[media] doc-rst: document v4l2-dev.h
Add documentation for v4l2-dev.h, and put it at v4l2-framework.rst, where struct video_device is currently documented. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Mauro Carvalho Chehab
parent
041d8211a0
commit
d9d3d1761a
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@ -699,3 +699,8 @@ methods.
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It is expected that once the CCF becomes available on all relevant
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architectures this API will be removed.
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video_device kAPI
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^^^^^^^^^^^^^^^^^
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.. kernel-doc:: include/media/v4l2-dev.h
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@ -812,40 +812,6 @@ static int video_register_media_controller(struct video_device *vdev, int type)
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return 0;
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}
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/**
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* __video_register_device - register video4linux devices
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* @vdev: video device structure we want to register
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* @type: type of device to register
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* @nr: which device node number (0 == /dev/video0, 1 == /dev/video1, ...
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* -1 == first free)
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* @warn_if_nr_in_use: warn if the desired device node number
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* was already in use and another number was chosen instead.
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* @owner: module that owns the video device node
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*
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* The registration code assigns minor numbers and device node numbers
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* based on the requested type and registers the new device node with
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* the kernel.
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*
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* This function assumes that struct video_device was zeroed when it
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* was allocated and does not contain any stale date.
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*
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* An error is returned if no free minor or device node number could be
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* found, or if the registration of the device node failed.
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*
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* Zero is returned on success.
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*
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* Valid types are
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*
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* %VFL_TYPE_GRABBER - A frame grabber
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*
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* %VFL_TYPE_VBI - Vertical blank data (undecoded)
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*
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* %VFL_TYPE_RADIO - A radio card
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*
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* %VFL_TYPE_SUBDEV - A subdevice
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*
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* %VFL_TYPE_SDR - Software Defined Radio
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*/
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int __video_register_device(struct video_device *vdev, int type, int nr,
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int warn_if_nr_in_use, struct module *owner)
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{
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@ -47,19 +47,105 @@ struct v4l2_ctrl_handler;
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/* Priority helper functions */
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/**
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* struct v4l2_prio_state - stores the priority states
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*
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* @prios: array with elements to store the array priorities
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*
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*
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* .. note::
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* The size of @prios array matches the number of priority types defined
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* by :ref:`enum v4l2_priority <v4l2-priority>`.
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*/
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struct v4l2_prio_state {
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atomic_t prios[4];
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};
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/**
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* v4l2_prio_init - initializes a struct v4l2_prio_state
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*
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* @global: pointer to &struct v4l2_prio_state
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*/
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void v4l2_prio_init(struct v4l2_prio_state *global);
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/**
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* v4l2_prio_change - changes the v4l2 file handler priority
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*
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* @global: pointer to the &struct v4l2_prio_state of the device node.
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* @local: pointer to the desired priority, as defined by :ref:`enum v4l2_priority <v4l2-priority>`
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* @new: Priority type requested, as defined by :ref:`enum v4l2_priority <v4l2-priority>`.
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*
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* .. note::
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* This function should be used only by the V4L2 core.
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*/
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int v4l2_prio_change(struct v4l2_prio_state *global, enum v4l2_priority *local,
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enum v4l2_priority new);
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/**
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* v4l2_prio_open - Implements the priority logic for a file handler open
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*
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* @global: pointer to the &struct v4l2_prio_state of the device node.
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* @local: pointer to the desired priority, as defined by :ref:`enum v4l2_priority <v4l2-priority>`
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*
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* .. note::
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* This function should be used only by the V4L2 core.
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*/
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void v4l2_prio_open(struct v4l2_prio_state *global, enum v4l2_priority *local);
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/**
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* v4l2_prio_close - Implements the priority logic for a file handler close
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*
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* @global: pointer to the &struct v4l2_prio_state of the device node.
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* @local: priority to be released, as defined by :ref:`enum v4l2_priority <v4l2-priority>`
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*
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* .. note::
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* This function should be used only by the V4L2 core.
