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TOMOYO Linux Cross Reference
Linux/include/media/v4l2-ctrls.h

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  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 /** union v4l2_ctrl_ptr - A pointer to a control value.
 40  * @p_s32:      Pointer to a 32-bit signed value.
 41  * @p_s64:      Pointer to a 64-bit signed value.
 42  * @p_u8:       Pointer to a 8-bit unsigned value.
 43  * @p_u16:      Pointer to a 16-bit unsigned value.
 44  * @p_u32:      Pointer to a 32-bit unsigned value.
 45  * @p_char:     Pointer to a string.
 46  * @p:          Pointer to a compound value.
 47  */
 48 union v4l2_ctrl_ptr {
 49         s32 *p_s32;
 50         s64 *p_s64;
 51         u8 *p_u8;
 52         u16 *p_u16;
 53         u32 *p_u32;
 54         char *p_char;
 55         void *p;
 56 };
 57 
 58 /** struct v4l2_ctrl_ops - The control operations that the driver has to provide.
 59   * @g_volatile_ctrl: Get a new value for this control. Generally only relevant
 60   *             for volatile (and usually read-only) controls such as a control
 61   *             that returns the current signal strength which changes
 62   *             continuously.
 63   *             If not set, then the currently cached value will be returned.
 64   * @try_ctrl:  Test whether the control's value is valid. Only relevant when
 65   *             the usual min/max/step checks are not sufficient.
 66   * @s_ctrl:    Actually set the new control value. s_ctrl is compulsory. The
 67   *             ctrl->handler->lock is held when these ops are called, so no
 68   *             one else can access controls owned by that handler.
 69   */
 70 struct v4l2_ctrl_ops {
 71         int (*g_volatile_ctrl)(struct v4l2_ctrl *ctrl);
 72         int (*try_ctrl)(struct v4l2_ctrl *ctrl);
 73         int (*s_ctrl)(struct v4l2_ctrl *ctrl);
 74 };
 75 
 76 /** struct v4l2_ctrl_type_ops - The control type operations that the driver has to provide.
 77   * @equal: return true if both values are equal.
 78   * @init: initialize the value.
 79   * @log: log the value.
 80   * @validate: validate the value. Return 0 on success and a negative value otherwise.
 81   */
 82 struct v4l2_ctrl_type_ops {
 83         bool (*equal)(const struct v4l2_ctrl *ctrl, u32 idx,
 84                       union v4l2_ctrl_ptr ptr1,
 85                       union v4l2_ctrl_ptr ptr2);
 86         void (*init)(const struct v4l2_ctrl *ctrl, u32 idx,
 87                      union v4l2_ctrl_ptr ptr);
 88         void (*log)(const struct v4l2_ctrl *ctrl);
 89         int (*validate)(const struct v4l2_ctrl *ctrl, u32 idx,
 90                         union v4l2_ctrl_ptr ptr);
 91 };
 92 
 93 typedef void (*v4l2_ctrl_notify_fnc)(struct v4l2_ctrl *ctrl, void *priv);
 94 
 95 /** struct v4l2_ctrl - The control structure.
 96   * @node:      The list node.
 97   * @ev_subs:   The list of control event subscriptions.
 98   * @handler:   The handler that owns the control.
 99   * @cluster:   Point to start of cluster array.
100   * @ncontrols: Number of controls in cluster array.
101   * @done:      Internal flag: set for each processed control.
102   * @is_new:    Set when the user specified a new value for this control. It
103   *             is also set when called from v4l2_ctrl_handler_setup. Drivers
104   *             should never set this flag.
105   * @has_changed: Set when the current value differs from the new value. Drivers
106   *             should never use this flag.
107   * @is_private: If set, then this control is private to its handler and it
108   *             will not be added to any other handlers. Drivers can set
109   *             this flag.
110   * @is_auto:   If set, then this control selects whether the other cluster
111   *             members are in 'automatic' mode or 'manual' mode. This is
112   *             used for autogain/gain type clusters. Drivers should never
113   *             set this flag directly.
114   * @is_int:    If set, then this control has a simple integer value (i.e. it
115   *             uses ctrl->val).
116   * @is_string: If set, then this control has type V4L2_CTRL_TYPE_STRING.
117   * @is_ptr:    If set, then this control is an array and/or has type >= V4L2_CTRL_COMPOUND_TYPES
118   *             and/or has type V4L2_CTRL_TYPE_STRING. In other words, struct
119   *             v4l2_ext_control uses field p to point to the data.
