xref: /linux/include/media/v4l2-ctrls.h (revision c0c914eca7f251c70facc37dfebeaf176601918d)
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     You should have received a copy of the GNU General Public License
17     along with this program; if not, write to the Free Software
18     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
19  */
20 
21 #ifndef _V4L2_CTRLS_H
22 #define _V4L2_CTRLS_H
23 
24 #include <linux/list.h>
25 #include <linux/mutex.h>
26 #include <linux/videodev2.h>
27 
28 /* forward references */
29 struct file;
30 struct v4l2_ctrl_handler;
31 struct v4l2_ctrl_helper;
32 struct v4l2_ctrl;
33 struct video_device;
34 struct v4l2_subdev;
35 struct v4l2_subscribed_event;
36 struct v4l2_fh;
37 struct poll_table_struct;
38 
39 /**
40  * union v4l2_ctrl_ptr - A pointer to a control value.
41  * @p_s32:	Pointer to a 32-bit signed value.
42  * @p_s64:	Pointer to a 64-bit signed value.
43  * @p_u8:	Pointer to a 8-bit unsigned value.
44  * @p_u16:	Pointer to a 16-bit unsigned value.
45  * @p_u32:	Pointer to a 32-bit unsigned value.
46  * @p_char:	Pointer to a string.
47  * @p:		Pointer to a compound value.
48  */
49 union v4l2_ctrl_ptr {
50 	s32 *p_s32;
51 	s64 *p_s64;
52 	u8 *p_u8;
53 	u16 *p_u16;
54 	u32 *p_u32;
55 	char *p_char;
56 	void *p;
57 };
58 
59 /**
60  * struct v4l2_ctrl_ops - The control operations that the driver has to provide.
61  * @g_volatile_ctrl: Get a new value for this control. Generally only relevant
62  *		for volatile (and usually read-only) controls such as a control
63  *		that returns the current signal strength which changes
64  *		continuously.
65  *		If not set, then the currently cached value will be returned.
66  * @try_ctrl:	Test whether the control's value is valid. Only relevant when
67  *		the usual min/max/step checks are not sufficient.
68  * @s_ctrl:	Actually set the new control value. s_ctrl is compulsory. The
69  *		ctrl->handler->lock is held when these ops are called, so no
70  *		one else can access controls owned by that handler.
71  */
72 struct v4l2_ctrl_ops {
73 	int (*g_volatile_ctrl)(struct v4l2_ctrl *ctrl);
74 	int (*try_ctrl)(struct v4l2_ctrl *ctrl);
75 	int (*s_ctrl)(struct v4l2_ctrl *ctrl);
76 };
77 
78 /**
79  * struct v4l2_ctrl_type_ops - The control type operations that the driver
80  * 			       has to provide.
81  *
82  * @equal: return true if both values are equal.
83  * @init: initialize the value.
84  * @log: log the value.
85  * @validate: validate the value. Return 0 on success and a negative value otherwise.
86  */
87 struct v4l2_ctrl_type_ops {
88 	bool (*equal)(const struct v4l2_ctrl *ctrl, u32 idx,
89 		      union v4l2_ctrl_ptr ptr1,
90 		      union v4l2_ctrl_ptr ptr2);
91 	void (*init)(const struct v4l2_ctrl *ctrl, u32 idx,
92 		     union v4l2_ctrl_ptr ptr);
93 	void (*log)(const struct v4l2_ctrl *ctrl);
94 	int (*validate)(const struct v4l2_ctrl *ctrl, u32 idx,
95 			union v4l2_ctrl_ptr ptr);
96 };
97 
98 typedef void (*v4l2_ctrl_notify_fnc)(struct v4l2_ctrl *ctrl, void *priv);
99 
100 /**
101  * struct v4l2_ctrl - The control structure.
102  * @node:	The list node.
103  * @ev_subs:	The list of control event subscriptions.
104  * @handler:	The handler that owns the control.
105  * @cluster:	Point to start of cluster array.
106  * @ncontrols:	Number of controls in cluster array.
107  * @done:	Internal flag: set for each processed control.
108  * @is_new:	Set when the user specified a new value for this control. It
109  *		is also set when called from v4l2_ctrl_handler_setup. Drivers
110  *		should never set this flag.
111  * @has_changed: Set when the current value differs from the new value. Drivers
112  *		should never use this flag.
113  * @is_private: If set, then this control is private to its handler and it
114  *		will not be added to any other handlers. Drivers can set
115  *		this flag.
116  * @is_auto:   If set, then this control selects whether the other cluster
117  *		members are in 'automatic' mode or 'manual' mode. This is
118  *		used for autogain/gain type clusters. Drivers should never
119  *		set this flag directly.
120  * @is_int:    If set, then this control has a simple integer value (i.e. it
121  *		uses ctrl->val).
122  * @is_string: If set, then this control has type V4L2_CTRL_TYPE_STRING.
