Re: [PATCH 06/10] arm64: allwinner: a64: Add devicetree binding for DMA controller

Rob Herring
2017-09-12T16:52:24Z

On Mon, Sep 04, 2017 at 12:40:57AM +0200, Stefan Brüns wrote:
> The A64 is register compatible with the H3, but has a different number
> of dma channels and request ports.
>
> Attach additional properties to the node to allow future reuse of the
> compatible for controllers with different number of channels/requests.
>
> If dma-requests is not specified, the register layout defined maximum
> of 32 is used.

This belongs in the binding.

>
> Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
> ---
> .../devicetree/bindings/dma/sun6i-dma.txt | 26 ++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/dma/sun6i-dma.txt b/Documentation/devicetree/bindings/dma/sun6i-dma.txt
> index 6b267045f522..66195fb31296 100644
> --- a/Documentation/devicetree/bindings/dma/sun6i-dma.txt
> +++ b/Documentation/devicetree/bindings/dma/sun6i-dma.txt
> @@ -26,6 +26,32 @@ Example:
> #dma-cells = <1>;
> };
>
> +------------------------------------------------------------------------------
> +For A64 DMA controller:
> +
> +Required properties:
> +- compatible: "allwinner,sun50i-a64-dma"
> +- dma-channels: Number of DMA channels supported by the controller.
> + Refer to Documentation/devicetree/bindings/dma/dma.txt

dma.txt already explains what these properties are. You just need to
state what are valid values.

> +- all properties above, i.e. reg, interrupts, clocks, resets and #dma-cells
> +
> +Optional properties:
> +- dma-requests: Number of DMA request signals supported by the controller.
> + Refer to Documentation/devicetree/bindings/dma/dma.txt
> +
> +Example:
> + dma: dma-controller@01c02000 {

Drop the leading 0. Building dtbs with W=2 will tell you this.

> + compatible = "allwinner,sun50i-a64-dma";
> + reg = <0x01c02000 0x1000>;
> + interrupts = <GIC_SPI 50 IRQ_TYPE_LEVEL_HIGH>;
> + clocks = <&ccu CLK_BUS_DMA>;
> + dma-channels = <8>;
> + dma-requests = <27>;
> + resets = <&ccu RST_BUS_DMA>;
> + #dma-cells = <1>;
> + };
> +------------------------------------------------------------------------------
> +
> Clients:
>
> DMA clients connected to the A31 DMA controller must use the format
> --
> 2.14.1
>