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Date:   Sun, 7 Oct 2018 20:29:30 +0530
From:   Vinod <vkoul@kernel.org>
To:     Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
Cc:     Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexandre Torgue <alexandre.torgue@st.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Dan Williams <dan.j.williams@intel.com>,
        devicetree@vger.kernel.org, dmaengine@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 3/7] dt-bindings: stm32-mdma: Add DMA/MDMA chaining
 support bindings
Message-ID: <20181007145930.GA2372@vkoul-mobl>
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On 28-09-18, 15:01, Pierre-Yves MORDRET wrote:
> From: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
> 
> This patch adds the description of the 2 properties needed to support M2M
> transfer triggered by STM32 DMA when his transfer is complete.
> 
> Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
> ---
>   Version history:
>     v3:
>     v2:
>        * rework content
>     v1:
>        * Initial
> ---
> ---
>  Documentation/devicetree/bindings/dma/stm32-mdma.txt | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/dma/stm32-mdma.txt b/Documentation/devicetree/bindings/dma/stm32-mdma.txt
> index d18772d..27c2812 100644
> --- a/Documentation/devicetree/bindings/dma/stm32-mdma.txt
> +++ b/Documentation/devicetree/bindings/dma/stm32-mdma.txt
> @@ -10,7 +10,7 @@ Required properties:
>  - interrupts: Should contain the MDMA interrupt.
>  - clocks: Should contain the input clock of the DMA instance.
>  - resets: Reference to a reset controller asserting the DMA controller.
> -- #dma-cells : Must be <5>. See DMA client paragraph for more details.
> +- #dma-cells : Must be <6>. See DMA client paragraph for more details.

can you update the example for 6 cells?

Also what happens to dts using 5 cells..

>  
>  Optional properties:
>  - dma-channels: Number of DMA channels supported by the controller.
> @@ -26,7 +26,7 @@ Example:
>  		interrupts = <122>;
>  		clocks = <&timer_clk>;
>  		resets = <&rcc 992>;
> -		#dma-cells = <5>;
> +		#dma-cells = <6>;
>  		dma-channels = <16>;
>  		dma-requests = <32>;
>  		st,ahb-addr-masks = <0x20000000>, <0x00000000>;
> @@ -35,8 +35,8 @@ Example:
>  * DMA client
>  
>  DMA clients connected to the STM32 MDMA controller must use the format
> -described in the dma.txt file, using a five-cell specifier for each channel:
> -a phandle to the MDMA controller plus the following five integer cells:
> +described in the dma.txt file, using a six-cell specifier for each channel:
> +a phandle to the MDMA controller plus the following six integer cells:
>  
>  1. The request line number
>  2. The priority level
> @@ -76,6 +76,10 @@ a phandle to the MDMA controller plus the following five integer cells:
>     if no HW ack signal is used by the MDMA client
>  5. A 32bit mask specifying the value to be written to acknowledge the request
>     if no HW ack signal is used by the MDMA client
> +6. A bitfield value specifying if the MDMA client wants to generate M2M
> +   transfer with HW trigger (1) or not (0). This bitfield should be only
> +   enabled for M2M transfer triggered by STM32 DMA client. The memory devices
> +   involved in this kind of transfer are SRAM and DDR.
>  
>  Example:
>  
> -- 
> 2.7.4

-- 
~Vinod