123  * @is_ptr:	If set, then this control is an array and/or has type >= V4L2_CTRL_COMPOUND_TYPES
124  *		and/or has type V4L2_CTRL_TYPE_STRING. In other words, struct
125  *		v4l2_ext_control uses field p to point to the data.
126  * @is_array: If set, then this control contains an N-dimensional array.
127  * @has_volatiles: If set, then one or more members of the cluster are volatile.
128  *		Drivers should never touch this flag.
129  * @call_notify: If set, then call the handler's notify function whenever the
130  *		control's value changes.
131  * @manual_mode_value: If the is_auto flag is set, then this is the value
132  *		of the auto control that determines if that control is in
133  *		manual mode. So if the value of the auto control equals this
134  *		value, then the whole cluster is in manual mode. Drivers should
135  *		never set this flag directly.
136  * @ops:	The control ops.
137  * @type_ops:	The control type ops.
138  * @id:	The control ID.
139  * @name:	The control name.
140  * @type:	The control type.
141  * @minimum:	The control's minimum value.
142  * @maximum:	The control's maximum value.
143  * @default_value: The control's default value.
144  * @step:	The control's step value for non-menu controls.
145  * @elems:	The number of elements in the N-dimensional array.
146  * @elem_size:	The size in bytes of the control.
147  * @dims:	The size of each dimension.
148  * @nr_of_dims:The number of dimensions in @dims.
149  * @menu_skip_mask: The control's skip mask for menu controls. This makes it
150  *		easy to skip menu items that are not valid. If bit X is set,
151  *		then menu item X is skipped. Of course, this only works for
152  *		menus with <= 32 menu items. There are no menus that come
153  *		close to that number, so this is OK. Should we ever need more,
154  *		then this will have to be extended to a u64 or a bit array.
155  * @qmenu:	A const char * array for all menu items. Array entries that are
156  *		empty strings ("") correspond to non-existing menu items (this
157  *		is in addition to the menu_skip_mask above). The last entry
158  *		must be NULL.
159  * @flags:	The control's flags.
160  * @cur:	The control's current value.
161  * @val:	The control's new s32 value.
162  * @priv:	The control's private pointer. For use by the driver. It is
163  *		untouched by the control framework. Note that this pointer is
164  *		not freed when the control is deleted. Should this be needed
165  *		then a new internal bitfield can be added to tell the framework
166  *		to free this pointer.
167  * @p_cur:	The control's current value represented via an union with
168  *		provides a standard way of accessing control types
169  *		through a pointer.
170  * @p_new:	The control's new value represented via an union with provides
171  *		a standard way of accessing control types
172  *		through a pointer.
173  */
174 struct v4l2_ctrl {
175 	/* Administrative fields */
176 	struct list_head node;
177 	struct list_head ev_subs;
178 	struct v4l2_ctrl_handler *handler;
179 	struct v4l2_ctrl **cluster;
180 	unsigned ncontrols;
181 	unsigned int done:1;
182 
183 	unsigned int is_new:1;
184 	unsigned int has_changed:1;
185 	unsigned int is_private:1;
186 	unsigned int is_auto:1;
187 	unsigned int is_int:1;
188 	unsigned int is_string:1;
189 	unsigned int is_ptr:1;
190 	unsigned int is_array:1;
191 	unsigned int has_volatiles:1;
192 	unsigned int call_notify:1;
193 	unsigned int manual_mode_value:8;
194 
195 	const struct v4l2_ctrl_ops *ops;
196 	const struct v4l2_ctrl_type_ops *type_ops;
197 	u32 id;
198 	const char *name;
199 	enum v4l2_ctrl_type type;
200 	s64 minimum, maximum, default_value;
201 	u32 elems;
202 	u32 elem_size;
203 	u32 dims[V4L2_CTRL_MAX_DIMS];
204 	u32 nr_of_dims;
205 	union {
206 		u64 step;
207 		u64 menu_skip_mask;
208 	};
209 	union {
210 		const char * const *qmenu;
211 		const s64 *qmenu_int;
212 	};
213 	unsigned long flags;
214 	void *priv;
215 	s32 val;
216 	struct {
217 		s32 val;
218 	} cur;
219 
220 	union v4l2_ctrl_ptr p_new;
221 	union v4l2_ctrl_ptr p_cur;
222 };
223 
224 /**
225  * struct v4l2_ctrl_ref - The control reference.
226  * @node:	List node for the sorted list.
227  * @next:	Single-link list node for the hash.
228  * @ctrl:	The actual control information.
229  * @helper:	Pointer to helper struct. Used internally in prepare_ext_ctrls().
230  *
231  * Each control handler has a list of these refs. The list_head is used to
232  * keep a sorted-by-control-ID list of all controls, while the next pointer
233  * is used to link the control in the hash's bucket.
