diff options
| -rw-r--r-- | Documentation/media/kapi/v4l2-framework.rst | 5 | ||||
| -rw-r--r-- | drivers/media/v4l2-core/v4l2-dev.c | 34 | ||||
| -rw-r--r-- | include/media/v4l2-dev.h | 364 |
3 files changed, 320 insertions, 83 deletions
diff --git a/Documentation/media/kapi/v4l2-framework.rst b/Documentation/media/kapi/v4l2-framework.rst index de341fc5b235..315388ef6593 100644 --- a/Documentation/media/kapi/v4l2-framework.rst +++ b/Documentation/media/kapi/v4l2-framework.rst @@ -699,3 +699,8 @@ methods. It is expected that once the CCF becomes available on all relevant architectures this API will be removed. + +video_device kAPI +^^^^^^^^^^^^^^^^^ + +.. kernel-doc:: include/media/v4l2-dev.h diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c index 70b559d7ca80..e6da353b39bc 100644 --- a/drivers/media/v4l2-core/v4l2-dev.c +++ b/drivers/media/v4l2-core/v4l2-dev.c @@ -812,40 +812,6 @@ static int video_register_media_controller(struct video_device *vdev, int type) return 0; } -/** - * __video_register_device - register video4linux devices - * @vdev: video device structure we want to register - * @type: type of device to register - * @nr: which device node number (0 == /dev/video0, 1 == /dev/video1, ... - * -1 == first free) - * @warn_if_nr_in_use: warn if the desired device node number - * was already in use and another number was chosen instead. - * @owner: module that owns the video device node - * - * The registration code assigns minor numbers and device node numbers - * based on the requested type and registers the new device node with - * the kernel. - * - * This function assumes that struct video_device was zeroed when it - * was allocated and does not contain any stale date. - * - * An error is returned if no free minor or device node number could be - * found, or if the registration of the device node failed. - * - * Zero is returned on success. - * - * Valid types are - * - * %VFL_TYPE_GRABBER - A frame grabber - * - * %VFL_TYPE_VBI - Vertical blank data (undecoded) - * - * %VFL_TYPE_RADIO - A radio card - * - * %VFL_TYPE_SUBDEV - A subdevice - * - * %VFL_TYPE_SDR - Software Defined Radio - */ int __video_register_device(struct video_device *vdev, int type, int nr, int warn_if_nr_in_use, struct module *owner) { diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h index 25a3190308fb..5921c24565cf 100644 --- a/include/media/v4l2-dev.h +++ b/include/media/v4l2-dev.h @@ -47,19 +47,105 @@ struct v4l2_ctrl_handler; /* Priority helper functions */ +/** + * struct v4l2_prio_state - stores the priority states + * + * @prios: array with elements to store the array priorities + * + * + * .. note:: + * The size of @prios array matches the number of priority types defined + * by :ref:`enum v4l2_priority <v4l2-priority>`. + */ struct v4l2_prio_state { atomic_t prios[4]; }; +/** + * v4l2_prio_init - initializes a struct v4l2_prio_state + * + * @global: pointer to &struct v4l2_prio_state + */ void v4l2_prio_init(struct v4l2_prio_state *global); + +/** + * v4l2_prio_change - changes the v4l2 file handler priority + * + * @global: pointer to the &struct v4l2_prio_state of the device node. + * @local: pointer to the desired priority, as defined by :ref:`enum v4l2_priority <v4l2-priority>` + * @new: Priority type requested, as defined by :ref:`enum v4l2_priority <v4l2-priority>`. + * + * .. note:: + * This function should be used only by the V4L2 core. + */ int v4l2_prio_change(struct v4l2_prio_state *global, enum v4l2_priority *local, enum v4l2_priority new); + +/** + * v4l2_prio_open - Implements the priority logic for a file handler open + * + * @global: pointer to the &struct v4l2_prio_state of the device node. + * @local: pointer to the desired priority, as defined by :ref:`enum v4l2_priority <v4l2-priority>` + * + * .. note:: + * This function should be used only by the V4L2 core. + */ void v4l2_prio_open(struct v4l2_prio_state *global, enum v4l2_priority *local); + +/** + * v4l2_prio_close - Implements the priority logic for a file handler close + * + * @global: pointer to the &struct v4l2_prio_state of the device node. + * @local: priority to be released, as defined by :ref:`enum v4l2_priority <v4l2-priority>` + * + * .. note:: + * This function should be used only by the V4L2 core. + */ void v4l2_prio_close(struct v4l2_prio_state *global, enum v4l2_priority local); + +/** + * v4l2_prio_max - Return the maximum priority, as stored at the @global array. + * + * @global: pointer to the &struct v4l2_prio_state of the device node. + * + * .. note:: + * This function should be used only by the V4L2 core. + */ enum v4l2_priority v4l2_prio_max(struct v4l2_prio_state *global); -int v4l2_prio_check(struct v4l2_prio_state *global, enum v4l2_priority local); +/** + * v4l2_prio_close - Implements the priority logic for a file handler close + * + * @global: pointer to the &struct v4l2_prio_state of the device node. + * @local: desired priority, as defined by :ref:`enum v4l2_priority <v4l2-priority>` local + * + * .. note:: + * This function should be used only by the V4L2 core. + */ +int v4l2_prio_check(struct v4l2_prio_state *global, enum v4l2_priority local); +/** + * struct v4l2_file_operations - fs operations used by a V4L2 device + * + * @owner: pointer to struct module + * @read: operations needed to implement the read() syscall + * @write: operations needed to implement the write() syscall + * @poll: operations needed to implement the poll() syscall + * @unlocked_ioctl: operations needed to implement the ioctl() syscall + * @compat_ioctl32: operations needed to implement the ioctl() syscall for + * the special case where the Kernel uses 64 bits instructions, but + * the userspace uses 32 bits. + * @get_unmapped_area: called by the mmap() syscall, used when %!CONFIG_MMU + * @mmap: operations needed to implement the mmap() syscall + * @open: operations needed to implement the open() syscall + * @release: operations needed to implement the release() syscall + * + * .. note:: + * + * Those operations are used to implemente the fs struct file_operations + * at the V4L2 drivers. The V4L2 core overrides the fs ops with some + * extra logic needed by the subsystem. + */ struct v4l2_file_operations { struct module *owner; ssize_t (*read) (struct file *, char __user *, size_t, loff_t *); @@ -82,6 +168,47 @@ struct v4l2_file_operations { * the common handler */ +/** + * struct video_device - Structure used to create and manage the V4L2 device + * nodes. + * + * @entity: &struct media_entity + * @intf_devnode: pointer to &struct media_intf_devnode + * @pipe: &struct media_pipeline + * @fops: pointer to &struct v4l2_file_operations for the video device + * @device_caps: device capabilities as used in v4l2_capabilities + * @dev: &struct device for the video device + * @cdev: character device + * @v4l2_dev: pointer to &struct v4l2_device parent + * @dev_parent: pointer to &struct device parent + * @ctrl_handler: Control handler associated with this device node. + * May be NULL. + * @queue: &struct vb2_queue associated with this device node. May be NULL. + * @prio: pointer to &struct v4l2_prio_state with device's Priority state. + * If NULL, then v4l2_dev->prio will be used. + * @name: video device name + * @vfl_type: V4L device type + * @vfl_dir: V4L receiver, transmitter or m2m + * @minor: device node 'minor'. It is set to -1 if the registration failed + * @num: number of the video device node + * @flags: video device flags. Use bitops to set/clear/test flags + * @index: attribute to differentiate multiple indices on one physical device + * @fh_lock: Lock for all v4l2_fhs + * @fh_list: List of &struct v4l2_fh + * @dev_debug: Internal device debug flags, not for use by drivers + * @tvnorms: Supported tv norms + * + * @release: video device release() callback + * @ioctl_ops: pointer to &struct v4l2_ioctl_ops with ioctl callbacks + * + * @valid_ioctls: bitmap with the valid ioctls for this device + * @disable_locking: bitmap with the ioctls that don't require locking + * @lock: pointer to &struct mutex serialization lock + * + * .. note:: + * Only set @dev_parent if that can't be deduced from @v4l2_dev. + */ + struct video_device { #if defined(CONFIG_MEDIA_CONTROLLER) @@ -89,59 +216,45 @@ struct video_device struct media_intf_devnode *intf_devnode; struct media_pipeline pipe; #endif - /* device ops */ const struct v4l2_file_operations *fops; - /* device capabilities as used in v4l2_capabilities */ u32 device_caps; /* sysfs */ - struct device dev; /* v4l device */ - struct cdev *cdev; /* character device */ + struct device dev; + struct cdev *cdev; - struct v4l2_device *v4l2_dev; /* v4l2_device parent */ - /* Only set parent if that can't be deduced from v4l2_dev */ - struct device *dev_parent; /* device parent */ + struct v4l2_device *v4l2_dev; + struct device *dev_parent; - /* Control handler associated with this device node. May be NULL. */ struct v4l2_ctrl_handler *ctrl_handler; - /* vb2_queue associated with this device node. May be NULL. */ struct vb2_queue *queue; - /* Priority state. If NULL, then v4l2_dev->prio will be used. */ struct v4l2_prio_state *prio; /* device info */ char name[32]; - int vfl_type; /* device type */ - int vfl_dir; /* receiver, transmitter or m2m */ - /* 'minor' is set to -1 if the registration failed */ + int vfl_type; + int vfl_dir; int minor; u16 num; - /* use bitops to set/clear/test flags */ unsigned long flags; - /* attribute to differentiate multiple indices on one physical device */ int index; /* V4L2 