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Hans Verkuil09965172010-08-01 14:32:42 -03001/*
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
27/* forward references */
28struct v4l2_ctrl_handler;
29struct v4l2_ctrl;
30struct video_device;
31struct v4l2_subdev;
32
33/** struct v4l2_ctrl_ops - The control operations that the driver has to provide.
34 * @g_volatile_ctrl: Get a new value for this control. Generally only relevant
35 * for volatile (and usually read-only) controls such as a control
36 * that returns the current signal strength which changes
37 * continuously.
38 * If not set, then the currently cached value will be returned.
39 * @try_ctrl: Test whether the control's value is valid. Only relevant when
40 * the usual min/max/step checks are not sufficient.
41 * @s_ctrl: Actually set the new control value. s_ctrl is compulsory. The
42 * ctrl->handler->lock is held when these ops are called, so no
43 * one else can access controls owned by that handler.
44 */
45struct v4l2_ctrl_ops {
46 int (*g_volatile_ctrl)(struct v4l2_ctrl *ctrl);
47 int (*try_ctrl)(struct v4l2_ctrl *ctrl);
48 int (*s_ctrl)(struct v4l2_ctrl *ctrl);
49};
50
51/** struct v4l2_ctrl - The control structure.
52 * @node: The list node.
53 * @handler: The handler that owns the control.
54 * @cluster: Point to start of cluster array.
55 * @ncontrols: Number of controls in cluster array.
56 * @has_new: Internal flag: set when there is a valid new value.
57 * @done: Internal flag: set for each processed control.
58 * @is_private: If set, then this control is private to its handler and it
59 * will not be added to any other handlers. Drivers can set
60 * this flag.
61 * @is_volatile: If set, then this control is volatile. This means that the
62 * control's current value cannot be cached and needs to be
63 * retrieved through the g_volatile_ctrl op. Drivers can set
64 * this flag.
65 * @ops: The control ops.
66 * @id: The control ID.
67 * @name: The control name.
68 * @type: The control type.
69 * @minimum: The control's minimum value.
70 * @maximum: The control's maximum value.
71 * @default_value: The control's default value.
72 * @step: The control's step value for non-menu controls.
73 * @menu_skip_mask: The control's skip mask for menu controls. This makes it
74 * easy to skip menu items that are not valid. If bit X is set,
75 * then menu item X is skipped. Of course, this only works for
76 * menus with <= 32 menu items. There are no menus that come
77 * close to that number, so this is OK. Should we ever need more,
78 * then this will have to be extended to a u64 or a bit array.
79 * @qmenu: A const char * array for all menu items. Array entries that are
80 * empty strings ("") correspond to non-existing menu items (this
81 * is in addition to the menu_skip_mask above). The last entry
82 * must be NULL.
83 * @flags: The control's flags.
84 * @cur: The control's current value.
85 * @val: The control's new s32 value.
86 * @val64: The control's new s64 value.
87 * @string: The control's new string value.
88 * @priv: The control's private pointer. For use by the driver. It is
89 * untouched by the control framework. Note that this pointer is
90 * not freed when the control is deleted. Should this be needed
91 * then a new internal bitfield can be added to tell the framework
92 * to free this pointer.
93 */
94struct v4l2_ctrl {
95 /* Administrative fields */
96 struct list_head node;
97 struct v4l2_ctrl_handler *handler;
98 struct v4l2_ctrl **cluster;
99 unsigned ncontrols;
100 unsigned int has_new:1;
101 unsigned int done:1;
102
103 unsigned int is_private:1;
104 unsigned int is_volatile:1;
105
106 const struct v4l2_ctrl_ops *ops;
107 u32 id;
108 const char *name;
109 enum v4l2_ctrl_type type;
110 s32 minimum, maximum, default_value;
111 union {
112 u32 step;
113 u32 menu_skip_mask;
114 };
115 const char **qmenu;
116 unsigned long flags;
117 union {
118 s32 val;
119 s64 val64;
120 char *string;
121 } cur;
122 union {
123 s32 val;
124 s64 val64;
125 char *string;
126 };
127 void *priv;
128};
129
130/** struct v4l2_ctrl_ref - The control reference.
131 * @node: List node for the sorted list.
132 * @next: Single-link list node for the hash.
133 * @ctrl: The actual control information.
134 *
135 * Each control handler has a list of these refs. The list_head is used to
136 * keep a sorted-by-control-ID list of all controls, while the next pointer
137 * is used to link the control in the hash's bucket.