234  */
235 struct v4l2_ctrl_ref {
236 	struct list_head node;
237 	struct v4l2_ctrl_ref *next;
238 	struct v4l2_ctrl *ctrl;
239 	struct v4l2_ctrl_helper *helper;
240 };
241 
242 /**
243  * struct v4l2_ctrl_handler - The control handler keeps track of all the
244  * controls: both the controls owned by the handler and those inherited
245  * from other handlers.
246  * @_lock:	Default for "lock".
247  * @lock:	Lock to control access to this handler and its controls.
248  *		May be replaced by the user right after init.
249  * @ctrls:	The list of controls owned by this handler.
250  * @ctrl_refs:	The list of control references.
251  * @cached:	The last found control reference. It is common that the same
252  *		control is needed multiple times, so this is a simple
253  *		optimization.
254  * @buckets:	Buckets for the hashing. Allows for quick control lookup.
255  * @notify:	A notify callback that is called whenever the control changes value.
256  *		Note that the handler's lock is held when the notify function
257  *		is called!
258  * @notify_priv: Passed as argument to the v4l2_ctrl notify callback.
259  * @nr_of_buckets: Total number of buckets in the array.
260  * @error:	The error code of the first failed control addition.
261  */
262 struct v4l2_ctrl_handler {
263 	struct mutex _lock;
264 	struct mutex *lock;
265 	struct list_head ctrls;
266 	struct list_head ctrl_refs;
267 	struct v4l2_ctrl_ref *cached;
268 	struct v4l2_ctrl_ref **buckets;
269 	v4l2_ctrl_notify_fnc notify;
270 	void *notify_priv;
271 	u16 nr_of_buckets;
272 	int error;
273 };
274 
275 /**
276  * struct v4l2_ctrl_config - Control configuration structure.
277  * @ops:	The control ops.
278  * @type_ops:	The control type ops. Only needed for compound controls.
279  * @id:	The control ID.
280  * @name:	The control name.
281  * @type:	The control type.
282  * @min:	The control's minimum value.
283  * @max:	The control's maximum value.
284  * @step:	The control's step value for non-menu controls.
285  * @def: 	The control's default value.
286  * @dims:	The size of each dimension.
287  * @elem_size:	The size in bytes of the control.
288  * @flags:	The control's flags.
289  * @menu_skip_mask: The control's skip mask for menu controls. This makes it
290  *		easy to skip menu items that are not valid. If bit X is set,
291  *		then menu item X is skipped. Of course, this only works for
292  *		menus with <= 64 menu items. There are no menus that come
293  *		close to that number, so this is OK. Should we ever need more,
294  *		then this will have to be extended to a bit array.
295  * @qmenu:	A const char * array for all menu items. Array entries that are
296  *		empty strings ("") correspond to non-existing menu items (this
297  *		is in addition to the menu_skip_mask above). The last entry
298  *		must be NULL.
299  * @qmenu_int:	A const s64 integer array for all menu items of the type
300  * 		V4L2_CTRL_TYPE_INTEGER_MENU.
301  * @is_private: If set, then this control is private to its handler and it
302  *		will not be added to any other handlers.
303  */
304 struct v4l2_ctrl_config {
305 	const struct v4l2_ctrl_ops *ops;
306 	const struct v4l2_ctrl_type_ops *type_ops;
307 	u32 id;
308 	const char *name;
309 	enum v4l2_ctrl_type type;
310 	s64 min;
311 	s64 max;
312 	u64 step;
313 	s64 def;
314 	u32 dims[V4L2_CTRL_MAX_DIMS];
315 	u32 elem_size;
316 	u32 flags;
317 	u64 menu_skip_mask;
318 	const char * const *qmenu;
319 	const s64 *qmenu_int;
320 	unsigned int is_private:1;
321 };
322 
323 /*
324  * v4l2_ctrl_fill() - Fill in the control fields based on the control ID.
325  *
326  * This works for all standard V4L2 controls.
327  * For non-standard controls it will only fill in the given arguments
328  * and @name will be NULL.
329  *
330  * This function will overwrite the contents of @name, @type and @flags.
331  * The contents of @min, @max, @step and @def may be modified depending on
332  * the type.
333  *
334  * Do not use in drivers! It is used internally for backwards compatibility
335  * control handling only. Once all drivers are converted to use the new
336  * control framework this function will no longer be exported.
337  */
338 void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
339 		    s64 *min, s64 *max, u64 *step, s64 *def, u32 *flags);
340 
341 
342 /**
343  * v4l2_ctrl_handler_init_class() - Initialize the control handler.
344  * @hdl:	The control handler.
345  * @nr_of_controls_hint: A hint of how many controls this handler is
346  *		expected to refer to. This is the total number, so including
347  *		any inherited controls. It doesn't have to be precise, but if
348  *		it is way off, then you either waste memory (too many buckets
349  *		are allocated) or the control lookup becomes slower (not enough
350  *		buckets are allocated, so there are more slow list lookups).
351  *		It will always work, though.
352  * @key:	Used by the lock validator if CONFIG_LOCKDEP is set.
