xref: /openbmc/linux/include/media/v4l2-ctrls.h (revision 3557b3fd)
1 /*
2  *  V4L2 controls support header.
3  *
4  *  Copyright (C) 2010  Hans Verkuil <hverkuil@xs4all.nl>
5  *
6  *  This program is free software; you can redistribute it and/or modify
7  *  it under the terms of the GNU General Public License as published by
8  *  the Free Software Foundation; either version 2 of the License, or
9  *  (at your option) any later version.
10  *
11  *  This program is distributed in the hope that it will be useful,
12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *  GNU General Public License for more details.
15  */
16 
17 #ifndef _V4L2_CTRLS_H
18 #define _V4L2_CTRLS_H
19 
20 #include <linux/list.h>
21 #include <linux/mutex.h>
22 #include <linux/videodev2.h>
23 #include <media/media-request.h>
24 
25 /*
26  * Include the mpeg2 stateless codec compound control definitions.
27  * This will move to the public headers once this API is fully stable.
28  */
29 #include <media/mpeg2-ctrls.h>
30 
31 /* forward references */
32 struct file;
33 struct v4l2_ctrl_handler;
34 struct v4l2_ctrl_helper;
35 struct v4l2_ctrl;
36 struct video_device;
37 struct v4l2_subdev;
38 struct v4l2_subscribed_event;
39 struct v4l2_fh;
40 struct poll_table_struct;
41 
42 /**
43  * union v4l2_ctrl_ptr - A pointer to a control value.
44  * @p_s32:			Pointer to a 32-bit signed value.
45  * @p_s64:			Pointer to a 64-bit signed value.
46  * @p_u8:			Pointer to a 8-bit unsigned value.
47  * @p_u16:			Pointer to a 16-bit unsigned value.
48  * @p_u32:			Pointer to a 32-bit unsigned value.
49  * @p_char:			Pointer to a string.
50  * @p_mpeg2_slice_params:	Pointer to a MPEG2 slice parameters structure.
51  * @p_mpeg2_quantization:	Pointer to a MPEG2 quantization data structure.
52  * @p:				Pointer to a compound value.
53  */
54 union v4l2_ctrl_ptr {
55 	s32 *p_s32;
56 	s64 *p_s64;
57 	u8 *p_u8;
58 	u16 *p_u16;
59 	u32 *p_u32;
60 	char *p_char;
61 	struct v4l2_ctrl_mpeg2_slice_params *p_mpeg2_slice_params;
62 	struct v4l2_ctrl_mpeg2_quantization *p_mpeg2_quantization;
63 	void *p;
64 };
65 
66 /**
67  * struct v4l2_ctrl_ops - The control operations that the driver has to provide.
68  *
69  * @g_volatile_ctrl: Get a new value for this control. Generally only relevant
70  *		for volatile (and usually read-only) controls such as a control
71  *		that returns the current signal strength which changes
72  *		continuously.
73  *		If not set, then the currently cached value will be returned.
74  * @try_ctrl:	Test whether the control's value is valid. Only relevant when
75  *		the usual min/max/step checks are not sufficient.
76  * @s_ctrl:	Actually set the new control value. s_ctrl is compulsory. The
77  *		ctrl->handler->lock is held when these ops are called, so no
78  *		one else can access controls owned by that handler.
79  */
80 struct v4l2_ctrl_ops {
81 	int (*g_volatile_ctrl)(struct v4l2_ctrl *ctrl);
82 	int (*try_ctrl)(struct v4l2_ctrl *ctrl);
83 	int (*s_ctrl)(struct v4l2_ctrl *ctrl);
84 };
85 
86 /**
87  * struct v4l2_ctrl_type_ops - The control type operations that the driver
88  *			       has to provide.
89  *
90  * @equal: return true if both values are equal.
91  * @init: initialize the value.
92  * @log: log the value.
93  * @validate: validate the value. Return 0 on success and a negative value
94  *	otherwise.
95  */
96 struct v4l2_ctrl_type_ops {
97 	bool (*equal)(const struct v4l2_ctrl *ctrl, u32 idx,
98 		      union v4l2_ctrl_ptr ptr1,
99 		      union v4l2_ctrl_ptr ptr2);
100 	void (*init)(const struct v4l2_ctrl *ctrl, u32 idx,
101 		     union v4l2_ctrl_ptr ptr);
102 	void (*log)(const struct v4l2_ctrl *ctrl);
103 	int (*validate)(const struct v4l2_ctrl *ctrl, u32 idx,
104 			union v4l2_ctrl_ptr ptr);
105 };
106 
107 /**
108  * typedef v4l2_ctrl_notify_fnc - typedef for a notify argument with a function
109  *	that should be called when a control value has changed.
110  *
111  * @ctrl: pointer to struct &v4l2_ctrl
112  * @priv: control private data
113  *
114  * This typedef definition is used as an argument to v4l2_ctrl_notify()
115  * and as an argument at struct &v4l2_ctrl_handler.
116  */
117 typedef void (*v4l2_ctrl_notify_fnc)(struct v4l2_ctrl *ctrl, void *priv);
118 
119 /**
120  * struct v4l2_ctrl - The control structure.
121  *
122  * @node:	The list node.
123  * @ev_subs:	The list of control event subscriptions.
124  * @handler:	The handler that owns the control.
125  * @cluster:	Point to start of cluster array.
126  * @ncontrols:	Number of controls in cluster array.
127  * @done:	Internal flag: set for each processed control.
128  * @is_new:	Set when the user specified a new value for this control. It
129  *		is also set when called from v4l2_ctrl_handler_setup(). Drivers
130  *		should never set this flag.
131  * @has_changed: Set when the current value differs from the new value. Drivers
132  *		should never use this flag.
133  * @is_private: If set, then this control is private to its handler and it
134  *		will not be added to any other handlers. Drivers can set
135  *		this flag.
136  * @is_auto:   If set, then this control selects whether the other cluster
137  *		members are in 'automatic' mode or 'manual' mode. This is
138  *		used for autogain/gain type clusters. Drivers should never
139  *		set this flag directly.
140  * @is_int:    If set, then this control has a simple integer value (i.e. it
141  *		uses ctrl->val).
142  * @is_string: If set, then this control has type %V4L2_CTRL_TYPE_STRING.
143  * @is_ptr:	If set, then this control is an array and/or has type >=
144  *		%V4L2_CTRL_COMPOUND_TYPES
145  *		and/or has type %V4L2_CTRL_TYPE_STRING. In other words, &struct
146  *		v4l2_ext_control uses field p to point to the data.
147  * @is_array: If set, then this control contains an N-dimensional array.
148  * @has_volatiles: If set, then one or more members of the cluster are volatile.
149  *		Drivers should never touch this flag.
150  * @call_notify: If set, then call the handler's notify function whenever the
151  *		control's value changes.
