Re: [PATCH v3 09/10] media: Add media bus codes for MIPI CCS embedded data

[Sakari Ailus <sakari.ailus@linux.intel.com>]

Hi Laurent,

On Tue, Sep 05, 2023 at 08:25:35PM +0300, Laurent Pinchart wrote:
> Hi Sakari,
> 
> Thank you for the patch.
> 
> On Tue, Aug 08, 2023 at 10:55:37AM +0300, Sakari Ailus wrote:
> > Add new MIPI CCS embedded data media bus formats.
> > 
> > Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > ---
> >  .../media/v4l/subdev-formats.rst              | 32 +++++++++++++++++++
> >  include/uapi/linux/media-bus-format.h         | 10 +++++-
> >  2 files changed, 41 insertions(+), 1 deletion(-)
> > 
> > diff --git a/Documentation/userspace-api/media/v4l/subdev-formats.rst b/Documentation/userspace-api/media/v4l/subdev-formats.rst
> > index c615da08502d..5d5407738af9 100644
> > --- a/Documentation/userspace-api/media/v4l/subdev-formats.rst
> > +++ b/Documentation/userspace-api/media/v4l/subdev-formats.rst
> > @@ -8491,3 +8491,35 @@ and finally the bit number in subscript. "p" indicates a padding bit.
> >        - p
> >        - p
> >        - p
> > +
> > +MIPI CCS Embedded Data Formats
> > +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> > +
> > +`MIPI CCS <https://www.mipi.org/specifications/camera-command-set>`_ defines an
> 
> s/an$/a/

Yes. I think I had "embedded" there in the past...

> 
> > +metadata format for sensor embedded data, which is used to store the register
> > +configuration used for capturing a given frame. The format is defined in the CCS
> > +specification.
> 
> Strictly speaking, the MIPI CCS embedded data format specifies not just
> the data packing (insertion of padding bytes) and the data encoding (the
> data format byte and the tag codes), but also the register addresses and
> values that are reported in the embedded data. Do you envision the media
> bus formats defined here as being applicable to sensors that use the
> same packing and encoding as CCS, but different registers, or only to
> fully compliant CCS sensors ?

There are sensors that aren't fully compatible with CCS (including those
compatible with SMIA and SMIA++) but I wouldn't expect the format to be
used by devices that are entirely incompatible with CCS.

-- 
Regards,

Sakari Ailus