Stuck at home?

Check our new online training!

Stuck at home?

All Bootlin training courses
are now available
through on-line seminars

Bootlin logo

Elixir Cross Referencer

   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
/*
 *  V4L2 controls support header.
 *
 *  Copyright (C) 2010  Hans Verkuil <hverkuil@xs4all.nl>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 */

#ifndef _V4L2_CTRLS_H
#define _V4L2_CTRLS_H

#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/videodev2.h>

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

/**
 * 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:		Pointer to a compound value.
 */
union v4l2_ctrl_ptr {
	s32 *p_s32;
	s64 *p_s64;
	u8 *p_u8;
	u16 *p_u16;
	u32 *p_u32;
	char *p_char;
	void *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_cur:	The control's current value represented via a union with
 *		provides a standard way of accessing control types
 *		through a pointer.
 * @p_new:	The control's new value represented via a union with 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_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``.
 *
 * 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;
};

/**
 * 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.
 */
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;
};

/**
 * 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.
 * @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;
	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_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 additionaly
 * 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.
 *
 * 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);

/**
 * 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() - 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.
 */
void v4l2_ctrl_grab(struct v4l2_ctrl *ctrl, bool grabbed);

/**
 *__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:	TheControls name 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.
 *Controls name
 * 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;
}

/* 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);

/* 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
 * @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 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
 * @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 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
 * @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 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);

#endif