file handles */ - spinlock_t fh_lock; /* Lock for all v4l2_fhs */ - struct list_head fh_list; /* List of struct v4l2_fh */ + spinlock_t fh_lock; + struct list_head fh_list; - /* Internal device debug flags, not for use by drivers */ int dev_debug; - /* Video standard vars */ - v4l2_std_id tvnorms; /* Supported tv norms */ + v4l2_std_id tvnorms; /* callbacks */ void (*release)(struct video_device *vdev); - - /* ioctl callbacks */ const struct v4l2_ioctl_ops *ioctl_ops; DECLARE_BITMAP(valid_ioctls, BASE_VIDIOC_PRIVATE); - /* serialization lock */ DECLARE_BITMAP(disable_locking, BASE_VIDIOC_PRIVATE); struct mutex *lock; }; @@ -151,88 +264,241 @@ struct video_device /* dev to video-device */ #define to_video_device(cd) container_of(cd, struct video_device, dev) +/** + * __video_register_device - register video4linux devices + * + * @vdev: struct video_device to register + * @type: type of device to register + * @nr: which device node number is desired: + * (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free) + * @warn_if_nr_in_use: warn if the desired device node number + * was already in use and another number was chosen instead. + * @owner: module that owns the video device node + * + * The registration code assigns minor numbers and device node numbers + * based on the requested type and registers the new device node with + * the kernel. + * + * This function assumes that struct video_device was zeroed when it + * was allocated and does not contain any stale date. + * + * An error is returned if no free minor or device node number could be + * found, or if the registration of the device node failed. + * + * Returns 0 on success. + * + * Valid values for @type are: + * + * - %VFL_TYPE_GRABBER - A frame grabber + * - %VFL_TYPE_VBI - Vertical blank data (undecoded) + * - %VFL_TYPE_RADIO - A radio card + * - %VFL_TYPE_SUBDEV - A subdevice + * - %VFL_TYPE_SDR - Software Defined Radio + * + * .. note:: + * + * This function is meant to be used only inside the V4L2 core. + * Drivers should use video_register_device() or + * video_register_device_no_warn(). + */ int __must_check __video_register_device(struct video_device *vdev, int type, int nr, int warn_if_nr_in_use, struct module *owner); -/* Register video devices. Note that if video_register_device fails, - the release() callback of the video_device structure is *not* called, so - the caller is responsible for freeing any data. Usually that means that - you call video_device_release() on failure. */ +/** + * video_register_device - register video4linux devices + * + * @vdev: struct video_device to register + * @type: type of device to register + * @nr: which device node number is desired: + * (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free) + * + * Internally, it calls __video_register_device(). Please see its + * documentation for more details. + * + * .. note:: + * if video_register_device fails, the release() callback of + * &struct video_device structure is *not* called, so the caller + * is responsible for freeing any data. Usually that means that + * you video_device_release() should be called on failure. + */ static inline int __must_check video_register_device(struct video_device *vdev, int type, int nr) { return __video_register_device(vdev, type, nr, 1, vdev->fops->owner); } -/* Same as video_register_device, but no warning is issued if the desired - device node number was already in use. */ +/** + * video_register_device_no_warn - register video4linux devices + * + * @vdev: struct video_device to register + * @type: type of device to register + * @nr: which device node number is desired: + * (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free) + * + * This function is identical to video_register_device() except that no + * warning is issued if the desired device node number was already in use. + * + * Internally, it calls __video_register_device(). Please see its + * documentation for more details. + * + * .. note:: + * if video_register_device fails, the release() callback of + * &struct video_device structure is *not* called, so the caller + * is responsible for freeing any data. Usually that means that + * you video_device_release() should be called on failure. + */ static inline int __must_check video_register_device_no_warn( struct video_device *vdev, int type, int nr) { return __video_register_device(vdev, type, nr, 0, vdev->fops->owner); } -/* Unregister video devices. Will do nothing if vdev == NULL or - video_is_registered() returns false. */ +/** + * video_unregister_device - Unregister video devices. + * + * @vdev: &struct video_device to register + * + * Does nothing if vdev == NULL or if video_is_registered() returns false. + */ void video_unregister_device(struct