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.
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
24
#include <linux/list.h>
25
#include <linux/device.h>
26
#include <linux/videodev2.h>
28
/* forward references */
29
struct v4l2_ctrl_handler;
30
struct v4l2_ctrl_helper;
34
struct v4l2_subscribed_event;
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;
132
const char * const *qmenu;
147
/** struct v4l2_ctrl_ref - The control reference.
148
* @node: List node for the sorted list.
149
* @next: Single-link list node for the hash.
150
* @ctrl: The actual control information.
151
* @helper: Pointer to helper struct. Used internally in prepare_ext_ctrls().
153
* Each control handler has a list of these refs. The list_head is used to
154
* keep a sorted-by-control-ID list of all controls, while the next pointer
155
* is used to link the control in the hash's bucket.
157
struct v4l2_ctrl_ref {
158
struct list_head node;
159
struct v4l2_ctrl_ref *next;
160
struct v4l2_ctrl *ctrl;
161
struct v4l2_ctrl_helper *helper;
164
/** struct v4l2_ctrl_handler - The control handler keeps track of all the
165
* controls: both the controls owned by the handler and those inherited
166
* from other handlers.
167
* @lock: Lock to control access to this handler and its controls.
168
* @ctrls: The list of controls owned by this handler.
169
* @ctrl_refs: The list of control references.
170
* @cached: The last found control reference. It is common that the same
171
* control is needed multiple times, so this is a simple
173
* @buckets: Buckets for the hashing. Allows for quick control lookup.
174
* @nr_of_buckets: Total number of buckets in the array.
175
* @error: The error code of the first failed control addition.
177
struct v4l2_ctrl_handler {
179
struct list_head ctrls;
180
struct list_head ctrl_refs;
181
struct v4l2_ctrl_ref *cached;
182
struct v4l2_ctrl_ref **buckets;
187
/** struct v4l2_ctrl_config - Control configuration structure.
188
* @ops: The control ops.
189
* @id: The control ID.
190
* @name: The control name.
191
* @type: The control type.
192
* @min: The control's minimum value.
193
* @max: The control's maximum value.
194
* @step: The control's step value for non-menu controls.
195
* @def: The control's default value.
196
* @flags: The control's flags.
197
* @menu_skip_mask: The control's skip mask for menu controls. This makes it
198
* easy to skip menu items that are not valid. If bit X is set,
199
* then menu item X is skipped. Of course, this only works for
200
* menus with <= 32 menu items. There are no menus that come
201
* close to that number, so this is OK. Should we ever need more,
202
* then this will have to be extended to a u64 or a bit array.
203
* @qmenu: A const char * array for all menu items. Array entries that are
204
* empty strings ("") correspond to non-existing menu items (this
205
* is in addition to the menu_skip_mask above). The last entry
207
* @is_private: If set, then this control is private to its handler and it
208
* will not be added to any other handlers.
210
struct v4l2_ctrl_config {
211
const struct v4l2_ctrl_ops *ops;
214
enum v4l2_ctrl_type type;
221
const char * const *qmenu;
222
unsigned int is_private:1;
225
/** v4l2_ctrl_fill() - Fill in the control fields based on the control ID.
227
* This works for all standard V4L2 controls.
228
* For non-standard controls it will only fill in the given arguments
229
* and @name will be NULL.
231
* This function will overwrite the contents of @name, @type and @flags.
232
* The contents of @min, @max, @step and @def may be modified depending on
235
* Do not use in drivers! It is used internally for backwards compatibility
236
* control handling only. Once all drivers are converted to use the new
237
* control framework this function will no longer be exported.
239
void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
240
s32 *min, s32 *max, s32 *step, s32 *def, u32 *flags);
243
/** v4l2_ctrl_handler_init() - Initialize the control handler.
244
* @hdl: The control handler.
245
* @nr_of_controls_hint: A hint of how many controls this handler is
246
* expected to refer to. This is the total number, so including
247
* any inherited controls. It doesn't have to be precise, but if
248
* it is way off, then you either waste memory (too many buckets
249
* are allocated) or the control lookup becomes slower (not enough
250
* buckets are allocated, so there are more slow list lookups).
251
* It will always work, though.
253
* Returns an error if the buckets could not be allocated. This error will
254
* also be stored in @hdl->error.
256
int v4l2_ctrl_handler_init(struct v4l2_ctrl_handler *hdl,
257
unsigned nr_of_controls_hint);
259
/** v4l2_ctrl_handler_free() - Free all controls owned by the handler and free
261
* @hdl: The control handler.
263
* Does nothing if @hdl == NULL.
265
void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl);
267
/** v4l2_ctrl_handler_setup() - Call the s_ctrl op for all controls belonging
268
* to the handler to initialize the hardware to the current control values.
269
* @hdl: The control handler.
271
* Button controls will be skipped, as are read-only controls.
273
* If @hdl == NULL, then this just returns 0.
275
int v4l2_ctrl_handler_setup(struct v4l2_ctrl_handler *hdl);
277
/** v4l2_ctrl_handler_log_status() - Log all controls owned by the handler.
278
* @hdl: The control handler.