120   * @is_array: If set, then this control contains an N-dimensional array.
121   * @has_volatiles: If set, then one or more members of the cluster are volatile.
122   *             Drivers should never touch this flag.
123   * @call_notify: If set, then call the handler's notify function whenever the
124   *             control's value changes.
125   * @manual_mode_value: If the is_auto flag is set, then this is the value
126   *             of the auto control that determines if that control is in
127   *             manual mode. So if the value of the auto control equals this
128   *             value, then the whole cluster is in manual mode. Drivers should
129   *             never set this flag directly.
130   * @ops:       The control ops.
131   * @type_ops:  The control type ops.
132   * @id:        The control ID.
133   * @name:      The control name.
134   * @type:      The control type.
135   * @minimum:   The control's minimum value.
136   * @maximum:   The control's maximum value.
137   * @default_value: The control's default value.
138   * @step:      The control's step value for non-menu controls.
139   * @elems:     The number of elements in the N-dimensional array.
140   * @elem_size: The size in bytes of the control.
141   * @dims:      The size of each dimension.
142   * @nr_of_dims:The number of dimensions in @dims.
143   * @menu_skip_mask: The control's skip mask for menu controls. This makes it
144   *             easy to skip menu items that are not valid. If bit X is set,
145   *             then menu item X is skipped. Of course, this only works for
146   *             menus with <= 32 menu items. There are no menus that come
147   *             close to that number, so this is OK. Should we ever need more,
148   *             then this will have to be extended to a u64 or a bit array.
149   * @qmenu:     A const char * array for all menu items. Array entries that are
150   *             empty strings ("") correspond to non-existing menu items (this
151   *             is in addition to the menu_skip_mask above). The last entry
152   *             must be NULL.
153   * @flags:     The control's flags.
154   * @cur:       The control's current value.
155   * @val:       The control's new s32 value.
156   * @val64:     The control's new s64 value.
157   * @priv:      The control's private pointer. For use by the driver. It is
158   *             untouched by the control framework. Note that this pointer is
159   *             not freed when the control is deleted. Should this be needed
160   *             then a new internal bitfield can be added to tell the framework
161   *             to free this pointer.
162   */
163 struct v4l2_ctrl {
164         /* Administrative fields */
165         struct list_head node;
166         struct list_head ev_subs;
167         struct v4l2_ctrl_handler *handler;
168         struct v4l2_ctrl **cluster;
169         unsigned ncontrols;
170         unsigned int done:1;
171 
172         unsigned int is_new:1;
173         unsigned int has_changed:1;
174         unsigned int is_private:1;
175         unsigned int is_auto:1;
176         unsigned int is_int:1;
177         unsigned int is_string:1;
178         unsigned int is_ptr:1;
179         unsigned int is_array:1;
180         unsigned int has_volatiles:1;
181         unsigned int call_notify:1;
182         unsigned int manual_mode_value:8;
183 
184         const struct v4l2_ctrl_ops *ops;
185         const struct v4l2_ctrl_type_ops *type_ops;
186         u32 id;
187         const char *name;
188         enum v4l2_ctrl_type type;
189         s64 minimum, maximum, default_value;
190         u32 elems;
191         u32 elem_size;
192         u32 dims[V4L2_CTRL_MAX_DIMS];
193         u32 nr_of_dims;
194         union {
195                 u64 step;
196                 u64 menu_skip_mask;
197         };
198         union {
199                 const char * const *qmenu;
200                 const s64 *qmenu_int;
201         };
202         unsigned long flags;
203         void *priv;
204         s32 val;
205         struct {
206                 s32 val;
207         } cur;
208 
209         union v4l2_ctrl_ptr p_new;
210         union v4l2_ctrl_ptr p_cur;
211 };
212 
213 /** struct v4l2_ctrl_ref - The control reference.
214   * @node:      List node for the sorted list.
215   * @next:      Single-link list node for the hash.
216   * @ctrl:      The actual control information.
217   * @helper:    Pointer to helper struct. Used internally in prepare_ext_ctrls().
218   *
219   * Each control handler has a list of these refs. The list_head is used to
220   * keep a sorted-by-control-ID list of all controls, while the next pointer
221   * is used to link the control in the hash's bucket.