video_device *vdev); -/* helper functions to alloc/release struct video_device, the - latter can also be used for video_device->release(). */ +/** + * video_device_alloc - helper function to alloc &struct video_device + * + * Returns NULL if %-ENOMEM or a &struct video_device on success. + */ struct video_device * __must_check video_device_alloc(void); -/* this release function frees the vdev pointer */ +/** + * video_device_release - helper function to release &struct video_device + * + * @vdev: pointer to &struct video_device + * + * Can also be used for video_device->release(). + */ void video_device_release(struct video_device *vdev); -/* this release function does nothing, use when the video_device is a - static global struct. Note that having a static video_device is - a dubious construction at best. */ +/** + * video_device_release_empty - helper function to implement the + * video_device->release() callback. + * + * @vdev: pointer to &struct video_device + * + * This release function does nothing. + * + * It should be used when the video_device is a static global struct. + * + * .. note:: + * Having a static video_device is a dubious construction at best. + */ void video_device_release_empty(struct video_device *vdev); -/* returns true if cmd is a known V4L2 ioctl */ +/** + * v4l2_is_known_ioctl - Checks if a given cmd is a known V4L ioctl + * + * @cmd: ioctl command + * + * returns true if cmd is a known V4L2 ioctl + */ bool v4l2_is_known_ioctl(unsigned int cmd); -/* mark that this command shouldn't use core locking */ -static inline void v4l2_disable_ioctl_locking(struct video_device *vdev, unsigned int cmd) +/** v4l2_disable_ioctl_locking - mark that a given command + * shouldn't use core locking + * + * @vdev: pointer to &struct video_device + * @cmd: ioctl command + */ +static inline void v4l2_disable_ioctl_locking(struct video_device *vdev, + unsigned int cmd) { if (_IOC_NR(cmd) < BASE_VIDIOC_PRIVATE) set_bit(_IOC_NR(cmd), vdev->disable_locking); } -/* Mark that this command isn't implemented. This must be called before - video_device_register. See also the comments in determine_valid_ioctls(). - This function allows drivers to provide just one v4l2_ioctl_ops struct, but - disable ioctls based on the specific card that is actually found. */ -static inline void v4l2_disable_ioctl(struct video_device *vdev, unsigned int cmd) +/** + * v4l2_disable_ioctl- mark that a given command isn't implemented. + * shouldn't use core locking + * + * @vdev: pointer to &struct video_device + * @cmd: ioctl command + * + * This function allows drivers to provide just one v4l2_ioctl_ops struct, but + * disable ioctls based on the specific card that is actually found. + * + * .. note:: + * + * This must be called before video_register_device. + * See also the comments for determine_valid_ioctls(). + */ +static inline void v4l2_disable_ioctl(struct video_device *vdev, + unsigned int cmd) { if (_IOC_NR(cmd) < BASE_VIDIOC_PRIVATE) set_bit(_IOC_NR(cmd), vdev->valid_ioctls); } -/* helper functions to access driver private data. */ +/** + * video_get_drvdata - gets private data from &struct video_device. + * + * @vdev: pointer to &struct video_device + * + * returns a pointer to the private data + */ static inline void *video_get_drvdata(struct video_device *vdev) { return dev_get_drvdata(&vdev->dev); } +/** + * video_set_drvdata - sets private data from &struct video_device. + * + * @vdev: pointer to &struct video_device + * @data: private data pointer + */ static inline void video_set_drvdata(struct video_device *vdev, void *data) { dev_set_drvdata(&vdev->dev, data); } +/** + * video_devdata - gets &struct video_device from struct file. + * + * @file: pointer to struct file + */ struct video_device *video_devdata(struct file *file); -/* Combine video_get_drvdata and video_devdata as this is - used very often. */ +/** + * video_drvdata - gets private data from &struct video_device using the + * struct file. + * + * @file: pointer to struct file + * + * This is function combines both video_get_drvdata() and video_devdata() + * as this is used very often. + */ static inline void *video_drvdata(struct file *file) { return video_get_drvdata(video_devdata(file)); } +/** + * video_device_node_name - returns the video device name + * + * @vdev: pointer to &struct video_device + * + * Returns the device name string + */ static inline const char *video_device_node_name(struct video_device *vdev) { return dev_name(&vdev->dev); } +/** + * video_is_registered - returns true if the &struct video_device is registered. + * + * + * @vdev: pointer to &struct video_device + */ static inline int video_is_registered(struct video_device *vdev) { return test_bit(V4L2_FL_REGISTERED, &vdev->flags); |