mtd: spi-nor: add driver for STM32 quad spi flash controller

The quadspi is a specialized communication interface targeting single,
dual or quad SPI Flash memories.

It can operate in any of the following modes:
-indirect mode: all the operations are performed using the quadspi
 registers
-read memory-mapped mode: the external Flash memory is mapped to the
 microcontroller address space and is seen by the system as if it was
 an internal memory
Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Reviewed-by: Marek Vasut <marek.vasut@gmail.com>
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>

drivers/mtd/spi-nor/Kconfig

@@ -106,4 +106,11 @@ config SPI_INTEL_SPI_PLATFORM
 	  To compile this driver as a module, choose M here: the module
 	  will be called intel-spi-platform.
 
+config SPI_STM32_QUADSPI
+	tristate "STM32 Quad SPI controller"
+	depends on ARCH_STM32
+	help
+	  This enables support for the STM32 Quad SPI controller.
+	  We only connect the NOR to this controller.
+
 endif # MTD_SPI_NOR

drivers/mtd/spi-nor/Makefile

@@ -8,3 +8,4 @@ obj-$(CONFIG_MTD_MT81xx_NOR)    += mtk-quadspi.o
 obj-$(CONFIG_SPI_NXP_SPIFI)	+= nxp-spifi.o
 obj-$(CONFIG_SPI_INTEL_SPI)	+= intel-spi.o
 obj-$(CONFIG_SPI_INTEL_SPI_PLATFORM)	+= intel-spi-platform.o
+obj-$(CONFIG_SPI_STM32_QUADSPI)	+= stm32-quadspi.o
\ No newline at end of file