138 */
139struct v4l2_ctrl_ref {
140 struct list_head node;
141 struct v4l2_ctrl_ref *next;
142 struct v4l2_ctrl *ctrl;
143};
144
145/** struct v4l2_ctrl_handler - The control handler keeps track of all the
146 * controls: both the controls owned by the handler and those inherited
147 * from other handlers.
148 * @lock: Lock to control access to this handler and its controls.
149 * @ctrls: The list of controls owned by this handler.
150 * @ctrl_refs: The list of control references.
151 * @cached: The last found control reference. It is common that the same
152 * control is needed multiple times, so this is a simple
153 * optimization.
154 * @buckets: Buckets for the hashing. Allows for quick control lookup.
155 * @nr_of_buckets: Total number of buckets in the array.
156 * @error: The error code of the first failed control addition.
157 */
158struct v4l2_ctrl_handler {
159 struct mutex lock;
160 struct list_head ctrls;
161 struct list_head ctrl_refs;
162 struct v4l2_ctrl_ref *cached;
163 struct v4l2_ctrl_ref **buckets;
164 u16 nr_of_buckets;
165 int error;
166};
167
168/** struct v4l2_ctrl_config - Control configuration structure.
169 * @ops: The control ops.
170 * @id: The control ID.
171 * @name: The control name.
172 * @type: The control type.
173 * @min: The control's minimum value.
174 * @max: The control's maximum value.
175 * @step: The control's step value for non-menu controls.
176 * @def: The control's default value.
177 * @flags: The control's flags.
178 * @menu_skip_mask: The control's skip mask for menu controls. This makes it
179 * easy to skip menu items that are not valid. If bit X is set,
180 * then menu item X is skipped. Of course, this only works for
181 * menus with <= 32 menu items. There are no menus that come
182 * close to that number, so this is OK. Should we ever need more,
183 * then this will have to be extended to a u64 or a bit array.
184 * @qmenu: A const char * array for all menu items. Array entries that are
185 * empty strings ("") correspond to non-existing menu items (this
186 * is in addition to the menu_skip_mask above). The last entry
187 * must be NULL.
188 * @is_private: If set, then this control is private to its handler and it
189 * will not be added to any other handlers.
190 * @is_volatile: If set, then this control is volatile. This means that the
191 * control's current value cannot be cached and needs to be
192 * retrieved through the g_volatile_ctrl op.
193 */
194struct v4l2_ctrl_config {
195 const struct v4l2_ctrl_ops *ops;
196 u32 id;
197 const char *name;
198 enum v4l2_ctrl_type type;
199 s32 min;
200 s32 max;
201 u32 step;
202 s32 def;
203 u32 flags;
204 u32 menu_skip_mask;
205 const char **qmenu;
206 unsigned int is_private:1;
207 unsigned int is_volatile:1;
208};
209
210/** v4l2_ctrl_fill() - Fill in the control fields based on the control ID.
211 *
212 * This works for all standard V4L2 controls.
213 * For non-standard controls it will only fill in the given arguments
214 * and @name will be NULL.
215 *
216 * This function will overwrite the contents of @name, @type and @flags.
217 * The contents of @min, @max, @step and @def may be modified depending on
218 * the type.
219 *
220 * Do not use in drivers! It is used internally for backwards compatibility
221 * control handling only. Once all drivers are converted to use the new
222 * control framework this function will no longer be exported.
223 */
224void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
225 s32 *min, s32 *max, s32 *step, s32 *def, u32 *flags);
226
227
228/** v4l2_ctrl_handler_init() - Initialize the control handler.
229 * @hdl: The control handler.
230 * @nr_of_controls_hint: A hint of how many controls this handler is
231 * expected to refer to. This is the total number, so including
232 * any inherited controls. It doesn't have to be precise, but if
233 * it is way off, then you either waste memory (too many buckets
234 * are allocated) or the control lookup becomes slower (not enough
235 * buckets are allocated, so there are more slow list lookups).
236 * It will always work, though.
237 *
238 * Returns an error if the buckets could not be allocated. This error will
239 * also be stored in @hdl->error.
240 */
241int v4l2_ctrl_handler_init(struct v4l2_ctrl_handler *hdl,
242 unsigned nr_of_controls_hint);
243
244/** v4l2_ctrl_handler_free() - Free all controls owned by the handler and free
245 * the control list.
246 * @hdl: The control handler.
247 *
248 * Does nothing if @hdl == NULL.
249 */
250void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl);
251
252/** v4l2_ctrl_handler_setup() - Call the s_ctrl op for all controls belonging
253 * to the handler to initialize the hardware to the current control values.