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*/
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void v4l2_prio_close(struct v4l2_prio_state *global, enum v4l2_priority local);
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/**
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* v4l2_prio_max - Return the maximum priority, as stored at the @global array.
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*
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* @global: pointer to the &struct v4l2_prio_state of the device node.
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*
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* .. note::
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* This function should be used only by the V4L2 core.
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*/
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enum v4l2_priority v4l2_prio_max(struct v4l2_prio_state *global);
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/**
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* v4l2_prio_close - Implements the priority logic for a file handler close
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*
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* @global: pointer to the &struct v4l2_prio_state of the device node.
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* @local: desired priority, as defined by :ref:`enum v4l2_priority <v4l2-priority>` local
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*
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* .. note::
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* This function should be used only by the V4L2 core.
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*/
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int v4l2_prio_check(struct v4l2_prio_state *global, enum v4l2_priority local);
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/**
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* struct v4l2_file_operations - fs operations used by a V4L2 device
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*
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* @owner: pointer to struct module
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* @read: operations needed to implement the read() syscall
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* @write: operations needed to implement the write() syscall
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* @poll: operations needed to implement the poll() syscall
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* @unlocked_ioctl: operations needed to implement the ioctl() syscall
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* @compat_ioctl32: operations needed to implement the ioctl() syscall for
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* the special case where the Kernel uses 64 bits instructions, but
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* the userspace uses 32 bits.
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* @get_unmapped_area: called by the mmap() syscall, used when %!CONFIG_MMU
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* @mmap: operations needed to implement the mmap() syscall
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* @open: operations needed to implement the open() syscall
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* @release: operations needed to implement the release() syscall
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*
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* .. note::
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*
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* Those operations are used to implemente the fs struct file_operations
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* at the V4L2 drivers. The V4L2 core overrides the fs ops with some
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* extra logic needed by the subsystem.
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*/
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struct v4l2_file_operations {
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struct module *owner;
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ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
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@ -82,6 +168,47 @@ struct v4l2_file_operations {
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* the common handler
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*/
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/**
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* struct video_device - Structure used to create and manage the V4L2 device
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* nodes.
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*
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* @entity: &struct media_entity
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* @intf_devnode: pointer to &struct media_intf_devnode
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* @pipe: &struct media_pipeline
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* @fops: pointer to &struct v4l2_file_operations for the video device
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* @device_caps: device capabilities as used in v4l2_capabilities
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* @dev: &struct device for the video device
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* @cdev: character device
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* @v4l2_dev: pointer to &struct v4l2_device parent
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* @dev_parent: pointer to &struct device parent
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* @ctrl_handler: Control handler associated with this device node.
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* May be NULL.
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* @queue: &struct vb2_queue associated with this device node. May be NULL.
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* @prio: pointer to &struct v4l2_prio_state with device's Priority state.
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* If NULL, then v4l2_dev->prio will be used.
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* @name: video device name
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* @vfl_type: V4L device type
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* @vfl_dir: V4L receiver, transmitter or m2m
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* @minor: device node 'minor'. It is set to -1 if the registration failed
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* @num: number of the video device node
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* @flags: video device flags. Use bitops to set/clear/test flags
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* @index: attribute to differentiate multiple indices on one physical device
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* @fh_lock: Lock for all v4l2_fhs
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* @fh_list: List of &struct v4l2_fh
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* @dev_debug: Internal device debug flags, not for use by drivers
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* @tvnorms: Supported tv norms
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*
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* @release: video device release() callback
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* @ioctl_ops: pointer to &struct v4l2_ioctl_ops with ioctl callbacks
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*
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* @valid_ioctls: bitmap with the valid ioctls for this device
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* @disable_locking: bitmap with the ioctls that don't require locking
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* @lock: pointer to &struct mutex serialization lock
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*
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* .. note::
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* Only set @dev_parent if that can't be deduced from @v4l2_dev.