222   */
223 struct v4l2_ctrl_ref {
224         struct list_head node;
225         struct v4l2_ctrl_ref *next;
226         struct v4l2_ctrl *ctrl;
227         struct v4l2_ctrl_helper *helper;
228 };
229 
230 /** struct v4l2_ctrl_handler - The control handler keeps track of all the
231   * controls: both the controls owned by the handler and those inherited
232   * from other handlers.
233   * @_lock:     Default for "lock".
234   * @lock:      Lock to control access to this handler and its controls.
235   *             May be replaced by the user right after init.
236   * @ctrls:     The list of controls owned by this handler.
237   * @ctrl_refs: The list of control references.
238   * @cached:    The last found control reference. It is common that the same
239   *             control is needed multiple times, so this is a simple
240   *             optimization.
241   * @buckets:   Buckets for the hashing. Allows for quick control lookup.
242   * @notify:    A notify callback that is called whenever the control changes value.
243   *             Note that the handler's lock is held when the notify function
244   *             is called!
245   * @notify_priv: Passed as argument to the v4l2_ctrl notify callback.
246   * @nr_of_buckets: Total number of buckets in the array.
247   * @error:     The error code of the first failed control addition.
248   */
249 struct v4l2_ctrl_handler {
250         struct mutex _lock;
251         struct mutex *lock;
252         struct list_head ctrls;
253         struct list_head ctrl_refs;
254         struct v4l2_ctrl_ref *cached;
255         struct v4l2_ctrl_ref **buckets;
256         v4l2_ctrl_notify_fnc notify;
257         void *notify_priv;
258         u16 nr_of_buckets;
259         int error;
260 };
261 
262 /** struct v4l2_ctrl_config - Control configuration structure.
263   * @ops:       The control ops.
264   * @type_ops:  The control type ops. Only needed for compound controls.
265   * @id:        The control ID.
266   * @name:      The control name.
267   * @type:      The control type.
268   * @min:       The control's minimum value.
269   * @max:       The control's maximum value.
270   * @step:      The control's step value for non-menu controls.
271   * @def:       The control's default value.
272   * @dims:      The size of each dimension.
273   * @elem_size: The size in bytes of the control.
274   * @flags:     The control's flags.
275   * @menu_skip_mask: The control's skip mask for menu controls. This makes it
276   *             easy to skip menu items that are not valid. If bit X is set,
277   *             then menu item X is skipped. Of course, this only works for
278   *             menus with <= 64 menu items. There are no menus that come
279   *             close to that number, so this is OK. Should we ever need more,
280   *             then this will have to be extended to a bit array.
281   * @qmenu:     A const char * array for all menu items. Array entries that are
282   *             empty strings ("") correspond to non-existing menu items (this
283   *             is in addition to the menu_skip_mask above). The last entry
284   *             must be NULL.
285   * @is_private: If set, then this control is private to its handler and it
286   *             will not be added to any other handlers.
287   */
288 struct v4l2_ctrl_config {
289         const struct v4l2_ctrl_ops *ops;
290         const struct v4l2_ctrl_type_ops *type_ops;
291         u32 id;
292         const char *name;
293         enum v4l2_ctrl_type type;
294         s64 min;
295         s64 max;
296         u64 step;
297         s64 def;
298         u32 dims[V4L2_CTRL_MAX_DIMS];
299         u32 elem_size;
300         u32 flags;
301         u64 menu_skip_mask;
302         const char * const *qmenu;
303         const s64 *qmenu_int;
304         unsigned int is_private:1;
305 };
306 
307 /** v4l2_ctrl_fill() - Fill in the control fields based on the control ID.
308   *
309   * This works for all standard V4L2 controls.
310   * For non-standard controls it will only fill in the given arguments
311   * and @name will be NULL.
312   *
313   * This function will overwrite the contents of @name, @type and @flags.
314   * The contents of @min, @max, @step and @def may be modified depending on
315   * the type.
316   *
317   * Do not use in drivers! It is used internally for backwards compatibility
318   * control handling only. Once all drivers are converted to use the new
319   * control framework this function will no longer be exported.
320   */
321 void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
322                     s64 *min, s64 *max, u64 *step, s64 *def, u32 *flags);
323 
324 
325 /** v4l2_ctrl_handler_init_class() - Initialize the control handler.
326   * @hdl:       The control handler.
327   * @nr_of_controls_hint: A hint of how many controls this handler is
328   *             expected to refer to. This is the total number, so including
329   *             any inherited controls. It doesn't have to be precise, but if
330   *             it is way off, then you either waste memory (too many buckets
331   *             are allocated) or the control lookup becomes slower (not enough
332   *             buckets are allocated, so there are more slow list lookups).
