Linux preempt-rt

Check our new training course

Real-Time Linux with PREEMPT_RT

Check our new training course
with Creative Commons CC-BY-SA
lecture and lab materials

Bootlin logo

Elixir Cross Referencer

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
/*
    V4L2 controls support header.

    Copyright (C) 2010  Hans Verkuil <hverkuil@xs4all.nl>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifndef _V4L2_CTRLS_H
#define _V4L2_CTRLS_H

#include <linux/list.h>
#include <linux/device.h>
#include <linux/videodev2.h>

/* forward references */
struct v4l2_ctrl_handler;
struct v4l2_ctrl_helper;
struct v4l2_ctrl;
struct video_device;
struct v4l2_subdev;
struct v4l2_subscribed_event;
struct v4l2_fh;

/** struct v4l2_ctrl_ops - The control operations that the driver has to provide.
  * @g_volatile_ctrl: Get a new value for this control. Generally only relevant
  *		for volatile (and usually read-only) controls such as a control
  *		that returns the current signal strength which changes
  *		continuously.
  *		If not set, then the currently cached value will be returned.
  * @try_ctrl:	Test whether the control's value is valid. Only relevant when
  *		the usual min/max/step checks are not sufficient.
  * @s_ctrl:	Actually set the new control value. s_ctrl is compulsory. The
  *		ctrl->handler->lock is held when these ops are called, so no
  *		one else can access controls owned by that handler.
  */
struct v4l2_ctrl_ops {
	int (*g_volatile_ctrl)(struct v4l2_ctrl *ctrl);
	int (*try_ctrl)(struct v4l2_ctrl *ctrl);
	int (*s_ctrl)(struct v4l2_ctrl *ctrl);
};

/** struct v4l2_ctrl - The control structure.
  * @node:	The list node.
  * @ev_subs:	The list of control event subscriptions.
  * @handler:	The handler that owns the control.
  * @cluster:	Point to start of cluster array.
  * @ncontrols:	Number of controls in cluster array.
  * @done:	Internal flag: set for each processed control.
  * @is_new:	Set when the user specified a new value for this control. It
  *		is also set when called from v4l2_ctrl_handler_setup. Drivers
  *		should never set this flag.
  * @is_private: If set, then this control is private to its handler and it
  *		will not be added to any other handlers. Drivers can set
  *		this flag.
  * @is_volatile: If set, then this control is volatile. This means that the
  *		control's current value cannot be cached and needs to be
  *		retrieved through the g_volatile_ctrl op. Drivers can set
  *		this flag.
  * @is_auto:   If set, then this control selects whether the other cluster
  *		members are in 'automatic' mode or 'manual' mode. This is
  *		used for autogain/gain type clusters. Drivers should never
  *		set this flag directly.
  * @manual_mode_value: If the is_auto flag is set, then this is the value
  *		of the auto control that determines if that control is in
  *		manual mode. So if the value of the auto control equals this
  *		value, then the whole cluster is in manual mode. Drivers should
  *		never set this flag directly.
  * @ops:	The control ops.
  * @id:	The control ID.
  * @name:	The control name.
  * @type:	The control type.
  * @minimum:	The control's minimum value.
  * @maximum:	The control's maximum value.
  * @default_value: The control's default value.
  * @step:	The control's step value for non-menu controls.
  * @menu_skip_mask: The control's skip mask for menu controls. This makes it
  *		easy to skip menu items that are not valid. If bit X is set,
  *		then menu item X is skipped. Of course, this only works for
  *		menus with <= 32 menu items. There are no menus that come
  *		close to that number, so this is OK. Should we ever need more,
  *		then this will have to be extended to a u64 or a bit array.
  * @qmenu:	A const char * array for all menu items. Array entries that are
  *		empty strings ("") correspond to non-existing menu items (this
  *		is in addition to the menu_skip_mask above). The last entry
  *		must be NULL.
  * @flags:	The control's flags.
  * @cur:	The control's current value.
  * @val:	The control's new s32 value.
  * @val64:	The control's new s64 value.
  * @string:	The control's new string value.
  * @priv:	The control's private pointer. For use by the driver. It is
  *		untouched by the control framework. Note that this pointer is
  *		not freed when the control is deleted. Should this be needed
  *		then a new internal bitfield can be added to tell the framework
  *		to free this pointer.
  */
struct v4l2_ctrl {
	/* Administrative fields */
	struct list_head node;
	struct list_head ev_subs;
	struct v4l2_ctrl_handler *handler;
	struct v4l2_ctrl **cluster;
	unsigned ncontrols;
	unsigned int done:1;

