spi: Add s3c64xx SPI Controller driver

Each SPI controller has exactly one CS line and as such doesn't
provide for multi-cs. We implement a workaround to support
multi-cs by _not_ configuring the mux'ed CS pin for each SPI
controller. The CS mechanism is assumed to be fully machine
specific - the driver doesn't even assume some GPIO pin is used
to control the CS.

The driver selects between DMA and POLLING mode depending upon
the xfer size - DMA mode for xfers bigger than FIFO size, POLLING
mode otherwise.

The driver has been designed to be capable of running SoCs since
s3c64xx and till date, for that reason some of the register fields
have been passed via, SoC specific, platform data.
Signed-off-by: NJassi Brar <jassi.brar@samsung.com>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

drivers/spi/Kconfig

@@ -240,6 +240,13 @@ config SPI_S3C24XX_GPIO
 	  the inbuilt hardware cannot provide the transfer mode, or
 	  where the board is using non hardware connected pins.
 
+config SPI_S3C64XX
+	tristate "Samsung S3C64XX series type SPI"
+	depends on ARCH_S3C64XX && EXPERIMENTAL
+	select S3C64XX_DMA
+	help
+	  SPI driver for Samsung S3C64XX and newer SoCs.
+
 config SPI_SH_MSIOF
 	tristate "SuperH MSIOF SPI controller"
 	depends on SUPERH && HAVE_CLK

drivers/spi/Makefile

@@ -33,6 +33,7 @@ obj-$(CONFIG_SPI_MPC8xxx)		+= spi_mpc8xxx.o
 obj-$(CONFIG_SPI_PPC4xx)		+= spi_ppc4xx.o
 obj-$(CONFIG_SPI_S3C24XX_GPIO)		+= spi_s3c24xx_gpio.o
 obj-$(CONFIG_SPI_S3C24XX)		+= spi_s3c24xx_hw.o
+obj-$(CONFIG_SPI_S3C64XX)		+= spi_s3c64xx.o
 obj-$(CONFIG_SPI_TXX9)			+= spi_txx9.o
 obj-$(CONFIG_SPI_XILINX)		+= xilinx_spi.o
 obj-$(CONFIG_SPI_XILINX_OF)		+= xilinx_spi_of.o