From 2096a5dcf9704f5a86ecba37169eb813aaf0431c Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Wed, 9 Dec 2009 08:38:49 -0300 Subject: [media] v4l: subdev: Add device node support Create a device node named subdevX for every registered subdev. As the device node is registered before the subdev core::s_config function is called, return -EGAIN on open until initialization completes. Signed-off-by: Laurent Pinchart Signed-off-by: Vimarsh Zutshi Acked-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- Documentation/video4linux/v4l2-framework.txt | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'Documentation/video4linux') diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt index f22f35c271f..8b358710b2f 100644 --- a/Documentation/video4linux/v4l2-framework.txt +++ b/Documentation/video4linux/v4l2-framework.txt @@ -319,6 +319,22 @@ controlled through GPIO pins. This distinction is only relevant when setting up the device, but once the subdev is registered it is completely transparent. +V4L2 sub-device userspace API +----------------------------- + +Beside exposing a kernel API through the v4l2_subdev_ops structure, V4L2 +sub-devices can also be controlled directly by userspace applications. + +Device nodes named v4l-subdevX can be created in /dev to access sub-devices +directly. If a sub-device supports direct userspace configuration it must set +the V4L2_SUBDEV_FL_HAS_DEVNODE flag before being registered. + +After registering sub-devices, the v4l2_device driver can create device nodes +for all registered sub-devices marked with V4L2_SUBDEV_FL_HAS_DEVNODE by calling +v4l2_device_register_subdev_nodes(). Those device nodes will be automatically +removed when sub-devices are unregistered. + + I2C sub-device drivers ---------------------- -- cgit v1.2.3-18-g5258