152  * @manual_mode_value: If the is_auto flag is set, then this is the value
153  *		of the auto control that determines if that control is in
154  *		manual mode. So if the value of the auto control equals this
155  *		value, then the whole cluster is in manual mode. Drivers should
156  *		never set this flag directly.
157  * @ops:	The control ops.
158  * @type_ops:	The control type ops.
159  * @id:	The control ID.
160  * @name:	The control name.
161  * @type:	The control type.
162  * @minimum:	The control's minimum value.
163  * @maximum:	The control's maximum value.
164  * @default_value: The control's default value.
165  * @step:	The control's step value for non-menu controls.
166  * @elems:	The number of elements in the N-dimensional array.
167  * @elem_size:	The size in bytes of the control.
168  * @dims:	The size of each dimension.
169  * @nr_of_dims:The number of dimensions in @dims.
170  * @menu_skip_mask: The control's skip mask for menu controls. This makes it
171  *		easy to skip menu items that are not valid. If bit X is set,
172  *		then menu item X is skipped. Of course, this only works for
173  *		menus with <= 32 menu items. There are no menus that come
174  *		close to that number, so this is OK. Should we ever need more,
175  *		then this will have to be extended to a u64 or a bit array.
176  * @qmenu:	A const char * array for all menu items. Array entries that are
177  *		empty strings ("") correspond to non-existing menu items (this
178  *		is in addition to the menu_skip_mask above). The last entry
179  *		must be NULL.
180  *		Used only if the @type is %V4L2_CTRL_TYPE_MENU.
181  * @qmenu_int:	A 64-bit integer array for with integer menu items.
182  *		The size of array must be equal to the menu size, e. g.:
183  *		:math:`ceil(\frac{maximum - minimum}{step}) + 1`.
184  *		Used only if the @type is %V4L2_CTRL_TYPE_INTEGER_MENU.
185  * @flags:	The control's flags.
186  * @cur:	Structure to store the current value.
187  * @cur.val:	The control's current value, if the @type is represented via
188  *		a u32 integer (see &enum v4l2_ctrl_type).
189  * @val:	The control's new s32 value.
190  * @priv:	The control's private pointer. For use by the driver. It is
191  *		untouched by the control framework. Note that this pointer is
192  *		not freed when the control is deleted. Should this be needed
193  *		then a new internal bitfield can be added to tell the framework
194  *		to free this pointer.
195  * @p_cur:	The control's current value represented via a union which
196  *		provides a standard way of accessing control types
197  *		through a pointer.
198  * @p_new:	The control's new value represented via a union which provides
199  *		a standard way of accessing control types
200  *		through a pointer.
201  */
202 struct v4l2_ctrl {
203 	/* Administrative fields */
204 	struct list_head node;
205 	struct list_head ev_subs;
206 	struct v4l2_ctrl_handler *handler;
207 	struct v4l2_ctrl **cluster;
208 	unsigned int ncontrols;
209 
210 	unsigned int done:1;
211 
212 	unsigned int is_new:1;
213 	unsigned int has_changed:1;
214 	unsigned int is_private:1;
215 	unsigned int is_auto:1;
216 	unsigned int is_int:1;
217 	unsigned int is_string:1;
218 	unsigned int is_ptr:1;
219 	unsigned int is_array:1;
220 	unsigned int has_volatiles:1;
221 	unsigned int call_notify:1;
222 	unsigned int manual_mode_value:8;
223 
224 	const struct v4l2_ctrl_ops *ops;
225 	const struct v4l2_ctrl_type_ops *type_ops;
226 	u32 id;
227 	const char *name;
228 	enum v4l2_ctrl_type type;
229 	s64 minimum, maximum, default_value;
230 	u32 elems;
231 	u32 elem_size;
232 	u32 dims[V4L2_CTRL_MAX_DIMS];
233 	u32 nr_of_dims;
234 	union {
235 		u64 step;
236 		u64 menu_skip_mask;
237 	};
238 	union {
239 		const char * const *qmenu;
240 		const s64 *qmenu_int;
241 	};
242 	unsigned long flags;
243 	void *priv;
244 	s32 val;
245 	struct {
246 		s32 val;
247 	} cur;
248 
249 	union v4l2_ctrl_ptr p_new;
250 	union v4l2_ctrl_ptr p_cur;
251 };
252 
253 /**
254  * struct v4l2_ctrl_ref - The control reference.
255  *
256  * @node:	List node for the sorted list.
257  * @next:	Single-link list node for the hash.
258  * @ctrl:	The actual control information.
259  * @helper:	Pointer to helper struct. Used internally in
260  *		``prepare_ext_ctrls`` function at ``v4l2-ctrl.c``.
261  * @from_other_dev: If true, then @ctrl was defined in another
262  *		device than the &struct v4l2_ctrl_handler.
263  * @req_done:	Internal flag: if the control handler containing this control
264  *		reference is bound to a media request, then this is set when
265  *		the control has been applied. This prevents applying controls
266  *		from a cluster with multiple controls twice (when the first
267  *		control of a cluster is applied, they all are).
268  * @req:	If set, this refers to another request that sets this control.
269  * @p_req:	If the control handler containing this control reference
270  *		is bound to a media request, then this points to the
271  *		value of the control that should be applied when the request
272  *		is executed, or to the value of the control at the time
273  *		that the request was completed.
274  *
275  * Each control handler has a list of these refs. The list_head is used to
276  * keep a sorted-by-control-ID list of all controls, while the next pointer
277  * is used to link the control in the hash's bucket.
278  */
279 struct v4l2_ctrl_ref {
280 	struct list_head node;
281 	struct v4l2_ctrl_ref *next;
282 	struct v4l2_ctrl *ctrl;
283 	struct v4l2_ctrl_helper *helper;
284 	bool from_other_dev;
285 	bool req_done;
286 	struct v4l2_ctrl_ref *req;
287 	union v4l2_ctrl_ptr p_req;
288 };
289 
290 /**
291  * struct v4l2_ctrl_handler - The control handler keeps track of all the
292  *	controls: both the controls owned by the handler and those inherited
293  *	from other handlers.
294  *
295  * @_lock:	Default for "lock".
296  * @lock:	Lock to control access to this handler and its controls.
297  *		May be replaced by the user right after init.
298  * @ctrls:	The list of controls owned by this handler.
299  * @ctrl_refs:	The list of control references.
300  * @cached:	The last found control reference. It is common that the same
301  *		control is needed multiple times, so this is a simple
302  *		optimization.
303  * @buckets:	Buckets for the hashing. Allows for quick control lookup.
304  * @notify:	A notify callback that is called whenever the control changes
305  *		value.
306  *		Note that the handler's lock is held when the notify function
307  *		is called!
308  * @notify_priv: Passed as argument to the v4l2_ctrl notify callback.
309  * @nr_of_buckets: Total number of buckets in the array.
310  * @error:	The error code of the first failed control addition.
311  * @request_is_queued: True if the request was queued.
312  * @requests:	List to keep track of open control handler request objects.