333   *             It will always work, though.
334   * @key:       Used by the lock validator if CONFIG_LOCKDEP is set.
335   * @name:      Used by the lock validator if CONFIG_LOCKDEP is set.
336   *
337   * Returns an error if the buckets could not be allocated. This error will
338   * also be stored in @hdl->error.
339   *
340   * Never use this call directly, always use the v4l2_ctrl_handler_init
341   * macro that hides the @key and @name arguments.
342   */
343 int v4l2_ctrl_handler_init_class(struct v4l2_ctrl_handler *hdl,
344                                  unsigned nr_of_controls_hint,
345                                  struct lock_class_key *key, const char *name);
346 
347 #ifdef CONFIG_LOCKDEP
348 #define v4l2_ctrl_handler_init(hdl, nr_of_controls_hint)                \
349 (                                                                       \
350         ({                                                              \
351                 static struct lock_class_key _key;                      \
352                 v4l2_ctrl_handler_init_class(hdl, nr_of_controls_hint,  \
353                                         &_key,                          \
354                                         KBUILD_BASENAME ":"             \
355                                         __stringify(__LINE__) ":"       \
356                                         "(" #hdl ")->_lock");           \
357         })                                                              \
358 )
359 #else
360 #define v4l2_ctrl_handler_init(hdl, nr_of_controls_hint)                \
361         v4l2_ctrl_handler_init_class(hdl, nr_of_controls_hint, NULL, NULL)
362 #endif
363 
364 /** v4l2_ctrl_handler_free() - Free all controls owned by the handler and free
365   * the control list.
366   * @hdl:       The control handler.
367   *
368   * Does nothing if @hdl == NULL.
369   */
370 void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl);
371 
372 /** v4l2_ctrl_lock() - Helper function to lock the handler
373   * associated with the control.
374   * @ctrl:      The control to lock.
375   */
376 static inline void v4l2_ctrl_lock(struct v4l2_ctrl *ctrl)
377 {
378         mutex_lock(ctrl->handler->lock);
379 }
380 
381 /** v4l2_ctrl_unlock() - Helper function to unlock the handler
382   * associated with the control.
383   * @ctrl:      The control to unlock.
384   */
385 static inline void v4l2_ctrl_unlock(struct v4l2_ctrl *ctrl)
386 {
387         mutex_unlock(ctrl->handler->lock);
388 }
389 
390 /** v4l2_ctrl_handler_setup() - Call the s_ctrl op for all controls belonging
391   * to the handler to initialize the hardware to the current control values.
392   * @hdl:       The control handler.
393   *
394   * Button controls will be skipped, as are read-only controls.
395   *
396   * If @hdl == NULL, then this just returns 0.
397   */
398 int v4l2_ctrl_handler_setup(struct v4l2_ctrl_handler *hdl);
399 
400 /** v4l2_ctrl_handler_log_status() - Log all controls owned by the handler.
401   * @hdl:       The control handler.
402   * @prefix:    The prefix to use when logging the control values. If the
403   *             prefix does not end with a space, then ": " will be added
404   *             after the prefix. If @prefix == NULL, then no prefix will be
405   *             used.
406   *
407   * For use with VIDIOC_LOG_STATUS.
408   *
409   * Does nothing if @hdl == NULL.
410   */
411 void v4l2_ctrl_handler_log_status(struct v4l2_ctrl_handler *hdl,
412                                   const char *prefix);
413 
414 /** v4l2_ctrl_new_custom() - Allocate and initialize a new custom V4L2
415   * control.
416   * @hdl:       The control handler.
417   * @cfg:       The control's configuration data.
418   * @priv:      The control's driver-specific private data.
419   *
420   * If the &v4l2_ctrl struct could not be allocated then NULL is returned
421   * and @hdl->error is set to the error code (if it wasn't set already).
422   */
423 struct v4l2_ctrl *v4l2_ctrl_new_custom(struct v4l2_ctrl_handler *hdl,
424                         const struct v4l2_ctrl_config *cfg, void *priv);
425 
426 /** v4l2_ctrl_new_std() - Allocate and initialize a new standard V4L2 non-menu control.
427   * @hdl:       The control handler.
428   * @ops:       The control ops.
429   * @id:        The control ID.
430   * @min:       The control's minimum value.
431   * @max:       The control's maximum value.
432   * @step:      The control's step value
433   * @def:       The control's default value.
