Re: [PATCH] dt-bindings: host1x: Add missing 'dma-coherent'

[Krzysztof Kozlowski <krzk@kernel.org>]

On 09/04/2024 10:23, Jon Hunter wrote:
> The dtbs_check reports that the 'dma-coherent' property is "unevaluated
> and invalid" for the host1x@13e00000 device on Tegra194 and Tegra234
> platforms. Fix this by updating the dt-binding document for host1x to
> add the 'dma-coherent' property for these devices.

That's not really proper reason. What if DTS is wrong? The reason could
be if device is actually DMA coherent...

> 
> Fixes: 361238cdc525 ("arm64: tegra: Mark host1x as dma-coherent on Tegra194/234")
> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
> ---
>  .../bindings/display/tegra/nvidia,tegra20-host1x.yaml | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-host1x.yaml b/Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-host1x.yaml
> index 94c5242c03b2..3563378a01af 100644
> --- a/Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-host1x.yaml
> +++ b/Documentation/devicetree/bindings/display/tegra/nvidia,tegra20-host1x.yaml
> @@ -177,6 +177,15 @@ allOf:
>  
>        required:
>          - reg-names
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - nvidia,tegra194-host1x
> +    then:
> +      properties:
> +        dma-coherent: true

Do not define properties in allOf. Put it in top-level. If not all
devices are DMA coherent, you can disallow it for certain variants (:false).

Best regards,
Krzysztof