313  *		For the parent control handler (@req_obj.req == NULL) this
314  *		is the list header. When the parent control handler is
315  *		removed, it has to unbind and put all these requests since
316  *		they refer to the parent.
317  * @requests_queued: List of the queued requests. This determines the order
318  *		in which these controls are applied. Once the request is
319  *		completed it is removed from this list.
320  * @req_obj:	The &struct media_request_object, used to link into a
321  *		&struct media_request. This request object has a refcount.
322  */
323 struct v4l2_ctrl_handler {
324 	struct mutex _lock;
325 	struct mutex *lock;
326 	struct list_head ctrls;
327 	struct list_head ctrl_refs;
328 	struct v4l2_ctrl_ref *cached;
329 	struct v4l2_ctrl_ref **buckets;
330 	v4l2_ctrl_notify_fnc notify;
331 	void *notify_priv;
332 	u16 nr_of_buckets;
333 	int error;
334 	bool request_is_queued;
335 	struct list_head requests;
336 	struct list_head requests_queued;
337 	struct media_request_object req_obj;
338 };
339 
340 /**
341  * struct v4l2_ctrl_config - Control configuration structure.
342  *
343  * @ops:	The control ops.
344  * @type_ops:	The control type ops. Only needed for compound controls.
345  * @id:	The control ID.
346  * @name:	The control name.
347  * @type:	The control type.
348  * @min:	The control's minimum value.
349  * @max:	The control's maximum value.
350  * @step:	The control's step value for non-menu controls.
351  * @def:	The control's default value.
352  * @dims:	The size of each dimension.
353  * @elem_size:	The size in bytes of the control.
354  * @flags:	The control's flags.
355  * @menu_skip_mask: The control's skip mask for menu controls. This makes it
356  *		easy to skip menu items that are not valid. If bit X is set,
357  *		then menu item X is skipped. Of course, this only works for
358  *		menus with <= 64 menu items. There are no menus that come
359  *		close to that number, so this is OK. Should we ever need more,
360  *		then this will have to be extended to a bit array.
361  * @qmenu:	A const char * array for all menu items. Array entries that are
362  *		empty strings ("") correspond to non-existing menu items (this
363  *		is in addition to the menu_skip_mask above). The last entry
364  *		must be NULL.
365  * @qmenu_int:	A const s64 integer array for all menu items of the type
366  *		V4L2_CTRL_TYPE_INTEGER_MENU.
367  * @is_private: If set, then this control is private to its handler and it
368  *		will not be added to any other handlers.
369  */
370 struct v4l2_ctrl_config {
371 	const struct v4l2_ctrl_ops *ops;
372 	const struct v4l2_ctrl_type_ops *type_ops;
373 	u32 id;
374 	const char *name;
375 	enum v4l2_ctrl_type type;
376 	s64 min;
377 	s64 max;
378 	u64 step;
379 	s64 def;
380 	u32 dims[V4L2_CTRL_MAX_DIMS];
381 	u32 elem_size;
382 	u32 flags;
383 	u64 menu_skip_mask;
384 	const char * const *qmenu;
385 	const s64 *qmenu_int;
386 	unsigned int is_private:1;
387 };
388 
389 /**
390  * v4l2_ctrl_fill - Fill in the control fields based on the control ID.
391  *
392  * @id: ID of the control
393  * @name: pointer to be filled with a string with the name of the control
394  * @type: pointer for storing the type of the control
395  * @min: pointer for storing the minimum value for the control
396  * @max: pointer for storing the maximum value for the control
397  * @step: pointer for storing the control step
398  * @def: pointer for storing the default value for the control
399  * @flags: pointer for storing the flags to be used on the control
400  *
401  * This works for all standard V4L2 controls.
402  * For non-standard controls it will only fill in the given arguments
403  * and @name content will be set to %NULL.
404  *
405  * This function will overwrite the contents of @name, @type and @flags.
406  * The contents of @min, @max, @step and @def may be modified depending on
407  * the type.
408  *
409  * .. note::
410  *
411  *    Do not use in drivers! It is used internally for backwards compatibility
412  *    control handling only. Once all drivers are converted to use the new
413  *    control framework this function will no longer be exported.
414  */
415 void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
416 		    s64 *min, s64 *max, u64 *step, s64 *def, u32 *flags);
417 
418 
419 /**
420  * v4l2_ctrl_handler_init_class() - Initialize the control handler.
421  * @hdl:	The control handler.
422  * @nr_of_controls_hint: A hint of how many controls this handler is
423  *		expected to refer to. This is the total number, so including
424  *		any inherited controls. It doesn't have to be precise, but if
425  *		it is way off, then you either waste memory (too many buckets
426  *		are allocated) or the control lookup becomes slower (not enough
427  *		buckets are allocated, so there are more slow list lookups).
428  *		It will always work, though.
429  * @key:	Used by the lock validator if CONFIG_LOCKDEP is set.
430  * @name:	Used by the lock validator if CONFIG_LOCKDEP is set.
431  *
432  * .. attention::
433  *
434  *    Never use this call directly, always use the v4l2_ctrl_handler_init()
435  *    macro that hides the @key and @name arguments.
436  *
437  * Return: returns an error if the buckets could not be allocated. This
438  * error will also be stored in @hdl->error.
439  */
440 int v4l2_ctrl_handler_init_class(struct v4l2_ctrl_handler *hdl,
441 				 unsigned int nr_of_controls_hint,
442 				 struct lock_class_key *key, const char *name);
443 
444 #ifdef CONFIG_LOCKDEP
445 
446 /**
447  * v4l2_ctrl_handler_init - helper function to create a static struct
448  *	 &lock_class_key and calls v4l2_ctrl_handler_init_class()
449  *
450  * @hdl:	The control handler.
451  * @nr_of_controls_hint: A hint of how many controls this handler is
452  *		expected to refer to. This is the total number, so including
453  *		any inherited controls. It doesn't have to be precise, but if
454  *		it is way off, then you either waste memory (too many buckets
455  *		are allocated) or the control lookup becomes slower (not enough
456  *		buckets are allocated, so there are more slow list lookups).
457  *		It will always work, though.
458  *
459  * This helper function creates a static struct &lock_class_key and
460  * calls v4l2_ctrl_handler_init_class(), providing a proper name for the lock
461  * validador.
462  *
463  * Use this helper function to initialize a control handler.
464  */
465 #define v4l2_ctrl_handler_init(hdl, nr_of_controls_hint)		\
466 (									\
467 	({								\
468 		static struct lock_class_key _key;			\
469 		v4l2_ctrl_handler_init_class(hdl, nr_of_controls_hint,	\
470 					&_key,				\
471 					KBUILD_BASENAME ":"		\
472 					__stringify(__LINE__) ":"	\
473 					"(" #hdl ")->_lock");		\
474 	})								\
475 )
476 #else
477 #define v4l2_ctrl_handler_init(hdl, nr_of_controls_hint)		\
478 	v4l2_ctrl_handler_init_class(hdl, nr_of_controls_hint, NULL, NULL)
479 #endif
480 
481 /**
482  * v4l2_ctrl_handler_free() - Free all controls owned by the handler and free
483  * the control list.