	unsigned int is_new:1;
	unsigned int is_private:1;
	unsigned int is_volatile:1;
	unsigned int is_auto:1;
	unsigned int manual_mode_value:8;

	const struct v4l2_ctrl_ops *ops;
	u32 id;
	const char *name;
	enum v4l2_ctrl_type type;
	s32 minimum, maximum, default_value;
	union {
		u32 step;
		u32 menu_skip_mask;
	};
	const char * const *qmenu;
	unsigned long flags;
	union {
		s32 val;
		s64 val64;
		char *string;
	} cur;
	union {
		s32 val;
		s64 val64;
		char *string;
	};
	void *priv;
};

/** struct v4l2_ctrl_ref - The control reference.
  * @node:	List node for the sorted list.
  * @next:	Single-link list node for the hash.
  * @ctrl:	The actual control information.
  * @helper:	Pointer to helper struct. Used internally in prepare_ext_ctrls().
  *
  * Each control handler has a list of these refs. The list_head is used to
  * keep a sorted-by-control-ID list of all controls, while the next pointer
  * is used to link the control in the hash's bucket.
  */
struct v4l2_ctrl_ref {
	struct list_head node;
	struct v4l2_ctrl_ref *next;
	struct v4l2_ctrl *ctrl;
	struct v4l2_ctrl_helper *helper;
};

/** struct v4l2_ctrl_handler - The control handler keeps track of all the
  * controls: both the controls owned by the handler and those inherited
  * from other handlers.
  * @lock:	Lock to control access to this handler and its controls.
  * @ctrls:	The list of controls owned by this handler.
  * @ctrl_refs:	The list of control references.
  * @cached:	The last found control reference. It is common that the same
  *		control is needed multiple times, so this is a simple
  *		optimization.
  * @buckets:	Buckets for the hashing. Allows for quick control lookup.
  * @nr_of_buckets: Total number of buckets in the array.
  * @error:	The error code of the first failed control addition.
  */
struct v4l2_ctrl_handler {
	struct mutex lock;
	struct list_head ctrls;
	struct list_head ctrl_refs;
	struct v4l2_ctrl_ref *cached;
	struct v4l2_ctrl_ref **buckets;
	u16 nr_of_buckets;
	int error;
};

/** struct v4l2_ctrl_config - Control configuration structure.
  * @ops:	The control ops.
  * @id:	The control ID.
  * @name:	The control name.
  * @type:	The control type.
  * @min:	The control's minimum value.
  * @max:	The control's maximum value.
  * @step:	The control's step value for non-menu controls.
  * @def: 	The control's default value.
  * @flags:	The control's flags.
  * @menu_skip_mask: The control's skip mask for menu controls. This makes it
  *		easy to skip menu items that are not valid. If bit X is set,
  *		then menu item X is skipped. Of course, this only works for
  *		menus with <= 32 menu items. There are no menus that come
  *		close to that number, so this is OK. Should we ever need more,
  *		then this will have to be extended to a u64 or a bit array.
  * @qmenu:	A const char * array for all menu items. Array entries that are
  *		empty strings ("") correspond to non-existing menu items (this
  *		is in addition to the menu_skip_mask above). The last entry
  *		must be NULL.
  * @is_private: If set, then this control is private to its handler and it
  *		will not be added to any other handlers.
  * @is_volatile: If set, then this control is volatile. This means that the
  *		control's current value cannot be cached and needs to be
  *		retrieved through the g_volatile_ctrl op.
  */
struct v4l2_ctrl_config {
	const struct v4l2_ctrl_ops *ops;
	u32 id;
	const char *name;
	enum v4l2_ctrl_type type;
	s32 min;
	s32 max;
	u32 step;
	s32 def;
	u32 flags;
	u32 menu_skip_mask;
	const char * const *qmenu;
	unsigned int is_private:1;
	unsigned int is_volatile:1;
};

