Re: [PATCH v8 30/38] media: Documentation: ccs: Document routing

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

Hi Laurent,

On Thu, Mar 21, 2024 at 07:43:06PM +0200, Laurent Pinchart wrote:
> Hi Sakari,
> 
> Thank you for the patch.

Thank you for the review!

> 
> On Wed, Mar 13, 2024 at 09:25:08AM +0200, Sakari Ailus wrote:
> > Document which routes are available for the CCS driver (source) sub-device
> > and what configuration are possible.
> > 
> > Also update copyright.
> > 
> > Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > ---
> >  .../userspace-api/media/drivers/ccs.rst       | 34 ++++++++++++++++++-
> >  .../media/v4l/subdev-formats.rst              |  2 ++
> >  2 files changed, 35 insertions(+), 1 deletion(-)
> > 
> > diff --git a/Documentation/userspace-api/media/drivers/ccs.rst b/Documentation/userspace-api/media/drivers/ccs.rst
> > index 03015b33d5ab..bc2804ec663b 100644
> > --- a/Documentation/userspace-api/media/drivers/ccs.rst
> > +++ b/Documentation/userspace-api/media/drivers/ccs.rst
> > @@ -111,4 +111,36 @@ than in the centre.
> >  Shading correction needs to be enabled for luminance correction level to have an
> >  effect.
> >  
> > -**Copyright** |copy| 2020 Intel Corporation
> > +.. _media-ccs-routes:
> > +
> > +Routes
> > +------
> > +
> > +The CCS driver implements one or two :ref:`routes <subdev-routing>` in
> > +its source sub-device (scaler sub-device if exists for the device, otherwise
> > +binner) depending on whether the sensor supports embedded data. (All CCS
> > +compliant sensors do but the CCS driver supports preceding standards that did
> > +not require embedded data support, too.)
> 
> s/too.)/too).

Hmm. The entire sentence is in parentheses. Why should the period not be?

> 
> > +
> > +The first route of the CCS source sub-device is for pixel data (internal pad
> > +1/stream 0 -> pad 0/stream 0) and the second one is for embedded data (internal
> 
> I thought the source subdev had one external sink pad for image data,
> one internal sink pad for embedded data, and one source pad.

Hmm. I guess I was thinking of IMX219 when writing this. ;)

The text should have been:

The first route of the CCS source sub-device is for pixel data (sink pad
0/stream 0 -> source pad 1/stream 0) and the second one is for embedded data
(internal sink pad 2/stream 0 -> source pad 1/stream 1).


> 
> > +pad 2/stream 0 -> pad 0/stream 1).
> > +
> > +Embedded data
> > +~~~~~~~~~~~~~
> > +
> > +MIPI CCS supports generation of camera sensor embedded data. The media bus code
> > +used for this format is :ref:`MEDIA_BUS_FMT_CCS_EMBEDDDED
> > +<MEDIA-BUS-FMT-CCS-EMBEDDED>`.
> 
> Maybe state that this is the format on the internal ED sink pad.

Yes.

> 
> > +
> > +The bit depth of the CCS pixel data affects how the sensor will output the
> > +embedded data, adding padding to align with CSI-2 bus :ref:`Data units
> > +<media-glossary-data-unit>` for that particular bit depth. This is indicated by
> > +the generic metadata format on the sensor's source sub-device's source pad.
> > +
> > +Embedded data for bit depths greater than or equal to 16 may support more dense
> > +packing or legacy single metadata byte per data unit, or both of these,
> > +depending on the device. The supported embedded data formats can be enumerated
> > +and configured on stream 1 of the source pad (1) of the CCS source sub-device.
> > +
> > +**Copyright** |copy| 2020, 2023 Intel Corporation
> 
> 2024 ?

Indeed.

> 
> > diff --git a/Documentation/userspace-api/media/v4l/subdev-formats.rst b/Documentation/userspace-api/media/v4l/subdev-formats.rst
> > index c8f982411e70..ca4da6a400ff 100644
> > --- a/Documentation/userspace-api/media/v4l/subdev-formats.rst
> > +++ b/Documentation/userspace-api/media/v4l/subdev-formats.rst
> > @@ -8592,3 +8592,5 @@ levels above.
> >  This mbus code are only used for "2-byte simplified tagged data format" (code
> >  0xa) but their use may be extended further in the future, to cover other CCS
> >  embedded data format codes.
> > +
> > +Also see :ref:`CCS driver documentation <media-ccs-routes>`.
> 

-- 
Kind regards,

Sakari Ailus