[media] v4l: Add timestamp source flags, mask and document them

Some devices do not produce timestamps that correspond to the end of the
frame. The user space should be informed on the matter. This patch achieves
that by adding buffer flags (and a mask) for timestamp sources since more
possible timestamping points are expected than just two.

A three-bit mask is defined (V4L2_BUF_FLAG_TSTAMP_SRC_MASK) and two of the
eight possible values is are defined V4L2_BUF_FLAG_TSTAMP_SRC_EOF for end of
frame (value zero) V4L2_BUF_FLAG_TSTAMP_SRC_SOE for start of exposure (next
value).

Signed-off-by: Sakari Ailus <[email protected]>
Acked-by: Kamil Debski <[email protected]>
Acked-by: Hans Verkuil <[email protected]>
Signed-off-by: Mauro Carvalho Chehab <[email protected]>
This commit is contained in:
Sakari Ailus 2013-08-25 17:57:03 -03:00 • committed by Mauro Carvalho Chehab
commit 872484ce40
4 changed files with 39 additions and 7 deletions

View file

@ -312,6 +312,8 @@ struct v4l2_fh;
* @buf_struct_size: size of the driver-specific buffer structure;
* "0" indicates the driver doesn't want to use a custom buffer
* structure type, so sizeof(struct vb2_buffer) will is used
* @timestamp_flags: Timestamp flags; V4L2_BUF_FLAGS_TIMESTAMP_* and
* V4L2_BUF_FLAGS_TSTAMP_SRC_*
* @gfp_flags: additional gfp flags used when allocating the buffers.
* Typically this is 0, but it may be e.g. GFP_DMA or __GFP_DMA32
* to force the buffer allocation to a specific memory zone.