spi: Add support for Armada 3700 SPI Controller

Marvell Armada 3700 SoC comprises an SPI Controller. This Controller
supports up to 4 SPI slave devices, with dedicated chip selects,supports
SPI mode 0/1/2 and 3, CPIO or Fifo mode with DMA transfers and different
SPI transfer mode (Single, Dual or Quad).

This commit adds basic driver support for FIFO mode. In this mode,
dedicated registers are used to store the instruction, the address, the
read mode and the data. Write and Read FIFO are used to store the
outcoming or incoming data. The data FIFOs are accessible via DMA or by
the CPU. Only the CPU is supported for now.

Signed-off-by: Romain Perier <romain.perier@free-electrons.com>
Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/Kconfig

@@ -67,6 +67,13 @@ config SPI_ATH79
 	  This enables support for the SPI controller present on the
 	  Atheros AR71XX/AR724X/AR913X SoCs.
 
+config SPI_ARMADA_3700
+	tristate "Marvell Armada 3700 SPI Controller"
+	depends on (ARCH_MVEBU && OF) || COMPILE_TEST
+	help
+	  This enables support for the SPI controller present on the
+	  Marvell Armada 3700 SoCs.
+
 config SPI_ATMEL
 	tristate "Atmel SPI Controller"
 	depends on HAS_DMA

drivers/spi/Makefile

@@ -12,6 +12,7 @@ obj-$(CONFIG_SPI_LOOPBACK_TEST)		+= spi-loopback-test.o
 
 # SPI master controller drivers (bus)
 obj-$(CONFIG_SPI_ALTERA)		+= spi-altera.o
+obj-$(CONFIG_SPI_ARMADA_3700)		+= spi-armada-3700.o
 obj-$(CONFIG_SPI_ATMEL)			+= spi-atmel.o
 obj-$(CONFIG_SPI_ATH79)			+= spi-ath79.o
 obj-$(CONFIG_SPI_AU1550)		+= spi-au1550.o