h264_slice_params;
	struct v4l2_ctrl_h264_decode_params *p_h264_decode_params;
	struct v4l2_ctrl_vp8_frame_header *p_vp8_frame_header;
	struct v4l2_ctrl_hevc_sps *p_hevc_sps;
	struct v4l2_ctrl_hevc_pps *p_hevc_pps;
	struct v4l2_ctrl_hevc_slice_params *p_hevc_slice_params;
	struct v4l2_area *p_area;
	void *p;
	const void *p_const;
};

/**
 * v4l2_ctrl_ptr_create() - Helper function to return a v4l2_ctrl_ptr from a
 * void pointer
 * @ptr:	The void pointer
 */
static inline union v4l2_ctrl_ptr v4l2_ctrl_ptr_create(void *ptr)
{
	union v4l2_ctrl_ptr p = { .p = ptr };

	return p;
}

/**
 * struct v4l2_ctrl_ops - The control operations that the driver has to provide.
 *
 * @g_volatile_ctrl: Get a new value for this control. Generally only relevant
 *		for volatile (and usually read-only) controls such as a control
 *		that returns the current signal strength which changes
 *		continuously.
 *		If not set, then the currently cached value will be returned.
 * @try_ctrl:	Test whether the control's value is valid. Only relevant when
 *		the usual min/max/step checks are not sufficient.
 * @s_ctrl:	Actually set the new control value. s_ctrl is compulsory. The
 *		ctrl->handler->lock is held when these ops are called, so no
 *		one else can access controls owned by that handler.
 */
struct v4l2_ctrl_ops {
	int (*g_volatile_ctrl)(struct v4l2_ctrl *ctrl);
	int (*try_ctrl)(struct v4l2_ctrl *ctrl);
	int (*s_ctrl)(struct v4l2_ctrl *ctrl);
};

/**
 * struct v4l2_ctrl_type_ops - The control type operations that the driver
 *			       has to provide.
 *
 * @equal: return true if both values are equal.
 * @init: initialize the value.
 * @log: log the value.
 * @validate: validate the value. Return 0 on success and a negative value
 *	otherwise.
 */
struct v4l2_ctrl_type_ops {
	bool (*equal)(const struct v4l2_ctrl *ctrl, u32 idx,
		      union v4l2_ctrl_ptr ptr1,
		      union v4l2_ctrl_ptr ptr2);
	void (*init)(const struct v4l2_ctrl *ctrl, u32 idx,
		     union v4l2_ctrl_ptr ptr);
	void (*log)(const struct v4l2_ctrl *ctrl);
	int (*validate)(const struct v4l2_ctrl *ctrl, u32 idx,
			union v4l2_ctrl_ptr ptr);
};

/**
 * typedef v4l2_ctrl_notify_fnc - typedef for a notify argument with a function
 *	that should be called when a control value has changed.
 *
 * @ctrl: pointer to struct &v4l2_ctrl
 * @priv: control private data
 *
 * This typedef definition is used as an argument to v4l2_ctrl_notify()
 * and as an argument at struct &v4l2_ctrl_handler.
 */
typedef void (*v4l2_ctrl_notify_fnc)(struct v4l2_ctrl *ctrl, void *priv);

/**
 * struct v4l2_ctrl - The control structure.
 *
 * @node:	The list node.
 * @ev_subs:	The list of control event subscriptions.
 * @handler:	The handler that owns the control.
 * @cluster:	Point to start of cluster array.
 * @ncontrols:	Number of controls in cluster array.
 * @done:	Internal flag: set for each processed control.
 * @is_new:	Set when the user specified a new value for this control. It
 *		is also set when called from v4l2_ctrl_handler_setup(). Drivers
 *		should never set this flag.
 * @has_changed: Set when the current value differs from the new value. Drivers
 *		should never use this flag.
 * @is_private: If set, then this control is private to its handler and it
 *		will not be added to any other handlers. Drivers can set
 *		this flag.
 * @is_auto:   If set, then this control selects whether the other cluster
 *		members are in 'automatic' mode or 'manual' mode. This is
 *		used for autogain/gain type clusters. Drivers should never
 *		set this flag directly.
 * @is_int:    If set, then this control has a simple integer value (i.e. it
 *		uses ctrl->val).
 * @is_string: If set, then this control has type %V4L2_CTRL_TYPE_STRING.
 * @is_ptr:	If set, then this control is an array and/or has type >=
 *		%V4L2_CTRL_COMPOUND_TYPES
 *		and/or has type %V4L2_CTRL_TYPE_STRING. In other words, &struct
 *		v4l2_ext_control uses field p to point to the data.
 * @is_array: If set, then this control contains an N-dimensional array.
 * @has_volatiles: If set, then one or more members of the cluster are volatile.
 *		Drivers should never touch this flag.
 * @call_notify: If set, then call the handler's notify function whenever the
 *		control's value changes.
 * @manual_mode_value: If the is_auto flag is set, then this is the value
 *		of the auto control that determines if that control is in
 *		manual mode. So if the value of the auto control equals this
 *		value, then the whole cluster is in manual mode. Drivers should
 *		never set this flag directly.
 * @ops:	The control ops.
 * @type_ops:	The control type ops.
 * @id:	The control ID.
 * @name:	The control name.
 * @type:	The control type.
 * @minimum:	The control's minimum value.
 * @maximum:	The control's maximum value.
 * @default_value: The control's default value.
 * @step:	The control's step value for non-menu controls.
 * @elems:	The number of elements in the N-dimensional array.
 * @elem_size:	The size in bytes of the control.
 * @dims:	The size of each dimension.
 * @nr_of_dims:The number of dimensions in @dims.
 * @menu_skip_mask: The control's skip mask for menu controls. This makes it
 *		easy to skip menu items that are not valid. If bit X is set,
 *		then menu item X is skipped. Of course, this only works for
 *		menus with <= 32 menu items. There are no menus that come
 *		close to that number, so this is OK. Should we ever need more,
 *		then this will have to be extended to a u64 or a bit array.
 * @qmenu:	A const char * array for all menu items. Array entries that are
 *		empty strings ("") correspond to non-existing menu items (this
 *		is in addition to the menu_skip_mask above). The last entry
 *		must be NULL.
 *		Used only if the @type is %V4L2_CTRL_TYPE_MENU.
 * @qmenu_int:	A 64-bit integer array for with integer menu items.
 *		The size of array must be equal to the menu size, e. g.:
 *		:math:`ceil(\frac{maximum - minimum}{step}) + 1`.
 *		Used only if the @type is %V4L2_CTRL_TYPE_INTEGER_MENU.
 * @flags:	The control's flags.
 * @cur:	Structure to store the current value.
 * @cur.val:	The control's current value, if the @type is represented via
 *		a u32 integer (see &enum v4l2_ctrl_type).
 * @val:	The control's new s32 value.
 * @priv:	The control's private pointer. For use by the driver. It is
 *		untouched by the control framework. Note that this pointer is
 *		not freed when the control is deleted. Should this be needed
 *		then a new internal bitfield can be added to tell the framework
 *		to free this pointer.
 * @p_def:	The control's default value represented via a union which
 *		provides a standard way of accessing control types
 *		through a pointer (for compound controls only).
 * @p_cur:	The control's current value represented via a union which
 *		provides a standard way of accessing control types
 *		through a pointer.
 * @p_new:	The control's new value represented via a union which provides
 *		a standard way of accessing control types
 *		through a pointer.
 */
struct v4l2_ctrl {
	/* Administrative fields */
	struct list_head node;
	struct list_head ev_subs;
	struct v4l2_ctrl_handler *handler;
	struct v4l2_ctrl **cluster;
	unsigned int ncontrols;