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*/
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struct video_device
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{
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#if defined(CONFIG_MEDIA_CONTROLLER)
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@ -89,59 +216,45 @@ struct video_device
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struct media_intf_devnode *intf_devnode;
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struct media_pipeline pipe;
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#endif
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/* device ops */
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const struct v4l2_file_operations *fops;
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/* device capabilities as used in v4l2_capabilities */
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u32 device_caps;
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/* sysfs */
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struct device dev; /* v4l device */
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struct cdev *cdev; /* character device */
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struct device dev;
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struct cdev *cdev;
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struct v4l2_device *v4l2_dev; /* v4l2_device parent */
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/* Only set parent if that can't be deduced from v4l2_dev */
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struct device *dev_parent; /* device parent */
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struct v4l2_device *v4l2_dev;
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struct device *dev_parent;
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/* Control handler associated with this device node. May be NULL. */
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struct v4l2_ctrl_handler *ctrl_handler;
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/* vb2_queue associated with this device node. May be NULL. */
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struct vb2_queue *queue;
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/* Priority state. If NULL, then v4l2_dev->prio will be used. */
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struct v4l2_prio_state *prio;
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/* device info */
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char name[32];
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int vfl_type; /* device type */
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int vfl_dir; /* receiver, transmitter or m2m */
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/* 'minor' is set to -1 if the registration failed */
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int vfl_type;
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int vfl_dir;
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int minor;
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u16 num;
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/* use bitops to set/clear/test flags */
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unsigned long flags;
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/* attribute to differentiate multiple indices on one physical device */
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int index;
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/* V4L2 file handles */
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spinlock_t fh_lock; /* Lock for all v4l2_fhs */
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struct list_head fh_list; /* List of struct v4l2_fh */
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spinlock_t fh_lock;
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struct list_head fh_list;
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/* Internal device debug flags, not for use by drivers */
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int dev_debug;
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/* Video standard vars */
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v4l2_std_id tvnorms; /* Supported tv norms */
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v4l2_std_id tvnorms;
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/* callbacks */
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void (*release)(struct video_device *vdev);
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/* ioctl callbacks */
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const struct v4l2_ioctl_ops *ioctl_ops;
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DECLARE_BITMAP(valid_ioctls, BASE_VIDIOC_PRIVATE);
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/* serialization lock */
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DECLARE_BITMAP(disable_locking, BASE_VIDIOC_PRIVATE);
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struct mutex *lock;
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};
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@ -151,88 +264,241 @@ struct video_device
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/* dev to video-device */
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#define to_video_device(cd) container_of(cd, struct video_device, dev)
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/**
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* __video_register_device - register video4linux devices
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*
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* @vdev: struct video_device to register
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* @type: type of device to register
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* @nr: which device node number is desired:
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* (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
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* @warn_if_nr_in_use: warn if the desired device node number
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* was already in use and another number was chosen instead.
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* @owner: module that owns the video device node
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*
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* The registration code assigns minor numbers and device node numbers
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* based on the requested type and registers the new device node with
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* the kernel.
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*
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* This function assumes that struct video_device was zeroed when it
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* was allocated and does not contain any stale date.
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*
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* An error is returned if no free minor or device node number could be
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* found, or if the registration of the device node failed.
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*
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* Returns 0 on success.
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*
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* Valid values for @type are:
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*
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* - %VFL_TYPE_GRABBER - A frame grabber
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* - %VFL_TYPE_VBI - Vertical blank data (undecoded)
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* - %VFL_TYPE_RADIO - A radio card
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* - %VFL_TYPE_SUBDEV - A subdevice
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* - %VFL_TYPE_SDR - Software Defined Radio
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*
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* .. note::
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*
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* This function is meant to be used only inside the V4L2 core.
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* Drivers should use video_register_device() or
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* video_register_device_no_warn().