/** v4l2_ctrl_fill() - Fill in the control fields based on the control ID.
  *
  * This works for all standard V4L2 controls.
  * For non-standard controls it will only fill in the given arguments
  * and @name will be NULL.
  *
  * This function will overwrite the contents of @name, @type and @flags.
  * The contents of @min, @max, @step and @def may be modified depending on
  * the type.
  *
  * Do not use in drivers! It is used internally for backwards compatibility
  * control handling only. Once all drivers are converted to use the new
  * control framework this function will no longer be exported.
  */
void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
		    s32 *min, s32 *max, s32 *step, s32 *def, u32 *flags);


/** v4l2_ctrl_handler_init() - Initialize the control handler.
  * @hdl:	The control handler.
  * @nr_of_controls_hint: A hint of how many controls this handler is
  *		expected to refer to. This is the total number, so including
  *		any inherited controls. It doesn't have to be precise, but if
  *		it is way off, then you either waste memory (too many buckets
  *		are allocated) or the control lookup becomes slower (not enough
  *		buckets are allocated, so there are more slow list lookups).
  *		It will always work, though.
  *
  * Returns an error if the buckets could not be allocated. This error will
  * also be stored in @hdl->error.
  */
int v4l2_ctrl_handler_init(struct v4l2_ctrl_handler *hdl,
			   unsigned nr_of_controls_hint);

/** v4l2_ctrl_handler_free() - Free all controls owned by the handler and free
  * the control list.
  * @hdl:	The control handler.
  *
  * Does nothing if @hdl == NULL.
  */
void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl);

/** v4l2_ctrl_handler_setup() - Call the s_ctrl op for all controls belonging
  * to the handler to initialize the hardware to the current control values.
  * @hdl:	The control handler.
  *
  * Button controls will be skipped, as are read-only controls.
  *
  * If @hdl == NULL, then this just returns 0.
  */
int v4l2_ctrl_handler_setup(struct v4l2_ctrl_handler *hdl);

/** v4l2_ctrl_handler_log_status() - Log all controls owned by the handler.
  * @hdl:	The control handler.
  * @prefix:	The prefix to use when logging the control values. If the
  *		prefix does not end with a space, then ": " will be added
  *		after the prefix. If @prefix == NULL, then no prefix will be
  *		used.
  *
  * For use with VIDIOC_LOG_STATUS.
  *
  * Does nothing if @hdl == NULL.
  */
void v4l2_ctrl_handler_log_status(struct v4l2_ctrl_handler *hdl,
				  const char *prefix);

/** v4l2_ctrl_new_custom() - Allocate and initialize a new custom V4L2
  * control.
  * @hdl:	The control handler.
  * @cfg:	The control's configuration data.
  * @priv:	The control's driver-specific private data.
  *
  * If the &v4l2_ctrl struct could not be allocated then NULL is returned
  * and @hdl->error is set to the error code (if it wasn't set already).
  */
struct v4l2_ctrl *v4l2_ctrl_new_custom(struct v4l2_ctrl_handler *hdl,
			const struct v4l2_ctrl_config *cfg, void *priv);

/** v4l2_ctrl_new_std() - Allocate and initialize a new standard V4L2 non-menu control.
  * @hdl:	The control handler.
  * @ops:	The control ops.
  * @id:	The control ID.
  * @min:	The control's minimum value.
  * @max:	The control's maximum value.
  * @step:	The control's step value
  * @def: 	The control's default value.
  *
  * If the &v4l2_ctrl struct could not be allocated, or the control
  * ID is not known, then NULL is returned and @hdl->error is set to the
  * appropriate error code (if it wasn't set already).
  *
  * If @id refers to a menu control, then this function will return NULL.
  *
  * Use v4l2_ctrl_new_std_menu() when adding menu controls.
  */
struct v4l2_ctrl *v4l2_ctrl_new_std(struct v4l2_ctrl_handler *hdl,
			const struct v4l2_ctrl_ops *ops,
			u32 id, s32 min, s32 max, u32 step, s32 def);