434   *
435   * If the &v4l2_ctrl struct could not be allocated, or the control
436   * ID is not known, then NULL is returned and @hdl->error is set to the
437   * appropriate error code (if it wasn't set already).
438   *
439   * If @id refers to a menu control, then this function will return NULL.
440   *
441   * Use v4l2_ctrl_new_std_menu() when adding menu controls.
442   */
443 struct v4l2_ctrl *v4l2_ctrl_new_std(struct v4l2_ctrl_handler *hdl,
444                         const struct v4l2_ctrl_ops *ops,
445                         u32 id, s64 min, s64 max, u64 step, s64 def);
446 
447 /** v4l2_ctrl_new_std_menu() - Allocate and initialize a new standard V4L2 menu control.
448   * @hdl:       The control handler.
449   * @ops:       The control ops.
450   * @id:        The control ID.
451   * @max:       The control's maximum value.
452   * @mask:      The control's skip mask for menu controls. This makes it
453   *             easy to skip menu items that are not valid. If bit X is set,
454   *             then menu item X is skipped. Of course, this only works for
455   *             menus with <= 64 menu items. There are no menus that come
456   *             close to that number, so this is OK. Should we ever need more,
457   *             then this will have to be extended to a bit array.
458   * @def:       The control's default value.
459   *
460   * Same as v4l2_ctrl_new_std(), but @min is set to 0 and the @mask value
461   * determines which menu items are to be skipped.
462   *
463   * If @id refers to a non-menu control, then this function will return NULL.
464   */
465 struct v4l2_ctrl *v4l2_ctrl_new_std_menu(struct v4l2_ctrl_handler *hdl,
466                         const struct v4l2_ctrl_ops *ops,
467                         u32 id, u8 max, u64 mask, u8 def);
468 
469 /** v4l2_ctrl_new_std_menu_items() - Create a new standard V4L2 menu control
470   * with driver specific menu.
471   * @hdl:       The control handler.
472   * @ops:       The control ops.
473   * @id:        The control ID.
474   * @max:       The control's maximum value.
475   * @mask:      The control's skip mask for menu controls. This makes it
476   *             easy to skip menu items that are not valid. If bit X is set,
477   *             then menu item X is skipped. Of course, this only works for
478   *             menus with <= 64 menu items. There are no menus that come
479   *             close to that number, so this is OK. Should we ever need more,
480   *             then this will have to be extended to a bit array.
481   * @def:       The control's default value.
482   * @qmenu:     The new menu.
483   *
484   * Same as v4l2_ctrl_new_std_menu(), but @qmenu will be the driver specific
485   * menu of this control.
486   *
487   */
488 struct v4l2_ctrl *v4l2_ctrl_new_std_menu_items(struct v4l2_ctrl_handler *hdl,
489                         const struct v4l2_ctrl_ops *ops, u32 id, u8 max,
490                         u64 mask, u8 def, const char * const *qmenu);
491 
492 /** v4l2_ctrl_new_int_menu() - Create a new standard V4L2 integer menu control.
493   * @hdl:       The control handler.
494   * @ops:       The control ops.
495   * @id:        The control ID.
496   * @max:       The control's maximum value.
497   * @def:       The control's default value.
498   * @qmenu_int: The control's menu entries.
499   *
500   * Same as v4l2_ctrl_new_std_menu(), but @mask is set to 0 and it additionaly
501   * takes as an argument an array of integers determining the menu items.
502   *
503   * If @id refers to a non-integer-menu control, then this function will return NULL.
504   */
505 struct v4l2_ctrl *v4l2_ctrl_new_int_menu(struct v4l2_ctrl_handler *hdl,
506                         const struct v4l2_ctrl_ops *ops,
507                         u32 id, u8 max, u8 def, const s64 *qmenu_int);
508 
509 /** v4l2_ctrl_add_ctrl() - Add a control from another handler to this handler.
510   * @hdl:       The control handler.
511   * @ctrl:      The control to add.
512   *
513   * It will return NULL if it was unable to add the control reference.
514   * If the control already belonged to the handler, then it will do
515   * nothing and just return @ctrl.
516   */
517 struct v4l2_ctrl *v4l2_ctrl_add_ctrl(struct v4l2_ctrl_handler *hdl,
518                                           struct v4l2_ctrl *ctrl);
519 
520 /** v4l2_ctrl_add_handler() - Add all controls from handler @add to
521   * handler @hdl.
522   * @hdl:       The control handler.
