Hi Sylwester and Vincent,
My apologies for the late reply on this topic. I've been quite busy lately.
Sylwester Nawrocki wrote:
On 10/09/2012 03:36 PM, Vincent ABRIOU wrote:
Hi Sylwester,
I'm wondering why don't you simply define V4L2_MBUS_FMT_UYVY_JPEG_1X8
without any reference to your camera?
Because it's not a plain UYVY/JPEG data. There is an additional meta-data
that follows interleaved UYVY/JPEG. It's all on a single User Defined
MIPI CSI-2 DT. In addition to that there is some more meta data transmitted
on MIPI CSI-2 Embedded Data DT. If there was no meta-data present at the
User Defined DT, then we could think about using generic
V4L2_MBUS_FMT_UYVY_JPEG_1X8 pixel code and handling the meta-data on
separate DT with the frame_desc calls.
Anyway this S5C media bus format is an experimental thing and if there are
cameras generating plain JPEG/YUV we need to search for better, more generic
solution.
Vincent: what's the frame layout that your sensor produces? There are two
cases that could be easy (sort of, everything's relative) that I can see for
the standard interfaces.
1. Different parts of the image are transmitted over different CSI-2
contexts. This way the receiver may separate them to separate memory
regions, and the end result is a single multi-plane buffer.
2. If the distance in octets of the intermittent image strides is constant,
then we could do some tricks with multi-plane buffers. The two planes of the
buffer could be interleaved, with correct base addresses.
I think Sylwester's case fits into neither of the above. A device-specific
format does not resolve configuring the two formats.
Both require adding plane-specific pixel codes, agreement over how frame
descriptors are used for describing frames of multiple independent content
planes, and how the multiple formats are configured on the sensor. Use of
sub-subdevs come to mind for the last one as an alternative --- this issue
stems from the fact we're using the same interface to model the bus and the
image format on that bus. It no longer works out the way it used to when
there are two formats on the same bus.
Each of these probably require a separate RFC and someone to implement the
changes.
Kind regards,
--
Sakari Ailus
sakari.ailus@xxxxxx
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