spi: add driver for MTK SPI NAND Flash Interface

This driver implements support for the SPI-NAND mode of MTK NAND Flash
Interface as a SPI-MEM controller with pipelined ECC capability.
Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
Tested-by: Daniel Golle <daniel@makrotopia.org>
Link: https://lore.kernel.org/r/20220424032527.673605-3-gch981213@gmail.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/Kconfig

@@ -590,6 +590,16 @@ config SPI_MTK_NOR
 	  SPI interface as well as several SPI NOR specific instructions
 	  via SPI MEM interface.
 
+config SPI_MTK_SNFI
+	tristate "MediaTek SPI NAND Flash Interface"
+	depends on ARCH_MEDIATEK || COMPILE_TEST
+	depends on MTD_NAND_ECC_MEDIATEK
+	help
+	  This enables support for SPI-NAND mode on the MediaTek NAND
+	  Flash Interface found on MediaTek ARM SoCs. This controller
+	  is implemented as a SPI-MEM controller with pipelined ECC
+	  capcability.
+
 config SPI_NPCM_FIU
 	tristate "Nuvoton NPCM FLASH Interface Unit"
 	depends on ARCH_NPCM || COMPILE_TEST

drivers/spi/Makefile

@@ -76,6 +76,7 @@ obj-$(CONFIG_SPI_MPC52xx)		+= spi-mpc52xx.o
 obj-$(CONFIG_SPI_MT65XX)                += spi-mt65xx.o
 obj-$(CONFIG_SPI_MT7621)		+= spi-mt7621.o
 obj-$(CONFIG_SPI_MTK_NOR)		+= spi-mtk-nor.o
+obj-$(CONFIG_SPI_MTK_SNFI)		+= spi-mtk-snfi.o
 obj-$(CONFIG_SPI_MXIC)			+= spi-mxic.o
 obj-$(CONFIG_SPI_MXS)			+= spi-mxs.o
 obj-$(CONFIG_SPI_NPCM_FIU)		+= spi-npcm-fiu.o