[media] Add vfl_dir field documentation
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt
index e7006ca..32bfe92 100644
--- a/Documentation/video4linux/v4l2-framework.txt
+++ b/Documentation/video4linux/v4l2-framework.txt
@@ -583,11 +583,19 @@
- name: set to something descriptive and unique.
+- vfl_dir: set this to VFL_DIR_RX for capture devices (VFL_DIR_RX has value 0,
+ so this is normally already the default), set to VFL_DIR_TX for output
+ devices and VFL_DIR_M2M for mem2mem (codec) devices.
+
- fops: set to the v4l2_file_operations struct.
- ioctl_ops: if you use the v4l2_ioctl_ops to simplify ioctl maintenance
(highly recommended to use this and it might become compulsory in the
- future!), then set this to your v4l2_ioctl_ops struct.
+ future!), then set this to your v4l2_ioctl_ops struct. The vfl_type and
+ vfl_dir fields are used to disable ops that do not match the type/dir
+ combination. E.g. VBI ops are disabled for non-VBI nodes, and output ops
+ are disabled for a capture device. This makes it possible to provide
+ just one v4l2_ioctl_ops struct for both vbi and video nodes.
- lock: leave to NULL if you want to do all the locking in the driver.
Otherwise you give it a pointer to a struct mutex_lock and before the