spi: synquacer: Add HSSPI SPI controller driver for SynQuacer

This is a driver for the HSSPI SPI controller on SynQuacer SoC.
The HSSPI has command sequence mode (memory mapped) and
direct mode (FIFO access). The driver will operate it under
the direct mode. And before booting OS, it switch back to the
command sequence mode since that is compatible with default
EDK2 behavior.

Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu@linaro.org>
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index e317d8a..5c2a60a 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -488,4 +488,12 @@
 	  Enable the MXC SPI controller driver. This driver can be used
 	  on various i.MX SoCs such as i.MX31/35/51/6/7.
 
+config SYNQUACER_SPI
+	bool "Socionext SynQuacer HS-SPI driver"
+	depends on ARCH_SYNQUACER
+	help
+	  Enable the Socionext HS-SPI driver for SynQuacer. This driver can
+	  be used to access the SPI interface and SPI NOR flash on platforms
+	  embedding this HS-SPI IP core.
+
 endif # menu "SPI Support"