523   * @add:       The control handler whose controls you want to add to
524   *             the @hdl control handler.
525   * @filter:    This function will filter which controls should be added.
526   *
527   * Does nothing if either of the two handlers is a NULL pointer.
528   * If @filter is NULL, then all controls are added. Otherwise only those
529   * controls for which @filter returns true will be added.
530   * In case of an error @hdl->error will be set to the error code (if it
531   * wasn't set already).
532   */
533 int v4l2_ctrl_add_handler(struct v4l2_ctrl_handler *hdl,
534                           struct v4l2_ctrl_handler *add,
535                           bool (*filter)(const struct v4l2_ctrl *ctrl));
536 
537 /** v4l2_ctrl_radio_filter() - Standard filter for radio controls.
538   * @ctrl:      The control that is filtered.
539   *
540   * This will return true for any controls that are valid for radio device
541   * nodes. Those are all of the V4L2_CID_AUDIO_* user controls and all FM
542   * transmitter class controls.
543   *
544   * This function is to be used with v4l2_ctrl_add_handler().
545   */
546 bool v4l2_ctrl_radio_filter(const struct v4l2_ctrl *ctrl);
547 
548 /** v4l2_ctrl_cluster() - Mark all controls in the cluster as belonging to that cluster.
549   * @ncontrols: The number of controls in this cluster.
550   * @controls:  The cluster control array of size @ncontrols.
551   */
552 void v4l2_ctrl_cluster(unsigned ncontrols, struct v4l2_ctrl **controls);
553 
554 
555 /** v4l2_ctrl_auto_cluster() - Mark all controls in the cluster as belonging to
556   * that cluster and set it up for autofoo/foo-type handling.
557   * @ncontrols: The number of controls in this cluster.
558   * @controls:  The cluster control array of size @ncontrols. The first control
559   *             must be the 'auto' control (e.g. autogain, autoexposure, etc.)
560   * @manual_val: The value for the first control in the cluster that equals the
561   *             manual setting.
562   * @set_volatile: If true, then all controls except the first auto control will
563   *             be volatile.
564   *
565   * Use for control groups where one control selects some automatic feature and
566   * the other controls are only active whenever the automatic feature is turned
567   * off (manual mode). Typical examples: autogain vs gain, auto-whitebalance vs
568   * red and blue balance, etc.
569   *
570   * The behavior of such controls is as follows:
571   *
572   * When the autofoo control is set to automatic, then any manual controls
573   * are set to inactive and any reads will call g_volatile_ctrl (if the control
574   * was marked volatile).
575   *
576   * When the autofoo control is set to manual, then any manual controls will
577   * be marked active, and any reads will just return the current value without
578   * going through g_volatile_ctrl.
579   *
580   * In addition, this function will set the V4L2_CTRL_FLAG_UPDATE flag
581   * on the autofoo control and V4L2_CTRL_FLAG_INACTIVE on the foo control(s)
582   * if autofoo is in auto mode.
583   */
584 void v4l2_ctrl_auto_cluster(unsigned ncontrols, struct v4l2_ctrl **controls,
585                         u8 manual_val, bool set_volatile);
586 
587 
588 /** v4l2_ctrl_find() - Find a control with the given ID.
589   * @hdl:       The control handler.
590   * @id:        The control ID to find.
591   *
592   * If @hdl == NULL this will return NULL as well. Will lock the handler so
593   * do not use from inside &v4l2_ctrl_ops.
594   */
595 struct v4l2_ctrl *v4l2_ctrl_find(struct v4l2_ctrl_handler *hdl, u32 id);
596 
597 /** v4l2_ctrl_activate() - Make the control active or inactive.
598   * @ctrl:      The control to (de)activate.
599   * @active:    True if the control should become active.
600   *
601   * This sets or clears the V4L2_CTRL_FLAG_INACTIVE flag atomically.
602   * Does nothing if @ctrl == NULL.
603   * This will usually be called from within the s_ctrl op.
604   * The V4L2_EVENT_CTRL event will be generated afterwards.
605   *
606   * This function assumes that the control handler is locked.
607   */
608 void v4l2_ctrl_activate(struct v4l2_ctrl *ctrl, bool active);
609 
610 /** v4l2_ctrl_grab() - Mark the control as grabbed or not grabbed.
611   * @ctrl:      The control to (de)activate.
612   * @grabbed:   True if the control should become grabbed.
613   *
614   * This sets or clears the V4L2_CTRL_FLAG_GRABBED flag atomically.
