Re: [PATCH 7/8] dt-bindings: dma: qcom: bam-dma: Add missing required properties

[Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>]

On 12.02.2025 6:03 PM, Stephan Gerhold wrote:
> num-channels and qcom,num-ees are required when there are no clocks
> specified in the device tree, because we have no reliable way to read them
> from the hardware registers if we cannot ensure the BAM hardware is up when
> the device is being probed.
> 
> This has often been forgotten when adding new SoC device trees, so make
> this clear by describing this requirement in the schema.
> 
> Signed-off-by: Stephan Gerhold <stephan.gerhold@linaro.org>
> ---
>  Documentation/devicetree/bindings/dma/qcom,bam-dma.yaml | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/dma/qcom,bam-dma.yaml b/Documentation/devicetree/bindings/dma/qcom,bam-dma.yaml
> index 3ad0d9b1fbc5e4f83dd316d1ad79773c288748ba..5f7e7763615578717651014cfd52745ea2132115 100644
> --- a/Documentation/devicetree/bindings/dma/qcom,bam-dma.yaml
> +++ b/Documentation/devicetree/bindings/dma/qcom,bam-dma.yaml
> @@ -90,8 +90,12 @@ required:
>  anyOf:
>    - required:
>        - qcom,powered-remotely
> +      - num-channels
> +      - qcom,num-ees
>    - required:
>        - qcom,controlled-remotely
> +      - num-channels
> +      - qcom,num-ees

I think I'd rather see these deprecated and add the clock everywhere..
Do we know which one we need to add on newer platforms? Or maybe it's
been transformed into an icc path?

Reading back things from this piece of HW only to add it to DT to avoid
reading it later is a really messy solution.

Konrad

>    - required:
>        - clocks
>        - clock-names
>