From 8227c92b69688403dee2adf5f399a49539ae5049 Mon Sep 17 00:00:00 2001 From: Sakari Ailus Date: Mon, 10 Oct 2011 17:01:25 -0300 Subject: [media] v4l: Implement v4l2_subdev_link_validate() v4l2_subdev_link_validate() is the default op for validating a link. In V4L2 subdev context, it is used to call a pad op which performs the proper link check without much extra work. Signed-off-by: Sakari Ailus Acked-by: Laurent Pinchart Signed-off-by: Mauro Carvalho Chehab --- Documentation/video4linux/v4l2-framework.txt | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'Documentation') diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt index 493ffd1b1cf5..fe53177f0d3c 100644 --- a/Documentation/video4linux/v4l2-framework.txt +++ b/Documentation/video4linux/v4l2-framework.txt @@ -316,6 +316,18 @@ If the subdev driver intends to process video and integrate with the media framework, it must implement format related functionality using v4l2_subdev_pad_ops instead of v4l2_subdev_video_ops. +In that case, the subdev driver may set the link_validate field to provide +its own link validation function. The link validation function is called for +every link in the pipeline where both of the ends of the links are V4L2 +sub-devices. The driver is still responsible for validating the correctness +of the format configuration between sub-devices and video nodes. + +If link_validate op is not set, the default function +v4l2_subdev_link_validate_default() is used instead. This function ensures +that width, height and the media bus pixel code are equal on both source and +sink of the link. Subdev drivers are also free to use this function to +perform the checks mentioned above in addition to their own checks. + A device (bridge) driver needs to register the v4l2_subdev with the v4l2_device: -- cgit v1.2.3