	unsigned int done:1;

	unsigned int is_new:1;
	unsigned int has_changed:1;
	unsigned int is_private:1;
	unsigned int is_auto:1;
	unsigned int is_int:1;
	unsigned int is_string:1;
	unsigned int is_ptr:1;
	unsigned int is_array:1;
	unsigned int has_volatiles:1;
	unsigned int call_notify:1;
	unsigned int manual_mode_value:8;

	const struct v4l2_ctrl_ops *ops;
	const struct v4l2_ctrl_type_ops *type_ops;
	u32 id;
	const char *name;
	enum v4l2_ctrl_type type;
	s64 minimum, maximum, default_value;
	u32 elems;
	u32 elem_size;
	u32 dims[V4L2_CTRL_MAX_DIMS];
	u32 nr_of_dims;
	union {
		u64 step;
		u64 menu_skip_mask;
	};
	union {
		const char * const *qmenu;
		const s64 *qmenu_int;
	};
	unsigned long flags;
	void *priv;
	s32 val;
	struct {
		s32 val;
	} cur;

	union v4l2_ctrl_ptr p_def;
	union v4l2_ctrl_ptr p_new;
	union v4l2_ctrl_ptr p_cur;
};

/**
 * struct v4l2_ctrl_ref - The control reference.
 *
 * @node:	List node for the sorted list.
 * @next:	Single-link list node for the hash.
 * @ctrl:	The actual control information.
 * @helper:	Pointer to helper struct. Used internally in
 *		``prepare_ext_ctrls`` function at ``v4l2-ctrl.c``.
 * @from_other_dev: If true, then @ctrl was defined in another
 *		device than the &struct v4l2_ctrl_handler.
 * @req_done:	Internal flag: if the control handler containing this control
 *		reference is bound to a media request, then this is set when
 *		the control has been applied. This prevents applying controls
 *		from a cluster with multiple controls twice (when the first
 *		control of a cluster is applied, they all are).
 * @req:	If set, this refers to another request that sets this control.
 * @p_req:	If the control handler containing this control reference
 *		is bound to a media request, then this points to the
 *		value of the control that should be applied when the request
 *		is executed, or to the value of the control at the time
 *		that the request was completed.
 *
 * Each control handler has a list of these refs. The list_head is used to
 * keep a sorted-by-control-ID list of all controls, while the next pointer
 * is used to link the control in the hash's bucket.
 */
struct v4l2_ctrl_ref {
	struct list_head node;
	struct v4l2_ctrl_ref *next;
	struct v4l2_ctrl *ctrl;
	struct v4l2_ctrl_helper *helper;
	bool from_other_dev;
	bool req_done;
	struct v4l2_ctrl_ref *req;
	union v4l2_ctrl_ptr p_req;
};

/**
 * struct v4l2_ctrl_handler - The control handler keeps track of all the
 *	controls: both the controls owned by the handler and those inherited
 *	from other handlers.
 *
 * @_lock:	Default for "lock".
 * @lock:	Lock to control access to this handler and its controls.
 *		May be replaced by the user right after init.
 * @ctrls:	The list of controls owned by this handler.
 * @ctrl_refs:	The list of control references.
 * @cached:	The last found control reference. It is common that the same
 *		control is needed multiple times, so this is a simple
 *		optimization.
 * @buckets:	Buckets for the hashing. Allows for quick control lookup.
 * @notify:	A notify callback that is called whenever the control changes
 *		value.
 *		Note that the handler's lock is held when the notify function
 *		is called!
 * @notify_priv: Passed as argument to the v4l2_ctrl notify callback.
 * @nr_of_buckets: Total number of buckets in the array.
 * @error:	The error code of the first failed control addition.
 * @request_is_queued: True if the request was queued.
 * @requests:	List to keep track of open control handler request objects.
 *		For the parent control handler (@req_obj.req == NULL) this
 *		is the list header. When the parent control handler is
 *		removed, it has to unbind and put all these requests since
 *		they refer to the parent.
 * @requests_queued: List of the queued requests. This determines the order
 *		in which these controls are applied. Once the request is
 *		completed it is removed from this list.
 * @req_obj:	The &struct media_request_object, used to link into a
 *		&struct media_request. This request object has a refcount.
 */
struct v4l2_ctrl_handler {
	struct mutex _lock;
	struct mutex *lock;
	struct list_head ctrls;
	struct list_head ctrl_refs;
	struct v4l2_ctrl_ref *cached;
	struct v4l2_ctrl_ref **buckets;
	v4l2_ctrl_notify_fnc notify;
	void *notify_priv;
	u16 nr_of_buckets;
	int error;
	bool request_is_queued;
	struct list_head requests;
	struct list_head requests_queued;
	struct media_request_object req_obj;
};

