spi: meson: Add support for Amlogic Meson SPIFC

This is a driver for the Amlogic Meson SPIFC (SPI flash controller),
which is one of the two SPI controllers available on the SoC. It
doesn't support DMA and has a 64-byte unified transmit/receive buffer.

The device is optimized for interfacing with SPI NOR memories and
allows the execution of standard operations such as read, page
program, sector erase, etc. in a simplified way, toggling a bit in a
dedicated register. The driver doesn't use those predefined commands
and relies only on custom transfers.

Signed-off-by: Beniamino Galvani <b.galvani@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/Kconfig

@@ -301,6 +301,13 @@ config SPI_FSL_ESPI
 	  From MPC8536, 85xx platform uses the controller, and all P10xx,
 	  P20xx, P30xx,P40xx, P50xx uses this controller.
 
+config SPI_MESON_SPIFC
+	tristate "Amlogic Meson SPIFC controller"
+	depends on ARCH_MESON || COMPILE_TEST
+	help
+	  This enables master mode support for the SPIFC (SPI flash
+	  controller) available in Amlogic Meson SoCs.
+
 config SPI_OC_TINY
 	tristate "OpenCores tiny SPI"
 	depends on GPIOLIB

drivers/spi/Makefile

@@ -42,6 +42,7 @@ obj-$(CONFIG_SPI_FSL_SPI)		+= spi-fsl-spi.o
 obj-$(CONFIG_SPI_GPIO)			+= spi-gpio.o
 obj-$(CONFIG_SPI_IMX)			+= spi-imx.o
 obj-$(CONFIG_SPI_LM70_LLP)		+= spi-lm70llp.o
+obj-$(CONFIG_SPI_MESON_SPIFC)		+= spi-meson-spifc.o
 obj-$(CONFIG_SPI_MPC512x_PSC)		+= spi-mpc512x-psc.o
 obj-$(CONFIG_SPI_MPC52xx_PSC)		+= spi-mpc52xx-psc.o
 obj-$(CONFIG_SPI_MPC52xx)		+= spi-mpc52xx.o