279
* @prefix: The prefix to use when logging the control values. If the
280
* prefix does not end with a space, then ": " will be added
281
* after the prefix. If @prefix == NULL, then no prefix will be
284
* For use with VIDIOC_LOG_STATUS.
286
* Does nothing if @hdl == NULL.
288
void v4l2_ctrl_handler_log_status(struct v4l2_ctrl_handler *hdl,
291
/** v4l2_ctrl_new_custom() - Allocate and initialize a new custom V4L2
293
* @hdl: The control handler.
294
* @cfg: The control's configuration data.
295
* @priv: The control's driver-specific private data.
297
* If the &v4l2_ctrl struct could not be allocated then NULL is returned
298
* and @hdl->error is set to the error code (if it wasn't set already).
300
struct v4l2_ctrl *v4l2_ctrl_new_custom(struct v4l2_ctrl_handler *hdl,
301
const struct v4l2_ctrl_config *cfg, void *priv);
303
/** v4l2_ctrl_new_std() - Allocate and initialize a new standard V4L2 non-menu control.
304
* @hdl: The control handler.
305
* @ops: The control ops.
306
* @id: The control ID.
307
* @min: The control's minimum value.
308
* @max: The control's maximum value.
309
* @step: The control's step value
310
* @def: The control's default value.
312
* If the &v4l2_ctrl struct could not be allocated, or the control
313
* ID is not known, then NULL is returned and @hdl->error is set to the
314
* appropriate error code (if it wasn't set already).
316
* If @id refers to a menu control, then this function will return NULL.
318
* Use v4l2_ctrl_new_std_menu() when adding menu controls.
320
struct v4l2_ctrl *v4l2_ctrl_new_std(struct v4l2_ctrl_handler *hdl,
321
const struct v4l2_ctrl_ops *ops,
322
u32 id, s32 min, s32 max, u32 step, s32 def);
324
/** v4l2_ctrl_new_std_menu() - Allocate and initialize a new standard V4L2 menu control.
325
* @hdl: The control handler.
326
* @ops: The control ops.
327
* @id: The control ID.
328
* @max: The control's maximum value.
329
* @mask: The control's skip mask for menu controls. This makes it
330
* easy to skip menu items that are not valid. If bit X is set,
331
* then menu item X is skipped. Of course, this only works for
332
* menus with <= 32 menu items. There are no menus that come
333
* close to that number, so this is OK. Should we ever need more,
334
* then this will have to be extended to a u64 or a bit array.
335
* @def: The control's default value.
337
* Same as v4l2_ctrl_new_std(), but @min is set to 0 and the @mask value
338
* determines which menu items are to be skipped.
340
* If @id refers to a non-menu control, then this function will return NULL.
342
struct v4l2_ctrl *v4l2_ctrl_new_std_menu(struct v4l2_ctrl_handler *hdl,
343
const struct v4l2_ctrl_ops *ops,
344
u32 id, s32 max, s32 mask, s32 def);
346
/** v4l2_ctrl_add_ctrl() - Add a control from another handler to this handler.
347
* @hdl: The control handler.
348
* @ctrl: The control to add.
350
* It will return NULL if it was unable to add the control reference.
351
* If the control already belonged to the handler, then it will do
352
* nothing and just return @ctrl.
354
struct v4l2_ctrl *v4l2_ctrl_add_ctrl(struct v4l2_ctrl_handler *hdl,
355
struct v4l2_ctrl *ctrl);
357
/** v4l2_ctrl_add_handler() - Add all controls from handler @add to
359
* @hdl: The control handler.
360
* @add: The control handler whose controls you want to add to
361
* the @hdl control handler.
363
* Does nothing if either of the two is a NULL pointer.
364
* In case of an error @hdl->error will be set to the error code (if it
365
* wasn't set already).
367
int v4l2_ctrl_add_handler(struct v4l2_ctrl_handler *hdl,
368
struct v4l2_ctrl_handler *add);
371
/** v4l2_ctrl_cluster() - Mark all controls in the cluster as belonging to that cluster.
372
* @ncontrols: The number of controls in this cluster.
373
* @controls: The cluster control array of size @ncontrols.
375
void v4l2_ctrl_cluster(unsigned ncontrols, struct v4l2_ctrl **controls);
378
/** v4l2_ctrl_auto_cluster() - Mark all controls in the cluster as belonging to
379
* that cluster and set it up for autofoo/foo-type handling.
380
* @ncontrols: The number of controls in this cluster.
381
* @controls: The cluster control array of size @ncontrols. The first control
382
* must be the 'auto' control (e.g. autogain, autoexposure, etc.)
383
* @manual_val: The value for the first control in the cluster that equals the
385
* @set_volatile: If true, then all controls except the first auto control will
388
* Use for control groups where one control selects some automatic feature and
389
* the other controls are only active whenever the automatic feature is turned
390
* off (manual mode). Typical examples: autogain vs gain, auto-whitebalance vs
391
* red and blue balance, etc.
393
* The behavior of such controls is as follows:
395
* When the autofoo control is set to automatic, then any manual controls
396
* are set to inactive and any reads will call g_volatile_ctrl (if the control
397
* was marked volatile).