353  * @name:	Used by the lock validator if CONFIG_LOCKDEP is set.
354  *
355  * Returns an error if the buckets could not be allocated. This error will
356  * also be stored in @hdl->error.
357  *
358  * Never use this call directly, always use the v4l2_ctrl_handler_init
359  * macro that hides the @key and @name arguments.
360  */
361 int v4l2_ctrl_handler_init_class(struct v4l2_ctrl_handler *hdl,
362 				 unsigned nr_of_controls_hint,
363 				 struct lock_class_key *key, const char *name);
364 
365 #ifdef CONFIG_LOCKDEP
366 #define v4l2_ctrl_handler_init(hdl, nr_of_controls_hint)		\
367 (									\
368 	({								\
369 		static struct lock_class_key _key;			\
370 		v4l2_ctrl_handler_init_class(hdl, nr_of_controls_hint,	\
371 					&_key,				\
372 					KBUILD_BASENAME ":"		\
373 					__stringify(__LINE__) ":"	\
374 					"(" #hdl ")->_lock");		\
375 	})								\
376 )
377 #else
378 #define v4l2_ctrl_handler_init(hdl, nr_of_controls_hint)		\
379 	v4l2_ctrl_handler_init_class(hdl, nr_of_controls_hint, NULL, NULL)
380 #endif
381 
382 /**
383  * v4l2_ctrl_handler_free() - Free all controls owned by the handler and free
384  * the control list.
385  * @hdl:	The control handler.
386  *
387  * Does nothing if @hdl == NULL.
388  */
389 void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl);
390 
391 /**
392  * v4l2_ctrl_lock() - Helper function to lock the handler
393  * associated with the control.
394  * @ctrl:	The control to lock.
395  */
396 static inline void v4l2_ctrl_lock(struct v4l2_ctrl *ctrl)
397 {
398 	mutex_lock(ctrl->handler->lock);
399 }
400 
401 /**
402  * v4l2_ctrl_unlock() - Helper function to unlock the handler
403  * associated with the control.
404  * @ctrl:	The control to unlock.
405  */
406 static inline void v4l2_ctrl_unlock(struct v4l2_ctrl *ctrl)
407 {
408 	mutex_unlock(ctrl->handler->lock);
409 }
410 
411 /**
412  * v4l2_ctrl_handler_setup() - Call the s_ctrl op for all controls belonging
413  * to the handler to initialize the hardware to the current control values.
414  * @hdl:	The control handler.
415  *
416  * Button controls will be skipped, as are read-only controls.
417  *
418  * If @hdl == NULL, then this just returns 0.
419  */
420 int v4l2_ctrl_handler_setup(struct v4l2_ctrl_handler *hdl);
421 
422 /**
423  * v4l2_ctrl_handler_log_status() - Log all controls owned by the handler.
424  * @hdl:	The control handler.
425  * @prefix:	The prefix to use when logging the control values. If the
426  *		prefix does not end with a space, then ": " will be added
427  *		after the prefix. If @prefix == NULL, then no prefix will be
428  *		used.
429  *
430  * For use with VIDIOC_LOG_STATUS.
431  *
432  * Does nothing if @hdl == NULL.
433  */
434 void v4l2_ctrl_handler_log_status(struct v4l2_ctrl_handler *hdl,
435 				  const char *prefix);
436 
437 /**
438  * v4l2_ctrl_new_custom() - Allocate and initialize a new custom V4L2
439  * control.
440  * @hdl:	The control handler.
441  * @cfg:	The control's configuration data.
442  * @priv:	The control's driver-specific private data.
443  *
444  * If the &v4l2_ctrl struct could not be allocated then NULL is returned
445  * and @hdl->error is set to the error code (if it wasn't set already).
446  */
447 struct v4l2_ctrl *v4l2_ctrl_new_custom(struct v4l2_ctrl_handler *hdl,
448 			const struct v4l2_ctrl_config *cfg, void *priv);
449 
450 /**
451  * v4l2_ctrl_new_std() - Allocate and initialize a new standard V4L2 non-menu control.
452  * @hdl:	The control handler.
453  * @ops:	The control ops.
454  * @id:	The control ID.
455  * @min:	The control's minimum value.
456  * @max:	The control's maximum value.
457  * @step:	The control's step value
458  * @def: 	The control's default value.
459  *
460  * If the &v4l2_ctrl struct could not be allocated, or the control
461  * ID is not known, then NULL is returned and @hdl->error is set to the
462  * appropriate error code (if it wasn't set already).
463  *
464  * If @id refers to a menu control, then this function will return NULL.
465  *
466  * Use v4l2_ctrl_new_std_menu() when adding menu controls.
467  */
468 struct v4l2_ctrl *v4l2_ctrl_new_std(struct v4l2_ctrl_handler *hdl,
469 			const struct v4l2_ctrl_ops *ops,
470 			u32 id, s64 min, s64 max, u64 step, s64 def);
471 
472 /**
473  * v4l2_ctrl_new_std_menu() - Allocate and initialize a new standard V4L2 menu control.