/** v4l2_ctrl_new_std_menu() - Allocate and initialize a new standard V4L2 menu control.
  * @hdl:	The control handler.
  * @ops:	The control ops.
  * @id:	The control ID.
  * @max:	The control's maximum value.
  * @mask: 	The control's skip mask for menu controls. This makes it
  *		easy to skip menu items that are not valid. If bit X is set,
  *		then menu item X is skipped. Of course, this only works for
  *		menus with <= 32 menu items. There are no menus that come
  *		close to that number, so this is OK. Should we ever need more,
  *		then this will have to be extended to a u64 or a bit array.
  * @def: 	The control's default value.
  *
  * Same as v4l2_ctrl_new_std(), but @min is set to 0 and the @mask value
  * determines which menu items are to be skipped.
  *
  * If @id refers to a non-menu control, then this function will return NULL.
  */
struct v4l2_ctrl *v4l2_ctrl_new_std_menu(struct v4l2_ctrl_handler *hdl,
			const struct v4l2_ctrl_ops *ops,
			u32 id, s32 max, s32 mask, s32 def);

/** v4l2_ctrl_add_ctrl() - Add a control from another handler to this handler.
  * @hdl:	The control handler.
  * @ctrl:	The control to add.
  *
  * It will return NULL if it was unable to add the control reference.
  * If the control already belonged to the handler, then it will do
  * nothing and just return @ctrl.
  */
struct v4l2_ctrl *v4l2_ctrl_add_ctrl(struct v4l2_ctrl_handler *hdl,
					  struct v4l2_ctrl *ctrl);

/** v4l2_ctrl_add_handler() - Add all controls from handler @add to
  * handler @hdl.
  * @hdl:	The control handler.
  * @add:	The control handler whose controls you want to add to
  *		the @hdl control handler.
  *
  * Does nothing if either of the two is a NULL pointer.
  * In case of an error @hdl->error will be set to the error code (if it
  * wasn't set already).
  */
int v4l2_ctrl_add_handler(struct v4l2_ctrl_handler *hdl,
			  struct v4l2_ctrl_handler *add);


/** v4l2_ctrl_cluster() - Mark all controls in the cluster as belonging to that cluster.
  * @ncontrols:	The number of controls in this cluster.
  * @controls: 	The cluster control array of size @ncontrols.
  */
void v4l2_ctrl_cluster(unsigned ncontrols, struct v4l2_ctrl **controls);


/** v4l2_ctrl_auto_cluster() - Mark all controls in the cluster as belonging to
  * that cluster and set it up for autofoo/foo-type handling.
  * @ncontrols:	The number of controls in this cluster.
  * @controls:	The cluster control array of size @ncontrols. The first control
  *		must be the 'auto' control (e.g. autogain, autoexposure, etc.)
  * @manual_val: The value for the first control in the cluster that equals the
  *		manual setting.
  * @set_volatile: If true, then all controls except the first auto control will
  *		have is_volatile set to true. If false, then is_volatile will not
  *		be touched.
  *
  * Use for control groups where one control selects some automatic feature and
  * the other controls are only active whenever the automatic feature is turned
  * off (manual mode). Typical examples: autogain vs gain, auto-whitebalance vs
  * red and blue balance, etc.
  *
  * The behavior of such controls is as follows:
  *
  * When the autofoo control is set to automatic, then any manual controls
  * are set to inactive and any reads will call g_volatile_ctrl (if the control
  * was marked volatile).
  *
  * When the autofoo control is set to manual, then any manual controls will
  * be marked active, and any reads will just return the current value without
  * going through g_volatile_ctrl.
  *
  * In addition, this function will set the V4L2_CTRL_FLAG_UPDATE flag
  * on the autofoo control and V4L2_CTRL_FLAG_INACTIVE on the foo control(s)
  * if autofoo is in auto mode.
  */
void v4l2_ctrl_auto_cluster(unsigned ncontrols, struct v4l2_ctrl **controls,
			u8 manual_val, bool set_volatile);


/** v4l2_ctrl_find() - Find a control with the given ID.
  * @hdl:	The control handler.
  * @id:	The control ID to find.
  *
  * If @hdl == NULL this will return NULL as well. Will lock the handler so
  * do not use from inside &v4l2_ctrl_ops.
  */
struct v4l2_ctrl *v4l2_ctrl_find(struct v4l2_ctrl_handler *hdl, u32 id);

