linux-kernel - Re: [PATCH v2 1/2] dt-bindings: display: ti,am65x-dss: Add support for AM62L DSS

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Message-ID: <eb8883f2-fc34-44f5-90a9-f4b14f0c45f2@ideasonboard.com>
Date: Tue, 4 Feb 2025 15:55:47 +0200
From: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
To: Devarsh Thakkar <devarsht@...com>
Cc: praneeth@...com, vigneshr@...com, aradhya.bhatia@...ux.dev,
 s-jain1@...com, r-donadkar@...com, j-choudhary@...com, h-shenoy@...com,
 jyri.sarha@....fi, airlied@...il.com, maarten.lankhorst@...ux.intel.com,
 mripard@...nel.org, tzimmermann@...e.de, dri-devel@...ts.freedesktop.org,
 simona@...ll.ch, linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
 robh@...nel.org, krzk+dt@...nel.org, conor+dt@...nel.org
Subject: Re: [PATCH v2 1/2] dt-bindings: display: ti,am65x-dss: Add support
 for AM62L DSS

Hi,

On 04/02/2025 08:15, Devarsh Thakkar wrote:
> The DSS controller on TI's AM62L SoC is an update from that on TI's
> AM625/AM65x/AM62A7 SoC. The AM62L DSS [1] only supports a single display
> pipeline using a single overlay manager, single video port and a single
> video lite pipeline which does not support scaling.
> 
> The output of video port is routed to SoC boundary via DPI interface and
> the DPI signals from the video port are also routed to DSI Tx controller
> present within the SoC.
> 
> [1]: Section 11.7 (Display Subsystem and Peripherals)
> Link : https://www.ti.com/lit/pdf/sprujb4
> 
> Reviewed-by: Krzysztof Kozlowski <krzk@...nel.org>
> Reviewed-by: Jayesh Choudhary <j-choudhary@...com>
> Signed-off-by: Devarsh Thakkar <devarsht@...com>
> ---
> - Add Reviewed-by
> - s/ti,am62l,dss/ti,am62l-dss
> 
> NOTE: This patch needs to be applied on top of AM62A dt-binding fix:
> https://lore.kernel.org/all/20250203155431.2174170-1-devarsht@ti.com/
> 
>   .../bindings/display/ti/ti,am65x-dss.yaml     | 25 ++++++++++++++++++-
>   1 file changed, 24 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/display/ti/ti,am65x-dss.yaml b/Documentation/devicetree/bindings/display/ti/ti,am65x-dss.yaml
> index 31c4ffcb599c..f82e9a84e8a8 100644
> --- a/Documentation/devicetree/bindings/display/ti/ti,am65x-dss.yaml
> +++ b/Documentation/devicetree/bindings/display/ti/ti,am65x-dss.yaml
> @@ -12,18 +12,29 @@ maintainers:
>     - Tomi Valkeinen <tomi.valkeinen@...com>
>   
>   description: |
> -  The AM625 and AM65x TI Keystone Display SubSystem with two output
> +  The AM625 and AM65x TI Keystone Display SubSystem has two output
>     ports and two video planes. In AM65x DSS, the first video port
>     supports 1 OLDI TX and in AM625 DSS, the first video port output is
>     internally routed to 2 OLDI TXes. The second video port supports DPI
>     format. The first plane is full video plane with all features and the
>     second is a "lite plane" without scaling support.
> +  The AM62A7 display subsystem has a single output port supporting DPI format
> +  although similar to AM625 and AM65x Socs, it has two video planes where first
> +  is full video plane with all features and second is a video "lite" plane which
> +  does not support scaling.

The part above doesn't belong into "add AM62L" patch. It's also quite 
confusing. "although similar to..."? Maybe drop the text "although 
similar to AM625 and AM65x Socs, ", and start a new sentence from "it"?

For the AM62L parts:

Reviewed-by: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>

  Tomi

> +  The AM62L display subsystem also has a single output port which supports DPI
> +  format but it only supports single video "lite plane" which does not support
> +  scaling. The output port is routed to SoC boundary via DPI interface and same
> +  DPI signals are also routed internally to DSI Tx controller present within the
> +  SoC. Due to clocking limitations only one of the interface i.e. either DSI or
> +  DPI can be used at once.
>   
>   properties:
>     compatible:
>       enum:
>         - ti,am625-dss
>         - ti,am62a7-dss
> +      - ti,am62l-dss
>         - ti,am65x-dss
>   
>     reg:
> @@ -91,6 +102,8 @@ properties:
>             For AM625 DSS, the internal DPI output port node from video
>             port 1.
>             For AM62A7 DSS, the port is tied off inside the SoC.
> +          For AM62L DSS, the DSS DPI output port node from video port 1
> +          or DSI Tx controller node connected to video port 1.
>   
>         port@1:
>           $ref: /schemas/graph.yaml#/properties/port
> @@ -123,6 +136,16 @@ allOf:
>           ports:
>             properties:
>               port@0: false
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: ti,am62l-dss
> +    then:
> +      properties:
> +        ports:
> +          properties:
> +            port@1: false
>   
>   required:
>     - compatible