474  * @hdl:	The control handler.
475  * @ops:	The control ops.
476  * @id:	The control ID.
477  * @max:	The control's maximum value.
478  * @mask: 	The control's skip mask for menu controls. This makes it
479  *		easy to skip menu items that are not valid. If bit X is set,
480  *		then menu item X is skipped. Of course, this only works for
481  *		menus with <= 64 menu items. There are no menus that come
482  *		close to that number, so this is OK. Should we ever need more,
483  *		then this will have to be extended to a bit array.
484  * @def: 	The control's default value.
485  *
486  * Same as v4l2_ctrl_new_std(), but @min is set to 0 and the @mask value
487  * determines which menu items are to be skipped.
488  *
489  * If @id refers to a non-menu control, then this function will return NULL.
490  */
491 struct v4l2_ctrl *v4l2_ctrl_new_std_menu(struct v4l2_ctrl_handler *hdl,
492 			const struct v4l2_ctrl_ops *ops,
493 			u32 id, u8 max, u64 mask, u8 def);
494 
495 /**
496  * v4l2_ctrl_new_std_menu_items() - Create a new standard V4L2 menu control
497  * with driver specific menu.
498  * @hdl:	The control handler.
499  * @ops:	The control ops.
500  * @id:	The control ID.
501  * @max:	The control's maximum value.
502  * @mask:	The control's skip mask for menu controls. This makes it
503  *		easy to skip menu items that are not valid. If bit X is set,
504  *		then menu item X is skipped. Of course, this only works for
505  *		menus with <= 64 menu items. There are no menus that come
506  *		close to that number, so this is OK. Should we ever need more,
507  *		then this will have to be extended to a bit array.
508  * @def:	The control's default value.
509  * @qmenu:	The new menu.
510  *
511  * Same as v4l2_ctrl_new_std_menu(), but @qmenu will be the driver specific
512  * menu of this control.
513  *
514  */
515 struct v4l2_ctrl *v4l2_ctrl_new_std_menu_items(struct v4l2_ctrl_handler *hdl,
516 			const struct v4l2_ctrl_ops *ops, u32 id, u8 max,
517 			u64 mask, u8 def, const char * const *qmenu);
518 
519 /**
520  * v4l2_ctrl_new_int_menu() - Create a new standard V4L2 integer menu control.
521  * @hdl:	The control handler.
522  * @ops:	The control ops.
523  * @id:	The control ID.
524  * @max:	The control's maximum value.
525  * @def:	The control's default value.
526  * @qmenu_int:	The control's menu entries.
527  *
528  * Same as v4l2_ctrl_new_std_menu(), but @mask is set to 0 and it additionaly
529  * takes as an argument an array of integers determining the menu items.
530  *
531  * If @id refers to a non-integer-menu control, then this function will return NULL.
532  */
533 struct v4l2_ctrl *v4l2_ctrl_new_int_menu(struct v4l2_ctrl_handler *hdl,
534 			const struct v4l2_ctrl_ops *ops,
535 			u32 id, u8 max, u8 def, const s64 *qmenu_int);
536 
537 /**
538  * v4l2_ctrl_add_handler() - Add all controls from handler @add to
539  * handler @hdl.
540  * @hdl:	The control handler.
541  * @add:	The control handler whose controls you want to add to
542  *		the @hdl control handler.
543  * @filter:	This function will filter which controls should be added.
544  *
545  * Does nothing if either of the two handlers is a NULL pointer.
546  * If @filter is NULL, then all controls are added. Otherwise only those
547  * controls for which @filter returns true will be added.
548  * In case of an error @hdl->error will be set to the error code (if it
549  * wasn't set already).
550  */
551 int v4l2_ctrl_add_handler(struct v4l2_ctrl_handler *hdl,
552 			  struct v4l2_ctrl_handler *add,
553 			  bool (*filter)(const struct v4l2_ctrl *ctrl));
554 
555 /**
556  * v4l2_ctrl_radio_filter() - Standard filter for radio controls.
557  * @ctrl:	The control that is filtered.
558  *
559  * This will return true for any controls that are valid for radio device
560  * nodes. Those are all of the V4L2_CID_AUDIO_* user controls and all FM
561  * transmitter class controls.
562  *
563  * This function is to be used with v4l2_ctrl_add_handler().
564  */
565 bool v4l2_ctrl_radio_filter(const struct v4l2_ctrl *ctrl);
566 
567 /**
568  * v4l2_ctrl_cluster() - Mark all controls in the cluster as belonging to that cluster.
569  * @ncontrols:	The number of controls in this cluster.
570  * @controls: 	The cluster control array of size @ncontrols.
