2 V4L2 controls support header.
4 Copyright (C) 2010 Hans Verkuil <hverkuil@xs4all.nl>
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.
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.
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18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 #include <linux/list.h>
25 #include <linux/videodev2.h>
27 /* forward references */
28 struct v4l2_ctrl_handler;
29 struct v4l2_ctrl_helper;
33 struct v4l2_subscribed_event;
35 struct poll_table_struct;
37 /** struct v4l2_ctrl_ops - The control operations that the driver has to provide.
38 * @g_volatile_ctrl: Get a new value for this control. Generally only relevant
39 * for volatile (and usually read-only) controls such as a control
40 * that returns the current signal strength which changes
42 * If not set, then the currently cached value will be returned.
43 * @try_ctrl: Test whether the control's value is valid. Only relevant when
44 * the usual min/max/step checks are not sufficient.
45 * @s_ctrl: Actually set the new control value. s_ctrl is compulsory. The
46 * ctrl->handler->lock is held when these ops are called, so no
47 * one else can access controls owned by that handler.
49 struct v4l2_ctrl_ops {
50 int (*g_volatile_ctrl)(struct v4l2_ctrl *ctrl);
51 int (*try_ctrl)(struct v4l2_ctrl *ctrl);
52 int (*s_ctrl)(struct v4l2_ctrl *ctrl);
55 /** struct v4l2_ctrl - The control structure.
56 * @node: The list node.
57 * @ev_subs: The list of control event subscriptions.
58 * @handler: The handler that owns the control.
59 * @cluster: Point to start of cluster array.
60 * @ncontrols: Number of controls in cluster array.
61 * @done: Internal flag: set for each processed control.
62 * @is_new: Set when the user specified a new value for this control. It
63 * is also set when called from v4l2_ctrl_handler_setup. Drivers
64 * should never set this flag.
65 * @is_private: If set, then this control is private to its handler and it
66 * will not be added to any other handlers. Drivers can set
68 * @is_auto: If set, then this control selects whether the other cluster
69 * members are in 'automatic' mode or 'manual' mode. This is
70 * used for autogain/gain type clusters. Drivers should never
71 * set this flag directly.
72 * @has_volatiles: If set, then one or more members of the cluster are volatile.
73 * Drivers should never touch this flag.
74 * @manual_mode_value: If the is_auto flag is set, then this is the value
75 * of the auto control that determines if that control is in
76 * manual mode. So if the value of the auto control equals this
77 * value, then the whole cluster is in manual mode. Drivers should
78 * never set this flag directly.
79 * @ops: The control ops.
80 * @id: The control ID.
81 * @name: The control name.
82 * @type: The control type.
83 * @minimum: The control's minimum value.
84 * @maximum: The control's maximum value.
85 * @default_value: The control's default value.
86 * @step: The control's step value for non-menu controls.
87 * @menu_skip_mask: The control's skip mask for menu controls. This makes it
88 * easy to skip menu items that are not valid. If bit X is set,
89 * then menu item X is skipped. Of course, this only works for
90 * menus with <= 32 menu items. There are no menus that come
91 * close to that number, so this is OK. Should we ever need more,
92 * then this will have to be extended to a u64 or a bit array.
93 * @qmenu: A const char * array for all menu items. Array entries that are
94 * empty strings ("") correspond to non-existing menu items (this
95 * is in addition to the menu_skip_mask above). The last entry
97 * @flags: The control's flags.
98 * @cur: The control's current value.
99 * @val: The control's new s32 value.
100 * @val64: The control's new s64 value.
101 * @string: The control's new string value.
102 * @priv: The control's private pointer. For use by the driver. It is
103 * untouched by the control framework. Note that this pointer is
104 * not freed when the control is deleted. Should this be needed
105 * then a new internal bitfield can be added to tell the framework
106 * to free this pointer.