484  * @hdl:	The control handler.
485  *
486  * Does nothing if @hdl == NULL.
487  */
488 void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl);
489 
490 /**
491  * v4l2_ctrl_lock() - Helper function to lock the handler
492  * associated with the control.
493  * @ctrl:	The control to lock.
494  */
495 static inline void v4l2_ctrl_lock(struct v4l2_ctrl *ctrl)
496 {
497 	mutex_lock(ctrl->handler->lock);
498 }
499 
500 /**
501  * v4l2_ctrl_unlock() - Helper function to unlock the handler
502  * associated with the control.
503  * @ctrl:	The control to unlock.
504  */
505 static inline void v4l2_ctrl_unlock(struct v4l2_ctrl *ctrl)
506 {
507 	mutex_unlock(ctrl->handler->lock);
508 }
509 
510 /**
511  * __v4l2_ctrl_handler_setup() - Call the s_ctrl op for all controls belonging
512  * to the handler to initialize the hardware to the current control values. The
513  * caller is responsible for acquiring the control handler mutex on behalf of
514  * __v4l2_ctrl_handler_setup().
515  * @hdl:	The control handler.
516  *
517  * Button controls will be skipped, as are read-only controls.
518  *
519  * If @hdl == NULL, then this just returns 0.
520  */
521 int __v4l2_ctrl_handler_setup(struct v4l2_ctrl_handler *hdl);
522 
523 /**
524  * v4l2_ctrl_handler_setup() - Call the s_ctrl op for all controls belonging
525  * to the handler to initialize the hardware to the current control values.
526  * @hdl:	The control handler.
527  *
528  * Button controls will be skipped, as are read-only controls.
529  *
530  * If @hdl == NULL, then this just returns 0.
531  */
532 int v4l2_ctrl_handler_setup(struct v4l2_ctrl_handler *hdl);
533 
534 /**
535  * v4l2_ctrl_handler_log_status() - Log all controls owned by the handler.
536  * @hdl:	The control handler.
537  * @prefix:	The prefix to use when logging the control values. If the
538  *		prefix does not end with a space, then ": " will be added
539  *		after the prefix. If @prefix == NULL, then no prefix will be
540  *		used.
541  *
542  * For use with VIDIOC_LOG_STATUS.
543  *
544  * Does nothing if @hdl == NULL.
545  */
546 void v4l2_ctrl_handler_log_status(struct v4l2_ctrl_handler *hdl,
547 				  const char *prefix);
548 
549 /**
550  * v4l2_ctrl_new_custom() - Allocate and initialize a new custom V4L2
551  *	control.
552  *
553  * @hdl:	The control handler.
554  * @cfg:	The control's configuration data.
555  * @priv:	The control's driver-specific private data.
556  *
557  * If the &v4l2_ctrl struct could not be allocated then NULL is returned
558  * and @hdl->error is set to the error code (if it wasn't set already).
559  */
560 struct v4l2_ctrl *v4l2_ctrl_new_custom(struct v4l2_ctrl_handler *hdl,
561 				       const struct v4l2_ctrl_config *cfg,
562 				       void *priv);
563 
564 /**
565  * v4l2_ctrl_new_std() - Allocate and initialize a new standard V4L2 non-menu
566  *	control.
567  *
568  * @hdl:	The control handler.
569  * @ops:	The control ops.
570  * @id:		The control ID.
571  * @min:	The control's minimum value.
572  * @max:	The control's maximum value.
573  * @step:	The control's step value
574  * @def:	The control's default value.
575  *
576  * If the &v4l2_ctrl struct could not be allocated, or the control
577  * ID is not known, then NULL is returned and @hdl->error is set to the
578  * appropriate error code (if it wasn't set already).
579  *
580  * If @id refers to a menu control, then this function will return NULL.
581  *
582  * Use v4l2_ctrl_new_std_menu() when adding menu controls.
583  */
584 struct v4l2_ctrl *v4l2_ctrl_new_std(struct v4l2_ctrl_handler *hdl,
585 				    const struct v4l2_ctrl_ops *ops,
586 				    u32 id, s64 min, s64 max, u64 step,
587 				    s64 def);
588 
589 /**
590  * v4l2_ctrl_new_std_menu() - Allocate and initialize a new standard V4L2
591  *	menu control.
592  *
593  * @hdl:	The control handler.
594  * @ops:	The control ops.
595  * @id:		The control ID.
596  * @max:	The control's maximum value.
597  * @mask:	The control's skip mask for menu controls. This makes it
598  *		easy to skip menu items that are not valid. If bit X is set,
599  *		then menu item X is skipped. Of course, this only works for
600  *		menus with <= 64 menu items. There are no menus that come
601  *		close to that number, so this is OK. Should we ever need more,
602  *		then this will have to be extended to a bit array.
603  * @def:	The control's default value.
604  *
605  * Same as v4l2_ctrl_new_std(), but @min is set to 0 and the @mask value
606  * determines which menu items are to be skipped.
607  *
608  * If @id refers to a non-menu control, then this function will return NULL.
609  */
610 struct v4l2_ctrl *v4l2_ctrl_new_std_menu(struct v4l2_ctrl_handler *hdl,
611 					 const struct v4l2_ctrl_ops *ops,
612 					 u32 id, u8 max, u64 mask, u8 def);
613 
614 /**
615  * v4l2_ctrl_new_std_menu_items() - Create a new standard V4L2 menu control
616  *	with driver specific menu.
617  *
618  * @hdl:	The control handler.
619  * @ops:	The control ops.
620  * @id:	The control ID.
621  * @max:	The control's maximum value.
622  * @mask:	The control's skip mask for menu controls. This makes it
623  *		easy to skip menu items that are not valid. If bit X is set,
624  *		then menu item X is skipped. Of course, this only works for
625  *		menus with <= 64 menu items. There are no menus that come
626  *		close to that number, so this is OK. Should we ever need more,
627  *		then this will have to be extended to a bit array.
628  * @def:	The control's default value.
629  * @qmenu:	The new menu.
630  *
631  * Same as v4l2_ctrl_new_std_menu(), but @qmenu will be the driver specific
632  * menu of this control.
633  *
634  */
635 struct v4l2_ctrl *v4l2_ctrl_new_std_menu_items(struct v4l2_ctrl_handler *hdl,
636 					       const struct v4l2_ctrl_ops *ops,
637 					       u32 id, u8 max,
638 					       u64 mask, u8 def,
639 					       const char * const *qmenu);
640 
641 /**
642  * v4l2_ctrl_new_int_menu() - Create a new standard V4L2 integer menu control.
643  *
644  * @hdl:	The control handler.
645  * @ops:	The control ops.
646  * @id:	The control ID.