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*/
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int __must_check __video_register_device(struct video_device *vdev, int type,
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int nr, int warn_if_nr_in_use, struct module *owner);
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/* Register video devices. Note that if video_register_device fails,
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the release() callback of the video_device structure is *not* called, so
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the caller is responsible for freeing any data. Usually that means that
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you call video_device_release() on failure. */
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/**
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* video_register_device - register video4linux devices
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*
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* @vdev: struct video_device to register
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* @type: type of device to register
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* @nr: which device node number is desired:
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* (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
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*
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* Internally, it calls __video_register_device(). Please see its
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* documentation for more details.
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*
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* .. note::
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* if video_register_device fails, the release() callback of
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* &struct video_device structure is *not* called, so the caller
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* is responsible for freeing any data. Usually that means that
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* you video_device_release() should be called on failure.
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*/
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static inline int __must_check video_register_device(struct video_device *vdev,
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int type, int nr)
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{
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return __video_register_device(vdev, type, nr, 1, vdev->fops->owner);
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}
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/* Same as video_register_device, but no warning is issued if the desired
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device node number was already in use. */
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/**
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* video_register_device_no_warn - register video4linux devices
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*
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* @vdev: struct video_device to register
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* @type: type of device to register
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* @nr: which device node number is desired:
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* (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
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*
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* This function is identical to video_register_device() except that no
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* warning is issued if the desired device node number was already in use.
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*
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* Internally, it calls __video_register_device(). Please see its
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* documentation for more details.
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*
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* .. note::
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* if video_register_device fails, the release() callback of
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* &struct video_device structure is *not* called, so the caller
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* is responsible for freeing any data. Usually that means that
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* you video_device_release() should be called on failure.
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*/
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static inline int __must_check video_register_device_no_warn(
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struct video_device *vdev, int type, int nr)
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{
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return __video_register_device(vdev, type, nr, 0, vdev->fops->owner);
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}
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/* Unregister video devices. Will do nothing if vdev == NULL or
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video_is_registered() returns false. */
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/**
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* video_unregister_device - Unregister video devices.
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*
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* @vdev: &struct video_device to register
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*
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* Does nothing if vdev == NULL or if video_is_registered() returns false.
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*/
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void video_unregister_device(struct video_device *vdev);
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/* helper functions to alloc/release struct video_device, the
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latter can also be used for video_device->release(). */
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/**
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* video_device_alloc - helper function to alloc &struct video_device
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*
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* Returns NULL if %-ENOMEM or a &struct video_device on success.
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*/
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struct video_device * __must_check video_device_alloc(void);
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/* this release function frees the vdev pointer */
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/**
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* video_device_release - helper function to release &struct video_device
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*
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* @vdev: pointer to &struct video_device
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*
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* Can also be used for video_device->release().
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*/
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void video_device_release(struct video_device *vdev);
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/* this release function does nothing, use when the video_device is a
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static global struct. Note that having a static video_device is
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a dubious construction at best. */
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/**
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* video_device_release_empty - helper function to implement the
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* video_device->release() callback.
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*
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* @vdev: pointer to &struct video_device
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*
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* This release function does nothing.
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*
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* It should be used when the video_device is a static global struct.
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*
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* .. note::
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* Having a static video_device is a dubious construction at best.
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*/
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void video_device_release_empty(struct video_device *vdev);
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/* returns true if cmd is a known V4L2 ioctl */
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/**
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* v4l2_is_known_ioctl - Checks if a given cmd is a known V4L ioctl
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*
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* @cmd: ioctl command
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*
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* returns true if cmd is a known V4L2 ioctl
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*/
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bool v4l2_is_known_ioctl(unsigned int cmd);
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/* mark that this command shouldn't use core locking */
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static inline void v4l2_disable_ioctl_locking(struct video_device *vdev, unsigned int cmd)
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/** v4l2_disable_ioctl_locking - mark that a given command
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* shouldn't use core locking
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*
|
||||
* @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);
|
||||
|
|
|
|||
Loading…
Reference in New Issue