109 /* Administrative fields */
110 struct list_head node;
111 struct list_head ev_subs;
112 struct v4l2_ctrl_handler *handler;
113 struct v4l2_ctrl **cluster;
117 unsigned int is_new:1;
118 unsigned int is_private:1;
119 unsigned int is_auto:1;
120 unsigned int has_volatiles:1;
121 unsigned int manual_mode_value:8;
123 const struct v4l2_ctrl_ops *ops;
126 enum v4l2_ctrl_type type;
127 s32 minimum, maximum, default_value;
133 const char * const *qmenu;
134 const s64 *qmenu_int;
150 /** struct v4l2_ctrl_ref - The control reference.
151 * @node: List node for the sorted list.
152 * @next: Single-link list node for the hash.
153 * @ctrl: The actual control information.
154 * @helper: Pointer to helper struct. Used internally in prepare_ext_ctrls().
156 * Each control handler has a list of these refs. The list_head is used to
157 * keep a sorted-by-control-ID list of all controls, while the next pointer
158 * is used to link the control in the hash's bucket.
160 struct v4l2_ctrl_ref {
161 struct list_head node;
162 struct v4l2_ctrl_ref *next;
163 struct v4l2_ctrl *ctrl;
164 struct v4l2_ctrl_helper *helper;
167 /** struct v4l2_ctrl_handler - The control handler keeps track of all the
168 * controls: both the controls owned by the handler and those inherited
169 * from other handlers.
170 * @_lock: Default for "lock".
171 * @lock: Lock to control access to this handler and its controls.
172 * May be replaced by the user right after init.
173 * @ctrls: The list of controls owned by this handler.
174 * @ctrl_refs: The list of control references.
175 * @cached: The last found control reference. It is common that the same
176 * control is needed multiple times, so this is a simple
178 * @buckets: Buckets for the hashing. Allows for quick control lookup.
179 * @nr_of_buckets: Total number of buckets in the array.
180 * @error: The error code of the first failed control addition.
182 struct v4l2_ctrl_handler {
185 struct list_head ctrls;
186 struct list_head ctrl_refs;
187 struct v4l2_ctrl_ref *cached;
188 struct v4l2_ctrl_ref **buckets;
193 /** struct v4l2_ctrl_config - Control configuration structure.
194 * @ops: The control ops.
195 * @id: The control ID.
196 * @name: The control name.
197 * @type: The control type.
198 * @min: The control's minimum value.
199 * @max: The control's maximum value.
200 * @step: The control's step value for non-menu controls.
201 * @def: The control's default value.
202 * @flags: The control's flags.
203 * @menu_skip_mask: The control's skip mask for menu controls. This makes it
204 * easy to skip menu items that are not valid. If bit X is set,
205 * then menu item X is skipped. Of course, this only works for
206 * menus with <= 32 menu items. There are no menus that come
207 * close to that number, so this is OK. Should we ever need more,
208 * then this will have to be extended to a u64 or a bit array.
209 * @qmenu: A const char * array for all menu items. Array entries that are
210 * empty strings ("") correspond to non-existing menu items (this
211 * is in addition to the menu_skip_mask above). The last entry
213 * @is_private: If set, then this control is private to its handler and it
214 * will not be added to any other handlers.
216 struct v4l2_ctrl_config {
217 const struct v4l2_ctrl_ops *ops;
220 enum v4l2_ctrl_type type;
227 const char * const *qmenu;
228 const s64 *qmenu_int;
229 unsigned int is_private:1;
232 /** v4l2_ctrl_fill() - Fill in the control fields based on the control ID.
234 * This works for all standard V4L2 controls.
235 * For non-standard controls it will only fill in the given arguments
236 * and @name will be NULL.
238 * This function will overwrite the contents of @name, @type and @flags.
239 * The contents of @min, @max, @step and @def may be modified depending on
242 * Do not use in drivers! It is used internally for backwards compatibility
243 * control handling only. Once all drivers are converted to use the new
244 * control framework this function will no longer be exported.
246 void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
247 s32 *min, s32 *max, s32 *step, s32 *def, u32 *flags);
250 /** v4l2_ctrl_handler_init() - Initialize the control handler.
251 * @hdl: The control handler.
