Re: [PATCH 1/7] dt-bindings: display/msm/dsi: allow specifying TE source

[Abhinav Kumar <quic_abhinavk@quicinc.com>]

On 5/20/2024 5:12 AM, Dmitry Baryshkov wrote:
> Command mode panels provide TE signal back to the DSI host to signal
> that the frame display has completed and update of the image will not
> cause tearing. Usually it is connected to the first GPIO with the
> mdp_vsync function, which is the default. In such case the property can
> be skipped.
> 

This is a good addition overall. Some comments below.

> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> ---
>   .../bindings/display/msm/dsi-controller-main.yaml        | 16 ++++++++++++++++
>   1 file changed, 16 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/display/msm/dsi-controller-main.yaml b/Documentation/devicetree/bindings/display/msm/dsi-controller-main.yaml
> index 1fa28e976559..c1771c69b247 100644
> --- a/Documentation/devicetree/bindings/display/msm/dsi-controller-main.yaml
> +++ b/Documentation/devicetree/bindings/display/msm/dsi-controller-main.yaml
> @@ -162,6 +162,21 @@ properties:
>                   items:
>                     enum: [ 0, 1, 2, 3 ]
>   
> +              qcom,te-source:
> +                $ref: /schemas/types.yaml#/definitions/string
> +                description:
> +                  Specifies the source of vsync signal from the panel used for
> +                  tearing elimination. The default is mdp_gpio0.

panel --> command mode panel?

> +                enum:
> +                  - mdp_gpio0
> +                  - mdp_gpio1
> +                  - mdp_gpio2

are gpio0, gpio1 and gpio2 referring to the vsync_p, vsync_s and vsync_e 
sources?

In that case wouldnt it be better to name it like that?

> +                  - timer0
> +                  - timer1
> +                  - timer2
> +                  - timer3
> +                  - timer4
> +

These are indicating watchdog timer sources right?

>       required:
>         - port@0
>         - port@1
> @@ -452,6 +467,7 @@ examples:
>                             dsi0_out: endpoint {
>                                      remote-endpoint = <&sn65dsi86_in>;
>                                      data-lanes = <0 1 2 3>;
> +                                   qcom,te-source = "mdp_gpio2";

I have a basic doubt on this. Should te-source should be in the input 
port or the output one for the controller? Because TE is an input to the 
DSI. And if the source is watchdog timer then it aligns even more as a 
property of the input endpoint.

>                             };
>                     };
>              };
>