399
* When the autofoo control is set to manual, then any manual controls will
400
* be marked active, and any reads will just return the current value without
401
* going through g_volatile_ctrl.
403
* In addition, this function will set the V4L2_CTRL_FLAG_UPDATE flag
404
* on the autofoo control and V4L2_CTRL_FLAG_INACTIVE on the foo control(s)
405
* if autofoo is in auto mode.
407
void v4l2_ctrl_auto_cluster(unsigned ncontrols, struct v4l2_ctrl **controls,
408
u8 manual_val, bool set_volatile);
411
/** v4l2_ctrl_find() - Find a control with the given ID.
412
* @hdl: The control handler.
413
* @id: The control ID to find.
415
* If @hdl == NULL this will return NULL as well. Will lock the handler so
416
* do not use from inside &v4l2_ctrl_ops.
418
struct v4l2_ctrl *v4l2_ctrl_find(struct v4l2_ctrl_handler *hdl, u32 id);
420
/** v4l2_ctrl_activate() - Make the control active or inactive.
421
* @ctrl: The control to (de)activate.
422
* @active: True if the control should become active.
424
* This sets or clears the V4L2_CTRL_FLAG_INACTIVE flag atomically.
425
* Does nothing if @ctrl == NULL.
426
* This will usually be called from within the s_ctrl op.
427
* The V4L2_EVENT_CTRL event will be generated afterwards.
429
* This function assumes that the control handler is locked.
431
void v4l2_ctrl_activate(struct v4l2_ctrl *ctrl, bool active);
433
/** v4l2_ctrl_grab() - Mark the control as grabbed or not grabbed.
434
* @ctrl: The control to (de)activate.
435
* @grabbed: True if the control should become grabbed.
437
* This sets or clears the V4L2_CTRL_FLAG_GRABBED flag atomically.
438
* Does nothing if @ctrl == NULL.
439
* The V4L2_EVENT_CTRL event will be generated afterwards.
440
* This will usually be called when starting or stopping streaming in the
443
* This function assumes that the control handler is not locked and will
444
* take the lock itself.
446
void v4l2_ctrl_grab(struct v4l2_ctrl *ctrl, bool grabbed);
448
/** v4l2_ctrl_lock() - Helper function to lock the handler
449
* associated with the control.
450
* @ctrl: The control to lock.
452
static inline void v4l2_ctrl_lock(struct v4l2_ctrl *ctrl)
454
mutex_lock(&ctrl->handler->lock);
457
/** v4l2_ctrl_lock() - Helper function to unlock the handler
458
* associated with the control.
459
* @ctrl: The control to unlock.
461
static inline void v4l2_ctrl_unlock(struct v4l2_ctrl *ctrl)
463
mutex_unlock(&ctrl->handler->lock);
466
/** v4l2_ctrl_g_ctrl() - Helper function to get the control's value from within a driver.
467
* @ctrl: The control.
469
* This returns the control's value safely by going through the control
470
* framework. This function will lock the control's handler, so it cannot be
471
* used from within the &v4l2_ctrl_ops functions.
473
* This function is for integer type controls only.
475
s32 v4l2_ctrl_g_ctrl(struct v4l2_ctrl *ctrl);
477
/** v4l2_ctrl_s_ctrl() - Helper function to set the control's value from within a driver.
478
* @ctrl: The control.
479
* @val: The new value.
481
* This set the control's new value safely by going through the control
482
* framework. This function will lock the control's handler, so it cannot be
483
* used from within the &v4l2_ctrl_ops functions.
485
* This function is for integer type controls only.
487
int v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val);
489
/* Internal helper functions that deal with control events. */
490
void v4l2_ctrl_add_event(struct v4l2_ctrl *ctrl,
491
struct v4l2_subscribed_event *sev);
492
void v4l2_ctrl_del_event(struct v4l2_ctrl *ctrl,
493
struct v4l2_subscribed_event *sev);
495
/* Helpers for ioctl_ops. If hdl == NULL then they will all return -EINVAL. */
496
int v4l2_queryctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_queryctrl *qc);
497
int v4l2_querymenu(struct v4l2_ctrl_handler *hdl, struct v4l2_querymenu *qm);
498
int v4l2_g_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_control *ctrl);
499
int v4l2_s_ctrl(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
500
struct v4l2_control *ctrl);
501
int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *c);
502
int v4l2_try_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *c);
503
int v4l2_s_ext_ctrls(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
504
struct v4l2_ext_controls *c);
506
/* Helpers for subdevices. If the associated ctrl_handler == NULL then they
507
will all return -EINVAL. */
508
int v4l2_subdev_queryctrl(struct v4l2_subdev *sd, struct v4l2_queryctrl *qc);
509
int v4l2_subdev_querymenu(struct v4l2_subdev *sd, struct v4l2_querymenu *qm);
510
int v4l2_subdev_g_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
511
int v4l2_subdev_try_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
512
int v4l2_subdev_s_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
513
int v4l2_subdev_g_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
514
int v4l2_subdev_s_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl);