Re: [PATCH 6/8] dt-bindings: media: nxp,imx-mipi-csi2: Add fsl,num-channels property

[Adam Ford <aford173@gmail.com>]

On Mon, Jun 9, 2025 at 10:32 AM Frank Li <Frank.li@nxp.com> wrote:
>
> On Mon, Jun 09, 2025 at 02:58:38AM +0300, Laurent Pinchart wrote:
> > The CSI-2 receiver can be instantiated with up to four output channels.
> > This is an integration-specific property, specify the number of
> > instantiated channels through a new fsl,num-channels property. The
> > property is optional, and defaults to 1 as only one channel is currently
> > supported by drivers.
> >
> > The only known SoC to have more than one channel is the i.MX8MP. As the
> > binding examples do not cover that SoC, don't update them.
> >
> > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > ---
> >  .../devicetree/bindings/media/nxp,imx-mipi-csi2.yaml       | 7 +++++++
> >  1 file changed, 7 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/media/nxp,imx-mipi-csi2.yaml b/Documentation/devicetree/bindings/media/nxp,imx-mipi-csi2.yaml
> > index db4889bf881e..41ad5b84eaeb 100644
> > --- a/Documentation/devicetree/bindings/media/nxp,imx-mipi-csi2.yaml
> > +++ b/Documentation/devicetree/bindings/media/nxp,imx-mipi-csi2.yaml
> > @@ -68,6 +68,13 @@ properties:
> >      default: 166000000
> >      deprecated: true
> >
> > +  fsl,num-channels:
> > +    $ref: /schemas/types.yaml#/definitions/uint32
> > +    description: Number of output channels
> > +    minimum: 1
> > +    maximum: 4
> > +    default: 1
> > +
>
> Look like it is fixed value for each compabiable string, So it is not
> suitable for adding new property. It should be in driver data of each
> compatible strings.
>
> I met similar case before. DT team generally don't agree on add such
> property, unless there are two instances in the same chip, which have
> difference channel number.

If the DT changes are rejected, can the number of channels be added to
the data structure inside mipi_csis_of_match?  We have compatibles for
8mm and imx7.  If we add an imx8mp compatible we could add a reference
to the number of channels.

adam
>
> Frank
>
> >    ports:
> >      $ref: /schemas/graph.yaml#/properties/ports
> >
> > --
> > Regards,
> >
> > Laurent Pinchart
> >
>