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/device.h>
26 #include <linux/videodev2.h>
27
28 /* forward references */
29 struct v4l2_ctrl_handler;
30 struct v4l2_ctrl;
31 struct video_device;
32 struct v4l2_subdev;
33
34 /** struct v4l2_ctrl_ops - The control operations that the driver has to provide.
35 * @g_volatile_ctrl: Get a new value for this control. Generally only relevant
36 * for volatile (and usually read-only) controls such as a control
37 * that returns the current signal strength which changes
38 * continuously.
39 * If not set, then the currently cached value will be returned.
40 * @try_ctrl: Test whether the control's value is valid. Only relevant when
41 * the usual min/max/step checks are not sufficient.
42 * @s_ctrl: Actually set the new control value. s_ctrl is compulsory. The
43 * ctrl->handler->lock is held when these ops are called, so no
44 * one else can access controls owned by that handler.
45 */
46 struct v4l2_ctrl_ops {
47 int (*g_volatile_ctrl)(struct v4l2_ctrl *ctrl);
48 int (*try_ctrl)(struct v4l2_ctrl *ctrl);
49 int (*s_ctrl)(struct v4l2_ctrl *ctrl);
50 };
51
52 /** struct v4l2_ctrl - The control structure.
53 * @node: The list node.
54 * @handler: The handler that owns the control.
55 * @cluster: Point to start of cluster array.
56 * @ncontrols: Number of controls in cluster array.
57 * @done: Internal flag: set for each processed control.
58 * @is_new: Set when the user specified a new value for this control. It
59 * is also set when called from v4l2_ctrl_handler_setup. Drivers
60 * should never set this flag.
61 * @is_private: If set, then this control is private to its handler and it
62 * will not be added to any other handlers. Drivers can set
63 * this flag.
64 * @is_volatile: If set, then this control is volatile. This means that the
65 * control's current value cannot be cached and needs to be
66 * retrieved through the g_volatile_ctrl op. Drivers can set
67 * this flag.
68 * @ops: The control ops.
69 * @id: The control ID.
70 * @name: The control name.
71 * @type: The control type.
72 * @minimum: The control's minimum value.
73 * @maximum: The control's maximum value.
74 * @default_value: The control's default value.
75 * @step: The control's step value for non-menu controls.
76 * @menu_skip_mask: The control's skip mask for menu controls. This makes it
77 * easy to skip menu items that are not valid. If bit X is set,
78 * then menu item X is skipped. Of course, this only works for
79 * menus with <= 32 menu items. There are no menus that come
80 * close to that number, so this is OK. Should we ever need more,
81 * then this will have to be extended to a u64 or a bit array.
82 * @qmenu: A const char * array for all menu items. Array entries that are
83 * empty strings ("") correspond to non-existing menu items (this
84 * is in addition to the menu_skip_mask above). The last entry
85 * must be NULL.
86 * @flags: The control's flags.
87 * @cur: The control's current value.
88 * @val: The control's new s32 value.
89 * @val64: The control's new s64 value.
90 * @string: The control's new string value.
91 * @priv: The control's private pointer. For use by the driver. It is
92 * untouched by the control framework. Note that this pointer is
93 * not freed when the control is deleted. Should this be needed
94 * then a new internal bitfield can be added to tell the framework
95 * to free this pointer.
96 */
97 struct v4l2_ctrl {
98 /* Administrative fields */
99 struct list_head node;
100 struct v4l2_ctrl_handler *handler;
101 struct v4l2_ctrl **cluster;
102 unsigned ncontrols;
103 unsigned int done:1;
104
105 unsigned int is_new:1;
106 unsigned int is_private:1;
107 unsigned int is_volatile:1;
108
109 const struct v4l2_ctrl_ops *ops;
110 u32 id;
111 const char *name;
112 enum v4l2_ctrl_type type;
113 s32 minimum, maximum, default_value;
114 union {
115 u32 step;
116 u32 menu_skip_mask;
117 };
118 const char * const *qmenu;
119 unsigned long flags;
120 union {
121 s32 val;
122 s64 val64;
123 char *string;
124 } cur;
125 union {
126 s32 val;
127 s64 val64;
128 char *string;
129 };
130 void *priv;
131 };
132
133 /** struct v4l2_ctrl_ref - The control reference.
134 * @node: List node for the sorted list.
135 * @next: Single-link list node for the hash.
136 * @ctrl: The actual control information.
137 *
138 * Each control handler has a list of these refs. The list_head is used to
139 * keep a sorted-by-control-ID list of all controls, while the next pointer
140 * is used to link the control in the hash's bucket.
