[PATCH] spi: Add support for specifing 3-wire mode via device tree

[Rob Herring]

On 07/13/2012 07:43 AM, Lars-Peter Clausen wrote:
> This patch allows to specify that a SPI device is connected in 3-wire mode via
> the device tree.
> 
> Signed-off-by: Lars-Peter Clausen <lars at metafoo.de>
> ---

Might explain what 3-wire mode is, but otherwise

Acked-by: Rob Herring <rob.herring at calxeda.com>

>  Documentation/devicetree/bindings/spi/spi-bus.txt |    2 ++
>  drivers/spi/spi.c                                 |    2 ++
>  2 files changed, 4 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/spi/spi-bus.txt b/Documentation/devicetree/bindings/spi/spi-bus.txt
> index e782add..46f2f3b 100644
> --- a/Documentation/devicetree/bindings/spi/spi-bus.txt
> +++ b/Documentation/devicetree/bindings/spi/spi-bus.txt
> @@ -33,6 +33,8 @@ contain the following properties.
>      		shifted clock phase (CPHA) mode
>  - spi-cs-high     - (optional) Empty property indicating device requires
>      		chip select active high
> +- spi-3wire       - (optional) Empty property indicating device requires
> +    		    3-wire mode.
>  
>  SPI example for an MPC5200 SPI bus:
>  	spi at f00 {
> diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
> index fc0da39..09da7de 100644
> --- a/drivers/spi/spi.c
> +++ b/drivers/spi/spi.c
> @@ -856,6 +856,8 @@ static void of_register_spi_devices(struct spi_master *master)
>  			spi->mode |= SPI_CPOL;
>  		if (of_find_property(nc, "spi-cs-high", NULL))
>  			spi->mode |= SPI_CS_HIGH;
> +		if (of_find_property(nc, "spi-3wire", NULL))
> +			spi->mode |= SPI_3WIRE;
>  
>  		/* Device speed */
>  		prop = of_get_property(nc, "spi-max-frequency", &len);
>