diff options
Diffstat (limited to 'Documentation/video4linux/v4l2-framework.txt')
| -rw-r--r-- | Documentation/video4linux/v4l2-framework.txt | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt index 89318be6c1d2..32bfe926e8d7 100644 --- a/Documentation/video4linux/v4l2-framework.txt +++ b/Documentation/video4linux/v4l2-framework.txt @@ -583,11 +583,19 @@ You should also set these fields: - 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 @@ -1054,4 +1062,4 @@ The first event type in the class is reserved for future use, so the first available event type is 'class base + 1'. An example on how the V4L2 events may be used can be found in the OMAP -3 ISP driver (drivers/media/video/omap3isp). +3 ISP driver (drivers/media/platform/omap3isp). |