647  * @max:	The control's maximum value.
648  * @def:	The control's default value.
649  * @qmenu_int:	The control's menu entries.
650  *
651  * Same as v4l2_ctrl_new_std_menu(), but @mask is set to 0 and it additionally
652  * takes as an argument an array of integers determining the menu items.
653  *
654  * If @id refers to a non-integer-menu control, then this function will
655  * return %NULL.
656  */
657 struct v4l2_ctrl *v4l2_ctrl_new_int_menu(struct v4l2_ctrl_handler *hdl,
658 					 const struct v4l2_ctrl_ops *ops,
659 					 u32 id, u8 max, u8 def,
660 					 const s64 *qmenu_int);
661 
662 /**
663  * typedef v4l2_ctrl_filter - Typedef to define the filter function to be
664  *	used when adding a control handler.
665  *
666  * @ctrl: pointer to struct &v4l2_ctrl.
667  */
668 
669 typedef bool (*v4l2_ctrl_filter)(const struct v4l2_ctrl *ctrl);
670 
671 /**
672  * v4l2_ctrl_add_handler() - Add all controls from handler @add to
673  *	handler @hdl.
674  *
675  * @hdl:	The control handler.
676  * @add:	The control handler whose controls you want to add to
677  *		the @hdl control handler.
678  * @filter:	This function will filter which controls should be added.
679  * @from_other_dev: If true, then the controls in @add were defined in another
680  *		device than @hdl.
681  *
682  * Does nothing if either of the two handlers is a NULL pointer.
683  * If @filter is NULL, then all controls are added. Otherwise only those
684  * controls for which @filter returns true will be added.
685  * In case of an error @hdl->error will be set to the error code (if it
686  * wasn't set already).
687  */
688 int v4l2_ctrl_add_handler(struct v4l2_ctrl_handler *hdl,
689 			  struct v4l2_ctrl_handler *add,
690 			  v4l2_ctrl_filter filter,
691 			  bool from_other_dev);
692 
693 /**
694  * v4l2_ctrl_radio_filter() - Standard filter for radio controls.
695  *
696  * @ctrl:	The control that is filtered.
697  *
698  * This will return true for any controls that are valid for radio device
699  * nodes. Those are all of the V4L2_CID_AUDIO_* user controls and all FM
700  * transmitter class controls.
701  *
702  * This function is to be used with v4l2_ctrl_add_handler().
703  */
704 bool v4l2_ctrl_radio_filter(const struct v4l2_ctrl *ctrl);
705 
706 /**
707  * v4l2_ctrl_cluster() - Mark all controls in the cluster as belonging
708  *	to that cluster.
709  *
710  * @ncontrols:	The number of controls in this cluster.
711  * @controls:	The cluster control array of size @ncontrols.
712  */
713 void v4l2_ctrl_cluster(unsigned int ncontrols, struct v4l2_ctrl **controls);
714 
715 
716 /**
717  * v4l2_ctrl_auto_cluster() - Mark all controls in the cluster as belonging
718  *	to that cluster and set it up for autofoo/foo-type handling.
719  *
720  * @ncontrols:	The number of controls in this cluster.
721  * @controls:	The cluster control array of size @ncontrols. The first control
722  *		must be the 'auto' control (e.g. autogain, autoexposure, etc.)
723  * @manual_val: The value for the first control in the cluster that equals the
724  *		manual setting.
725  * @set_volatile: If true, then all controls except the first auto control will
726  *		be volatile.
727  *
728  * Use for control groups where one control selects some automatic feature and
729  * the other controls are only active whenever the automatic feature is turned
730  * off (manual mode). Typical examples: autogain vs gain, auto-whitebalance vs
731  * red and blue balance, etc.
732  *
733  * The behavior of such controls is as follows:
734  *
735  * When the autofoo control is set to automatic, then any manual controls
736  * are set to inactive and any reads will call g_volatile_ctrl (if the control
737  * was marked volatile).
738  *
739  * When the autofoo control is set to manual, then any manual controls will
740  * be marked active, and any reads will just return the current value without
741  * going through g_volatile_ctrl.
742  *
743  * In addition, this function will set the %V4L2_CTRL_FLAG_UPDATE flag
744  * on the autofoo control and %V4L2_CTRL_FLAG_INACTIVE on the foo control(s)
745  * if autofoo is in auto mode.
746  */
747 void v4l2_ctrl_auto_cluster(unsigned int ncontrols,
748 			    struct v4l2_ctrl **controls,
749 			    u8 manual_val, bool set_volatile);
750 
751 
752 /**
753  * v4l2_ctrl_find() - Find a control with the given ID.
754  *
755  * @hdl:	The control handler.
756  * @id:	The control ID to find.
757  *
758  * If @hdl == NULL this will return NULL as well. Will lock the handler so
759  * do not use from inside &v4l2_ctrl_ops.
760  */
761 struct v4l2_ctrl *v4l2_ctrl_find(struct v4l2_ctrl_handler *hdl, u32 id);
762 
763 /**
764  * v4l2_ctrl_activate() - Make the control active or inactive.
765  * @ctrl:	The control to (de)activate.
766  * @active:	True if the control should become active.
767  *
768  * This sets or clears the V4L2_CTRL_FLAG_INACTIVE flag atomically.
769  * Does nothing if @ctrl == NULL.
770  * This will usually be called from within the s_ctrl op.
771  * The V4L2_EVENT_CTRL event will be generated afterwards.
772  *
773  * This function assumes that the control handler is locked.
774  */
775 void v4l2_ctrl_activate(struct v4l2_ctrl *ctrl, bool active);
776 
777 /**
778  * __v4l2_ctrl_grab() - Unlocked variant of v4l2_ctrl_grab.
779  *
780  * @ctrl:	The control to (de)activate.
781  * @grabbed:	True if the control should become grabbed.
782  *
783  * This sets or clears the V4L2_CTRL_FLAG_GRABBED flag atomically.
784  * Does nothing if @ctrl == NULL.
785  * The V4L2_EVENT_CTRL event will be generated afterwards.
786  * This will usually be called when starting or stopping streaming in the
787  * driver.
788  *
789  * This function assumes that the control handler is locked by the caller.
790  */
791 void __v4l2_ctrl_grab(struct v4l2_ctrl *ctrl, bool grabbed);
792 
793 /**
794  * v4l2_ctrl_grab() - Mark the control as grabbed or not grabbed.
795  *
796  * @ctrl:	The control to (de)activate.
797  * @grabbed:	True if the control should become grabbed.
798  *
799  * This sets or clears the V4L2_CTRL_FLAG_GRABBED flag atomically.
800  * Does nothing if @ctrl == NULL.
801  * The V4L2_EVENT_CTRL event will be generated afterwards.
802  * This will usually be called when starting or stopping streaming in the
803  * driver.
804  *
805  * This function assumes that the control handler is not locked and will
806  * take the lock itself.
