1 /* SPDX-License-Identifier: GPL-2.0 */
4 * V 4 L 2 D R I V E R H E L P E R A P I
6 * Moved from videodev2.h
8 * Some commonly needed functions for drivers (v4l2-common.o module)
13 #include <linux/poll.h>
15 #include <linux/device.h>
16 #include <linux/cdev.h>
17 #include <linux/mutex.h>
18 #include <linux/videodev2.h>
20 #include <media/media-entity.h>
22 #define VIDEO_MAJOR 81
25 * enum vfl_devnode_type - type of V4L2 device node
27 * @VFL_TYPE_VIDEO: for video input/output devices
28 * @VFL_TYPE_GRABBER: deprecated, same as VFL_TYPE_VIDEO
29 * @VFL_TYPE_VBI: for vertical blank data (i.e. closed captions, teletext)
30 * @VFL_TYPE_RADIO: for radio tuners
31 * @VFL_TYPE_SUBDEV: for V4L2 subdevices
32 * @VFL_TYPE_SDR: for Software Defined Radio tuners
33 * @VFL_TYPE_TOUCH: for touch sensors
34 * @VFL_TYPE_MAX: number of VFL types, must always be last in the enum
36 enum vfl_devnode_type {
38 VFL_TYPE_GRABBER = VFL_TYPE_VIDEO,
44 VFL_TYPE_MAX /* Shall be the last one */
48 * enum vfl_direction - Identifies if a &struct video_device corresponds
49 * to a receiver, a transmitter or a mem-to-mem device.
51 * @VFL_DIR_RX: device is a receiver.
52 * @VFL_DIR_TX: device is a transmitter.
53 * @VFL_DIR_M2M: device is a memory to memory device.
55 * Note: Ignored if &enum vfl_devnode_type is %VFL_TYPE_SUBDEV.
57 enum vfl_devnode_direction {
63 struct v4l2_ioctl_callbacks;
66 struct v4l2_ctrl_handler;
69 * enum v4l2_video_device_flags - Flags used by &struct video_device
71 * @V4L2_FL_REGISTERED:
72 * indicates that a &struct video_device is registered.
73 * Drivers can clear this flag if they want to block all future
74 * device access. It is cleared by video_unregister_device.
75 * @V4L2_FL_USES_V4L2_FH:
76 * indicates that file->private_data points to &struct v4l2_fh.
77 * This flag is set by the core when v4l2_fh_init() is called.
78 * All new drivers should use it.
79 * @V4L2_FL_QUIRK_INVERTED_CROP:
80 * some old M2M drivers use g/s_crop/cropcap incorrectly: crop and
81 * compose are swapped. If this flag is set, then the selection
82 * targets are swapped in the g/s_crop/cropcap functions in v4l2-ioctl.c.
83 * This allows those drivers to correctly implement the selection API,
84 * but the old crop API will still work as expected in order to preserve
85 * backwards compatibility.
86 * Never set this flag for new drivers.
88 enum v4l2_video_device_flags {
89 V4L2_FL_REGISTERED = 0,
90 V4L2_FL_USES_V4L2_FH = 1,
91 V4L2_FL_QUIRK_INVERTED_CROP = 2,
94 /* Priority helper functions */
97 * struct v4l2_prio_state - stores the priority states
99 * @prios: array with elements to store the array priorities
103 * The size of @prios array matches the number of priority types defined
104 * by enum &v4l2_priority.
106 struct v4l2_prio_state {
111 * v4l2_prio_init - initializes a struct v4l2_prio_state
113 * @global: pointer to &struct v4l2_prio_state
115 void v4l2_prio_init(struct v4l2_prio_state *global);
118 * v4l2_prio_change - changes the v4l2 file handler priority
120 * @global: pointer to the &struct v4l2_prio_state of the device node.
121 * @local: pointer to the desired priority, as defined by enum &v4l2_priority
122 * @new: Priority type requested, as defined by enum &v4l2_priority.
125 * This function should be used only by the V4L2 core.
