Hi Sylwester,
On Fri, Feb 17, 2012 at 03:26:29PM +0100, Sylwester Nawrocki wrote:
> On 02/16/2012 08:46 PM, Sakari Ailus wrote:
> > On Thu, Feb 16, 2012 at 07:23:54PM +0100, Sylwester Nawrocki wrote:
> >> This patch adds media bus pixel code for the interleaved JPEG/YUYV image
> >> format used by S5C73MX Samsung cameras. The interleaved image data is
> >> transferred on MIPI-CSI2 bus as User Defined Byte-based Data.
> >>
> >> Signed-off-by: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
> >> Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> >> ---
> >> include/linux/v4l2-mediabus.h | 3 +++
> >> 1 files changed, 3 insertions(+), 0 deletions(-)
> >>
> >> diff --git a/include/linux/v4l2-mediabus.h b/include/linux/v4l2-mediabus.h
> >> index 5ea7f75..c2f0e4e 100644
> >> --- a/include/linux/v4l2-mediabus.h
> >> +++ b/include/linux/v4l2-mediabus.h
> >> @@ -92,6 +92,9 @@ enum v4l2_mbus_pixelcode {
> >>
> >> /* JPEG compressed formats - next is 0x4002 */
> >> V4L2_MBUS_FMT_JPEG_1X8 = 0x4001,
> >> +
> >> + /* Interleaved JPEG and YUV formats - next is 0x4102 */
> >> + V4L2_MBUS_FMT_VYUY_JPEG_I1_1X8 = 0x4101,
> >> };
> >
> > Thanks for the patch. Just a tiny comment:
> >
> > I'd go with a new hardware-specific buffer range, e.g. 0x5000.
>
> Sure, that makes more sense. But I guess you mean "format" not "buffer" range ?
Yeah, a format that begins a new range.
> > Guennadi also proposed an interesting idea: a "pass-through" format. Does
> > your format have dimensions that the driver would use for something or is
> > that just a blob?
>
> It's just a blob for the drivers, dimensions may be needed for subdevs to
> compute overall size of data for example. But the host driver, in case of
> Samsung devices, basically just needs to know the total size of frame data.
>
> I'm afraid the host would have to additionally configure subdevs in the data
> pipeline in case of hardware-specific format, when we have used a single
> binary blob media bus format identifier. For example MIPI-CSI2 data format
> would have to be set up along the pipeline. There might be more attributes
> in the future like this. Not sure if we want to go that path ?
>
> I'll try and see how it would look like with a single "pass-through" format.
> Probably using g/s_mbus_config operations ?
I think we could use the framesize control to tell the size of the frame, or
however it is done for jpeg blobs.
The issue I see in the pass-through mode is that the user would have no
information whatsoever what he's getting. This would be perhaps fixed by
adding the frame format descriptor: it could contain information how to
handle the data. (Just thinking out loud. :))
I'm fine keeping this approach with sensor specific pixel code for now at
least, but we must mark it experimental IMHO.
Kind regards,
--
Sakari Ailus
e-mail: sakari.ailus@xxxxxx jabber/XMPP/Gmail: sailus@xxxxxxxxxxxxxx
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