807  */
808 static inline void v4l2_ctrl_grab(struct v4l2_ctrl *ctrl, bool grabbed)
809 {
810 	if (!ctrl)
811 		return;
812 
813 	v4l2_ctrl_lock(ctrl);
814 	__v4l2_ctrl_grab(ctrl, grabbed);
815 	v4l2_ctrl_unlock(ctrl);
816 }
817 
818 /**
819  *__v4l2_ctrl_modify_range() - Unlocked variant of v4l2_ctrl_modify_range()
820  *
821  * @ctrl:	The control to update.
822  * @min:	The control's minimum value.
823  * @max:	The control's maximum value.
824  * @step:	The control's step value
825  * @def:	The control's default value.
826  *
827  * Update the range of a control on the fly. This works for control types
828  * INTEGER, BOOLEAN, MENU, INTEGER MENU and BITMASK. For menu controls the
829  * @step value is interpreted as a menu_skip_mask.
830  *
831  * An error is returned if one of the range arguments is invalid for this
832  * control type.
833  *
834  * The caller is responsible for acquiring the control handler mutex on behalf
835  * of __v4l2_ctrl_modify_range().
836  */
837 int __v4l2_ctrl_modify_range(struct v4l2_ctrl *ctrl,
838 			     s64 min, s64 max, u64 step, s64 def);
839 
840 /**
841  * v4l2_ctrl_modify_range() - Update the range of a control.
842  *
843  * @ctrl:	The control to update.
844  * @min:	The control's minimum value.
845  * @max:	The control's maximum value.
846  * @step:	The control's step value
847  * @def:	The control's default value.
848  *
849  * Update the range of a control on the fly. This works for control types
850  * INTEGER, BOOLEAN, MENU, INTEGER MENU and BITMASK. For menu controls the
851  * @step value is interpreted as a menu_skip_mask.
852  *
853  * An error is returned if one of the range arguments is invalid for this
854  * control type.
855  *
856  * This function assumes that the control handler is not locked and will
857  * take the lock itself.
858  */
859 static inline int v4l2_ctrl_modify_range(struct v4l2_ctrl *ctrl,
860 					 s64 min, s64 max, u64 step, s64 def)
861 {
862 	int rval;
863 
864 	v4l2_ctrl_lock(ctrl);
865 	rval = __v4l2_ctrl_modify_range(ctrl, min, max, step, def);
866 	v4l2_ctrl_unlock(ctrl);
867 
868 	return rval;
869 }
870 
871 /**
872  * v4l2_ctrl_notify() - Function to set a notify callback for a control.
873  *
874  * @ctrl:	The control.
875  * @notify:	The callback function.
876  * @priv:	The callback private handle, passed as argument to the callback.
877  *
878  * This function sets a callback function for the control. If @ctrl is NULL,
879  * then it will do nothing. If @notify is NULL, then the notify callback will
880  * be removed.
881  *
882  * There can be only one notify. If another already exists, then a WARN_ON
883  * will be issued and the function will do nothing.
884  */
885 void v4l2_ctrl_notify(struct v4l2_ctrl *ctrl, v4l2_ctrl_notify_fnc notify,
886 		      void *priv);
887 
888 /**
889  * v4l2_ctrl_get_name() - Get the name of the control
890  *
891  * @id:		The control ID.
892  *
893  * This function returns the name of the given control ID or NULL if it isn't
894  * a known control.
895  */
896 const char *v4l2_ctrl_get_name(u32 id);
897 
898 /**
899  * v4l2_ctrl_get_menu() - Get the menu string array of the control
900  *
901  * @id:		The control ID.
902  *
903  * This function returns the NULL-terminated menu string array name of the
904  * given control ID or NULL if it isn't a known menu control.
905  */
906 const char * const *v4l2_ctrl_get_menu(u32 id);
907 
908 /**
909  * v4l2_ctrl_get_int_menu() - Get the integer menu array of the control
910  *
911  * @id:		The control ID.
912  * @len:	The size of the integer array.
913  *
914  * This function returns the integer array of the given control ID or NULL if it
915  * if it isn't a known integer menu control.
916  */
917 const s64 *v4l2_ctrl_get_int_menu(u32 id, u32 *len);
918 
919 /**
920  * v4l2_ctrl_g_ctrl() - Helper function to get the control's value from
921  *	within a driver.
922  *
923  * @ctrl:	The control.
924  *
925  * This returns the control's value safely by going through the control
926  * framework. This function will lock the control's handler, so it cannot be
927  * used from within the &v4l2_ctrl_ops functions.
928  *
929  * This function is for integer type controls only.
930  */
931 s32 v4l2_ctrl_g_ctrl(struct v4l2_ctrl *ctrl);
932 
933 /**
934  * __v4l2_ctrl_s_ctrl() - Unlocked variant of v4l2_ctrl_s_ctrl().
935  *
936  * @ctrl:	The control.
937  * @val:	TheControls name new value.
938  *
939  * This sets the control's new value safely by going through the control
940  * framework. This function assumes the control's handler is already locked,
941  * allowing it to be used from within the &v4l2_ctrl_ops functions.
942  *
943  * This function is for integer type controls only.
944  */
945 int __v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val);
946 
947 /**
948  * v4l2_ctrl_s_ctrl() - Helper function to set the control's value from
949  *	within a driver.
950  * @ctrl:	The control.
951  * @val:	The new value.
952  *
953  * This sets the control's new value safely by going through the control
954  * framework. This function will lock the control's handler, so it cannot be
955  * used from within the &v4l2_ctrl_ops functions.
956  *
957  * This function is for integer type controls only.
958  */
959 static inline int v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val)
960 {
961 	int rval;
962 
963 	v4l2_ctrl_lock(ctrl);
964 	rval = __v4l2_ctrl_s_ctrl(ctrl, val);
965 	v4l2_ctrl_unlock(ctrl);
966 
967 	return rval;
968 }
969 
970 /**
971  * v4l2_ctrl_g_ctrl_int64() - Helper function to get a 64-bit control's value
972  *	from within a driver.
973  *
974  * @ctrl:	The control.
975  *
976  * This returns the control's value safely by going through the control
977  * framework. This function will lock the control's handler, so it cannot be
978  * used from within the &v4l2_ctrl_ops functions.
979  *
980  * This function is for 64-bit integer type controls only.
981  */
982 s64 v4l2_ctrl_g_ctrl_int64(struct v4l2_ctrl *ctrl);
983 
984 /**
985  * __v4l2_ctrl_s_ctrl_int64() - Unlocked variant of v4l2_ctrl_s_ctrl_int64().
986  *
987  * @ctrl:	The control.
988  * @val:	The new value.
989  *
990  * This sets the control's new value safely by going through the control
991  * framework. This function assumes the control's handler is already locked,
992  * allowing it to be used from within the &v4l2_ctrl_ops functions.
993  *
994  * This function is for 64-bit integer type controls only.
