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 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 461