[PATCH v6 3/5] doc: dt: add cyclone-ps-spi binding document

[Alan Tull]

On Fri, 16 Dec 2016, Joshua Clayton wrote:

> Describe a cyclone-ps-spi devicetree entry, required features
> 
> Signed-off-by: Joshua Clayton <stillcompiling at gmail.com>
> Acked-by: Rob Herring <robh at kernel.org>

Acked-by: Alan Tull <atull at opensource.altera.com>

> ---
>  .../bindings/fpga/cyclone-ps-spi-fpga-mgr.txt      | 25 ++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/fpga/cyclone-ps-spi-fpga-mgr.txt
> 
> diff --git a/Documentation/devicetree/bindings/fpga/cyclone-ps-spi-fpga-mgr.txt b/Documentation/devicetree/bindings/fpga/cyclone-ps-spi-fpga-mgr.txt
> new file mode 100644
> index 0000000..3f515c7
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/fpga/cyclone-ps-spi-fpga-mgr.txt
> @@ -0,0 +1,25 @@
> +Altera Cyclone Passive Serial SPI FPGA Manager
> +
> +Altera Cyclone FPGAs support a method of loading the bitstream over what is
> +referred to as "passive serial".
> +The passive serial link is not technically spi, and might require extra
> +circuits in order to play nicely with other spi slaves on the same bus.
> +
> +See https://www.altera.com/literature/hb/cyc/cyc_c51013.pdf
> +
> +Required properties:
> +- compatible  : should contain "altr,cyclone-ps-spi-fpga-mgr"
> +- reg         : spi slave id of the fpga
> +- config-gpios : config pin (referred to as nCONFIG in the cyclone manual)
> +- status-gpios : status pin (referred to as nSTATUS in the cyclone manual)
> +
> +both gpios pins are normally active low open drain.
> +
> +Example:
> +	fpga_spi: evi-fpga-spi at 0 {
> +		compatible = "altr,cyclone-ps-spi-fpga-mgr";
> +		spi-max-frequency = <20000000>;
> +		reg = <0>;
> +		config-gpios = <&gpio4 9 GPIO_ACTIVE_LOW>;
> +		status-gpios = <&gpio4 11 GPIO_ACTIVE_LOW>;
> +	};
> -- 
> 2.9.3
> 
>