v4l2-ctrls.h 17 KB

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  1. /*
  2. V4L2 controls support header.
  3. Copyright (C) 2010 Hans Verkuil <hverkuil@xs4all.nl>
  4. This program is free software; you can redistribute it and/or modify
  5. it under the terms of the GNU General Public License as published by
  6. the Free Software Foundation; either version 2 of the License, or
  7. (at your option) any later version.
  8. This program is distributed in the hope that it will be useful,
  9. but WITHOUT ANY WARRANTY; without even the implied warranty of
  10. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11. GNU General Public License for more details.
  12. You should have received a copy of the GNU General Public License
  13. along with this program; if not, write to the Free Software
  14. Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  15. */
  16. #ifndef _V4L2_CTRLS_H
  17. #define _V4L2_CTRLS_H
  18. #include <linux/list.h>
  19. #include <linux/device.h>
  20. /* forward references */
  21. struct v4l2_ctrl_handler;
  22. struct v4l2_ctrl;
  23. struct video_device;
  24. struct v4l2_subdev;
  25. /** struct v4l2_ctrl_ops - The control operations that the driver has to provide.
  26. * @g_volatile_ctrl: Get a new value for this control. Generally only relevant
  27. * for volatile (and usually read-only) controls such as a control
  28. * that returns the current signal strength which changes
  29. * continuously.
  30. * If not set, then the currently cached value will be returned.
  31. * @try_ctrl: Test whether the control's value is valid. Only relevant when
  32. * the usual min/max/step checks are not sufficient.
  33. * @s_ctrl: Actually set the new control value. s_ctrl is compulsory. The
  34. * ctrl->handler->lock is held when these ops are called, so no
  35. * one else can access controls owned by that handler.
  36. */
  37. struct v4l2_ctrl_ops {
  38. int (*g_volatile_ctrl)(struct v4l2_ctrl *ctrl);
  39. int (*try_ctrl)(struct v4l2_ctrl *ctrl);
  40. int (*s_ctrl)(struct v4l2_ctrl *ctrl);
  41. };
  42. /** struct v4l2_ctrl - The control structure.
  43. * @node: The list node.
  44. * @handler: The handler that owns the control.
  45. * @cluster: Point to start of cluster array.
  46. * @ncontrols: Number of controls in cluster array.
  47. * @has_new: Internal flag: set when there is a valid new value.
  48. * @done: Internal flag: set for each processed control.
  49. * @is_private: If set, then this control is private to its handler and it
  50. * will not be added to any other handlers. Drivers can set
  51. * this flag.
  52. * @is_volatile: If set, then this control is volatile. This means that the
  53. * control's current value cannot be cached and needs to be
  54. * retrieved through the g_volatile_ctrl op. Drivers can set
  55. * this flag.
  56. * @ops: The control ops.
  57. * @id: The control ID.
  58. * @name: The control name.
  59. * @type: The control type.
  60. * @minimum: The control's minimum value.
  61. * @maximum: The control's maximum value.
  62. * @default_value: The control's default value.
  63. * @step: The control's step value for non-menu controls.
  64. * @menu_skip_mask: The control's skip mask for menu controls. This makes it
  65. * easy to skip menu items that are not valid. If bit X is set,
  66. * then menu item X is skipped. Of course, this only works for
  67. * menus with <= 32 menu items. There are no menus that come
  68. * close to that number, so this is OK. Should we ever need more,
  69. * then this will have to be extended to a u64 or a bit array.
  70. * @qmenu: A const char * array for all menu items. Array entries that are
  71. * empty strings ("") correspond to non-existing menu items (this
  72. * is in addition to the menu_skip_mask above). The last entry
  73. * must be NULL.
  74. * @flags: The control's flags.
  75. * @cur: The control's current value.
  76. * @val: The control's new s32 value.
  77. * @val64: The control's new s64 value.
  78. * @string: The control's new string value.
  79. * @priv: The control's private pointer. For use by the driver. It is
  80. * untouched by the control framework. Note that this pointer is
  81. * not freed when the control is deleted. Should this be needed
  82. * then a new internal bitfield can be added to tell the framework
  83. * to free this pointer.