141 */
142 struct v4l2_ctrl_ref {
143 struct list_head node;
144 struct v4l2_ctrl_ref *next;
145 struct v4l2_ctrl *ctrl;
146 };
147
148 /** struct v4l2_ctrl_handler - The control handler keeps track of all the
149 * controls: both the controls owned by the handler and those inherited
150 * from other handlers.
151 * @lock: Lock to control access to this handler and its controls.
152 * @ctrls: The list of controls owned by this handler.
153 * @ctrl_refs: The list of control references.
154 * @cached: The last found control reference. It is common that the same
155 * control is needed multiple times, so this is a simple
156 * optimization.
157 * @buckets: Buckets for the hashing. Allows for quick control lookup.
158 * @nr_of_buckets: Total number of buckets in the array.
159 * @error: The error code of the first failed control addition.
160 */
161 struct v4l2_ctrl_handler {
162 struct mutex lock;
163 struct list_head ctrls;
164 struct list_head ctrl_refs;
165 struct v4l2_ctrl_ref *cached;
166 struct v4l2_ctrl_ref **buckets;
167 u16 nr_of_buckets;
168 int error;
169 };
170
171 /** struct v4l2_ctrl_config - Control configuration structure.
172 * @ops: The control ops.
173 * @id: The control ID.
174 * @name: The control name.
175 * @type: The control type.
176 * @min: The control's minimum value.
177 * @max: The control's maximum value.
178 * @step: The control's step value for non-menu controls.
179 * @def: The control's default value.
180 * @flags: The control's flags.
181 * @menu_skip_mask: The control's skip mask for menu controls. This makes it
182 * easy to skip menu items that are not valid. If bit X is set,
183 * then menu item X is skipped. Of course, this only works for
184 * menus with <= 32 menu items. There are no menus that come
185 * close to that number, so this is OK. Should we ever need more,
186 * then this will have to be extended to a u64 or a bit array.
187 * @qmenu: A const char * array for all menu items. Array entries that are
188 * empty strings ("") correspond to non-existing menu items (this
189 * is in addition to the menu_skip_mask above). The last entry
190 * must be NULL.
191 * @is_private: If set, then this control is private to its handler and it
192 * will not be added to any other handlers.
193 * @is_volatile: If set, then this control is volatile. This means that the
194 * control's current value cannot be cached and needs to be
195 * retrieved through the g_volatile_ctrl op.
196 */
197 struct v4l2_ctrl_config {
198 const struct v4l2_ctrl_ops *ops;
199 u32 id;
200 const char *name;
201 enum v4l2_ctrl_type type;
202 s32 min;
203 s32 max;
204 u32 step;
205 s32 def;
206 u32 flags;
207 u32 menu_skip_mask;
208 const char * const *qmenu;
209 unsigned int is_private:1;
210 unsigned int is_volatile:1;
211 };
212
213 /** v4l2_ctrl_fill() - Fill in the control fields based on the control ID.
214 *
215 * This works for all standard V4L2 controls.
216 * For non-standard controls it will only fill in the given arguments
217 * and @name will be NULL.
218 *
219 * This function will overwrite the contents of @name, @type and @flags.
220 * The contents of @min, @max, @step and @def may be modified depending on
221 * the type.
222 *
223 * Do not use in drivers! It is used internally for backwards compatibility
224 * control handling only. Once all drivers are converted to use the new
225 * control framework this function will no longer be exported.
226 */
227 void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
228 s32 *min, s32 *max, s32 *step, s32 *def, u32 *flags);
229
230
231 /** v4l2_ctrl_handler_init() - Initialize the control handler.
232 * @hdl: The control handler.
233 * @nr_of_controls_hint: A hint of how many controls this handler is
234 * expected to refer to. This is the total number, so including
235 * any inherited controls. It doesn't have to be precise, but if
236 * it is way off, then you either waste memory (too many buckets
237 * are allocated) or the control lookup becomes slower (not enough
238 * buckets are allocated, so there are more slow list lookups).
239 * It will always work, though.
240 *
241 * Returns an error if the buckets could not be allocated. This error will
242 * also be stored in @hdl->error.
243 */
244 int v4l2_ctrl_handler_init(struct v4l2_ctrl_handler *hdl,
245 unsigned nr_of_controls_hint);
246
247 /** v4l2_ctrl_handler_free() - Free all controls owned by the handler and free
248 * the control list.
249 * @hdl: The control handler.
250 *
251 * Does nothing if @hdl == NULL.
252 */
253 void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl);
254
255 /** v4l2_ctrl_handler_setup() - Call the s_ctrl op for all controls belonging
256 * to the handler to initialize the hardware to the current control values.
257 * @hdl: The control handler.