571  */
572 void v4l2_ctrl_cluster(unsigned ncontrols, struct v4l2_ctrl **controls);
573 
574 
575 /**
576  * v4l2_ctrl_auto_cluster() - Mark all controls in the cluster as belonging to
577  * that cluster and set it up for autofoo/foo-type handling.
578  * @ncontrols:	The number of controls in this cluster.
579  * @controls:	The cluster control array of size @ncontrols. The first control
580  *		must be the 'auto' control (e.g. autogain, autoexposure, etc.)
581  * @manual_val: The value for the first control in the cluster that equals the
582  *		manual setting.
583  * @set_volatile: If true, then all controls except the first auto control will
584  *		be volatile.
585  *
586  * Use for control groups where one control selects some automatic feature and
587  * the other controls are only active whenever the automatic feature is turned
588  * off (manual mode). Typical examples: autogain vs gain, auto-whitebalance vs
589  * red and blue balance, etc.
590  *
591  * The behavior of such controls is as follows:
592  *
593  * When the autofoo control is set to automatic, then any manual controls
594  * are set to inactive and any reads will call g_volatile_ctrl (if the control
595  * was marked volatile).
596  *
597  * When the autofoo control is set to manual, then any manual controls will
598  * be marked active, and any reads will just return the current value without
599  * going through g_volatile_ctrl.
600  *
601  * In addition, this function will set the V4L2_CTRL_FLAG_UPDATE flag
602  * on the autofoo control and V4L2_CTRL_FLAG_INACTIVE on the foo control(s)
603  * if autofoo is in auto mode.
604  */
605 void v4l2_ctrl_auto_cluster(unsigned ncontrols, struct v4l2_ctrl **controls,
606 			u8 manual_val, bool set_volatile);
607 
608 
609 /**
610  * v4l2_ctrl_find() - Find a control with the given ID.
611  * @hdl:	The control handler.
612  * @id:	The control ID to find.
613  *
614  * If @hdl == NULL this will return NULL as well. Will lock the handler so
615  * do not use from inside &v4l2_ctrl_ops.
616  */
617 struct v4l2_ctrl *v4l2_ctrl_find(struct v4l2_ctrl_handler *hdl, u32 id);
618 
619 /**
620  * v4l2_ctrl_activate() - Make the control active or inactive.
621  * @ctrl:	The control to (de)activate.
622  * @active:	True if the control should become active.
623  *
624  * This sets or clears the V4L2_CTRL_FLAG_INACTIVE flag atomically.
625  * Does nothing if @ctrl == NULL.
626  * This will usually be called from within the s_ctrl op.
627  * The V4L2_EVENT_CTRL event will be generated afterwards.
628  *
629  * This function assumes that the control handler is locked.
630  */
631 void v4l2_ctrl_activate(struct v4l2_ctrl *ctrl, bool active);
632 
633 /**
634  * v4l2_ctrl_grab() - Mark the control as grabbed or not grabbed.
635  * @ctrl:	The control to (de)activate.
636  * @grabbed:	True if the control should become grabbed.
637  *
638  * This sets or clears the V4L2_CTRL_FLAG_GRABBED flag atomically.
639  * Does nothing if @ctrl == NULL.
640  * The V4L2_EVENT_CTRL event will be generated afterwards.
641  * This will usually be called when starting or stopping streaming in the
642  * driver.
643  *
644  * This function assumes that the control handler is not locked and will
645  * take the lock itself.
646  */
647 void v4l2_ctrl_grab(struct v4l2_ctrl *ctrl, bool grabbed);
648 
649 
650 /**
651  *__v4l2_ctrl_modify_range() - Unlocked variant of v4l2_ctrl_modify_range()
652  *
653  * @ctrl:	The control to update.
654  * @min:	The control's minimum value.
655  * @max:	The control's maximum value.
656  * @step:	The control's step value
657  * @def:	The control's default value.
658  *
659  * Update the range of a control on the fly. This works for control types
660  * INTEGER, BOOLEAN, MENU, INTEGER MENU and BITMASK. For menu controls the
661  * @step value is interpreted as a menu_skip_mask.
662  *
663  * An error is returned if one of the range arguments is invalid for this
664  * control type.
665  *
666  * This function assumes that the control handler is not locked and will
667  * take the lock itself.
668  */
669 int __v4l2_ctrl_modify_range(struct v4l2_ctrl *ctrl,
670 			     s64 min, s64 max, u64 step, s64 def);
671 
672 /**
673  * v4l2_ctrl_modify_range() - Update the range of a control.
674  * @ctrl:	The control to update.
675  * @min:	The control's minimum value.
676  * @max:	The control's maximum value.
677  * @step:	The control's step value
678  * @def:	The control's default value.
679  *
680  * Update the range of a control on the fly. This works for control types
681  * INTEGER, BOOLEAN, MENU, INTEGER MENU and BITMASK. For menu controls the
682  * @step value is interpreted as a menu_skip_mask.
683  *
684  * An error is returned if one of the range arguments is invalid for this
685  * control type.
