spi: add OpenCores tiny SPI driver

This patch adds support of OpenCores tiny SPI driver.

http://opencores.org/project,tiny_spiSigned-off-by: Thomas Chou <thomas@wytron.com.tw>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

Documentation/devicetree/bindings/spi/spi_oc_tiny.txt

+OpenCores tiny SPI
+
+Required properties:
+- compatible : should be "opencores,tiny-spi-rtlsvn2".
+- gpios : should specify GPIOs used for chipselect.
+Optional properties:
+- clock-frequency : input clock frequency to the core.
+- baud-width: width, in bits, of the programmable divider used to scale
+	the input clock to SCLK.
+
+The clock-frequency and baud-width properties are needed only if the divider
+is programmable. They are not needed if the divider is fixed.

drivers/spi/Kconfig

@@ -231,6 +231,13 @@ config SPI_FSL_ESPI
 	  From MPC8536, 85xx platform uses the controller, and all P10xx,
 	  P20xx, P30xx,P40xx, P50xx uses this controller.
 
+config SPI_OC_TINY
+	tristate "OpenCores tiny SPI"
+	depends on GENERIC_GPIO
+	select SPI_BITBANG
+	help
+	  This is the driver for OpenCores tiny SPI master controller.
+
 config SPI_OMAP_UWIRE
 	tristate "OMAP1 MicroWire"
 	depends on ARCH_OMAP1

drivers/spi/Makefile

@@ -27,6 +27,7 @@ obj-$(CONFIG_SPI_IMX)			+= spi_imx.o
 obj-$(CONFIG_SPI_LM70_LLP)		+= spi_lm70llp.o
 obj-$(CONFIG_SPI_PXA2XX)		+= pxa2xx_spi.o
 obj-$(CONFIG_SPI_PXA2XX_PCI)		+= pxa2xx_spi_pci.o
+obj-$(CONFIG_SPI_OC_TINY)		+= spi_oc_tiny.o
 obj-$(CONFIG_SPI_OMAP_UWIRE)		+= omap_uwire.o
 obj-$(CONFIG_SPI_OMAP24XX)		+= omap2_mcspi.o
 obj-$(CONFIG_SPI_OMAP_100K)		+= omap_spi_100k.o

include/linux/spi/spi_oc_tiny.h

+#ifndef _LINUX_SPI_SPI_OC_TINY_H
+#define _LINUX_SPI_SPI_OC_TINY_H
+
+/**
+ * struct tiny_spi_platform_data - platform data of the OpenCores tiny SPI
+ * @freq:	input clock freq to the core.
+ * @baudwidth:	baud rate divider width of the core.
+ * @gpio_cs_count:	number of gpio pins used for chipselect.
+ * @gpio_cs:	array of gpio pins used for chipselect.
+ *
+ * freq and baudwidth are used only if the divider is programmable.
+ */
+struct tiny_spi_platform_data {
+	unsigned int freq;
+	unsigned int baudwidth;
+	unsigned int gpio_cs_count;
+	int *gpio_cs;
+};
+
+#endif /* _LINUX_SPI_SPI_OC_TINY_H */