615   * Does nothing if @ctrl == NULL.
616   * The V4L2_EVENT_CTRL event will be generated afterwards.
617   * This will usually be called when starting or stopping streaming in the
618   * driver.
619   *
620   * This function assumes that the control handler is not locked and will
621   * take the lock itself.
622   */
623 void v4l2_ctrl_grab(struct v4l2_ctrl *ctrl, bool grabbed);
624 
625 
626 /** __v4l2_ctrl_modify_range() - Unlocked variant of v4l2_ctrl_modify_range() */
627 int __v4l2_ctrl_modify_range(struct v4l2_ctrl *ctrl,
628                              s64 min, s64 max, u64 step, s64 def);
629 
630 /** v4l2_ctrl_modify_range() - Update the range of a control.
631   * @ctrl:      The control to update.
632   * @min:       The control's minimum value.
633   * @max:       The control's maximum value.
634   * @step:      The control's step value
635   * @def:       The control's default value.
636   *
637   * Update the range of a control on the fly. This works for control types
638   * INTEGER, BOOLEAN, MENU, INTEGER MENU and BITMASK. For menu controls the
639   * @step value is interpreted as a menu_skip_mask.
640   *
641   * An error is returned if one of the range arguments is invalid for this
642   * control type.
643   *
644   * This function assumes that the control handler is not locked and will
645   * take the lock itself.
646   */
647 static inline int v4l2_ctrl_modify_range(struct v4l2_ctrl *ctrl,
648                                          s64 min, s64 max, u64 step, s64 def)
649 {
650         int rval;
651 
652         v4l2_ctrl_lock(ctrl);
653         rval = __v4l2_ctrl_modify_range(ctrl, min, max, step, def);
654         v4l2_ctrl_unlock(ctrl);
655 
656         return rval;
657 }
658 
659 /** v4l2_ctrl_notify() - Function to set a notify callback for a control.
660   * @ctrl:      The control.
661   * @notify:    The callback function.
662   * @priv:      The callback private handle, passed as argument to the callback.
663   *
664   * This function sets a callback function for the control. If @ctrl is NULL,
665   * then it will do nothing. If @notify is NULL, then the notify callback will
666   * be removed.
667   *
668   * There can be only one notify. If another already exists, then a WARN_ON
669   * will be issued and the function will do nothing.
670   */
671 void v4l2_ctrl_notify(struct v4l2_ctrl *ctrl, v4l2_ctrl_notify_fnc notify, void *priv);
672 
673 /** v4l2_ctrl_g_ctrl() - Helper function to get the control's value from within a driver.
674   * @ctrl:      The control.
675   *
676   * This returns the control's value safely by going through the control
677   * framework. This function will lock the control's handler, so it cannot be
678   * used from within the &v4l2_ctrl_ops functions.
679   *
680   * This function is for integer type controls only.
681   */
682 s32 v4l2_ctrl_g_ctrl(struct v4l2_ctrl *ctrl);
683 
684 /** __v4l2_ctrl_s_ctrl() - Unlocked variant of v4l2_ctrl_s_ctrl(). */
685 int __v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val);
686 /** v4l2_ctrl_s_ctrl() - Helper function to set the control's value from within a driver.
687   * @ctrl:      The control.
688   * @val:       The new value.
689   *
690   * This set the control's new value safely by going through the control
691   * framework. This function will lock the control's handler, so it cannot be
692   * used from within the &v4l2_ctrl_ops functions.
693   *
694   * This function is for integer type controls only.
695   */
696 static inline int v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val)
697 {
698         int rval;
699 
700         v4l2_ctrl_lock(ctrl);
701         rval = __v4l2_ctrl_s_ctrl(ctrl, val);
702         v4l2_ctrl_unlock(ctrl);
703 
704         return rval;
705 }
706 
707 /** v4l2_ctrl_g_ctrl_int64() - Helper function to get a 64-bit control's value from within a driver.
708   * @ctrl:      The control.
709   *
710   * This returns the control's value safely by going through the control
711   * framework. This function will lock the control's handler, so it cannot be
712   * used from within the &v4l2_ctrl_ops functions.
713   *
714   * This function is for 64-bit integer type controls only.
715   */
716 s64 v4l2_ctrl_g_ctrl_int64(struct v4l2_ctrl *ctrl);
717 
718 /** __v4l2_ctrl_s_ctrl_int64() - Unlocked variant of v4l2_ctrl_s_ctrl_int64(). */
719 int __v4l2_ctrl_s_ctrl_int64(struct v4l2_ctrl *ctrl, s64 val);
720 
721 /** v4l2_ctrl_s_ctrl_int64() - Helper function to set a 64-bit control's value from within a driver.