254 * @hdl: The control handler.
255 *
256 * Button controls will be skipped, as are read-only controls.
257 *
258 * If @hdl == NULL, then this just returns 0.
259 */
260int v4l2_ctrl_handler_setup(struct v4l2_ctrl_handler *hdl);
261
262/** v4l2_ctrl_handler_log_status() - Log all controls owned by the handler.
263 * @hdl: The control handler.
264 * @prefix: The prefix to use when logging the control values. If the
265 * prefix does not end with a space, then ": " will be added
266 * after the prefix. If @prefix == NULL, then no prefix will be
267 * used.
268 *
269 * For use with VIDIOC_LOG_STATUS.
270 *
271 * Does nothing if @hdl == NULL.
272 */
273void v4l2_ctrl_handler_log_status(struct v4l2_ctrl_handler *hdl,
274 const char *prefix);
275
276/** v4l2_ctrl_new_custom() - Allocate and initialize a new custom V4L2
277 * control.
278 * @hdl: The control handler.
279 * @cfg: The control's configuration data.
280 * @priv: The control's driver-specific private data.
281 *
282 * If the &v4l2_ctrl struct could not be allocated then NULL is returned
283 * and @hdl->error is set to the error code (if it wasn't set already).
284 */
285struct v4l2_ctrl *v4l2_ctrl_new_custom(struct v4l2_ctrl_handler *hdl,
286 const struct v4l2_ctrl_config *cfg, void *priv);
287
288/** v4l2_ctrl_new_std() - Allocate and initialize a new standard V4L2 non-menu control.
289 * @hdl: The control handler.
290 * @ops: The control ops.
291 * @id: The control ID.
292 * @min: The control's minimum value.
293 * @max: The control's maximum value.
294 * @step: The control's step value
295 * @def: The control's default value.
296 *
297 * If the &v4l2_ctrl struct could not be allocated, or the control
298 * ID is not known, then NULL is returned and @hdl->error is set to the
299 * appropriate error code (if it wasn't set already).
300 *
301 * If @id refers to a menu control, then this function will return NULL.
302 *
303 * Use v4l2_ctrl_new_std_menu() when adding menu controls.
304 */
305struct v4l2_ctrl *v4l2_ctrl_new_std(struct v4l2_ctrl_handler *hdl,
306 const struct v4l2_ctrl_ops *ops,
307 u32 id, s32 min, s32 max, u32 step, s32 def);
308
309/** v4l2_ctrl_new_std_menu() - Allocate and initialize a new standard V4L2 menu control.
310 * @hdl: The control handler.
311 * @ops: The control ops.
312 * @id: The control ID.
313 * @max: The control's maximum value.
314 * @mask: The control's skip mask for menu controls. This makes it
315 * easy to skip menu items that are not valid. If bit X is set,
316 * then menu item X is skipped. Of course, this only works for
317 * menus with <= 32 menu items. There are no menus that come
318 * close to that number, so this is OK. Should we ever need more,
319 * then this will have to be extended to a u64 or a bit array.
320 * @def: The control's default value.
321 *
322 * Same as v4l2_ctrl_new_std(), but @min is set to 0 and the @mask value
323 * determines which menu items are to be skipped.
324 *
325 * If @id refers to a non-menu control, then this function will return NULL.
326 */
327struct v4l2_ctrl *v4l2_ctrl_new_std_menu(struct v4l2_ctrl_handler *hdl,
328 const struct v4l2_ctrl_ops *ops,
329 u32 id, s32 max, s32 mask, s32 def);
330
331/** v4l2_ctrl_add_ctrl() - Add a control from another handler to this handler.
332 * @hdl: The control handler.
333 * @ctrl: The control to add.
334 *
335 * It will return NULL if it was unable to add the control reference.
336 * If the control already belonged to the handler, then it will do
337 * nothing and just return @ctrl.
338 */
339struct v4l2_ctrl *v4l2_ctrl_add_ctrl(struct v4l2_ctrl_handler *hdl,
340 struct v4l2_ctrl *ctrl);
341
342/** v4l2_ctrl_add_handler() - Add all controls from handler @add to
343 * handler @hdl.
344 * @hdl: The control handler.
345 * @add: The control handler whose controls you want to add to
346 * the @hdl control handler.
347 *
348 * Does nothing if either of the two is a NULL pointer.
349 * In case of an error @hdl->error will be set to the error code (if it
350 * wasn't set already).
