Add support for Cadence XSPI controller

This driver uses SPI-MEM framework and is capable to operate with
single, dual, quad and octal SPI-NOR memories.
Low-level controller work mode (STIG) is utilized to communicate
with flash memories.

Signed-off-by: Jayshri Pawar <jpawar@cadence.com>
Signed-off-by: Konrad Kociolek <konrad@cadence.com>

drivers/spi/Kconfig

@@ -212,6 +212,17 @@ config SPI_CADENCE_QUADSPI
 	  device with a Cadence QSPI controller and want to access the
 	  Flash as an MTD device.
 
+config SPI_CADENCE_XSPI
+	tristate "Cadence XSPI controller"
+	depends on (OF || COMPILE_TEST) && HAS_IOMEM
+	help
+	  Enable support for the Cadence XSPI Flash controller.
+
+	  Cadence XSPI is a specialized controller for connecting an SPI
+	  Flash over upto 8bit wide bus. Enable this option if you have a
+	  device with a Cadence XSPI controller and want to access the
+	  Flash as an MTD device.
+
 config SPI_CLPS711X
 	tristate "CLPS711X host SPI controller"
 	depends on ARCH_CLPS711X || COMPILE_TEST

drivers/spi/Makefile

@@ -32,6 +32,7 @@ obj-$(CONFIG_SPI_BITBANG)		+= spi-bitbang.o
 obj-$(CONFIG_SPI_BUTTERFLY)		+= spi-butterfly.o
 obj-$(CONFIG_SPI_CADENCE)		+= spi-cadence.o
 obj-$(CONFIG_SPI_CADENCE_QUADSPI)	+= spi-cadence-quadspi.o
+obj-$(CONFIG_SPI_CADENCE_XSPI)      	+= spi-cadence-xspi.o
 obj-$(CONFIG_SPI_CLPS711X)		+= spi-clps711x.o
 obj-$(CONFIG_SPI_COLDFIRE_QSPI)		+= spi-coldfire-qspi.o
 obj-$(CONFIG_SPI_DAVINCI)		+= spi-davinci.o