[PATCH v2 2/5] dt-bindings: arm: amlogic: Add support for GXL S905W and the P281 board

[narmstrong@baylibre.com (Neil Armstrong)]

Hi Martin,

On 14/07/2018 21:37, Martin Blumenstingl wrote:
> S905W SoC is another SoC from the GXL family. It is a cost-reduced
> version of the S905X SoC. The following differences are known:
> - S905W supports HDMI resolutions up to 4k at 30fps (while S905X support
>   resolutions up to 4k at 60fps)
> - the built-in video decoders of S905W decode up to 4k at 30fps (while
>   S905X supports decoding up to 4k at 60fps)
> - CPU speed on S905W is limited to 1.2GHz (compared to 1.5GHz on S905X,
>   this is handled in the SCPI firmware)
> - the DRAM interface on S905W is limited to 16-bit (GXL supports both,
>   16-bit and 32-bit)
> 
> Notes based on Amlogic's GPL kernel sources:
> - the P281 is a development board from Amlogic which uses the S905W SoC.
>   Amlogic's GPL kernel sources indicate that it uses the same PCB layout
>   as the "P231" board (and simply replaces the S905D from the original
>   P231 board with a S905W SoC).
> - it is assumed that the S905W SoC is pin-compatible with the S905X SoC
>   since Amlogic's GPL kernel sources use the same driver for both SoCs.
> - gxl_p281_1g.dts contains a comment which mentions that "max gp pll for
>   gpu is 650M, temporarily disabled". However, it seems to boot fine
>   with 744MHz (as used on GXBB and the other GXL SoCs).
> 
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> Reviewed-by: Rob Herring <robh@kernel.org>
> ---
>  Documentation/devicetree/bindings/arm/amlogic.txt | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/arm/amlogic.txt b/Documentation/devicetree/bindings/arm/amlogic.txt
> index 849834cb1766..8178da8742c3 100644
> --- a/Documentation/devicetree/bindings/arm/amlogic.txt
> +++ b/Documentation/devicetree/bindings/arm/amlogic.txt
> @@ -45,6 +45,10 @@ Boards with the Amlogic Meson GXL S805X SoC shall have the following properties:
>    Required root node property:
>      compatible: "amlogic,s805x", "amlogic,meson-gxl";
>  
> +Boards with the Amlogic Meson GXL S905W SoC shall have the following properties:
> +  Required root node property:
> +    compatible: "amlogic,s905w", "amlogic,meson-gxl";
> +
>  Boards with the Amlogic Meson GXM S912 SoC shall have the following properties:
>    Required root node property:
>      compatible: "amlogic,s912", "amlogic,meson-gxm";
> @@ -85,6 +89,8 @@ Board compatible values (alphabetically, grouped by SoC):
>  
>    - "amlogic,p241" (Meson gxl s805x)
>  
> +  - "amlogic,p281" (Meson gxl s905w)
> +
>    - "amlogic,q200" (Meson gxm s912)
>    - "amlogic,q201" (Meson gxm s912)
>    - "khadas,vim2" (Meson gxm s912)
> 

Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>