Re: [PATCH v3 04/10] dt-bindings: media: snps,dw-hdmi-rx: add a port for a bridge in front

[Dmitry Osipenko <dmitry.osipenko@collabora.com>]

On 10/5/26 16:28, Sascha Hauer wrote:
> Describe the OF graph port connecting the receiver to an HDMI bridge in
> front of it. The schema sets additionalProperties: false, so without
> this a device tree carrying the endpoint does not validate at all.
> 
> hpd-gpios is the +5V line of the HDMI connector, which the source drives
> to announce itself. On a board whose HDMI connector belongs to such a
> bridge, that line goes to the bridge and there is nothing for the
> receiver to sense, so the property cannot be provided. The name is
> unfortunate: the hot plug detect line the receiver drives back at the
> source is a controller register, not this GPIO. Describe what it
> actually carries.
> 
> A board has either the connector wired to the receiver or a bridge in
> front of it, so require exactly one of hpd-gpios and port.
> 
> Assisted-by: LLM
> Acked-by: Conor Dooley <conor.dooley@microchip.com>
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>   .../devicetree/bindings/media/snps,dw-hdmi-rx.yaml  | 21 +++++++++++++++++++--
>   1 file changed, 19 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/media/snps,dw-hdmi-rx.yaml b/Documentation/devicetree/bindings/media/snps,dw-hdmi-rx.yaml
> index b7f6c87d0e06a..896f8ffbb5bf9 100644
> --- a/Documentation/devicetree/bindings/media/snps,dw-hdmi-rx.yaml
> +++ b/Documentation/devicetree/bindings/media/snps,dw-hdmi-rx.yaml
> @@ -63,9 +63,21 @@ properties:
>       maxItems: 1
>   
>     hpd-gpios:
> -    description: GPIO specifier for HPD.
> +    description:
> +      The +5V line of the HDMI connector, which the source drives to announce
> +      itself. Despite the name this is an input to the receiver; the hot plug
> +      detect line the receiver drives back at the source is handled inside the
> +      controller. Absent when the connector belongs to a bridge in front of
> +      this receiver rather than to the receiver itself.
>       maxItems: 1
>   
> +  port:
> +    $ref: /schemas/graph.yaml#/properties/port
> +    description:
> +      Connection to the HDMI source. Present when an HDMI bridge sits in
> +      front of this receiver instead of the connector being wired straight
> +      to it.
> +
>     rockchip,grf:
>       $ref: /schemas/types.yaml#/definitions/phandle
>       description:
> @@ -88,7 +100,12 @@ required:
>     - power-domains
>     - resets
>     - pinctrl-0
> -  - hpd-gpios
> +
> +oneOf:
> +  - required:
> +      - hpd-gpios
> +  - required:
> +      - port
>   
>   additionalProperties: false
>   
> 

Acked-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>

-- 
Best regards,
Dmitry