Date: Mon, 26 Jun 2017 14:28:49 -0500
From: Rob Herring <robh@kernel.org>
To: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
Cc: Vinod Koul <vinod.koul@intel.com>, Mark Rutland <mark.rutland@arm.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Alexandre Torgue <alexandre.torgue@st.com>,
        Russell King <linux@armlinux.org.uk>,
        Dan Williams <dan.j.williams@intel.com>,
        "M'boumba Cedric Madianga" <cedric.madianga@gmail.com>,
        Fabrice GASNIER <fabrice.gasnier@st.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Fabien DESSENNE <fabien.dessenne@st.com>,
        Amelie Delaunay <amelie.delaunay@st.com>, dmaengine@vger.kernel.org,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/5] dt-bindings: Document the STM32 DMAMUX bindings
Message-ID: <20170626192849.zd5e53cidgen3ypq@rob-hp-laptop>
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On Fri, Jun 23, 2017 at 03:00:49PM +0200, Pierre-Yves MORDRET wrote:
> This patch adds the documentation of device tree bindings for the STM32
> DMAMUX.
> 
> Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
> Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
> ---
>  Version history:
>     v2:
>         * Move clock bindings from optional to mandatory one
>         * Drop channelID bindings as managed dynamically from now on by
>           DMAMUX driver.
> ---
> ---
>  .../devicetree/bindings/dma/stm32-dmamux.txt       | 57 ++++++++++++++++++++++
>  1 file changed, 57 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/dma/stm32-dmamux.txt
> 
> diff --git a/Documentation/devicetree/bindings/dma/stm32-dmamux.txt b/Documentation/devicetree/bindings/dma/stm32-dmamux.txt
> new file mode 100644
> index 0000000..1d413c5
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/dma/stm32-dmamux.txt
> @@ -0,0 +1,57 @@
> +STM32 DMA MUX (DMA request router)
> +
> +Required properties:
> +- compatible:	"st,stm32-dmamux"

This should be SoC specific (or at least have f4, h7, etc.).

> +- reg:		Memory map for accessing module
> +- #dma-cells:	Should be set to <3>.
> +		For more details about the three cells, please see
> +		stm32-dma.txt documentation binding file

The example below has 4 cells for the dma ctrlr?

> +- dma-masters:	Phandle pointing to the DMA controller
> +
> +Optional properties:
> +- dma-channels : Number of DMA channels supported.
> +- dma-requests : Number of DMA requests supported.
> +- resets: Reference to a reset controller asserting the DMA controller
> +- clocks: Input clock of the DMAMUX instance.
> +
> +Example:
> +
> +/* DMA controller */
> +dma2: dma-controller@40026400 {
> +	compatible = "st,stm32-dma";
> +	reg = <0x40026400 0x400>;
> +	interrupts = <56>,
> +		     <57>,
> +		     <58>,
> +		     <59>,
> +		     <60>,
> +		     <68>,
> +		     <69>,
> +		     <70>;
> +	clocks = <&clk_hclk>;
> +	#dma-cells = <4>;
> +	st,mem2mem;
> +	resets = <&rcc 150>;
> +	st,dmamux;
> +	dma-channels = <8>;
> +};
> +
> +/* DMA mux */
> +dmamux2: dma-router@40020820 {
> +	compatible = "st,stm32-dmamux";
> +	reg = <0x40020800 0x1c>;
> +	#dma-cells = <3>;
> +	dma-requests = <128>;
> +	dma-masters = <&dma2>;
> +};
> +
> +/* DMA client */
> +usart1: serial@40011000 {
> +	compatible = "st,stm32-usart", "st,stm32-uart";
> +	reg = <0x40011000 0x400>;
> +	interrupts = <37>;
> +	clocks = <&clk_pclk2>;
> +	dmas = <&dmamux2 41 0x414 0>,
> +	       <&dmamux2 42 0x414 0>;
> +	dma-names = "rx", "tx";
> +};
> -- 
> 1.9.1
>