686  *
687  * This function assumes that the control handler is not locked and will
688  * take the lock itself.
689  */
690 static inline int v4l2_ctrl_modify_range(struct v4l2_ctrl *ctrl,
691 					 s64 min, s64 max, u64 step, s64 def)
692 {
693 	int rval;
694 
695 	v4l2_ctrl_lock(ctrl);
696 	rval = __v4l2_ctrl_modify_range(ctrl, min, max, step, def);
697 	v4l2_ctrl_unlock(ctrl);
698 
699 	return rval;
700 }
701 
702 /**
703  * v4l2_ctrl_notify() - Function to set a notify callback for a control.
704  * @ctrl:	The control.
705  * @notify:	The callback function.
706  * @priv:	The callback private handle, passed as argument to the callback.
707  *
708  * This function sets a callback function for the control. If @ctrl is NULL,
709  * then it will do nothing. If @notify is NULL, then the notify callback will
710  * be removed.
711  *
712  * There can be only one notify. If another already exists, then a WARN_ON
713  * will be issued and the function will do nothing.
714  */
715 void v4l2_ctrl_notify(struct v4l2_ctrl *ctrl, v4l2_ctrl_notify_fnc notify, void *priv);
716 
717 /**
718  * v4l2_ctrl_get_name() - Get the name of the control
719  * @id:		The control ID.
720  *
721  * This function returns the name of the given control ID or NULL if it isn't
722  * a known control.
723  */
724 const char *v4l2_ctrl_get_name(u32 id);
725 
726 /**
727  * v4l2_ctrl_get_menu() - Get the menu string array of the control
728  * @id:		The control ID.
729  *
730  * This function returns the NULL-terminated menu string array name of the
731  * given control ID or NULL if it isn't a known menu control.
732  */
733 const char * const *v4l2_ctrl_get_menu(u32 id);
734 
735 /**
736  * v4l2_ctrl_get_int_menu() - Get the integer menu array of the control
737  * @id:		The control ID.
738  * @len:	The size of the integer array.
739  *
740  * This function returns the integer array of the given control ID or NULL if it
741  * if it isn't a known integer menu control.
742  */
743 const s64 *v4l2_ctrl_get_int_menu(u32 id, u32 *len);
744 
745 /**
746  * v4l2_ctrl_g_ctrl() - Helper function to get the control's value from within a driver.
747  * @ctrl:	The control.
748  *
749  * This returns the control's value safely by going through the control
750  * framework. This function will lock the control's handler, so it cannot be
751  * used from within the &v4l2_ctrl_ops functions.
752  *
753  * This function is for integer type controls only.
754  */
755 s32 v4l2_ctrl_g_ctrl(struct v4l2_ctrl *ctrl);
756 
757 /**
758  * __v4l2_ctrl_s_ctrl() - Unlocked variant of v4l2_ctrl_s_ctrl().
759  * @ctrl:	The control.
760  * @val:	The new value.
761  *
762  * This set the control's new value safely by going through the control
763  * framework. This function will lock the control's handler, so it cannot be
764  * used from within the &v4l2_ctrl_ops functions.
765  *
766  * This function is for integer type controls only.
767  */
768 int __v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val);
769 
770 /** v4l2_ctrl_s_ctrl() - Helper function to set the control's value from within a driver.
771  * @ctrl:	The control.
772  * @val:	The new value.
773  *
774  * This set the control's new value safely by going through the control
775  * framework. This function will lock the control's handler, so it cannot be
776  * used from within the &v4l2_ctrl_ops functions.
777  *
778  * This function is for integer type controls only.
779  */
780 static inline int v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val)
781 {
782 	int rval;
783 
784 	v4l2_ctrl_lock(ctrl);
785 	rval = __v4l2_ctrl_s_ctrl(ctrl, val);
786 	v4l2_ctrl_unlock(ctrl);
787 
788 	return rval;
789 }
790 
791 /**
792  * v4l2_ctrl_g_ctrl_int64() - Helper function to get a 64-bit control's value
793  *	from within a driver.
794  * @ctrl:	The control.
795  *
796  * This returns the control's value safely by going through the control
797  * framework. This function will lock the control's handler, so it cannot be
798  * used from within the &v4l2_ctrl_ops functions.
799  *
800  * This function is for 64-bit integer type controls only.
801  */
802 s64 v4l2_ctrl_g_ctrl_int64(struct v4l2_ctrl *ctrl);
803 
804 /**
805  * __v4l2_ctrl_s_ctrl_int64() - Unlocked variant of v4l2_ctrl_s_ctrl_int64().
806  *
807  * @ctrl:	The control.
808  * @val:	The new value.
809  *
810  * This set the control's new value safely by going through the control
811  * framework. This function will lock the control's handler, so it cannot be
812  * used from within the &v4l2_ctrl_ops functions.
813  *
814  * This function is for 64-bit integer type controls only.
