linux-kernel - Re: [PATCH v3] dt-bindings: dma: xilinx: Add power-domains to xlnx,zynqmp-dpdma

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Date:   Fri, 12 May 2023 21:40:56 +0100
From:   Conor Dooley <conor@...nel.org>
To:     Michal Simek <michal.simek@....com>
Cc:     linux-kernel@...r.kernel.org, monstr@...str.eu,
        michal.simek@...inx.com, git@...inx.com,
        Conor Dooley <conor+dt@...nel.org>,
        Hyun Kwon <hyun.kwon@...inx.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Rob Herring <robh+dt@...nel.org>,
        Vinod Koul <vkoul@...nel.org>, devicetree@...r.kernel.org,
        dmaengine@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v3] dt-bindings: dma: xilinx: Add power-domains to
 xlnx,zynqmp-dpdma

On Fri, May 12, 2023 at 01:40:33PM +0200, Michal Simek wrote:
> DP DMA has own power domain that's why describe required power-domain
> property.
> 
> Signed-off-by: Michal Simek <michal.simek@....com>
> ---
> 
> Changes in v3:
> - make power-domains as required property
> - also update commit message
> 
> Changes in v2:
> - rewrite commit message - requested by Krzysztof
> 
> The commit b06112cd5e08 ("arm64: dts: zynqmp: Add power domain for the
> DisplayPort DMA controller") added this property already in Linux that's
> why the patch is also fixing dts_check warnings.
> 
> In v2 I got ack from Krzysztof but not adding it because of additional
> discussion about required property in v3.
> https://lore.kernel.org/r/029ba923-d13e-ea7c-018d-95e179dda2e5@linaro.org

It was not entirely clear reading that whether the driver actually
functions correctly if the property is omitted.
Is it the case that if the property is omitted, and the power domain
controller driver is enabled, that the dma controller will not operate
correctly?
If I am understanding correctly, it very much does sound like it
should be listed as required, so:
Acked-by: Conor Dooley <conor.dooley@...rochip.com>

Thanks,
Conor.

> 
> ---
>  .../devicetree/bindings/dma/xilinx/xlnx,zynqmp-dpdma.yaml   | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/dma/xilinx/xlnx,zynqmp-dpdma.yaml b/Documentation/devicetree/bindings/dma/xilinx/xlnx,zynqmp-dpdma.yaml
> index d6cbd95ec26d..2128f4645c98 100644
> --- a/Documentation/devicetree/bindings/dma/xilinx/xlnx,zynqmp-dpdma.yaml
> +++ b/Documentation/devicetree/bindings/dma/xilinx/xlnx,zynqmp-dpdma.yaml
> @@ -41,6 +41,9 @@ properties:
>    clock-names:
>      const: axi_clk
>  
> +  power-domains:
> +    maxItems: 1
> +
>  required:
>    - "#dma-cells"
>    - compatible
> @@ -48,12 +51,14 @@ required:
>    - interrupts
>    - clocks
>    - clock-names
> +  - power-domains
>  
>  additionalProperties: false
>  
>  examples:
>    - |
>      #include <dt-bindings/interrupt-controller/arm-gic.h>
> +    #include <dt-bindings/power/xlnx-zynqmp-power.h>
>  
>      dma: dma-controller@...c0000 {
>        compatible = "xlnx,zynqmp-dpdma";
> @@ -63,6 +68,7 @@ examples:
>        clocks = <&dpdma_clk>;
>        clock-names = "axi_clk";
>        #dma-cells = <1>;
> +      power-domains = <&zynqmp_firmware PD_DP>;
>      };
>  
>  ...
> -- 
> 2.36.1
> 

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