  84. */
  85. struct v4l2_ctrl {
  86. /* Administrative fields */
  87. struct list_head node;
  88. struct v4l2_ctrl_handler *handler;
  89. struct v4l2_ctrl **cluster;
  90. unsigned ncontrols;
  91. unsigned int has_new:1;
  92. unsigned int done:1;
  93. unsigned int is_private:1;
  94. unsigned int is_volatile:1;
  95. const struct v4l2_ctrl_ops *ops;
  96. u32 id;
  97. const char *name;
  98. enum v4l2_ctrl_type type;
  99. s32 minimum, maximum, default_value;
  100. union {
  101. u32 step;
  102. u32 menu_skip_mask;
  103. };
  104. const char **qmenu;
  105. unsigned long flags;
  106. union {
  107. s32 val;
  108. s64 val64;
  109. char *string;
  110. } cur;
  111. union {
  112. s32 val;
  113. s64 val64;
  114. char *string;
  115. };
  116. void *priv;
  117. };
  118. /** struct v4l2_ctrl_ref - The control reference.
  119. * @node: List node for the sorted list.
  120. * @next: Single-link list node for the hash.
  121. * @ctrl: The actual control information.
  122. *
  123. * Each control handler has a list of these refs. The list_head is used to
  124. * keep a sorted-by-control-ID list of all controls, while the next pointer
  125. * is used to link the control in the hash's bucket.
  126. */
  127. struct v4l2_ctrl_ref {
  128. struct list_head node;
  129. struct v4l2_ctrl_ref *next;
  130. struct v4l2_ctrl *ctrl;
  131. };
  132. /** struct v4l2_ctrl_handler - The control handler keeps track of all the
  133. * controls: both the controls owned by the handler and those inherited
  134. * from other handlers.
  135. * @lock: Lock to control access to this handler and its controls.
  136. * @ctrls: The list of controls owned by this handler.
  137. * @ctrl_refs: The list of control references.
  138. * @cached: The last found control reference. It is common that the same
  139. * control is needed multiple times, so this is a simple
  140. * optimization.
  141. * @buckets: Buckets for the hashing. Allows for quick control lookup.
  142. * @nr_of_buckets: Total number of buckets in the array.
  143. * @error: The error code of the first failed control addition.
  144. */
  145. struct v4l2_ctrl_handler {
  146. struct mutex lock;
  147. struct list_head ctrls;
  148. struct list_head ctrl_refs;
  149. struct v4l2_ctrl_ref *cached;
  150. struct v4l2_ctrl_ref **buckets;
  151. u16 nr_of_buckets;
  152. int error;
  153. };
  154. /** struct v4l2_ctrl_config - Control configuration structure.
  155. * @ops: The control ops.
  156. * @id: The control ID.
  157. * @name: The control name.
  158. * @type: The control type.
  159. * @min: The control's minimum value.
  160. * @max: The control's maximum value.
  161. * @step: The control's step value for non-menu controls.
  162. * @def: The control's default value.
  163. * @flags: The control's flags.
  164. * @menu_skip_mask: The control's skip mask for menu controls. This makes it
  165. * easy to skip menu items that are not valid. If bit X is set,
  166. * then menu item X is skipped. Of course, this only works for
  167. * menus with <= 32 menu items. There are no menus that come
  168. * close to that number, so this is OK. Should we ever need more,
  169. * then this will have to be extended to a u64 or a bit array.
  170. * @qmenu: A const char * array for all menu items. Array entries that are
  171. * empty strings ("") correspond to non-existing menu items (this
  172. * is in addition to the menu_skip_mask above). The last entry
  173. * must be NULL.
  174. * @is_private: If set, then this control is private to its handler and it
  175. * will not be added to any other handlers.
  176. * @is_volatile: If set, then this control is volatile. This means that the
  177. * control's current value cannot be cached and needs to be
  178. * retrieved through the g_volatile_ctrl op.
