Re: [RFC PATCH 0/3] media: qcom: camss: support for empty endpoint nodes

[Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>]

On 12/30/25 04:27, Richard Acayan wrote:
> This series adds support for empty endpoint nodes. It is currently RFC
> because it continues an ongoing discussion on how to selectively connect
> some CAMSS ports to cameras and leave others disconnected.
> 
> The SDM670 patches are for a full example. If agreed on, this should
> expand to SoCs that have CAMSS.
> 
> Example SoC dtsi:
> 
> 	camss: isp@00000000 {
> 		...
> 
> 		status = "disabled";
> 
> 		ports {
> 			#address-cells = <1>;
> 			#size-cells = <0>;
> 
> 			port@0 {
> 				reg = <0>;
> 
> 				camss_endpoint0: endpoint {
> 				};
> 			};

I do not see this device tree node layout as a valid one. A 'port' provides
an interface description (an option), and an 'endpoint' declares a connection
over a port (the accepted option).

 From dtschema/schemas/graph.yaml:

     Each port node contains an 'endpoint' subnode for each remote device port
     connected to this port.

This is violated in the example given by you above, when a remote device along
with its ports is just missing, thus there is no connection. A forced alternative
reading may (or will) break the legacy, so in this particular case you shall
start from making a change to the shared graph.yaml documentation, since it's
all not about CAMSS or even linux-media specifics.

-- 
Best wishes,
Vladimir