815  */
816 int __v4l2_ctrl_s_ctrl_int64(struct v4l2_ctrl *ctrl, s64 val);
817 
818 /** v4l2_ctrl_s_ctrl_int64() - Helper function to set a 64-bit control's value
819  *	from within a driver.
820  *
821  * @ctrl:	The control.
822  * @val:	The new value.
823  *
824  * This set the control's new value safely by going through the control
825  * framework. This function will lock the control's handler, so it cannot be
826  * used from within the &v4l2_ctrl_ops functions.
827  *
828  * This function is for 64-bit integer type controls only.
829  */
830 static inline int v4l2_ctrl_s_ctrl_int64(struct v4l2_ctrl *ctrl, s64 val)
831 {
832 	int rval;
833 
834 	v4l2_ctrl_lock(ctrl);
835 	rval = __v4l2_ctrl_s_ctrl_int64(ctrl, val);
836 	v4l2_ctrl_unlock(ctrl);
837 
838 	return rval;
839 }
840 
841 /** __v4l2_ctrl_s_ctrl_string() - Unlocked variant of v4l2_ctrl_s_ctrl_string().
842  *
843  * @ctrl:	The control.
844  * @s:		The new string.
845  *
846  * This set the control's new string safely by going through the control
847  * framework. This function will lock the control's handler, so it cannot be
848  * used from within the &v4l2_ctrl_ops functions.
849  *
850  * This function is for string type controls only.
851  */
852 int __v4l2_ctrl_s_ctrl_string(struct v4l2_ctrl *ctrl, const char *s);
853 
854 /** v4l2_ctrl_s_ctrl_string() - Helper function to set a control's string value
855  *	 from within a driver.
856  *
857  * @ctrl:	The control.
858  * @s:		The new string.
859  *
860  * This set the control's new string safely by going through the control
861  * framework. This function will lock the control's handler, so it cannot be
862  * used from within the &v4l2_ctrl_ops functions.
863  *
864  * This function is for string type controls only.
865  */
866 static inline int v4l2_ctrl_s_ctrl_string(struct v4l2_ctrl *ctrl, const char *s)
867 {
868 	int rval;
869 
870 	v4l2_ctrl_lock(ctrl);
871 	rval = __v4l2_ctrl_s_ctrl_string(ctrl, s);
872 	v4l2_ctrl_unlock(ctrl);
873 
874 	return rval;
875 }
876 
877 /* Internal helper functions that deal with control events. */
878 extern const struct v4l2_subscribed_event_ops v4l2_ctrl_sub_ev_ops;
879 void v4l2_ctrl_replace(struct v4l2_event *old, const struct v4l2_event *new);
880 void v4l2_ctrl_merge(const struct v4l2_event *old, struct v4l2_event *new);
881 
882 /* Can be used as a vidioc_log_status function that just dumps all controls
883    associated with the filehandle. */
884 int v4l2_ctrl_log_status(struct file *file, void *fh);
885 
886 /* Can be used as a vidioc_subscribe_event function that just subscribes
887    control events. */
888 int v4l2_ctrl_subscribe_event(struct v4l2_fh *fh,
889 				const struct v4l2_event_subscription *sub);
890 
891 /* Can be used as a poll function that just polls for control events. */
892 unsigned int v4l2_ctrl_poll(struct file *file, struct poll_table_struct *wait);
893 
894 /* Helpers for ioctl_ops. If hdl == NULL then they will all return -EINVAL. */
895 int v4l2_queryctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_queryctrl *qc);
896 int v4l2_query_ext_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_query_ext_ctrl *qc);
897 int v4l2_querymenu(struct v4l2_ctrl_handler *hdl, struct v4l2_querymenu *qm);
898 int v4l2_g_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_control *ctrl);
899 int v4l2_s_ctrl(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
900 						struct v4l2_control *ctrl);
901 int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *c);
902 int v4l2_try_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *c);
903 int v4l2_s_ext_ctrls(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
904 						struct v4l2_ext_controls *c);
905 
906 /* Helpers for subdevices. If the associated ctrl_handler == NULL then they
907    will all return -EINVAL. */
908 int v4l2_subdev_queryctrl(struct v4l2_subdev *sd, struct v4l2_queryctrl *qc);
909 int v4l2_subdev_querymenu(struct v4l2_subdev *sd, struct v4l2_querymenu *qm);
910 int v4l2_subdev_g_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
911 int v4l2_subdev_try_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
912 int v4l2_subdev_s_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
913 int v4l2_subdev_g_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
914 int v4l2_subdev_s_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
915 
916 /* Can be used as a subscribe_event function that just subscribes control
917    events. */
918 int v4l2_ctrl_subdev_subscribe_event(struct v4l2_subdev *sd, struct v4l2_fh *fh,
919 				     struct v4l2_event_subscription *sub);
920 
921 /* Log all controls owned by subdev's control handler. */
922 int v4l2_ctrl_subdev_log_status(struct v4l2_subdev *sd);
923 
924 #endif
925