  179. */
  180. struct v4l2_ctrl_config {
  181. const struct v4l2_ctrl_ops *ops;
  182. u32 id;
  183. const char *name;
  184. enum v4l2_ctrl_type type;
  185. s32 min;
  186. s32 max;
  187. u32 step;
  188. s32 def;
  189. u32 flags;
  190. u32 menu_skip_mask;
  191. const char **qmenu;
  192. unsigned int is_private:1;
  193. unsigned int is_volatile:1;
  194. };
  195. /** v4l2_ctrl_fill() - Fill in the control fields based on the control ID.
  196. *
  197. * This works for all standard V4L2 controls.
  198. * For non-standard controls it will only fill in the given arguments
  199. * and @name will be NULL.
  200. *
  201. * This function will overwrite the contents of @name, @type and @flags.
  202. * The contents of @min, @max, @step and @def may be modified depending on
  203. * the type.
  204. *
  205. * Do not use in drivers! It is used internally for backwards compatibility
  206. * control handling only. Once all drivers are converted to use the new
  207. * control framework this function will no longer be exported.
  208. */
  209. void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
  210. s32 *min, s32 *max, s32 *step, s32 *def, u32 *flags);
  211. /** v4l2_ctrl_handler_init() - Initialize the control handler.
  212. * @hdl: The control handler.
  213. * @nr_of_controls_hint: A hint of how many controls this handler is
  214. * expected to refer to. This is the total number, so including
  215. * any inherited controls. It doesn't have to be precise, but if
  216. * it is way off, then you either waste memory (too many buckets
  217. * are allocated) or the control lookup becomes slower (not enough
  218. * buckets are allocated, so there are more slow list lookups).
  219. * It will always work, though.
  220. *
  221. * Returns an error if the buckets could not be allocated. This error will
  222. * also be stored in @hdl->error.
  223. */
  224. int v4l2_ctrl_handler_init(struct v4l2_ctrl_handler *hdl,
  225. unsigned nr_of_controls_hint);
  226. /** v4l2_ctrl_handler_free() - Free all controls owned by the handler and free
  227. * the control list.
  228. * @hdl: The control handler.
  229. *
  230. * Does nothing if @hdl == NULL.
  231. */
  232. void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl);
  233. /** v4l2_ctrl_handler_setup() - Call the s_ctrl op for all controls belonging
  234. * to the handler to initialize the hardware to the current control values.
  235. * @hdl: The control handler.
  236. *
  237. * Button controls will be skipped, as are read-only controls.
  238. *
  239. * If @hdl == NULL, then this just returns 0.
  240. */
  241. int v4l2_ctrl_handler_setup(struct v4l2_ctrl_handler *hdl);
  242. /** v4l2_ctrl_handler_log_status() - Log all controls owned by the handler.
  243. * @hdl: The control handler.
  244. * @prefix: The prefix to use when logging the control values. If the
  245. * prefix does not end with a space, then ": " will be added
  246. * after the prefix. If @prefix == NULL, then no prefix will be
  247. * used.
  248. *
  249. * For use with VIDIOC_LOG_STATUS.
  250. *
  251. * Does nothing if @hdl == NULL.
  252. */
  253. void v4l2_ctrl_handler_log_status(struct v4l2_ctrl_handler *hdl,
  254. const char *prefix);
  255. /** v4l2_ctrl_new_custom() - Allocate and initialize a new custom V4L2
  256. * control.
  257. * @hdl: The control handler.
  258. * @cfg: The control's configuration data.
  259. * @priv: The control's driver-specific private data.
  260. *
  261. * If the &v4l2_ctrl struct could not be allocated then NULL is returned
  262. * and @hdl->error is set to the error code (if it wasn't set already).
  263. */
  264. struct v4l2_ctrl *v4l2_ctrl_new_custom(struct v4l2_ctrl_handler *hdl,
  265. const struct v4l2_ctrl_config *cfg, void *priv);
  266. /** v4l2_ctrl_new_std() - Allocate and initialize a new standard V4L2 non-menu control.
  267. * @hdl: The control handler.
  268. * @ops: The control ops.
  269. * @id: The control ID.
