Re: [PATCH v2 1/6] dt-bindings: dma: uniphier-xdmac: Remove extension register region description

[Masahiro Yamada <masahiroy@kernel.org>]

On Thu, Mar 19, 2020 at 4:51 PM Kunihiko Hayashi
<hayashi.kunihiko@socionext.com> wrote:
>
> The address of the extension register region in example is incorrect,
> however, this extension register region is optional


On which SoC is it optional?

In your previous DT submission, every reg was,
like this:

reg = <0x5fc10000 0x1000>, <0x5fc20000 0x800>;



and you meant

reg = <0x5fc10000 0x1000>, <0x5fc12000 0x800>;

?

> and isn't currently
> referred from the driver, so the description of the region should be
> suppressed until referred by the driver.

This sounds like you plan to get it back
as you extend the driver.

I checked the datasheet. This controller has more registers,
so you split the reg into small chunks, the final form will look scary:

reg = <0x5fc10000 0x1000>, <0x5fc12000 0x800>,
      <0x5fc14000 0x100>,  <0x5fc15000 0x100>;


My question is why you did not use a single reg tuple
that covers the whole registers.

Is any other hardware reg interleaved in between?






>
> Fixes: b9fb56b6ba8a ("dt-bindings: dmaengine: Add UniPhier external DMA controller bindings")
> Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
> ---
>  Documentation/devicetree/bindings/dma/socionext,uniphier-xdmac.yaml | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/dma/socionext,uniphier-xdmac.yaml b/Documentation/devicetree/bindings/dma/socionext,uniphier-xdmac.yaml
> index 86cfb59..f4c3f49 100644
> --- a/Documentation/devicetree/bindings/dma/socionext,uniphier-xdmac.yaml
> +++ b/Documentation/devicetree/bindings/dma/socionext,uniphier-xdmac.yaml
> @@ -24,7 +24,6 @@ properties:
>    reg:
>      items:
>        - description: XDMAC base register region (offset and length)
> -      - description: XDMAC extension register region (offset and length)
>
>    interrupts:
>      maxItems: 1
> @@ -54,7 +53,7 @@ examples:
>    - |
>      xdmac: dma-controller@5fc10000 {
>          compatible = "socionext,uniphier-xdmac";
> -        reg = <0x5fc10000 0x1000>, <0x5fc20000 0x800>;
> +        reg = <0x5fc10000 0x1000>;
>          interrupts = <0 188 4>;
>          #dma-cells = <2>;
>          dma-channels = <16>;
> --
> 2.7.4
>


-- 
Best Regards
Masahiro Yamada