/** v4l2_ctrl_activate() - Make the control active or inactive.
  * @ctrl:	The control to (de)activate.
  * @active:	True if the control should become active.
  *
  * This sets or clears the V4L2_CTRL_FLAG_INACTIVE flag atomically.
  * Does nothing if @ctrl == NULL.
  * This will usually be called from within the s_ctrl op.
  * The V4L2_EVENT_CTRL event will be generated afterwards.
  *
  * This function assumes that the control handler is locked.
  */
void v4l2_ctrl_activate(struct v4l2_ctrl *ctrl, bool active);

/** v4l2_ctrl_grab() - Mark the control as grabbed or not grabbed.
  * @ctrl:	The control to (de)activate.
  * @grabbed:	True if the control should become grabbed.
  *
  * This sets or clears the V4L2_CTRL_FLAG_GRABBED flag atomically.
  * Does nothing if @ctrl == NULL.
  * The V4L2_EVENT_CTRL event will be generated afterwards.
  * This will usually be called when starting or stopping streaming in the
  * driver.
  *
  * This function assumes that the control handler is not locked and will
  * take the lock itself.
  */
void v4l2_ctrl_grab(struct v4l2_ctrl *ctrl, bool grabbed);

/** v4l2_ctrl_lock() - Helper function to lock the handler
  * associated with the control.
  * @ctrl:	The control to lock.
  */
static inline void v4l2_ctrl_lock(struct v4l2_ctrl *ctrl)
{
	mutex_lock(&ctrl->handler->lock);
}

/** v4l2_ctrl_lock() - Helper function to unlock the handler
  * associated with the control.
  * @ctrl:	The control to unlock.
  */
static inline void v4l2_ctrl_unlock(struct v4l2_ctrl *ctrl)
{
	mutex_unlock(&ctrl->handler->lock);
}

/** v4l2_ctrl_g_ctrl() - Helper function to get the control's value from within a driver.
  * @ctrl:	The control.
  *
  * This returns the control's value safely by going through the control
  * framework. This function will lock the control's handler, so it cannot be
  * used from within the &v4l2_ctrl_ops functions.
  *
  * This function is for integer type controls only.
  */
s32 v4l2_ctrl_g_ctrl(struct v4l2_ctrl *ctrl);

/** v4l2_ctrl_s_ctrl() - Helper function to set the control's value from within a driver.
  * @ctrl:	The control.
  * @val:	The new value.
  *
  * This set the control's new value safely by going through the control
  * framework. This function will lock the control's handler, so it cannot be
  * used from within the &v4l2_ctrl_ops functions.
  *
  * This function is for integer type controls only.
  */
int v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val);

/* Internal helper functions that deal with control events. */
void v4l2_ctrl_add_event(struct v4l2_ctrl *ctrl,
		struct v4l2_subscribed_event *sev);
void v4l2_ctrl_del_event(struct v4l2_ctrl *ctrl,
		struct v4l2_subscribed_event *sev);

/* Helpers for ioctl_ops. If hdl == NULL then they will all return -EINVAL. */
int v4l2_queryctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_queryctrl *qc);
int v4l2_querymenu(struct v4l2_ctrl_handler *hdl, struct v4l2_querymenu *qm);
int v4l2_g_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_control *ctrl);
int v4l2_s_ctrl(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
						struct v4l2_control *ctrl);
int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *c);
int v4l2_try_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *c);
int v4l2_s_ext_ctrls(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
						struct v4l2_ext_controls *c);

/* Helpers for subdevices. If the associated ctrl_handler == NULL then they
   will all return -EINVAL. */
int v4l2_subdev_queryctrl(struct v4l2_subdev *sd, struct v4l2_queryctrl *qc);
int v4l2_subdev_querymenu(struct v4l2_subdev *sd, struct v4l2_querymenu *qm);
int v4l2_subdev_g_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
int v4l2_subdev_try_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
int v4l2_subdev_s_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
int v4l2_subdev_g_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
int v4l2_subdev_s_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl);

#endif