/**
 * struct v4l2_ctrl_config - Control configuration structure.
 *
 * @ops:	The control ops.
 * @type_ops:	The control type ops. Only needed for compound controls.
 * @id:	The control ID.
 * @name:	The control name.
 * @type:	The control type.
 * @min:	The control's minimum value.
 * @max:	The control's maximum value.
 * @step:	The control's step value for non-menu controls.
 * @def:	The control's default value.
 * @p_def:	The control's default value for compound controls.
 * @dims:	The size of each dimension.
 * @elem_size:	The size in bytes of the control.
 * @flags:	The control's flags.
 * @menu_skip_mask: The control's skip mask for menu controls. This makes it
 *		easy to skip menu items that are not valid. If bit X is set,
 *		then menu item X is skipped. Of course, this only works for
 *		menus with <= 64 menu items. There are no menus that come
 *		close to that number, so this is OK. Should we ever need more,
 *		then this will have to be extended to a bit array.
 * @qmenu:	A const char * array for all menu items. Array entries that are
 *		empty strings ("") correspond to non-existing menu items (this
 *		is in addition to the menu_skip_mask above). The last entry
 *		must be NULL.
 * @qmenu_int:	A const s64 integer array for all menu items of the type
 *		V4L2_CTRL_TYPE_INTEGER_MENU.
 * @is_private: If set, then this control is private to its handler and it
 *		will not be added to any other handlers.
 */
struct v4l2_ctrl_config {
	const struct v4l2_ctrl_ops *ops;
	const struct v4l2_ctrl_type_ops *type_ops;
	u32 id;
	const char *name;
	enum v4l2_ctrl_type type;
	s64 min;
	s64 max;
	u64 step;
	s64 def;
	union v4l2_ctrl_ptr p_def;
	u32 dims[V4L2_CTRL_MAX_DIMS];
	u32 elem_size;
	u32 flags;
	u64 menu_skip_mask;
	const char * const *qmenu;
	const s64 *qmenu_int;
	unsigned int is_private:1;
};

/**
 * v4l2_ctrl_fill - Fill in the control fields based on the control ID.
 *
 * @id: ID of the control
 * @name: pointer to be filled with a string with the name of the control
 * @type: pointer for storing the type of the control
 * @min: pointer for storing the minimum value for the control
 * @max: pointer for storing the maximum value for the control
 * @step: pointer for storing the control step
 * @def: pointer for storing the default value for the control
 * @flags: pointer for storing the flags to be used on the control
 *
 * This works for all standard V4L2 controls.
 * For non-standard controls it will only fill in the given arguments
 * and @name content will be set to %NULL.
 *
 * This function will overwrite the contents of @name, @type and @flags.
 * The contents of @min, @max, @step and @def may be modified depending on
 * the type.
 *
 * .. note::
 *
 *    Do not use in drivers! It is used internally for backwards compatibility
 *    control handling only. Once all drivers are converted to use the new
 *    control framework this function will no longer be exported.
 */
void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
		    s64 *min, s64 *max, u64 *step, s64 *def, u32 *flags);


/**
 * v4l2_ctrl_handler_init_class() - Initialize the control handler.
 * @hdl:	The control handler.
 * @nr_of_controls_hint: A hint of how many controls this handler is
 *		expected to refer to. This is the total number, so including
 *		any inherited controls. It doesn't have to be precise, but if
 *		it is way off, then you either waste memory (too many buckets
 *		are allocated) or the control lookup becomes slower (not enough
 *		buckets are allocated, so there are more slow list lookups).
 *		It will always work, though.
 * @key:	Used by the lock validator if CONFIG_LOCKDEP is set.
 * @name:	Used by the lock validator if CONFIG_LOCKDEP is set.
 *
 * .. attention::
 *
 *    Never use this call directly, always use the v4l2_ctrl_handler_init()
 *    macro that hides the @key and @name arguments.
 *
 * Return: returns an error if the buckets could not be allocated. This
 * error will also be stored in @hdl->error.
 */
int v4l2_ctrl_handler_init_class(struct v4l2_ctrl_handler *hdl,
				 unsigned int nr_of_controls_hint,
				 struct lock_class_key *key, const char *name);

#ifdef CONFIG_LOCKDEP

/**
 * v4l2_ctrl_handler_init - helper function to create a static struct
 *	 &lock_class_key and calls v4l2_ctrl_handler_init_class()
 *
 * @hdl:	The control handler.
 * @nr_of_controls_hint: A hint of how many controls this handler is
 *		expected to refer to. This is the total number, so including
 *		any inherited controls. It doesn't have to be precise, but if
 *		it is way off, then you either waste memory (too many buckets
 *		are allocated) or the control lookup becomes slower (not enough
 *		buckets are allocated, so there are more slow list lookups).
 *		It will always work, though.
 *
 * This helper function creates a static struct &lock_class_key and
 * calls v4l2_ctrl_handler_init_class(), providing a proper name for the lock
 * validador.
 *
 * Use this helper function to initialize a control handler.
 */
#define v4l2_ctrl_handler_init(hdl, nr_of_controls_hint)		\
(									\
	({								\
		static struct lock_class_key _key;			\
		v4l2_ctrl_handler_init_class(hdl, nr_of_controls_hint,	\
					&_key,				\
					KBUILD_BASENAME ":"		\
					__stringify(__LINE__) ":"	\
					"(" #hdl ")->_lock");		\
	})								\
)
#else
#define v4l2_ctrl_handler_init(hdl, nr_of_controls_hint)		\
	v4l2_ctrl_handler_init_class(hdl, nr_of_controls_hint, NULL, NULL)
#endif

/**
 * v4l2_ctrl_handler_free() - Free all controls owned by the handler and free
 * the control list.
 * @hdl:	The control handler.
 *
 * Does nothing if @hdl == NULL.
 */
void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl);

/**
 * v4l2_ctrl_lock() - Helper function to lock the handler
 * associated with the control.
 * @ctrl:	The control to lock.
 */
static inline void v4l2_ctrl_lock(struct v4l2_ctrl *ctrl)
{
	mutex_lock(ctrl->handler->lock);
}

/**
 * v4l2_ctrl_unlock() - Helper function to unlock the handler
 * associated with the control.
 * @ctrl:	The control to unlock.
 */
static inline void v4l2_ctrl_unlock(struct v4l2_ctrl *ctrl)
{
	mutex_unlock(ctrl->handler->lock);
}

/**
 * __v4l2_ctrl_handler_setup() - Call the s_ctrl op for all controls belonging
 * to the handler to initialize the hardware to the current control values. The
 * caller is responsible for acquiring the control handler mutex on behalf of
 * __v4l2_ctrl_handler_setup().
 * @hdl:	The control handler.
 *
 * Button controls will be skipped, as are read-only controls.
 *
 * If @hdl == NULL, then this just returns 0.
 */
int __v4l2_ctrl_handler_setup(struct v4l2_ctrl_handler *hdl);

/**
 * v4l2_ctrl_handler_setup() - Call the s_ctrl op for all controls belonging
 * to the handler to initialize the hardware to the current control values.
 * @hdl:	The control handler.
 *
 * Button controls will be skipped, as are read-only controls.
 *
 * If @hdl == NULL, then this just returns 0.
 */
int v4l2_ctrl_handler_setup(struct v4l2_ctrl_handler *hdl);