995  */
996 int __v4l2_ctrl_s_ctrl_int64(struct v4l2_ctrl *ctrl, s64 val);
997 
998 /**
999  * v4l2_ctrl_s_ctrl_int64() - Helper function to set a 64-bit control's value
1000  *	from within a driver.
1001  *
1002  * @ctrl:	The control.
1003  * @val:	The new value.
1004  *
1005  * This sets the control's new value safely by going through the control
1006  * framework. This function will lock the control's handler, so it cannot be
1007  * used from within the &v4l2_ctrl_ops functions.
1008  *
1009  * This function is for 64-bit integer type controls only.
1010  */
1011 static inline int v4l2_ctrl_s_ctrl_int64(struct v4l2_ctrl *ctrl, s64 val)
1012 {
1013 	int rval;
1014 
1015 	v4l2_ctrl_lock(ctrl);
1016 	rval = __v4l2_ctrl_s_ctrl_int64(ctrl, val);
1017 	v4l2_ctrl_unlock(ctrl);
1018 
1019 	return rval;
1020 }
1021 
1022 /**
1023  * __v4l2_ctrl_s_ctrl_string() - Unlocked variant of v4l2_ctrl_s_ctrl_string().
1024  *
1025  * @ctrl:	The control.
1026  * @s:		The new string.
1027  *
1028  * This sets the control's new string safely by going through the control
1029  * framework. This function assumes the control's handler is already locked,
1030  * allowing it to be used from within the &v4l2_ctrl_ops functions.
1031  *
1032  * This function is for string type controls only.
1033  */
1034 int __v4l2_ctrl_s_ctrl_string(struct v4l2_ctrl *ctrl, const char *s);
1035 
1036 /**
1037  * v4l2_ctrl_s_ctrl_string() - Helper function to set a control's string value
1038  *	 from within a driver.
1039  *
1040  * @ctrl:	The control.
1041  * @s:		The new string.
1042  *Controls name
1043  * This sets the control's new string safely by going through the control
1044  * framework. This function will lock the control's handler, so it cannot be
1045  * used from within the &v4l2_ctrl_ops functions.
1046  *
1047  * This function is for string type controls only.
1048  */
1049 static inline int v4l2_ctrl_s_ctrl_string(struct v4l2_ctrl *ctrl, const char *s)
1050 {
1051 	int rval;
1052 
1053 	v4l2_ctrl_lock(ctrl);
1054 	rval = __v4l2_ctrl_s_ctrl_string(ctrl, s);
1055 	v4l2_ctrl_unlock(ctrl);
1056 
1057 	return rval;
1058 }
1059 
1060 /* Internal helper functions that deal with control events. */
1061 extern const struct v4l2_subscribed_event_ops v4l2_ctrl_sub_ev_ops;
1062 
1063 /**
1064  * v4l2_ctrl_replace - Function to be used as a callback to
1065  *	&struct v4l2_subscribed_event_ops replace\(\)
1066  *
1067  * @old: pointer to struct &v4l2_event with the reported
1068  *	 event;
1069  * @new: pointer to struct &v4l2_event with the modified
1070  *	 event;
1071  */
1072 void v4l2_ctrl_replace(struct v4l2_event *old, const struct v4l2_event *new);
1073 
1074 /**
1075  * v4l2_ctrl_merge - Function to be used as a callback to
1076  *	&struct v4l2_subscribed_event_ops merge(\)
1077  *
1078  * @old: pointer to struct &v4l2_event with the reported
1079  *	 event;
1080  * @new: pointer to struct &v4l2_event with the merged
1081  *	 event;
1082  */
1083 void v4l2_ctrl_merge(const struct v4l2_event *old, struct v4l2_event *new);
1084 
1085 /**
1086  * v4l2_ctrl_log_status - helper function to implement %VIDIOC_LOG_STATUS ioctl
1087  *
1088  * @file: pointer to struct file
1089  * @fh: unused. Kept just to be compatible to the arguments expected by
1090  *	&struct v4l2_ioctl_ops.vidioc_log_status.
1091  *
1092  * Can be used as a vidioc_log_status function that just dumps all controls
1093  * associated with the filehandle.
1094  */
1095 int v4l2_ctrl_log_status(struct file *file, void *fh);
1096 
1097 /**
1098  * v4l2_ctrl_subscribe_event - Subscribes to an event
1099  *
1100  *
1101  * @fh: pointer to struct v4l2_fh
1102  * @sub: pointer to &struct v4l2_event_subscription
1103  *
1104  * Can be used as a vidioc_subscribe_event function that just subscribes
1105  * control events.
1106  */
1107 int v4l2_ctrl_subscribe_event(struct v4l2_fh *fh,
1108 				const struct v4l2_event_subscription *sub);
1109 
1110 /**
1111  * v4l2_ctrl_poll - function to be used as a callback to the poll()
1112  *	That just polls for control events.
1113  *
1114  * @file: pointer to struct file
1115  * @wait: pointer to struct poll_table_struct
1116  */
1117 __poll_t v4l2_ctrl_poll(struct file *file, struct poll_table_struct *wait);
1118 
1119 /**
1120  * v4l2_ctrl_request_setup - helper function to apply control values in a request
1121  *
1122  * @req: The request
1123  * @parent: The parent control handler ('priv' in media_request_object_find())
1124  *
1125  * This is a helper function to call the control handler's s_ctrl callback with
1126  * the control values contained in the request. Do note that this approach of
1127  * applying control values in a request is only applicable to memory-to-memory
1128  * devices.
1129  */
1130 void v4l2_ctrl_request_setup(struct media_request *req,
1131 			     struct v4l2_ctrl_handler *parent);
1132 
1133 /**
1134  * v4l2_ctrl_request_complete - Complete a control handler request object
1135  *
1136  * @req: The request
1137  * @parent: The parent control handler ('priv' in media_request_object_find())
1138  *
1139  * This function is to be called on each control handler that may have had a
1140  * request object associated with it, i.e. control handlers of a driver that
1141  * supports requests.
1142  *
1143  * The function first obtains the values of any volatile controls in the control
1144  * handler and attach them to the request. Then, the function completes the
1145  * request object.
1146  */
1147 void v4l2_ctrl_request_complete(struct media_request *req,
1148 				struct v4l2_ctrl_handler *parent);
1149 
1150 /**
1151  * v4l2_ctrl_request_hdl_find - Find the control handler in the request
1152  *
1153  * @req: The request
1154  * @parent: The parent control handler ('priv' in media_request_object_find())
1155  *
1156  * This function finds the control handler in the request. It may return
1157  * NULL if not found. When done, you must call v4l2_ctrl_request_put_hdl()
1158  * with the returned handler pointer.
1159  *
1160  * If the request is not in state VALIDATING or QUEUED, then this function
1161  * will always return NULL.
1162  *
1163  * Note that in state VALIDATING the req_queue_mutex is held, so
1164  * no objects can be added or deleted from the request.
1165  *
1166  * In state QUEUED it is the driver that will have to ensure this.
