Subject: Re: [PATCH 1/2] dt-bindings: spi: Document the STM32 SPI bindings
To: Amelie Delaunay <amelie.delaunay@st.com>,
        Mark Brown <broonie@kernel.org>, Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Alexandre Torgue <alexandre.torgue@st.com>
Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-spi@vger.kernel.org
References: <1498055526-6918-1-git-send-email-amelie.delaunay@st.com>
 <1498055526-6918-2-git-send-email-amelie.delaunay@st.com>
From: Neil Armstrong <narmstrong@baylibre.com>
Organization: Baylibre
Message-ID: <5df6d07a-59b7-6460-75c5-c3b239067616@baylibre.com>
Date: Wed, 21 Jun 2017 17:20:58 +0200
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On 06/21/2017 04:32 PM, Amelie Delaunay wrote:
> This patch adds the documentation of device tree bindings
> for the STM32 SPI controller.
> 
> Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
> ---
>  .../devicetree/bindings/spi/spi-stm32.txt          | 60 ++++++++++++++++++++++
>  1 file changed, 60 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/spi/spi-stm32.txt
> 
> diff --git a/Documentation/devicetree/bindings/spi/spi-stm32.txt b/Documentation/devicetree/bindings/spi/spi-stm32.txt
> new file mode 100644
> index 0000000..3958bf6
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/spi/spi-stm32.txt
> @@ -0,0 +1,60 @@
> +STMicroelectronics STM32 SPI Controller
> +
> +The STM32 SPI controller is used to communicate with external devices using
> +the Serial Peripheral Interface. It supports full-duplex, half-duplex and
> +simplex synchronous serial communication with external devices. It supports
> +from 4 to 32-bit data size. Although it can be configured as master or slave,
> +only master is supported by the driver.
> +
> +Required properties:
> +- compatible: Must be "st,stm32-spi".

Hi Amelie,

What about the gen1 SPI devices like the F4 ?

It should have been better to use SoC specific compatible, or specify the SPI HW gen like gen1 or gen2.

Neil

> +- reg: Offset and length of the device's register set.
> +- interrupts: Must contain the interrupt id.
> +- clocks: Must contain an entry for spiclk (which feeds the internal clock
> +	  generator).
> +- #address-cells:  Number of cells required to define a chip select address.
> +- #size-cells: Should be zero.
> +
> +Optional properties:
> +- resets: Must contain the phandle to the reset controller.
> +- A pinctrl state named "default" may be defined to set pins in mode of
> +  operation for SPI transfer.
> +- dmas: DMA specifiers for tx and rx dma. DMA fifo mode must be used. See the
> +  STM32 DMA bindings, Documentation/devicetree/bindings/dma/stm32-dma.txt.
> +- dma-names: DMA request names should include "tx" and "rx" if present.
> +- cs-gpios: list of GPIO chip selects. See the SPI bus bindings,
> +  Documentation/devicetree/bindings/spi/spi-bus.txt
> +
> +
> +Child nodes represent devices on the SPI bus
> +  See ../spi/spi-bus.txt
> +
> +Optional properties:
> +- st,spi-midi-ns: (Master Inter-Data Idleness) minimum time delay in
> +		  nanoseconds inserted between two consecutive data frames.
> +
> +
> +Example:
> +	spi2: spi@40003800 {
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +		compatible = "st,stm32-spi";
> +		reg = <0x40003800 0x400>;
> +		interrupts = <36>;
> +		clocks = <&rcc SPI2_CK>;
> +		resets = <&rcc 1166>;
> +		dmas = <&dmamux1 0 39 0x400 0x01>,
> +		       <&dmamux1 1 40 0x400 0x01>;
> +		dma-names = "rx", "tx";
> +		pinctrl-0 = <&spi2_pins_b>;
> +		pinctrl-names = "default";
> +		status = "okay";
> +		cs-gpios = <&gpioa 11 0>;
> +
> +		spidev@0 {
> +			compatible = "spidev";
> +			reg = <0>;
> +			spi-max-frequency = <4000000>;
> +			st,spi-midi = <4000>;
> +		};
> +	};
>