Re: [RFC PATCH v3 2/5] Documentation: synopsys-dw-mshc: add bindings for idmac and edmac

[Krzysztof Kozlowski <k.kozlowski@samsung.com>]

On 05.08.2015 17:17, Shawn Lin wrote:
> synopsys-dw-mshc supports three types of transfer mode. We add bindings
> and description for how to use them at runtime. Without idmac and edmac
> property, pio is the default transfer mode. Make sure that Idmac and emdac
> should not be used simultaneously.
> 
> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
> ---
> 
> Changes in v3: None
> Changes in v2: None
> 
>  .../devicetree/bindings/mmc/synopsys-dw-mshc.txt   | 41 ++++++++++++++++++++++
>  1 file changed, 41 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/mmc/synopsys-dw-mshc.txt b/Documentation/devicetree/bindings/mmc/synopsys-dw-mshc.txt
> index 346c609..30369cb 100644
> --- a/Documentation/devicetree/bindings/mmc/synopsys-dw-mshc.txt
> +++ b/Documentation/devicetree/bindings/mmc/synopsys-dw-mshc.txt
> @@ -75,6 +75,25 @@ Optional properties:
>  * vmmc-supply: The phandle to the regulator to use for vmmc.  If this is
>    specified we'll defer probe until we can find this regulator.
>  
> +* supports-idmac: Enables support for internal DMAC block within the Synopsys
> +  Designware Mobile Storage IP block. If supports-idmac property is present, then
> +  we MUST NOT add supports-edmac property since we'd assume that dw-mshc IP is
> +  integrated with only one type of dma master.
> +
> +* supports-edmac: Enables support for external DMAC block outside the Synopsys
> +  Designware Mobile Storage IP block. If supports-edmac property is present, then
> +  we MUST NOT add supports-idmac property since we'd assume that dw-mshc IP is
> +  integrated with only one type of dma master.
> +
> +  (Without "supports-idmac" and "supports-edmac", use PIO as default transfer mode)

Aren't you breaking here backward compatibility with existing DTB?

Best regards,
Krzysztof

> +
> +* dmas: List of DMA specifiers with the controller specific format as described
> +  in the generic DMA client binding. This property should be combined with
> +  supports-edmac. Refer to dma.txt for details.
> +
> +* dma-names: DMA request names. Must be "rx-tx". And This property should be
> +  combined with supports-edmac. Refer to dma.txt for details.
> +
>  Aliases:
>  
>  - All the MSHC controller nodes should be represented in the aliases node using
> @@ -95,6 +114,8 @@ board specific portions as listed below.
>  		#size-cells = <0>;
>  	};
>  
> +[board specific internal DMA resources]
> +
>  	dwmmc0@12200000 {
>  		clock-frequency = <400000000>;
>  		clock-freq-min-max = <400000 200000000>;
> @@ -106,4 +127,24 @@ board specific portions as listed below.
>  		bus-width = <8>;
>  		cap-mmc-highspeed;
>  		cap-sd-highspeed;
> +		supports-idmac;
>  	};
> +
> +[board specific generic DMA request binding]
> +
> +	dwmmc0@12200000 {
> +		clock-frequency = <400000000>;
> +		clock-freq-min-max = <400000 200000000>;
> +		num-slots = <1>;
> +		broken-cd;
> +		fifo-depth = <0x80>;
> +		card-detect-delay = <200>;
> +		vmmc-supply = <&buck8>;
> +		bus-width = <8>;
> +		cap-mmc-highspeed;
> +		cap-sd-highspeed;
> +		supports-edmac;
> +		dmas = <&pdma 12>;
> +		dma-names = "rx-tx";
> +	};
> +
>