Re: [PATCH v2 2/9] dt-bindings: dma: nvidia,tegra186-gpc-dma: Make reset optional

[Frank Li]

On Mon, Mar 02, 2026 at 06:02:32PM +0530, Akhil R wrote:
> In Tegra264, GPCDMA reset control is not exposed to Linux and is handled
> by the boot firmware.
>
> Although reset was not exposed in Tegra234 as well, the firmware supported
> a dummy reset which just returns success on reset without doing an actual
> reset. This is also not supported in Tegra264 BPMP. Therefore mark 'reset'
> and 'reset-names' properties as required only for devices prior to
> Tegra264.
>
> This also necessitates that the Tegra264 compatible to be standalone and
> cannot have the fallback compatible of Tegra186. Since there is no
> functional impact, we keep reset as required for Tegra234 to avoid
> breaking the ABI.
>
> Signed-off-by: Akhil R <akhilrajeev@xxxxxxxxxx>
> ---
>  .../bindings/dma/nvidia,tegra186-gpc-dma.yaml | 22 ++++++++++++++-----
>  1 file changed, 16 insertions(+), 6 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml b/Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml
> index 1e7b5ddd4658..34c9b41aecfc 100644
> --- a/Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml
> +++ b/Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml
> @@ -16,16 +16,13 @@ maintainers:
>    - Rajesh Gumasta <rgumasta@xxxxxxxxxx>
>    - Akhil R <akhilrajeev@xxxxxxxxxx>
>
> -allOf:
> -  - $ref: dma-controller.yaml#
> -
>  properties:
>    compatible:
>      oneOf:
> +      - const: nvidia,tegra264-gpcdma
>        - const: nvidia,tegra186-gpcdma

use enum

         - enum:
             - nvidia,tegra186-gpcdma
             - nvidia,tegra264-gpcdma

>        - items:
>            - enum:
> -              - nvidia,tegra264-gpcdma
>                - nvidia,tegra234-gpcdma
>                - nvidia,tegra194-gpcdma
>            - const: nvidia,tegra186-gpcdma
> @@ -65,12 +62,25 @@ required:
>    - compatible
>    - reg
>    - interrupts
> -  - resets
> -  - reset-names
>    - "#dma-cells"
>    - iommus
>    - dma-channel-mask
>
> +allOf:
> +  - $ref: dma-controller.yaml#
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - nvidia,tegra186-gpcdma
> +              - nvidia,tegra194-gpcdma
> +              - nvidia,tegra234-gpcdma

nvidia,tegra234-gpcdma must have fallback nvidia,tegra186-gpcdma, so
needn't nvidia,tegra234-gpcdma here.

Frank

> +    then:
> +      required:
> +        - resets
> +        - reset-names
> +
>  additionalProperties: false
>
>  examples:
> --
> 2.50.1
>