252 * @nr_of_controls_hint: A hint of how many controls this handler is
253 * expected to refer to. This is the total number, so including
254 * any inherited controls. It doesn't have to be precise, but if
255 * it is way off, then you either waste memory (too many buckets
256 * are allocated) or the control lookup becomes slower (not enough
257 * buckets are allocated, so there are more slow list lookups).
258 * It will always work, though.
260 * Returns an error if the buckets could not be allocated. This error will
261 * also be stored in @hdl->error.
263 int v4l2_ctrl_handler_init(struct v4l2_ctrl_handler *hdl,
264 unsigned nr_of_controls_hint);
266 /** v4l2_ctrl_handler_free() - Free all controls owned by the handler and free
268 * @hdl: The control handler.
270 * Does nothing if @hdl == NULL.
272 void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl);
274 /** v4l2_ctrl_handler_setup() - Call the s_ctrl op for all controls belonging
275 * to the handler to initialize the hardware to the current control values.
276 * @hdl: The control handler.
278 * Button controls will be skipped, as are read-only controls.
280 * If @hdl == NULL, then this just returns 0.
282 int v4l2_ctrl_handler_setup(struct v4l2_ctrl_handler *hdl);
284 /** v4l2_ctrl_handler_log_status() - Log all controls owned by the handler.
285 * @hdl: The control handler.
286 * @prefix: The prefix to use when logging the control values. If the
287 * prefix does not end with a space, then ": " will be added
288 * after the prefix. If @prefix == NULL, then no prefix will be
291 * For use with VIDIOC_LOG_STATUS.
293 * Does nothing if @hdl == NULL.
295 void v4l2_ctrl_handler_log_status(struct v4l2_ctrl_handler *hdl,
298 /** v4l2_ctrl_new_custom() - Allocate and initialize a new custom V4L2
300 * @hdl: The control handler.
301 * @cfg: The control's configuration data.
302 * @priv: The control's driver-specific private data.
304 * If the &v4l2_ctrl struct could not be allocated then NULL is returned
305 * and @hdl->error is set to the error code (if it wasn't set already).
307 struct v4l2_ctrl *v4l2_ctrl_new_custom(struct v4l2_ctrl_handler *hdl,
308 const struct v4l2_ctrl_config *cfg, void *priv);
310 /** v4l2_ctrl_new_std() - Allocate and initialize a new standard V4L2 non-menu control.
311 * @hdl: The control handler.
312 * @ops: The control ops.
313 * @id: The control ID.
314 * @min: The control's minimum value.
315 * @max: The control's maximum value.
316 * @step: The control's step value
317 * @def: The control's default value.
319 * If the &v4l2_ctrl struct could not be allocated, or the control
320 * ID is not known, then NULL is returned and @hdl->error is set to the
321 * appropriate error code (if it wasn't set already).
323 * If @id refers to a menu control, then this function will return NULL.
325 * Use v4l2_ctrl_new_std_menu() when adding menu controls.
327 struct v4l2_ctrl *v4l2_ctrl_new_std(struct v4l2_ctrl_handler *hdl,
328 const struct v4l2_ctrl_ops *ops,
329 u32 id, s32 min, s32 max, u32 step, s32 def);
331 /** v4l2_ctrl_new_std_menu() - Allocate and initialize a new standard V4L2 menu control.
332 * @hdl: The control handler.
333 * @ops: The control ops.
334 * @id: The control ID.
335 * @max: The control's maximum value.
336 * @mask: The control's skip mask for menu controls. This makes it
337 * easy to skip menu items that are not valid. If bit X is set,
338 * then menu item X is skipped. Of course, this only works for
339 * menus with <= 32 menu items. There are no menus that come
340 * close to that number, so this is OK. Should we ever need more,
341 * then this will have to be extended to a u64 or a bit array.
342 * @def: The control's default value.
344 * Same as v4l2_ctrl_new_std(), but @min is set to 0 and the @mask value
345 * determines which menu items are to be skipped.
347 * If @id refers to a non-menu control, then this function will return NULL.