  270. * @min: The control's minimum value.
  271. * @max: The control's maximum value.
  272. * @step: The control's step value
  273. * @def: The control's default value.
  274. *
  275. * If the &v4l2_ctrl struct could not be allocated, or the control
  276. * ID is not known, then NULL is returned and @hdl->error is set to the
  277. * appropriate error code (if it wasn't set already).
  278. *
  279. * If @id refers to a menu control, then this function will return NULL.
  280. *
  281. * Use v4l2_ctrl_new_std_menu() when adding menu controls.
  282. */
  283. struct v4l2_ctrl *v4l2_ctrl_new_std(struct v4l2_ctrl_handler *hdl,
  284. const struct v4l2_ctrl_ops *ops,
  285. u32 id, s32 min, s32 max, u32 step, s32 def);
  286. /** v4l2_ctrl_new_std_menu() - Allocate and initialize a new standard V4L2 menu control.
  287. * @hdl: The control handler.
  288. * @ops: The control ops.
  289. * @id: The control ID.
  290. * @max: The control's maximum value.
  291. * @mask: The control's skip mask for menu controls. This makes it
  292. * easy to skip menu items that are not valid. If bit X is set,
  293. * then menu item X is skipped. Of course, this only works for
  294. * menus with <= 32 menu items. There are no menus that come
  295. * close to that number, so this is OK. Should we ever need more,
  296. * then this will have to be extended to a u64 or a bit array.
  297. * @def: The control's default value.
  298. *
  299. * Same as v4l2_ctrl_new_std(), but @min is set to 0 and the @mask value
  300. * determines which menu items are to be skipped.
  301. *
  302. * If @id refers to a non-menu control, then this function will return NULL.
  303. */
  304. struct v4l2_ctrl *v4l2_ctrl_new_std_menu(struct v4l2_ctrl_handler *hdl,
  305. const struct v4l2_ctrl_ops *ops,
  306. u32 id, s32 max, s32 mask, s32 def);
  307. /** v4l2_ctrl_add_ctrl() - Add a control from another handler to this handler.
  308. * @hdl: The control handler.
  309. * @ctrl: The control to add.
  310. *
  311. * It will return NULL if it was unable to add the control reference.
  312. * If the control already belonged to the handler, then it will do
  313. * nothing and just return @ctrl.
  314. */
  315. struct v4l2_ctrl *v4l2_ctrl_add_ctrl(struct v4l2_ctrl_handler *hdl,
  316. struct v4l2_ctrl *ctrl);
  317. /** v4l2_ctrl_add_handler() - Add all controls from handler @add to
  318. * handler @hdl.
  319. * @hdl: The control handler.
  320. * @add: The control handler whose controls you want to add to
  321. * the @hdl control handler.
  322. *
  323. * Does nothing if either of the two is a NULL pointer.
  324. * In case of an error @hdl->error will be set to the error code (if it
  325. * wasn't set already).
  326. */
  327. int v4l2_ctrl_add_handler(struct v4l2_ctrl_handler *hdl,
  328. struct v4l2_ctrl_handler *add);
  329. /** v4l2_ctrl_cluster() - Mark all controls in the cluster as belonging to that cluster.
  330. * @ncontrols: The number of controls in this cluster.
  331. * @controls: The cluster control array of size @ncontrols.
  332. */
  333. void v4l2_ctrl_cluster(unsigned ncontrols, struct v4l2_ctrl **controls);
  334. /** v4l2_ctrl_find() - Find a control with the given ID.
  335. * @hdl: The control handler.
  336. * @id: The control ID to find.
  337. *
  338. * If @hdl == NULL this will return NULL as well. Will lock the handler so
  339. * do not use from inside &v4l2_ctrl_ops.
  340. */
  341. struct v4l2_ctrl *v4l2_ctrl_find(struct v4l2_ctrl_handler *hdl, u32 id);
  342. /** v4l2_ctrl_activate() - Make the control active or inactive.
  343. * @ctrl: The control to (de)activate.
  344. * @active: True if the control should become active.