/**
 * v4l2_ctrl_handler_log_status() - Log all controls owned by the handler.
 * @hdl:	The control handler.
 * @prefix:	The prefix to use when logging the control values. If the
 *		prefix does not end with a space, then ": " will be added
 *		after the prefix. If @prefix == NULL, then no prefix will be
 *		used.
 *
 * For use with VIDIOC_LOG_STATUS.
 *
 * Does nothing if @hdl == NULL.
 */
void v4l2_ctrl_handler_log_status(struct v4l2_ctrl_handler *hdl,
				  const char *prefix);

/**
 * v4l2_ctrl_new_custom() - Allocate and initialize a new custom V4L2
 *	control.
 *
 * @hdl:	The control handler.
 * @cfg:	The control's configuration data.
 * @priv:	The control's driver-specific private data.
 *
 * If the &v4l2_ctrl struct could not be allocated then NULL is returned
 * and @hdl->error is set to the error code (if it wasn't set already).
 */
struct v4l2_ctrl *v4l2_ctrl_new_custom(struct v4l2_ctrl_handler *hdl,
				       const struct v4l2_ctrl_config *cfg,
				       void *priv);

/**
 * v4l2_ctrl_new_std() - Allocate and initialize a new standard V4L2 non-menu
 *	control.
 *
 * @hdl:	The control handler.
 * @ops:	The control ops.
 * @id:		The control ID.
 * @min:	The control's minimum value.
 * @max:	The control's maximum value.
 * @step:	The control's step value
 * @def:	The control's default value.
 *
 * If the &v4l2_ctrl struct could not be allocated, or the control
 * ID is not known, then NULL is returned and @hdl->error is set to the
 * appropriate error code (if it wasn't set already).
 *
 * If @id refers to a menu control, then this function will return NULL.
 *
 * Use v4l2_ctrl_new_std_menu() when adding menu controls.
 */
struct v4l2_ctrl *v4l2_ctrl_new_std(struct v4l2_ctrl_handler *hdl,
				    const struct v4l2_ctrl_ops *ops,
				    u32 id, s64 min, s64 max, u64 step,
				    s64 def);

/**
 * v4l2_ctrl_new_std_menu() - Allocate and initialize a new standard V4L2
 *	menu control.
 *
 * @hdl:	The control handler.
 * @ops:	The control ops.
 * @id:		The control ID.
 * @max:	The control's maximum value.
 * @mask:	The control's skip mask for menu controls. This makes it
 *		easy to skip menu items that are not valid. If bit X is set,
 *		then menu item X is skipped. Of course, this only works for
 *		menus with <= 64 menu items. There are no menus that come
 *		close to that number, so this is OK. Should we ever need more,
 *		then this will have to be extended to a bit array.
 * @def:	The control's default value.
 *
 * Same as v4l2_ctrl_new_std(), but @min is set to 0 and the @mask value
 * determines which menu items are to be skipped.
 *
 * If @id refers to a non-menu control, then this function will return NULL.
 */
struct v4l2_ctrl *v4l2_ctrl_new_std_menu(struct v4l2_ctrl_handler *hdl,
					 const struct v4l2_ctrl_ops *ops,
					 u32 id, u8 max, u64 mask, u8 def);

/**
 * v4l2_ctrl_new_std_menu_items() - Create a new standard V4L2 menu control
 *	with driver specific menu.
 *
 * @hdl:	The control handler.
 * @ops:	The control ops.
 * @id:	The control ID.
 * @max:	The control's maximum value.
 * @mask:	The control's skip mask for menu controls. This makes it
 *		easy to skip menu items that are not valid. If bit X is set,
 *		then menu item X is skipped. Of course, this only works for
 *		menus with <= 64 menu items. There are no menus that come
 *		close to that number, so this is OK. Should we ever need more,
 *		then this will have to be extended to a bit array.
 * @def:	The control's default value.
 * @qmenu:	The new menu.
 *
 * Same as v4l2_ctrl_new_std_menu(), but @qmenu will be the driver specific
 * menu of this control.
 *
 */
struct v4l2_ctrl *v4l2_ctrl_new_std_menu_items(struct v4l2_ctrl_handler *hdl,
					       const struct v4l2_ctrl_ops *ops,
					       u32 id, u8 max,
					       u64 mask, u8 def,
					       const char * const *qmenu);

/**
 * v4l2_ctrl_new_std_compound() - Allocate and initialize a new standard V4L2
 *      compound control.
 *
 * @hdl:       The control handler.
 * @ops:       The control ops.
 * @id:        The control ID.
 * @p_def:     The control's default value.
 *
 * Sames as v4l2_ctrl_new_std(), but with support to compound controls, thanks
 * to the @p_def field. Use v4l2_ctrl_ptr_create() to create @p_def from a
 * pointer. Use v4l2_ctrl_ptr_create(NULL) if the default value of the
 * compound control should be all zeroes.
 *
 */
struct v4l2_ctrl *v4l2_ctrl_new_std_compound(struct v4l2_ctrl_handler *hdl,
					     const struct v4l2_ctrl_ops *ops,
					     u32 id,
					     const union v4l2_ctrl_ptr p_def);

/**
 * v4l2_ctrl_new_int_menu() - Create a new standard V4L2 integer menu control.
 *
 * @hdl:	The control handler.
 * @ops:	The control ops.
 * @id:	The control ID.
 * @max:	The control's maximum value.
 * @def:	The control's default value.
 * @qmenu_int:	The control's menu entries.
 *
 * Same as v4l2_ctrl_new_std_menu(), but @mask is set to 0 and it additionally
 * takes as an argument an array of integers determining the menu items.
 *
 * If @id refers to a non-integer-menu control, then this function will
 * return %NULL.
 */
struct v4l2_ctrl *v4l2_ctrl_new_int_menu(struct v4l2_ctrl_handler *hdl,
					 const struct v4l2_ctrl_ops *ops,
					 u32 id, u8 max, u8 def,
					 const s64 *qmenu_int);

/**
 * typedef v4l2_ctrl_filter - Typedef to define the filter function to be
 *	used when adding a control handler.
 *
 * @ctrl: pointer to struct &v4l2_ctrl.
 */

typedef bool (*v4l2_ctrl_filter)(const struct v4l2_ctrl *ctrl);