127 int v4l2_prio_change(struct v4l2_prio_state *global, enum v4l2_priority *local,
128 enum v4l2_priority new);
131 * v4l2_prio_open - Implements the priority logic for a file handler open
133 * @global: pointer to the &struct v4l2_prio_state of the device node.
134 * @local: pointer to the desired priority, as defined by enum &v4l2_priority
137 * This function should be used only by the V4L2 core.
139 void v4l2_prio_open(struct v4l2_prio_state *global, enum v4l2_priority *local);
142 * v4l2_prio_close - Implements the priority logic for a file handler close
144 * @global: pointer to the &struct v4l2_prio_state of the device node.
145 * @local: priority to be released, as defined by enum &v4l2_priority
148 * This function should be used only by the V4L2 core.
150 void v4l2_prio_close(struct v4l2_prio_state *global, enum v4l2_priority local);
153 * v4l2_prio_max - Return the maximum priority, as stored at the @global array.
155 * @global: pointer to the &struct v4l2_prio_state of the device node.
158 * This function should be used only by the V4L2 core.
160 enum v4l2_priority v4l2_prio_max(struct v4l2_prio_state *global);
163 * v4l2_prio_check - Implements the priority logic for a file handler close
165 * @global: pointer to the &struct v4l2_prio_state of the device node.
166 * @local: desired priority, as defined by enum &v4l2_priority local
169 * This function should be used only by the V4L2 core.
171 int v4l2_prio_check(struct v4l2_prio_state *global, enum v4l2_priority local);
174 * struct v4l2_file_operations - fs operations used by a V4L2 device
176 * @owner: pointer to struct module
177 * @read: operations needed to implement the read() syscall
178 * @write: operations needed to implement the write() syscall
179 * @poll: operations needed to implement the poll() syscall
180 * @unlocked_ioctl: operations needed to implement the ioctl() syscall
181 * @compat_ioctl32: operations needed to implement the ioctl() syscall for
182 * the special case where the Kernel uses 64 bits instructions, but
183 * the userspace uses 32 bits.
184 * @get_unmapped_area: called by the mmap() syscall, used when %!CONFIG_MMU
185 * @mmap: operations needed to implement the mmap() syscall
186 * @open: operations needed to implement the open() syscall
187 * @release: operations needed to implement the release() syscall
191 * Those operations are used to implemente the fs struct file_operations
192 * at the V4L2 drivers. The V4L2 core overrides the fs ops with some
193 * extra logic needed by the subsystem.
195 struct v4l2_file_operations {
196 struct module *owner;
197 ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
198 ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
199 __poll_t (*poll) (struct file *, struct poll_table_struct *);
200 long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
202 long (*compat_ioctl32) (struct file *, unsigned int, unsigned long);
204 unsigned long (*get_unmapped_area) (struct file *, unsigned long,
205 unsigned long, unsigned long, unsigned long);
206 int (*mmap) (struct file *, struct vm_area_struct *);
207 int (*open) (struct file *);
208 int (*release) (struct file *);
212 * Newer version of video_device, handled by videodev2.c
213 * This version moves redundant code from video device code to
218 * struct video_device - Structure used to create and manage the V4L2 device
221 * @entity: &struct media_entity
222 * @intf_devnode: pointer to &struct media_intf_devnode
223 * @pipe: &struct media_pipeline
224 * @fops: pointer to &struct v4l2_file_operations for the video device
225 * @device_caps: device capabilities as used in v4l2_capabilities
226 * @dev: &struct device for the video device
227 * @cdev: character device
228 * @v4l2_dev: pointer to &struct v4l2_device parent
229 * @dev_parent: pointer to &struct device parent
230 * @ctrl_handler: Control handler associated with this device node.
232 * @queue: &struct vb2_queue associated with this device node. May be NULL.
233 * @prio: pointer to &struct v4l2_prio_state with device's Priority state.
234 * If NULL, then v4l2_dev->prio will be used.