1167  */
1168 struct v4l2_ctrl_handler *v4l2_ctrl_request_hdl_find(struct media_request *req,
1169 					struct v4l2_ctrl_handler *parent);
1170 
1171 /**
1172  * v4l2_ctrl_request_hdl_put - Put the control handler
1173  *
1174  * @hdl: Put this control handler
1175  *
1176  * This function released the control handler previously obtained from'
1177  * v4l2_ctrl_request_hdl_find().
1178  */
1179 static inline void v4l2_ctrl_request_hdl_put(struct v4l2_ctrl_handler *hdl)
1180 {
1181 	if (hdl)
1182 		media_request_object_put(&hdl->req_obj);
1183 }
1184 
1185 /**
1186  * v4l2_ctrl_request_ctrl_find() - Find a control with the given ID.
1187  *
1188  * @hdl: The control handler from the request.
1189  * @id: The ID of the control to find.
1190  *
1191  * This function returns a pointer to the control if this control is
1192  * part of the request or NULL otherwise.
1193  */
1194 struct v4l2_ctrl *
1195 v4l2_ctrl_request_hdl_ctrl_find(struct v4l2_ctrl_handler *hdl, u32 id);
1196 
1197 /* Helpers for ioctl_ops */
1198 
1199 /**
1200  * v4l2_queryctrl - Helper function to implement
1201  *	:ref:`VIDIOC_QUERYCTRL <vidioc_queryctrl>` ioctl
1202  *
1203  * @hdl: pointer to &struct v4l2_ctrl_handler
1204  * @qc: pointer to &struct v4l2_queryctrl
1205  *
1206  * If hdl == NULL then they will all return -EINVAL.
1207  */
1208 int v4l2_queryctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_queryctrl *qc);
1209 
1210 /**
1211  * v4l2_query_ext_ctrl - Helper function to implement
1212  *	 :ref:`VIDIOC_QUERY_EXT_CTRL <vidioc_queryctrl>` ioctl
1213  *
1214  * @hdl: pointer to &struct v4l2_ctrl_handler
1215  * @qc: pointer to &struct v4l2_query_ext_ctrl
1216  *
1217  * If hdl == NULL then they will all return -EINVAL.
1218  */
1219 int v4l2_query_ext_ctrl(struct v4l2_ctrl_handler *hdl,
1220 			struct v4l2_query_ext_ctrl *qc);
1221 
1222 /**
1223  * v4l2_querymenu - Helper function to implement
1224  *	:ref:`VIDIOC_QUERYMENU <vidioc_queryctrl>` ioctl
1225  *
1226  * @hdl: pointer to &struct v4l2_ctrl_handler
1227  * @qm: pointer to &struct v4l2_querymenu
1228  *
1229  * If hdl == NULL then they will all return -EINVAL.
1230  */
1231 int v4l2_querymenu(struct v4l2_ctrl_handler *hdl, struct v4l2_querymenu *qm);
1232 
1233 /**
1234  * v4l2_g_ctrl - Helper function to implement
1235  *	:ref:`VIDIOC_G_CTRL <vidioc_g_ctrl>` ioctl
1236  *
1237  * @hdl: pointer to &struct v4l2_ctrl_handler
1238  * @ctrl: pointer to &struct v4l2_control
1239  *
1240  * If hdl == NULL then they will all return -EINVAL.
1241  */
1242 int v4l2_g_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_control *ctrl);
1243 
1244 /**
1245  * v4l2_s_ctrl - Helper function to implement
1246  *	:ref:`VIDIOC_S_CTRL <vidioc_g_ctrl>` ioctl
1247  *
1248  * @fh: pointer to &struct v4l2_fh
1249  * @hdl: pointer to &struct v4l2_ctrl_handler
1250  *
1251  * @ctrl: pointer to &struct v4l2_control
1252  *
1253  * If hdl == NULL then they will all return -EINVAL.
1254  */
1255 int v4l2_s_ctrl(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
1256 		struct v4l2_control *ctrl);
1257 
1258 /**
1259  * v4l2_g_ext_ctrls - Helper function to implement
1260  *	:ref:`VIDIOC_G_EXT_CTRLS <vidioc_g_ext_ctrls>` ioctl
1261  *
1262  * @hdl: pointer to &struct v4l2_ctrl_handler
1263  * @mdev: pointer to &struct media_device
1264  * @c: pointer to &struct v4l2_ext_controls
1265  *
1266  * If hdl == NULL then they will all return -EINVAL.
1267  */
1268 int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct media_device *mdev,
1269 		     struct v4l2_ext_controls *c);
1270 
1271 /**
1272  * v4l2_try_ext_ctrls - Helper function to implement
1273  *	:ref:`VIDIOC_TRY_EXT_CTRLS <vidioc_g_ext_ctrls>` ioctl
1274  *
1275  * @hdl: pointer to &struct v4l2_ctrl_handler
1276  * @mdev: pointer to &struct media_device
1277  * @c: pointer to &struct v4l2_ext_controls
1278  *
1279  * If hdl == NULL then they will all return -EINVAL.
1280  */
1281 int v4l2_try_ext_ctrls(struct v4l2_ctrl_handler *hdl,
1282 		       struct media_device *mdev,
1283 		       struct v4l2_ext_controls *c);
1284 
1285 /**
1286  * v4l2_s_ext_ctrls - Helper function to implement
1287  *	:ref:`VIDIOC_S_EXT_CTRLS <vidioc_g_ext_ctrls>` ioctl
1288  *
1289  * @fh: pointer to &struct v4l2_fh
1290  * @hdl: pointer to &struct v4l2_ctrl_handler
1291  * @mdev: pointer to &struct media_device
1292  * @c: pointer to &struct v4l2_ext_controls
1293  *
1294  * If hdl == NULL then they will all return -EINVAL.
1295  */
1296 int v4l2_s_ext_ctrls(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
1297 		     struct media_device *mdev,
1298 		     struct v4l2_ext_controls *c);
1299 
1300 /**
1301  * v4l2_ctrl_subdev_subscribe_event - Helper function to implement
1302  *	as a &struct v4l2_subdev_core_ops subscribe_event function
1303  *	that just subscribes control events.
1304  *
1305  * @sd: pointer to &struct v4l2_subdev
1306  * @fh: pointer to &struct v4l2_fh
1307  * @sub: pointer to &struct v4l2_event_subscription
1308  */
1309 int v4l2_ctrl_subdev_subscribe_event(struct v4l2_subdev *sd, struct v4l2_fh *fh,
1310 				     struct v4l2_event_subscription *sub);
1311 
1312 /**
1313  * v4l2_ctrl_subdev_log_status - Log all controls owned by subdev's control
1314  *	 handler.
1315  *
1316  * @sd: pointer to &struct v4l2_subdev
1317  */
1318 int v4l2_ctrl_subdev_log_status(struct v4l2_subdev *sd);
1319 
1320 #endif
1321