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

[Lars-Peter Clausen]

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>
---
 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);
-- 
1.7.10.4