722   * @ctrl:      The control.
723   * @val:       The new value.
724   *
725   * This set the control's new value safely by going through the control
726   * framework. This function will lock the control's handler, so it cannot be
727   * used from within the &v4l2_ctrl_ops functions.
728   *
729   * This function is for 64-bit integer type controls only.
730   */
731 static inline int v4l2_ctrl_s_ctrl_int64(struct v4l2_ctrl *ctrl, s64 val)
732 {
733         int rval;
734 
735         v4l2_ctrl_lock(ctrl);
736         rval = __v4l2_ctrl_s_ctrl_int64(ctrl, val);
737         v4l2_ctrl_unlock(ctrl);
738 
739         return rval;
740 }
741 
742 /** __v4l2_ctrl_s_ctrl_string() - Unlocked variant of v4l2_ctrl_s_ctrl_string(). */
743 int __v4l2_ctrl_s_ctrl_string(struct v4l2_ctrl *ctrl, const char *s);
744 
745 /** v4l2_ctrl_s_ctrl_string() - Helper function to set a control's string value from within a driver.
746   * @ctrl:      The control.
747   * @s:         The new string.
748   *
749   * This set the control's new string 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 string type controls only.
754   */
755 static inline int v4l2_ctrl_s_ctrl_string(struct v4l2_ctrl *ctrl, const char *s)
756 {
757         int rval;
758 
759         v4l2_ctrl_lock(ctrl);
760         rval = __v4l2_ctrl_s_ctrl_string(ctrl, s);
761         v4l2_ctrl_unlock(ctrl);
762 
763         return rval;
764 }
765 
766 /* Internal helper functions that deal with control events. */
767 extern const struct v4l2_subscribed_event_ops v4l2_ctrl_sub_ev_ops;
768 void v4l2_ctrl_replace(struct v4l2_event *old, const struct v4l2_event *new);
769 void v4l2_ctrl_merge(const struct v4l2_event *old, struct v4l2_event *new);
770 
771 /* Can be used as a vidioc_log_status function that just dumps all controls
772    associated with the filehandle. */
773 int v4l2_ctrl_log_status(struct file *file, void *fh);
774 
775 /* Can be used as a vidioc_subscribe_event function that just subscribes
776    control events. */
777 int v4l2_ctrl_subscribe_event(struct v4l2_fh *fh,
778                                 const struct v4l2_event_subscription *sub);
779 
780 /* Can be used as a poll function that just polls for control events. */
781 unsigned int v4l2_ctrl_poll(struct file *file, struct poll_table_struct *wait);
782 
783 /* Helpers for ioctl_ops. If hdl == NULL then they will all return -EINVAL. */
784 int v4l2_queryctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_queryctrl *qc);
785 int v4l2_query_ext_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_query_ext_ctrl *qc);
786 int v4l2_querymenu(struct v4l2_ctrl_handler *hdl, struct v4l2_querymenu *qm);
787 int v4l2_g_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_control *ctrl);
788 int v4l2_s_ctrl(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
789                                                 struct v4l2_control *ctrl);
790 int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *c);
791 int v4l2_try_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *c);
792 int v4l2_s_ext_ctrls(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
793                                                 struct v4l2_ext_controls *c);
794 
795 /* Helpers for subdevices. If the associated ctrl_handler == NULL then they
796    will all return -EINVAL. */
797 int v4l2_subdev_queryctrl(struct v4l2_subdev *sd, struct v4l2_queryctrl *qc);
798 int v4l2_subdev_querymenu(struct v4l2_subdev *sd, struct v4l2_querymenu *qm);
799 int v4l2_subdev_g_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
800 int v4l2_subdev_try_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
801 int v4l2_subdev_s_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
802 int v4l2_subdev_g_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
803 int v4l2_subdev_s_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
804 
805 /* Can be used as a subscribe_event function that just subscribes control
806    events. */
807 int v4l2_ctrl_subdev_subscribe_event(struct v4l2_subdev *sd, struct v4l2_fh *fh,
808                                      struct v4l2_event_subscription *sub);
809 
810 /* Log all controls owned by subdev's control handler. */
811 int v4l2_ctrl_subdev_log_status(struct v4l2_subdev *sd);
812 
813 #endif
814 

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