/**
 * v4l2_ctrl_add_handler() - Add all controls from handler @add to
 *	handler @hdl.
 *
 * @hdl:	The control handler.
 * @add:	The control handler whose controls you want to add to
 *		the @hdl control handler.
 * @filter:	This function will filter which controls should be added.
 * @from_other_dev: If true, then the controls in @add were defined in another
 *		device than @hdl.
 *
 * Does nothing if either of the two handlers is a NULL pointer.
 * If @filter is NULL, then all controls are added. Otherwise only those
 * controls for which @filter returns true will be added.
 * In case of an error @hdl->error will be set to the error code (if it
 * wasn't set already).
 */
int v4l2_ctrl_add_handler(struct v4l2_ctrl_handler *hdl,
			  struct v4l2_ctrl_handler *add,
			  v4l2_ctrl_filter filter,
			  bool from_other_dev);

/**
 * v4l2_ctrl_radio_filter() - Standard filter for radio controls.
 *
 * @ctrl:	The control that is filtered.
 *
 * This will return true for any controls that are valid for radio device
 * nodes. Those are all of the V4L2_CID_AUDIO_* user controls and all FM
 * transmitter class controls.
 *
 * This function is to be used with v4l2_ctrl_add_handler().
 */
bool v4l2_ctrl_radio_filter(const struct v4l2_ctrl *ctrl);

/**
 * v4l2_ctrl_cluster() - Mark all controls in the cluster as belonging
 *	to that cluster.
 *
 * @ncontrols:	The number of controls in this cluster.
 * @controls:	The cluster control array of size @ncontrols.
 */
void v4l2_ctrl_cluster(unsigned int ncontrols, struct v4l2_ctrl **controls);


/**
 * v4l2_ctrl_auto_cluster() - Mark all controls in the cluster as belonging
 *	to that cluster and set it up for autofoo/foo-type handling.
 *
 * @ncontrols:	The number of controls in this cluster.
 * @controls:	The cluster control array of size @ncontrols. The first control
 *		must be the 'auto' control (e.g. autogain, autoexposure, etc.)
 * @manual_val: The value for the first control in the cluster that equals the
 *		manual setting.
 * @set_volatile: If true, then all controls except the first auto control will
 *		be volatile.
 *
 * Use for control groups where one control selects some automatic feature and
 * the other controls are only active whenever the automatic feature is turned
 * off (manual mode). Typical examples: autogain vs gain, auto-whitebalance vs
 * red and blue balance, etc.
 *
 * The behavior of such controls is as follows:
 *
 * When the autofoo control is set to automatic, then any manual controls
 * are set to inactive and any reads will call g_volatile_ctrl (if the control
 * was marked volatile).
 *
 * When the autofoo control is set to manual, then any manual controls will
 * be marked active, and any reads will just return the current value without
 * going through g_volatile_ctrl.
 *
 * In addition, this function will set the %V4L2_CTRL_FLAG_UPDATE flag
 * on the autofoo control and %V4L2_CTRL_FLAG_INACTIVE on the foo control(s)
 * if autofoo is in auto mode.
 */
void v4l2_ctrl_auto_cluster(unsigned int ncontrols,
			    struct v4l2_ctrl **controls,
			    u8 manual_val, bool set_volatile);


/**
 * v4l2_ctrl_find() - Find a control with the given ID.
 *
 * @hdl:	The control handler.
 * @id:	The control ID to find.
 *
 * If @hdl == NULL this will return NULL as well. Will lock the handler so
 * do not use from inside &v4l2_ctrl_ops.
 */
struct v4l2_ctrl *v4l2_ctrl_find(struct v4l2_ctrl_handler *hdl, u32 id);

/**
 * v4l2_ctrl_activate() - Make the control active or inactive.
 * @ctrl:	The control to (de)activate.
 * @active:	True if the control should become active.
 *
 * This sets or clears the V4L2_CTRL_FLAG_INACTIVE flag atomically.
 * Does nothing if @ctrl == NULL.
 * This will usually be called from within the s_ctrl op.
 * The V4L2_EVENT_CTRL event will be generated afterwards.
 *
 * This function assumes that the control handler is locked.
 */
void v4l2_ctrl_activate(struct v4l2_ctrl *ctrl, bool active);

/**
 * __v4l2_ctrl_grab() - Unlocked variant of v4l2_ctrl_grab.
 *
 * @ctrl:	The control to (de)activate.
 * @grabbed:	True if the control should become grabbed.
 *
 * This sets or clears the V4L2_CTRL_FLAG_GRABBED flag atomically.
 * Does nothing if @ctrl == NULL.
 * The V4L2_EVENT_CTRL event will be generated afterwards.
 * This will usually be called when starting or stopping streaming in the
 * driver.
 *
 * This function assumes that the control handler is locked by the caller.
 */
void __v4l2_ctrl_grab(struct v4l2_ctrl *ctrl, bool grabbed);

/**
 * v4l2_ctrl_grab() - Mark the control as grabbed or not grabbed.
 *
 * @ctrl:	The control to (de)activate.
 * @grabbed:	True if the control should become grabbed.
 *
 * This sets or clears the V4L2_CTRL_FLAG_GRABBED flag atomically.
 * Does nothing if @ctrl == NULL.
 * The V4L2_EVENT_CTRL event will be generated afterwards.
 * This will usually be called when starting or stopping streaming in the
 * driver.
 *
 * This function assumes that the control handler is not locked and will
 * take the lock itself.
 */
static inline void v4l2_ctrl_grab(struct v4l2_ctrl *ctrl, bool grabbed)
{
	if (!ctrl)
		return;

	v4l2_ctrl_lock(ctrl);
	__v4l2_ctrl_grab(ctrl, grabbed);
	v4l2_ctrl_unlock(ctrl);
}

/**
 *__v4l2_ctrl_modify_range() - Unlocked variant of v4l2_ctrl_modify_range()
 *
 * @ctrl:	The control to update.
 * @min:	The control's minimum value.
 * @max:	The control's maximum value.
 * @step:	The control's step value
 * @def:	The control's default value.
 *
 * Update the range of a control on the fly. This works for control types
 * INTEGER, BOOLEAN, MENU, INTEGER MENU and BITMASK. For menu controls the
 * @step value is interpreted as a menu_skip_mask.
 *
 * An error is returned if one of the range arguments is invalid for this
 * control type.
 *
 * The caller is responsible for acquiring the control handler mutex on behalf
 * of __v4l2_ctrl_modify_range().
 */
int __v4l2_ctrl_modify_range(struct v4l2_ctrl *ctrl,
			     s64 min, s64 max, u64 step, s64 def);