258 *
259 * Button controls will be skipped, as are read-only controls.
260 *
261 * If @hdl == NULL, then this just returns 0.
262 */
263 int v4l2_ctrl_handler_setup(struct v4l2_ctrl_handler *hdl);
264
265 /** v4l2_ctrl_handler_log_status() - Log all controls owned by the handler.
266 * @hdl: The control handler.
267 * @prefix: The prefix to use when logging the control values. If the
268 * prefix does not end with a space, then ": " will be added
269 * after the prefix. If @prefix == NULL, then no prefix will be
270 * used.
271 *
272 * For use with VIDIOC_LOG_STATUS.
273 *
274 * Does nothing if @hdl == NULL.
275 */
276 void v4l2_ctrl_handler_log_status(struct v4l2_ctrl_handler *hdl,
277 const char *prefix);
278
279 /** v4l2_ctrl_new_custom() - Allocate and initialize a new custom V4L2
280 * control.
281 * @hdl: The control handler.
282 * @cfg: The control's configuration data.
283 * @priv: The control's driver-specific private data.
284 *
285 * If the &v4l2_ctrl struct could not be allocated then NULL is returned
286 * and @hdl->error is set to the error code (if it wasn't set already).
287 */
288 struct v4l2_ctrl *v4l2_ctrl_new_custom(struct v4l2_ctrl_handler *hdl,
289 const struct v4l2_ctrl_config *cfg, void *priv);
290
291 /** v4l2_ctrl_new_std() - Allocate and initialize a new standard V4L2 non-menu control.
292 * @hdl: The control handler.
293 * @ops: The control ops.
294 * @id: The control ID.
295 * @min: The control's minimum value.
296 * @max: The control's maximum value.
297 * @step: The control's step value
298 * @def: The control's default value.
299 *
300 * If the &v4l2_ctrl struct could not be allocated, or the control
301 * ID is not known, then NULL is returned and @hdl->error is set to the
302 * appropriate error code (if it wasn't set already).
303 *
304 * If @id refers to a menu control, then this function will return NULL.
305 *
306 * Use v4l2_ctrl_new_std_menu() when adding menu controls.
307 */
308 struct v4l2_ctrl *v4l2_ctrl_new_std(struct v4l2_ctrl_handler *hdl,
309 const struct v4l2_ctrl_ops *ops,
310 u32 id, s32 min, s32 max, u32 step, s32 def);
311
312 /** v4l2_ctrl_new_std_menu() - Allocate and initialize a new standard V4L2 menu control.
313 * @hdl: The control handler.
314 * @ops: The control ops.
315 * @id: The control ID.
316 * @max: The control's maximum value.
317 * @mask: The control's skip mask for menu controls. This makes it
318 * easy to skip menu items that are not valid. If bit X is set,
319 * then menu item X is skipped. Of course, this only works for
320 * menus with <= 32 menu items. There are no menus that come
321 * close to that number, so this is OK. Should we ever need more,
322 * then this will have to be extended to a u64 or a bit array.
323 * @def: The control's default value.
324 *
325 * Same as v4l2_ctrl_new_std(), but @min is set to 0 and the @mask value
326 * determines which menu items are to be skipped.
327 *
328 * If @id refers to a non-menu control, then this function will return NULL.
329 */
330 struct v4l2_ctrl *v4l2_ctrl_new_std_menu(struct v4l2_ctrl_handler *hdl,
331 const struct v4l2_ctrl_ops *ops,
332 u32 id, s32 max, s32 mask, s32 def);
333
334 /** v4l2_ctrl_add_ctrl() - Add a control from another handler to this handler.
335 * @hdl: The control handler.
336 * @ctrl: The control to add.
337 *
338 * It will return NULL if it was unable to add the control reference.
339 * If the control already belonged to the handler, then it will do
340 * nothing and just return @ctrl.
341 */
342 struct v4l2_ctrl *v4l2_ctrl_add_ctrl(struct v4l2_ctrl_handler *hdl,
343 struct v4l2_ctrl *ctrl);
344
345 /** v4l2_ctrl_add_handler() - Add all controls from handler @add to
346 * handler @hdl.
347 * @hdl: The control handler.
348 * @add: The control handler whose controls you want to add to
349 * the @hdl control handler.
350 *
351 * Does nothing if either of the two is a NULL pointer.
352 * In case of an error @hdl->error will be set to the error code (if it
353 * wasn't set already).
354 */
355 int v4l2_ctrl_add_handler(struct v4l2_ctrl_handler *hdl,
356 struct v4l2_ctrl_handler *add);
357
358
359 /** v4l2_ctrl_cluster() - Mark all controls in the cluster as belonging to that cluster.