351 */
352int v4l2_ctrl_add_handler(struct v4l2_ctrl_handler *hdl,
353 struct v4l2_ctrl_handler *add);
354
355
356/** v4l2_ctrl_cluster() - Mark all controls in the cluster as belonging to that cluster.
357 * @ncontrols: The number of controls in this cluster.
358 * @controls: The cluster control array of size @ncontrols.
359 */
360void v4l2_ctrl_cluster(unsigned ncontrols, struct v4l2_ctrl **controls);
361
362
363/** v4l2_ctrl_find() - Find a control with the given ID.
364 * @hdl: The control handler.
365 * @id: The control ID to find.
366 *
367 * If @hdl == NULL this will return NULL as well. Will lock the handler so
368 * do not use from inside &v4l2_ctrl_ops.
369 */
370struct v4l2_ctrl *v4l2_ctrl_find(struct v4l2_ctrl_handler *hdl, u32 id);
371
372/** v4l2_ctrl_activate() - Make the control active or inactive.
373 * @ctrl: The control to (de)activate.
374 * @active: True if the control should become active.
375 *
376 * This sets or clears the V4L2_CTRL_FLAG_INACTIVE flag atomically.
377 * Does nothing if @ctrl == NULL.
378 * This will usually be called from within the s_ctrl op.
379 *
380 * This function can be called regardless of whether the control handler
381 * is locked or not.
382 */
383void v4l2_ctrl_activate(struct v4l2_ctrl *ctrl, bool active);
384
385/** v4l2_ctrl_grab() - Mark the control as grabbed or not grabbed.
386 * @ctrl: The control to (de)activate.
387 * @grabbed: True if the control should become grabbed.
388 *
389 * This sets or clears the V4L2_CTRL_FLAG_GRABBED flag atomically.
390 * Does nothing if @ctrl == NULL.
391 * This will usually be called when starting or stopping streaming in the
392 * driver.
393 *
394 * This function can be called regardless of whether the control handler
395 * is locked or not.
396 */
397void v4l2_ctrl_grab(struct v4l2_ctrl *ctrl, bool grabbed);
398
399/** v4l2_ctrl_lock() - Helper function to lock the handler
400 * associated with the control.
401 * @ctrl: The control to lock.
402 */
403static inline void v4l2_ctrl_lock(struct v4l2_ctrl *ctrl)
404{
405 mutex_lock(&ctrl->handler->lock);
406}
407
408/** v4l2_ctrl_lock() - Helper function to unlock the handler
409 * associated with the control.
410 * @ctrl: The control to unlock.
411 */
412static inline void v4l2_ctrl_unlock(struct v4l2_ctrl *ctrl)
413{
414 mutex_unlock(&ctrl->handler->lock);
415}
416
417/** v4l2_ctrl_g_ctrl() - Helper function to get the control's value from within a driver.
418 * @ctrl: The control.
419 *
420 * This returns the control's value safely by going through the control
421 * framework. This function will lock the control's handler, so it cannot be
422 * used from within the &v4l2_ctrl_ops functions.
423 *
424 * This function is for integer type controls only.
425 */
426s32 v4l2_ctrl_g_ctrl(struct v4l2_ctrl *ctrl);
427
428/** v4l2_ctrl_s_ctrl() - Helper function to set the control's value from within a driver.
429 * @ctrl: The control.
430 * @val: The new value.
431 *
432 * This set the control's new value safely by going through the control
433 * framework. This function will lock the control's handler, so it cannot be
434 * used from within the &v4l2_ctrl_ops functions.
435 *
436 * This function is for integer type controls only.
437 */
438int v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val);
439
440
441/* Helpers for ioctl_ops. If hdl == NULL then they will all return -EINVAL. */
442int v4l2_queryctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_queryctrl *qc);
443int v4l2_querymenu(struct v4l2_ctrl_handler *hdl, struct v4l2_querymenu *qm);
444int v4l2_g_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_control *ctrl);
445int v4l2_s_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_control *ctrl);
446int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *c);
447int v4l2_try_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *c);
448int v4l2_s_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *c);
449
450/* Helpers for subdevices. If the associated ctrl_handler == NULL then they
451 will all return -EINVAL. */
452int v4l2_subdev_queryctrl(struct v4l2_subdev *sd, struct v4l2_queryctrl *qc);
453int v4l2_subdev_querymenu(struct v4l2_subdev *sd, struct v4l2_querymenu *qm);
454int v4l2_subdev_g_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
455int v4l2_subdev_try_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
456int v4l2_subdev_s_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
457int v4l2_subdev_g_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
458int v4l2_subdev_s_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
459
460#endif