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Date:   Mon, 19 Feb 2018 08:47:35 -0600
From:   Rob Herring <robh@kernel.org>
To:     Ludovic Barre <ludovic.Barre@st.com>
Cc:     Ulf Hansson <ulf.hansson@linaro.org>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Alexandre Torgue <alexandre.torgue@st.com>,
        Gerald Baeza <gerald.baeza@st.com>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org, linux-mmc@vger.kernel.org
Subject: Re: [PATCH 1/5] dt-bindings: mmc: document the stm32 sdmmc bindings
Message-ID: <20180219144735.sbxa76z6aik3w453@rob-hp-laptop>
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 <1518701697-14242-2-git-send-email-ludovic.Barre@st.com>
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On Thu, Feb 15, 2018 at 02:34:53PM +0100, Ludovic Barre wrote:
> From: Ludovic Barre <ludovic.barre@st.com>
> 
> Document the binding for stm32 sdmmc controller.
> 
> Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
> ---
>  .../devicetree/bindings/mmc/st,stm32-sdmmc.txt     | 35 ++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mmc/st,stm32-sdmmc.txt
> 
> diff --git a/Documentation/devicetree/bindings/mmc/st,stm32-sdmmc.txt b/Documentation/devicetree/bindings/mmc/st,stm32-sdmmc.txt
> new file mode 100644
> index 0000000..52eb1f8
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mmc/st,stm32-sdmmc.txt
> @@ -0,0 +1,35 @@
> +* STMicroelectronics STM32 SDMMC controller
> +
> +The highspeed MMC host controller on STM32 soc family
> +provides an interface for MMC, SD and SDIO types of memory cards.
> +
> +This file documents differences between the core properties described
> +by mmc.txt and the properties used by the sdmmc driver.
> +
> +Required properties:
> + - compatible: Should be "st,stm32h7-sdmmc"
> + - reg: mmc controller base registers
> + - interrupts: Should contain the interrupt number
> + - clocks: Should contain phandle for the clock feeding the controller
> + - resets: Should contain phandle for the reset feeding the controller
> +
> +Optional property:
> +- st,dirpol: Allow to select direction polarity of external voltage

This doesn't need to be so terse. Perhaps "st,dir-output-high".

> +  transceiver (which manage data and command direction).
> +  if set: Voltage transceiver IOs are driven as output when direction signals are high,
> +  else: Voltage transceiver IOs are driven as output when direction signals are low.
> +- st,negedge: generate data & command on sdmmc clock falling edge

st,neg-edge

> +- st,pin-ckin: use sdmmc_ckin pin from an external driver to sample
> +  the receive data (example: with voltage switch transceiver).

st,use-ckin

> +
> +Example:
> +	sdmmc1: sdmmc@52007000 {

mmc@...

> +		compatible = "st,stm32h7-sdmmc";
> +		reg = <0x52007000 0x1000>;
> +		interrupts = <49>;
> +		clocks = <&rcc SDMMC1_CK>;
> +		resets = <&rcc SDMMC1_R>;
> +		bus-width = <4>;
> +		cap-sd-highspeed;
> +		cap-mmc-highspeed;
> +	};
> -- 
> 2.7.4
>