/**
 * v4l2_ctrl_modify_range() - Update the range of a control.
 *
 * @ctrl:	The control to update.
 * @min:	The control's minimum value.
 * @max:	The control's maximum value.
 * @step:	The control's step value
 * @def:	The control's default value.
 *
 * Update the range of a control on the fly. This works for control types
 * INTEGER, BOOLEAN, MENU, INTEGER MENU and BITMASK. For menu controls the
 * @step value is interpreted as a menu_skip_mask.
 *
 * An error is returned if one of the range arguments is invalid for this
 * control type.
 *
 * This function assumes that the control handler is not locked and will
 * take the lock itself.
 */
static inline int v4l2_ctrl_modify_range(struct v4l2_ctrl *ctrl,
					 s64 min, s64 max, u64 step, s64 def)
{
	int rval;

	v4l2_ctrl_lock(ctrl);
	rval = __v4l2_ctrl_modify_range(ctrl, min, max, step, def);
	v4l2_ctrl_unlock(ctrl);

	return rval;
}

/**
 * v4l2_ctrl_notify() - Function to set a notify callback for a control.
 *
 * @ctrl:	The control.
 * @notify:	The callback function.
 * @priv:	The callback private handle, passed as argument to the callback.
 *
 * This function sets a callback function for the control. If @ctrl is NULL,
 * then it will do nothing. If @notify is NULL, then the notify callback will
 * be removed.
 *
 * There can be only one notify. If another already exists, then a WARN_ON
 * will be issued and the function will do nothing.
 */
void v4l2_ctrl_notify(struct v4l2_ctrl *ctrl, v4l2_ctrl_notify_fnc notify,
		      void *priv);

/**
 * v4l2_ctrl_get_name() - Get the name of the control
 *
 * @id:		The control ID.
 *
 * This function returns the name of the given control ID or NULL if it isn't
 * a known control.
 */
const char *v4l2_ctrl_get_name(u32 id);

/**
 * v4l2_ctrl_get_menu() - Get the menu string array of the control
 *
 * @id:		The control ID.
 *
 * This function returns the NULL-terminated menu string array name of the
 * given control ID or NULL if it isn't a known menu control.
 */
const char * const *v4l2_ctrl_get_menu(u32 id);

/**
 * v4l2_ctrl_get_int_menu() - Get the integer menu array of the control
 *
 * @id:		The control ID.
 * @len:	The size of the integer array.
 *
 * This function returns the integer array of the given control ID or NULL if it
 * if it isn't a known integer menu control.
 */
const s64 *v4l2_ctrl_get_int_menu(u32 id, u32 *len);

/**
 * v4l2_ctrl_g_ctrl() - Helper function to get the control's value from
 *	within a driver.
 *
 * @ctrl:	The control.
 *
 * This returns the control's value safely by going through the control
 * framework. This function will lock the control's handler, so it cannot be
 * used from within the &v4l2_ctrl_ops functions.
 *
 * This function is for integer type controls only.
 */
s32 v4l2_ctrl_g_ctrl(struct v4l2_ctrl *ctrl);

/**
 * __v4l2_ctrl_s_ctrl() - Unlocked variant of v4l2_ctrl_s_ctrl().
 *
 * @ctrl:	The control.
 * @val:	The new value.
 *
 * This sets the control's new value safely by going through the control
 * framework. This function assumes the control's handler is already locked,
 * allowing it to be used from within the &v4l2_ctrl_ops functions.
 *
 * This function is for integer type controls only.
 */
int __v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val);

/**
 * v4l2_ctrl_s_ctrl() - Helper function to set the control's value from
 *	within a driver.
 * @ctrl:	The control.
 * @val:	The new value.
 *
 * This sets the control's new value safely by going through the control
 * framework. This function will lock the control's handler, so it cannot be
 * used from within the &v4l2_ctrl_ops functions.
 *
 * This function is for integer type controls only.
 */
static inline int v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val)
{
	int rval;

	v4l2_ctrl_lock(ctrl);
	rval = __v4l2_ctrl_s_ctrl(ctrl, val);
	v4l2_ctrl_unlock(ctrl);

	return rval;
}

/**
 * v4l2_ctrl_g_ctrl_int64() - Helper function to get a 64-bit control's value
 *	from within a driver.
 *
 * @ctrl:	The control.
 *
 * This returns the control's value safely by going through the control
 * framework. This function will lock the control's handler, so it cannot be
 * used from within the &v4l2_ctrl_ops functions.
 *
 * This function is for 64-bit integer type controls only.
 */
s64 v4l2_ctrl_g_ctrl_int64(struct v4l2_ctrl *ctrl);

/**
 * __v4l2_ctrl_s_ctrl_int64() - Unlocked variant of v4l2_ctrl_s_ctrl_int64().
 *
 * @ctrl:	The control.
 * @val:	The new value.
 *
 * This sets the control's new value safely by going through the control
 * framework. This function assumes the control's handler is already locked,
 * allowing it to be used from within the &v4l2_ctrl_ops functions.
 *
 * This function is for 64-bit integer type controls only.
 */
int __v4l2_ctrl_s_ctrl_int64(struct v4l2_ctrl *ctrl, s64 val);

/**
 * v4l2_ctrl_s_ctrl_int64() - Helper function to set a 64-bit control's value
 *	from within a driver.
 *
 * @ctrl:	The control.
 * @val:	The new value.
 *
 * This sets the control's new value safely by going through the control
 * framework. This function will lock the control's handler, so it cannot be
 * used from within the &v4l2_ctrl_ops functions.
 *
 * This function is for 64-bit integer type controls only.
 */
static inline int v4l2_ctrl_s_ctrl_int64(struct v4l2_ctrl *ctrl, s64 val)
{
	int rval;

	v4l2_ctrl_lock(ctrl);
	rval = __v4l2_ctrl_s_ctrl_int64(ctrl, val);
	v4l2_ctrl_unlock(ctrl);

	return rval;
}

/**
 * __v4l2_ctrl_s_ctrl_string() - Unlocked variant of v4l2_ctrl_s_ctrl_string().
 *
 * @ctrl:	The control.
 * @s:		The new string.
 *
 * This sets the control's new string safely by going through the control
 * framework. This function assumes the control's handler is already locked,
 * allowing it to be used from within the &v4l2_ctrl_ops functions.
 *
 * This function is for string type controls only.
 */
int __v4l2_ctrl_s_ctrl_string(struct v4l2_ctrl *ctrl, const char *s);

