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-rw-r--r--Documentation/media/kapi/v4l2-framework.rst133
1 files changed, 0 insertions, 133 deletions
diff --git a/Documentation/media/kapi/v4l2-framework.rst b/Documentation/media/kapi/v4l2-framework.rst
index d46380ac7c1d..8b4f684e1a7a 100644
--- a/Documentation/media/kapi/v4l2-framework.rst
+++ b/Documentation/media/kapi/v4l2-framework.rst
@@ -80,139 +80,6 @@ The V4L2 framework also optionally integrates with the media framework. If a
driver sets the struct v4l2_device mdev field, sub-devices and video nodes
will automatically appear in the media framework as entities.
-struct v4l2_fh
---------------
-
-struct v4l2_fh provides a way to easily keep file handle specific data
-that is used by the V4L2 framework. New drivers must use struct v4l2_fh
-since it is also used to implement priority handling (VIDIOC_G/S_PRIORITY).
-
-The users of v4l2_fh (in the V4L2 framework, not the driver) know
-whether a driver uses v4l2_fh as its file->private_data pointer by
-testing the V4L2_FL_USES_V4L2_FH bit in video_device->flags. This bit is
-set whenever v4l2_fh_init() is called.
-
-struct v4l2_fh is allocated as a part of the driver's own file handle
-structure and file->private_data is set to it in the driver's open
-function by the driver.
-
-In many cases the struct v4l2_fh will be embedded in a larger structure.
-In that case you should call v4l2_fh_init+v4l2_fh_add in open() and
-v4l2_fh_del+v4l2_fh_exit in release().
-
-Drivers can extract their own file handle structure by using the container_of
-macro. Example:
-
-.. code-block:: none
-
- struct my_fh {
- int blah;
- struct v4l2_fh fh;
- };
-
- ...
-
- int my_open(struct file *file)
- {
- struct my_fh *my_fh;
- struct video_device *vfd;
- int ret;
-
- ...
-
- my_fh = kzalloc(sizeof(*my_fh), GFP_KERNEL);
-
- ...
-
- v4l2_fh_init(&my_fh->fh, vfd);
-
- ...
-
- file->private_data = &my_fh->fh;
- v4l2_fh_add(&my_fh->fh);
- return 0;
- }
-
- int my_release(struct file *file)
- {
- struct v4l2_fh *fh = file->private_data;
- struct my_fh *my_fh = container_of(fh, struct my_fh, fh);
-
- ...
- v4l2_fh_del(&my_fh->fh);
- v4l2_fh_exit(&my_fh->fh);
- kfree(my_fh);
- return 0;
- }
-
-Below is a short description of the v4l2_fh functions used:
-
-.. code-block:: none
-
- void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev)
-
- Initialise the file handle. This *MUST* be performed in the driver's
- v4l2_file_operations->open() handler.
-
-.. code-block:: none
-
- void v4l2_fh_add(struct v4l2_fh *fh)
-
- Add a v4l2_fh to video_device file handle list. Must be called once the
- file handle is completely initialized.
-
-.. code-block:: none
-
- void v4l2_fh_del(struct v4l2_fh *fh)
-
- Unassociate the file handle from video_device(). The file handle
- exit function may now be called.
-
-.. code-block:: none
-
- void v4l2_fh_exit(struct v4l2_fh *fh)
-
- Uninitialise the file handle. After uninitialisation the v4l2_fh
- memory can be freed.
-
-
-If struct v4l2_fh is not embedded, then you can use these helper functions:
-
-.. code-block:: none
-
- int v4l2_fh_open(struct file *filp)
-
- This allocates a struct v4l2_fh, initializes it and adds it to the struct
- video_device associated with the file struct.
-
-.. code-block:: none
-
- int v4l2_fh_release(struct file *filp)
-
- This deletes it from the struct video_device associated with the file
- struct, uninitialised the v4l2_fh and frees it.
-
-These two functions can be plugged into the v4l2_file_operation's open() and
-release() ops.
-
-
-Several drivers need to do something when the first file handle is opened and
-when the last file handle closes. Two helper functions were added to check
-whether the v4l2_fh struct is the only open filehandle of the associated
-device node:
-
-.. code-block:: none
-
- int v4l2_fh_is_singular(struct v4l2_fh *fh)
-
- Returns 1 if the file handle is the only open file handle, else 0.
-
-.. code-block:: none
-
- int v4l2_fh_is_singular_file(struct file *filp)
-
- Same, but it calls v4l2_fh_is_singular with filp->private_data.
-
V4L2 clocks
-----------