  345. *
  346. * This sets or clears the V4L2_CTRL_FLAG_INACTIVE flag atomically.
  347. * Does nothing if @ctrl == NULL.
  348. * This will usually be called from within the s_ctrl op.
  349. *
  350. * This function can be called regardless of whether the control handler
  351. * is locked or not.
  352. */
  353. void v4l2_ctrl_activate(struct v4l2_ctrl *ctrl, bool active);
  354. /** v4l2_ctrl_grab() - Mark the control as grabbed or not grabbed.
  355. * @ctrl: The control to (de)activate.
  356. * @grabbed: True if the control should become grabbed.
  357. *
  358. * This sets or clears the V4L2_CTRL_FLAG_GRABBED flag atomically.
  359. * Does nothing if @ctrl == NULL.
  360. * This will usually be called when starting or stopping streaming in the
  361. * driver.
  362. *
  363. * This function can be called regardless of whether the control handler
  364. * is locked or not.
  365. */
  366. void v4l2_ctrl_grab(struct v4l2_ctrl *ctrl, bool grabbed);
  367. /** v4l2_ctrl_lock() - Helper function to lock the handler
  368. * associated with the control.
  369. * @ctrl: The control to lock.
  370. */
  371. static inline void v4l2_ctrl_lock(struct v4l2_ctrl *ctrl)
  372. {
  373. mutex_lock(&ctrl->handler->lock);
  374. }
  375. /** v4l2_ctrl_lock() - Helper function to unlock the handler
  376. * associated with the control.
  377. * @ctrl: The control to unlock.
  378. */
  379. static inline void v4l2_ctrl_unlock(struct v4l2_ctrl *ctrl)
  380. {
  381. mutex_unlock(&ctrl->handler->lock);
  382. }
  383. /** v4l2_ctrl_g_ctrl() - Helper function to get the control's value from within a driver.
  384. * @ctrl: The control.
  385. *
  386. * This returns the control's value safely by going through the control
  387. * framework. This function will lock the control's handler, so it cannot be
  388. * used from within the &v4l2_ctrl_ops functions.
  389. *
  390. * This function is for integer type controls only.
  391. */
  392. s32 v4l2_ctrl_g_ctrl(struct v4l2_ctrl *ctrl);
  393. /** v4l2_ctrl_s_ctrl() - Helper function to set the control's value from within a driver.
  394. * @ctrl: The control.
  395. * @val: The new value.
  396. *
  397. * This set the control's new value safely by going through the control
  398. * framework. This function will lock the control's handler, so it cannot be
  399. * used from within the &v4l2_ctrl_ops functions.
  400. *
  401. * This function is for integer type controls only.
  402. */
  403. int v4l2_ctrl_s_ctrl(struct v4l2_ctrl *ctrl, s32 val);
  404. /* Helpers for ioctl_ops. If hdl == NULL then they will all return -EINVAL. */
  405. int v4l2_queryctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_queryctrl *qc);
  406. int v4l2_querymenu(struct v4l2_ctrl_handler *hdl, struct v4l2_querymenu *qm);
  407. int v4l2_g_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_control *ctrl);
  408. int v4l2_s_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_control *ctrl);
  409. int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *c);
  410. int v4l2_try_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *c);
  411. int v4l2_s_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct v4l2_ext_controls *c);
  412. /* Helpers for subdevices. If the associated ctrl_handler == NULL then they
  413. will all return -EINVAL. */
  414. int v4l2_subdev_queryctrl(struct v4l2_subdev *sd, struct v4l2_queryctrl *qc);
  415. int v4l2_subdev_querymenu(struct v4l2_subdev *sd, struct v4l2_querymenu *qm);
  416. int v4l2_subdev_g_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
  417. int v4l2_subdev_try_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
  418. int v4l2_subdev_s_ext_ctrls(struct v4l2_subdev *sd, struct v4l2_ext_controls *cs);
  419. int v4l2_subdev_g_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
  420. int v4l2_subdev_s_ctrl(struct v4l2_subdev *sd, struct v4l2_control *ctrl);
  421. #endif