/**
 * v4l2_ctrl_s_ctrl_string() - Helper function to set a control's string value
 *	 from within a driver.
 *
 * @ctrl:	The control.
 * @s:		The new string.
 *
 * This sets the control's new string safely by going through the control
 * framework. This function will lock the control's handler, so it cannot be
 * used from within the &v4l2_ctrl_ops functions.
 *
 * This function is for string type controls only.
 */
static inline int v4l2_ctrl_s_ctrl_string(struct v4l2_ctrl *ctrl, const char *s)
{
	int rval;

	v4l2_ctrl_lock(ctrl);
	rval = __v4l2_ctrl_s_ctrl_string(ctrl, s);
	v4l2_ctrl_unlock(ctrl);

	return rval;
}

/**
 * __v4l2_ctrl_s_ctrl_compound() - Unlocked variant to set a compound control
 *
 * @ctrl: The control.
 * @type: The type of the data.
 * @p:    The new compound payload.
 *
 * This sets the control's new compound payload safely by going through the
 * control framework. This function assumes the control's handler is already
 * locked, allowing it to be used from within the &v4l2_ctrl_ops functions.
 *
 * This function is for compound type controls only.
 */
int __v4l2_ctrl_s_ctrl_compound(struct v4l2_ctrl *ctrl,
				enum v4l2_ctrl_type type, const void *p);

/**
 * v4l2_ctrl_s_ctrl_compound() - Helper function to set a compound control
 *	from within a driver.
 *
 * @ctrl: The control.
 * @type: The type of the data.
 * @p:    The new compound payload.
 *
 * This sets the control's new compound payload safely by going through the
 * control framework. This function will lock the control's handler, so it
 * cannot be used from within the &v4l2_ctrl_ops functions.
 *
 * This function is for compound type controls only.
 */
static inline int v4l2_ctrl_s_ctrl_compound(struct v4l2_ctrl *ctrl,
					    enum v4l2_ctrl_type type,
					    const void *p)
{
	int rval;

	v4l2_ctrl_lock(ctrl);
	rval = __v4l2_ctrl_s_ctrl_compound(ctrl, type, p);
	v4l2_ctrl_unlock(ctrl);

	return rval;
}

/* Helper defines for area type controls */
#define __v4l2_ctrl_s_ctrl_area(ctrl, area) \
	__v4l2_ctrl_s_ctrl_compound((ctrl), V4L2_CTRL_TYPE_AREA, (area))
#define v4l2_ctrl_s_ctrl_area(ctrl, area) \
	v4l2_ctrl_s_ctrl_compound((ctrl), V4L2_CTRL_TYPE_AREA, (area))

/* Internal helper functions that deal with control events. */
extern const struct v4l2_subscribed_event_ops v4l2_ctrl_sub_ev_ops;

/**
 * v4l2_ctrl_replace - Function to be used as a callback to
 *	&struct v4l2_subscribed_event_ops replace\(\)
 *
 * @old: pointer to struct &v4l2_event with the reported
 *	 event;
 * @new: pointer to struct &v4l2_event with the modified
 *	 event;
 */
void v4l2_ctrl_replace(struct v4l2_event *old, const struct v4l2_event *new);

/**
 * v4l2_ctrl_merge - Function to be used as a callback to
 *	&struct v4l2_subscribed_event_ops merge(\)
 *
 * @old: pointer to struct &v4l2_event with the reported
 *	 event;
 * @new: pointer to struct &v4l2_event with the merged
 *	 event;
 */
void v4l2_ctrl_merge(const struct v4l2_event *old, struct v4l2_event *new);

/**
 * v4l2_ctrl_log_status - helper function to implement %VIDIOC_LOG_STATUS ioctl
 *
 * @file: pointer to struct file
 * @fh: unused. Kept just to be compatible to the arguments expected by
 *	&struct v4l2_ioctl_ops.vidioc_log_status.
 *
 * Can be used as a vidioc_log_status function that just dumps all controls
 * associated with the filehandle.
 */
int v4l2_ctrl_log_status(struct file *file, void *fh);

/**
 * v4l2_ctrl_subscribe_event - Subscribes to an event
 *
 *
 * @fh: pointer to struct v4l2_fh
 * @sub: pointer to &struct v4l2_event_subscription
 *
 * Can be used as a vidioc_subscribe_event function that just subscribes
 * control events.
 */
int v4l2_ctrl_subscribe_event(struct v4l2_fh *fh,
				const struct v4l2_event_subscription *sub);

/**
 * v4l2_ctrl_poll - function to be used as a callback to the poll()
 *	That just polls for control events.
 *
 * @file: pointer to struct file
 * @wait: pointer to struct poll_table_struct
 */
__poll_t v4l2_ctrl_poll(struct file *file, struct poll_table_struct *wait);

/**
 * v4l2_ctrl_request_setup - helper function to apply control values in a request
 *
 * @req: The request
 * @parent: The parent control handler ('priv' in media_request_object_find())
 *
 * This is a helper function to call the control handler's s_ctrl callback with
 * the control values contained in the request. Do note that this approach of
 * applying control values in a request is only applicable to memory-to-memory
 * devices.
 */
int v4l2_ctrl_request_setup(struct media_request *req,
			     struct v4l2_ctrl_handler *parent);

/**
 * v4l2_ctrl_request_complete - Complete a control handler request object
 *
 * @req: The request
 * @parent: The parent control handler ('priv' in media_request_object_find())
 *
 * This function is to be called on each control handler that may have had a
 * request object associated with it, i.e. control handlers of a driver that
 * supports requests.
 *
 * The function first obtains the values of any volatile controls in the control
 * handler and attach them to the request. Then, the function completes the
 * request object.
 */
void v4l2_ctrl_request_complete(struct media_request *req,
				struct v4l2_ctrl_handler *parent);

/**
 * v4l2_ctrl_request_hdl_find - Find the control handler in the request
 *
 * @req: The request
 * @parent: The parent control handler ('priv' in media_request_object_find())
 *
 * This function finds the control handler in the request. It may return
 * NULL if not found. When done, you must call v4l2_ctrl_request_put_hdl()
 * with the returned handler pointer.
 *
 * If the request is not in state VALIDATING or QUEUED, then this function
 * will always return NULL.
 *
 * Note that in state VALIDATING the req_queue_mutex is held, so
 * no objects can be added or deleted from the request.
 *
 * In state QUEUED it is the driver that will have to ensure this.
 */
struct v4l2_ctrl_handler *v4l2_ctrl_request_hdl_find(struct media_request *req,
					struct v4l2_ctrl_handler *parent);

/**
 * v4l2_ctrl_request_hdl_put - Put the control handler
 *
 * @hdl: Put this control handler
 *
 * This function released the control handler previously obtained from'
 * v4l2_ctrl_request_hdl_find().
 */
static inline void v4l2_ctrl_request_hdl_put(struct v4l2_ctrl_handler *hdl)
{
	if (hdl)
		media_request_object_put(&hdl->req_obj);
}

