[PATCH v3 1/2] dt-bindings: display: bridge: tc358867: Document default DP preemphasis

[Marek Vasut]

On 6/26/24 9:29 AM, Alexander Stein wrote:

Hi,

>> +
>>       oneOf:
>>         - required:
>>             - port at 0
>>
> 
> I get this warning:
>> mx8mp-tqma8mpql-mba8mpxl.dtb: bridge at f: ports:port at 2:endpoint: Unevaluated
>> properties are not allowed ('toshiba,pre-emphasis' was unexpected)
> 
> DT node looks like this:
> 
> port at 2 {
> 	reg = <2>;
> 
> 	endpoint {
> 		toshiba,pre-emphasis = /bits/ 8 <1 1>;
> 	};
> };
> 
> I think you are missing this change as well:
> -- 8< --
> --- a/Documentation/devicetree/bindings/display/bridge/toshiba,tc358767.yaml
> +++ b/Documentation/devicetree/bindings/display/bridge/toshiba,tc358767.yaml
> @@ -92,7 +92,8 @@ properties:
>               reference to a valid DPI output or input endpoint node.
>   
>         port at 2:
> -        $ref: /schemas/graph.yaml#/properties/port
> +        $ref: /schemas/graph.yaml#/$defs/port-base
> +        unevaluatedProperties: false
>           description: |
>               eDP/DP output port. The remote endpoint phandle should be a
>               reference to a valid eDP panel input endpoint node. This port is
> -- 8< --

Picked for V4, thank you !

> How would you determine the values to be set here? I suspect it's the value
> from register DP0_SnkLTChReq (0x6d4) after link training. Are they dependent
> on the actual display to be attached?

In my case, I only did trial-and-error, because the test hardware I have 
available right now ... well, it is a test hardware and won't work 
reliably with pre-emphasis 0, so I had to up it a bit.