235 * @name: video device name
236 * @vfl_type: V4L device type, as defined by &enum vfl_devnode_type
237 * @vfl_dir: V4L receiver, transmitter or m2m
238 * @minor: device node 'minor'. It is set to -1 if the registration failed
239 * @num: number of the video device node
240 * @flags: video device flags. Use bitops to set/clear/test flags.
241 * Contains a set of &enum v4l2_video_device_flags.
242 * @index: attribute to differentiate multiple indices on one physical device
243 * @fh_lock: Lock for all v4l2_fhs
244 * @fh_list: List of &struct v4l2_fh
245 * @dev_debug: Internal device debug flags, not for use by drivers
246 * @tvnorms: Supported tv norms
248 * @release: video device release() callback
249 * @ioctl_ops: pointer to &struct v4l2_ioctl_ops with ioctl callbacks
251 * @valid_ioctls: bitmap with the valid ioctls for this device
252 * @lock: pointer to &struct mutex serialization lock
255 * Only set @dev_parent if that can't be deduced from @v4l2_dev.
260 #if defined(CONFIG_MEDIA_CONTROLLER)
261 struct media_entity entity;
262 struct media_intf_devnode *intf_devnode;
263 struct media_pipeline pipe;
265 const struct v4l2_file_operations *fops;
273 struct v4l2_device *v4l2_dev;
274 struct device *dev_parent;
276 struct v4l2_ctrl_handler *ctrl_handler;
278 struct vb2_queue *queue;
280 struct v4l2_prio_state *prio;
284 enum vfl_devnode_type vfl_type;
285 enum vfl_devnode_direction vfl_dir;
291 /* V4L2 file handles */
293 struct list_head fh_list;
300 void (*release)(struct video_device *vdev);
301 const struct v4l2_ioctl_ops *ioctl_ops;
302 DECLARE_BITMAP(valid_ioctls, BASE_VIDIOC_PRIVATE);
308 * media_entity_to_video_device - Returns a &struct video_device from
309 * the &struct media_entity embedded on it.
311 * @__entity: pointer to &struct media_entity
313 #define media_entity_to_video_device(__entity) \
314 container_of(__entity, struct video_device, entity)
317 * to_video_device - Returns a &struct video_device from the
318 * &struct device embedded on it.
320 * @cd: pointer to &struct device
322 #define to_video_device(cd) container_of(cd, struct video_device, dev)
325 * __video_register_device - register video4linux devices
327 * @vdev: struct video_device to register
328 * @type: type of device to register, as defined by &enum vfl_devnode_type
329 * @nr: which device node number is desired:
330 * (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
331 * @warn_if_nr_in_use: warn if the desired device node number
332 * was already in use and another number was chosen instead.
333 * @owner: module that owns the video device node
335 * The registration code assigns minor numbers and device node numbers
336 * based on the requested type and registers the new device node with
339 * This function assumes that struct video_device was zeroed when it
340 * was allocated and does not contain any stale date.
342 * An error is returned if no free minor or device node number could be
343 * found, or if the registration of the device node failed.
345 * Returns 0 on success.
349 * This function is meant to be used only inside the V4L2 core.
350 * Drivers should use video_register_device() or
351 * video_register_device_no_warn().
353 int __must_check __video_register_device(struct video_device *vdev,
354 enum vfl_devnode_type type,
355 int nr, int warn_if_nr_in_use,
356 struct module *owner);
359 * video_register_device - register video4linux devices
361 * @vdev: struct video_device to register
362 * @type: type of device to register, as defined by &enum vfl_devnode_type
363 * @nr: which device node number is desired:
364 * (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
366 * Internally, it calls __video_register_device(). Please see its
367 * documentation for more details.
370 * if video_register_device fails, the release() callback of
371 * &struct video_device structure is *not* called, so the caller
372 * is responsible for freeing any data. Usually that means that
373 * you video_device_release() should be called on failure.