/**
 * v4l2_ctrl_request_ctrl_find() - Find a control with the given ID.
 *
 * @hdl: The control handler from the request.
 * @id: The ID of the control to find.
 *
 * This function returns a pointer to the control if this control is
 * part of the request or NULL otherwise.
 */
struct v4l2_ctrl *
v4l2_ctrl_request_hdl_ctrl_find(struct v4l2_ctrl_handler *hdl, u32 id);

/* Helpers for ioctl_ops */

/**
 * v4l2_queryctrl - Helper function to implement
 *	:ref:`VIDIOC_QUERYCTRL <vidioc_queryctrl>` ioctl
 *
 * @hdl: pointer to &struct v4l2_ctrl_handler
 * @qc: pointer to &struct v4l2_queryctrl
 *
 * If hdl == NULL then they will all return -EINVAL.
 */
int v4l2_queryctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_queryctrl *qc);

/**
 * v4l2_query_ext_ctrl - Helper function to implement
 *	 :ref:`VIDIOC_QUERY_EXT_CTRL <vidioc_queryctrl>` ioctl
 *
 * @hdl: pointer to &struct v4l2_ctrl_handler
 * @qc: pointer to &struct v4l2_query_ext_ctrl
 *
 * If hdl == NULL then they will all return -EINVAL.
 */
int v4l2_query_ext_ctrl(struct v4l2_ctrl_handler *hdl,
			struct v4l2_query_ext_ctrl *qc);

/**
 * v4l2_querymenu - Helper function to implement
 *	:ref:`VIDIOC_QUERYMENU <vidioc_queryctrl>` ioctl
 *
 * @hdl: pointer to &struct v4l2_ctrl_handler
 * @qm: pointer to &struct v4l2_querymenu
 *
 * If hdl == NULL then they will all return -EINVAL.
 */
int v4l2_querymenu(struct v4l2_ctrl_handler *hdl, struct v4l2_querymenu *qm);

/**
 * v4l2_g_ctrl - Helper function to implement
 *	:ref:`VIDIOC_G_CTRL <vidioc_g_ctrl>` ioctl
 *
 * @hdl: pointer to &struct v4l2_ctrl_handler
 * @ctrl: pointer to &struct v4l2_control
 *
 * If hdl == NULL then they will all return -EINVAL.
 */
int v4l2_g_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_control *ctrl);

/**
 * v4l2_s_ctrl - Helper function to implement
 *	:ref:`VIDIOC_S_CTRL <vidioc_g_ctrl>` ioctl
 *
 * @fh: pointer to &struct v4l2_fh
 * @hdl: pointer to &struct v4l2_ctrl_handler
 *
 * @ctrl: pointer to &struct v4l2_control
 *
 * If hdl == NULL then they will all return -EINVAL.
 */
int v4l2_s_ctrl(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
		struct v4l2_control *ctrl);

/**
 * v4l2_g_ext_ctrls - Helper function to implement
 *	:ref:`VIDIOC_G_EXT_CTRLS <vidioc_g_ext_ctrls>` ioctl
 *
 * @hdl: pointer to &struct v4l2_ctrl_handler
 * @vdev: pointer to &struct video_device
 * @mdev: pointer to &struct media_device
 * @c: pointer to &struct v4l2_ext_controls
 *
 * If hdl == NULL then they will all return -EINVAL.
 */
int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct video_device *vdev,
		     struct media_device *mdev, struct v4l2_ext_controls *c);

/**
 * v4l2_try_ext_ctrls - Helper function to implement
 *	:ref:`VIDIOC_TRY_EXT_CTRLS <vidioc_g_ext_ctrls>` ioctl
 *
 * @hdl: pointer to &struct v4l2_ctrl_handler
 * @vdev: pointer to &struct video_device
 * @mdev: pointer to &struct media_device
 * @c: pointer to &struct v4l2_ext_controls
 *
 * If hdl == NULL then they will all return -EINVAL.
 */
int v4l2_try_ext_ctrls(struct v4l2_ctrl_handler *hdl,
		       struct video_device *vdev,
		       struct media_device *mdev,
		       struct v4l2_ext_controls *c);

/**
 * v4l2_s_ext_ctrls - Helper function to implement
 *	:ref:`VIDIOC_S_EXT_CTRLS <vidioc_g_ext_ctrls>` ioctl
 *
 * @fh: pointer to &struct v4l2_fh
 * @hdl: pointer to &struct v4l2_ctrl_handler
 * @vdev: pointer to &struct video_device
 * @mdev: pointer to &struct media_device
 * @c: pointer to &struct v4l2_ext_controls
 *
 * If hdl == NULL then they will all return -EINVAL.
 */
int v4l2_s_ext_ctrls(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
		     struct video_device *vdev,
		     struct media_device *mdev,
		     struct v4l2_ext_controls *c);

/**
 * v4l2_ctrl_subdev_subscribe_event - Helper function to implement
 *	as a &struct v4l2_subdev_core_ops subscribe_event function
 *	that just subscribes control events.
 *
 * @sd: pointer to &struct v4l2_subdev
 * @fh: pointer to &struct v4l2_fh
 * @sub: pointer to &struct v4l2_event_subscription
 */
int v4l2_ctrl_subdev_subscribe_event(struct v4l2_subdev *sd, struct v4l2_fh *fh,
				     struct v4l2_event_subscription *sub);

/**
 * v4l2_ctrl_subdev_log_status - Log all controls owned by subdev's control
 *	 handler.
 *
 * @sd: pointer to &struct v4l2_subdev
 */
int v4l2_ctrl_subdev_log_status(struct v4l2_subdev *sd);

/**
 * v4l2_ctrl_new_fwnode_properties() - Register controls for the device
 *				       properties
 *
 * @hdl: pointer to &struct v4l2_ctrl_handler to register controls on
 * @ctrl_ops: pointer to &struct v4l2_ctrl_ops to register controls with
 * @p: pointer to &struct v4l2_fwnode_device_properties
 *
 * This function registers controls associated to device properties, using the
 * property values contained in @p parameter, if the property has been set to
 * a value.
 *
 * Currently the following v4l2 controls are parsed and registered:
 * - V4L2_CID_CAMERA_ORIENTATION
 * - V4L2_CID_CAMERA_SENSOR_ROTATION;
 *
 * Controls already registered by the caller with the @hdl control handler are
 * not overwritten. Callers should register the controls they want to handle
 * themselves before calling this function.
 *
 * Return: 0 on success, a negative error code on failure.
 */
int v4l2_ctrl_new_fwnode_properties(struct v4l2_ctrl_handler *hdl,
				    const struct v4l2_ctrl_ops *ctrl_ops,
				    const struct v4l2_fwnode_device_properties *p);
#endif