349 struct v4l2_ctrl *v4l2_ctrl_new_std_menu(struct v4l2_ctrl_handler *hdl,
350 const struct v4l2_ctrl_ops *ops,
351 u32 id, s32 max, s32 mask, s32 def);
353 /** v4l2_ctrl_add_ctrl() - Add a control from another handler to this handler.
354 * @hdl: The control handler.
355 * @ctrl: The control to add.
357 * It will return NULL if it was unable to add the control reference.
358 * If the control already belonged to the handler, then it will do
359 * nothing and just return @ctrl.
361 struct v4l2_ctrl *v4l2_ctrl_add_ctrl(struct v4l2_ctrl_handler *hdl,
362 struct v4l2_ctrl *ctrl);
364 /** v4l2_ctrl_add_handler() - Add all controls from handler @add to
366 * @hdl: The control handler.
367 * @add: The control handler whose controls you want to add to
368 * the @hdl control handler.
370 * Does nothing if either of the two is a NULL pointer.
371 * In case of an error @hdl->error will be set to the error code (if it
372 * wasn't set already).
374 int v4l2_ctrl_add_handler(struct v4l2_ctrl_handler *hdl,
375 struct v4l2_ctrl_handler *add);
378 /** v4l2_ctrl_cluster() - Mark all controls in the cluster as belonging to that cluster.
379 * @ncontrols: The number of controls in this cluster.
380 * @controls: The cluster control array of size @ncontrols.
382 void v4l2_ctrl_cluster(unsigned ncontrols, struct v4l2_ctrl **controls);
385 /** v4l2_ctrl_auto_cluster() - Mark all controls in the cluster as belonging to
386 * that cluster and set it up for autofoo/foo-type handling.
387 * @ncontrols: The number of controls in this cluster.
388 * @controls: The cluster control array of size @ncontrols. The first control
389 * must be the 'auto' control (e.g. autogain, autoexposure, etc.)
390 * @manual_val: The value for the first control in the cluster that equals the
392 * @set_volatile: If true, then all controls except the first auto control will
395 * Use for control groups where one control selects some automatic feature and
396 * the other controls are only active whenever the automatic feature is turned
397 * off (manual mode). Typical examples: autogain vs gain, auto-whitebalance vs
398 * red and blue balance, etc.
400 * The behavior of such controls is as follows:
402 * When the autofoo control is set to automatic, then any manual controls
403 * are set to inactive and any reads will call g_volatile_ctrl (if the control
404 * was marked volatile).
406 * When the autofoo control is set to manual, then any manual controls will
407 * be marked active, and any reads will just return the current value without
408 * going through g_volatile_ctrl.
410 * In addition, this function will set the V4L2_CTRL_FLAG_UPDATE flag
411 * on the autofoo control and V4L2_CTRL_FLAG_INACTIVE on the foo control(s)
412 * if autofoo is in auto mode.
414 void v4l2_ctrl_auto_cluster(unsigned ncontrols, struct v4l2_ctrl **controls,
415 u8 manual_val, bool set_volatile);
418 /** v4l2_ctrl_find() - Find a control with the given ID.
419 * @hdl: The control handler.
420 * @id: The control ID to find.
422 * If @hdl == NULL this will return NULL as well. Will lock the handler so
423 * do not use from inside &v4l2_ctrl_ops.
425 struct v4l2_ctrl *v4l2_ctrl_find(struct v4l2_ctrl_handler *hdl, u32 id);
427 /** v4l2_ctrl_activate() - Make the control active or inactive.
428 * @ctrl: The control to (de)activate.
429 * @active: True if the control should become active.
431 * This sets or clears the V4L2_CTRL_FLAG_INACTIVE flag atomically.
432 * Does nothing if @ctrl == NULL.
433 * This will usually be called from within the s_ctrl op.
434 * The V4L2_EVENT_CTRL event will be generated afterwards.
436 * This function assumes that the control handler is locked.
438 void v4l2_ctrl_activate(struct v4l2_ctrl *ctrl, bool active);
440 /** v4l2_ctrl_grab() - Mark the control as grabbed or not grabbed.