375 static inline int __must_check video_register_device(struct video_device *vdev,
376 enum vfl_devnode_type type,
379 return __video_register_device(vdev, type, nr, 1, vdev->fops->owner);
383 * video_register_device_no_warn - register video4linux devices
385 * @vdev: struct video_device to register
386 * @type: type of device to register, as defined by &enum vfl_devnode_type
387 * @nr: which device node number is desired:
388 * (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
390 * This function is identical to video_register_device() except that no
391 * warning is issued if the desired device node number was already in use.
393 * Internally, it calls __video_register_device(). Please see its
394 * documentation for more details.
397 * if video_register_device fails, the release() callback of
398 * &struct video_device structure is *not* called, so the caller
399 * is responsible for freeing any data. Usually that means that
400 * you video_device_release() should be called on failure.
402 static inline int __must_check
403 video_register_device_no_warn(struct video_device *vdev,
404 enum vfl_devnode_type type, int nr)
406 return __video_register_device(vdev, type, nr, 0, vdev->fops->owner);
410 * video_unregister_device - Unregister video devices.
412 * @vdev: &struct video_device to register
414 * Does nothing if vdev == NULL or if video_is_registered() returns false.
416 void video_unregister_device(struct video_device *vdev);
419 * video_device_alloc - helper function to alloc &struct video_device
421 * Returns NULL if %-ENOMEM or a &struct video_device on success.
423 struct video_device * __must_check video_device_alloc(void);
426 * video_device_release - helper function to release &struct video_device
428 * @vdev: pointer to &struct video_device
430 * Can also be used for video_device->release\(\).
432 void video_device_release(struct video_device *vdev);
435 * video_device_release_empty - helper function to implement the
436 * video_device->release\(\) callback.
438 * @vdev: pointer to &struct video_device
440 * This release function does nothing.
442 * It should be used when the video_device is a static global struct.
445 * Having a static video_device is a dubious construction at best.
447 void video_device_release_empty(struct video_device *vdev);
450 * v4l2_disable_ioctl- mark that a given command isn't implemented.
451 * shouldn't use core locking
453 * @vdev: pointer to &struct video_device
454 * @cmd: ioctl command
456 * This function allows drivers to provide just one v4l2_ioctl_ops struct, but
457 * disable ioctls based on the specific card that is actually found.
461 * This must be called before video_register_device.
462 * See also the comments for determine_valid_ioctls().
464 static inline void v4l2_disable_ioctl(struct video_device *vdev,
467 if (_IOC_NR(cmd) < BASE_VIDIOC_PRIVATE)
468 set_bit(_IOC_NR(cmd), vdev->valid_ioctls);
472 * video_get_drvdata - gets private data from &struct video_device.
474 * @vdev: pointer to &struct video_device
476 * returns a pointer to the private data
478 static inline void *video_get_drvdata(struct video_device *vdev)
480 return dev_get_drvdata(&vdev->dev);
484 * video_set_drvdata - sets private data from &struct video_device.
486 * @vdev: pointer to &struct video_device
487 * @data: private data pointer
489 static inline void video_set_drvdata(struct video_device *vdev, void *data)
491 dev_set_drvdata(&vdev->dev, data);
495 * video_devdata - gets &struct video_device from struct file.
497 * @file: pointer to struct file
499 struct video_device *video_devdata(struct file *file);
502 * video_drvdata - gets private data from &struct video_device using the
505 * @file: pointer to struct file
507 * This is function combines both video_get_drvdata() and video_devdata()
508 * as this is used very often.
510 static inline void *video_drvdata(struct file *file)
512 return video_get_drvdata(video_devdata(file));
516 * video_device_node_name - returns the video device name
518 * @vdev: pointer to &struct video_device
520 * Returns the device name string
522 static inline const char *video_device_node_name(struct video_device *vdev)
524 return dev_name(&vdev->dev);
528 * video_is_registered - returns true if the &struct video_device is registered.
531 * @vdev: pointer to &struct video_device
533 static inline int video_is_registered(struct video_device *vdev)
535 return test_bit(V4L2_FL_REGISTERED, &vdev->flags);
538 #endif /* _V4L2_DEV_H */