360 * @ncontrols: The number of controls in this cluster.
361 * @controls: The cluster control array of size @ncontrols.
362 */
363 void v4l2_ctrl_cluster(unsigned ncontrols, struct v4l2_ctrl **controls);
364
365
366 /** v4l2_ctrl_find() - Find a control with the given ID.
367 * @hdl: The control handler.
368 * @id: The control ID to find.
369 *
370 * If @hdl == NULL this will return NULL as well. Will lock the handler so
371 * do not use from inside &v4l2_ctrl_ops.
372 */
373 struct v4l2_ctrl *v4l2_ctrl_find(struct v4l2_ctrl_handler *hdl, u32 id);
374
375 /** v4l2_ctrl_activate() - Make the control active or inactive.
376 * @ctrl: The control to (de)activate.
377 * @active: True if the control should become active.
378 *
379 * This sets or clears the V4L2_CTRL_FLAG_INACTIVE flag atomically.
380 * Does nothing if @ctrl == NULL.
381 * This will usually be called from within the s_ctrl op.
382 *
383 * This function can be called regardless of whether the control handler
384 * is locked or not.
385 */
386 void v4l2_ctrl_activate(struct v4l2_ctrl *ctrl, bool active);
387
388 /** v4l2_ctrl_grab() - Mark the control as grabbed or not grabbed.
389 * @ctrl: The control to (de)activate.
390 * @grabbed: True if the control should become grabbed.
391 *
392 * This sets or clears the V4L2_CTRL_FLAG_GRABBED flag atomically.
393 * Does nothing if @ctrl == NULL.
394 * This will usually be called when starting or stopping streaming in the
395 * driver.
396 *
397 * This function can be called regardless of whether the control handler
398 * is locked or not.
399 */
400 void v4l2_ctrl_grab(struct v4l2_ctrl *ctrl, bool grabbed);
401
402 /** v4l2_ctrl_lock() - Helper function to lock the handler
403 * associated with the control.
404 * @ctrl: The control to lock.
405 */
v4l2_ctrl_lock(struct v4l2_ctrl * ctrl)406 static inline void v4l2_ctrl_lock(struct v4l2_ctrl *ctrl)
407 {
408 mutex_lock(&ctrl->handler->lock);
409 }
410
411 /** v4l2_ctrl_lock() - Helper function to unlock the handler
412 * associated with the control.
413 * @ctrl: The control to unlock.
414 */
v4l2_ctrl_unlock(struct v4l2_ctrl * ctrl)415 static inline void v4l2_ctrl_unlock(struct v4l2_ctrl *ctrl)
416 {
417 mutex_unlock(&ctrl->handler->lock);
418 }
419
420 /** v4l2_ctrl_g_ctrl() - Helper function to get the control's value from within a driver.
421 * @ctrl: The control.
422 *
423 * This returns the control's value safely by going through the control
424 * framework. This function will lock the control's handler, so it cannot be
425 * used from within the &v4l2_ctrl_ops functions.
426 *
427 * This function is for integer type controls only.
428 */
429 s32 v4l2_ctrl_g_ctrl(struct v4l2_ctrl *ctrl);
430
431 /** v4l2_ctrl_s_ctrl() - Helper function to set the control's value from within a driver.
432 * @ctrl: The control.
433 * @val: The new value.
434 *
435 * This set the control's new value safely by going through the control
436 * framework. This function will lock the control's handler, so it cannot be
437 * used from within the &v4l2_ctrl_ops functions.
438 *
439 * This function is for integer type controls only.
440 */
441 int v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val);
442
443
444 /* Helpers for ioctl_ops. If hdl == NULL then they will all return -EINVAL. */
445 int v4l2_queryctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_queryctrl *qc);
446 int v4l2_querymenu(struct v4l2_ctrl_handler *hdl, struct v4l2_querymenu *qm);
447 int v4l2_g_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_control *ctrl);
448 int v4l2_s_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_control *ctrl);
449 int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *c);
450 int v4l2_try_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *c);
451 int v4l2_s_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *c);
452
453 /* Helpers for subdevices. If the associated ctrl_handler == NULL then they
454 will all return -EINVAL. */
455 int v4l2_subdev_queryctrl(struct v4l2_subdev *sd, struct v4l2_queryctrl *qc);
456 int v4l2_subdev_querymenu(struct v4l2_subdev *sd, struct v4l2_querymenu *qm);
457 int v4l2_subdev_g_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
458 int v4l2_subdev_try_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
459 int v4l2_subdev_s_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
460 int v4l2_subdev_g_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
461 int v4l2_subdev_s_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
462
463 #endif
464