441 * @ctrl: The control to (de)activate.
442 * @grabbed: True if the control should become grabbed.
444 * This sets or clears the V4L2_CTRL_FLAG_GRABBED flag atomically.
445 * Does nothing if @ctrl == NULL.
446 * The V4L2_EVENT_CTRL event will be generated afterwards.
447 * This will usually be called when starting or stopping streaming in the
450 * This function assumes that the control handler is not locked and will
451 * take the lock itself.
453 void v4l2_ctrl_grab(struct v4l2_ctrl *ctrl, bool grabbed);
455 /** v4l2_ctrl_lock() - Helper function to lock the handler
456 * associated with the control.
457 * @ctrl: The control to lock.
459 static inline void v4l2_ctrl_lock(struct v4l2_ctrl *ctrl)
461 mutex_lock(ctrl->handler->lock);
464 /** v4l2_ctrl_lock() - Helper function to unlock the handler
465 * associated with the control.
466 * @ctrl: The control to unlock.
468 static inline void v4l2_ctrl_unlock(struct v4l2_ctrl *ctrl)
470 mutex_unlock(ctrl->handler->lock);
473 /** v4l2_ctrl_g_ctrl() - Helper function to get the control's value from within a driver.
474 * @ctrl: The control.
476 * This returns the control's value safely by going through the control
477 * framework. This function will lock the control's handler, so it cannot be
478 * used from within the &v4l2_ctrl_ops functions.
480 * This function is for integer type controls only.
482 s32 v4l2_ctrl_g_ctrl(struct v4l2_ctrl *ctrl);
484 /** v4l2_ctrl_s_ctrl() - Helper function to set the control's value from within a driver.
485 * @ctrl: The control.
486 * @val: The new value.
488 * This set the control's new value safely by going through the control
489 * framework. This function will lock the control's handler, so it cannot be
490 * used from within the &v4l2_ctrl_ops functions.
492 * This function is for integer type controls only.
494 int v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val);
496 /* Internal helper functions that deal with control events. */
497 extern const struct v4l2_subscribed_event_ops v4l2_ctrl_sub_ev_ops;
498 void v4l2_ctrl_replace(struct v4l2_event *old, const struct v4l2_event *new);
499 void v4l2_ctrl_merge(const struct v4l2_event *old, struct v4l2_event *new);
502 /* Can be used as a vidioc_log_status function that just dumps all controls
503 associated with the filehandle. */
504 int v4l2_ctrl_log_status(struct file *file, void *fh);
506 /* Can be used as a vidioc_subscribe_event function that just subscribes
508 int v4l2_ctrl_subscribe_event(struct v4l2_fh *fh,
509 struct v4l2_event_subscription *sub);
511 /* Can be used as a poll function that just polls for control events. */
512 unsigned int v4l2_ctrl_poll(struct file *file, struct poll_table_struct *wait);
514 /* Helpers for ioctl_ops. If hdl == NULL then they will all return -EINVAL. */
515 int v4l2_queryctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_queryctrl *qc);
516 int v4l2_querymenu(struct v4l2_ctrl_handler *hdl, struct v4l2_querymenu *qm);
517 int v4l2_g_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_control *ctrl);
518 int v4l2_s_ctrl(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
519 struct v4l2_control *ctrl);
520 int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *c);
521 int v4l2_try_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *c);
522 int v4l2_s_ext_ctrls(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
523 struct v4l2_ext_controls *c);
525 /* Helpers for subdevices. If the associated ctrl_handler == NULL then they
526 will all return -EINVAL. */
527 int v4l2_subdev_queryctrl(struct v4l2_subdev *sd, struct v4l2_queryctrl *qc);
528 int v4l2_subdev_querymenu(struct v4l2_subdev *sd, struct v4l2_querymenu *qm);
529 int v4l2_subdev_g_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
530 int v4l2_subdev_try_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
531 int v4l2_subdev_s_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
532 int v4l2_subdev_g_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
533 int v4l2_subdev_s_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl);