mtd: rawnand: renesas: Add new NAND controller driver

Introduce Renesas NAND controller driver which currently supports the
following features on R-Car Gen3 and RZ/N1 SoCs:
- All ONFI timing modes
- Different configurations of its internal ECC controller
- On-die (not tested) and software ECC support
- Several chips (not tested)
- Subpage accesses
- DMA and PIO

This controller was originally provided by Evatronix before being bought
by Cadence.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Tested-by: Ralph Siemsen <ralph.siemsen@linaro.org>
Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/linux-mtd/20211217142033.353599-3-miquel.raynal@bootlin.com

drivers/mtd/nand/raw/Kconfig

@@ -461,6 +461,13 @@ config MTD_NAND_PL35X
 	  Enables support for PrimeCell SMC PL351 and PL353 NAND
 	  controller found on Zynq7000.
 
+config MTD_NAND_RENESAS
+	tristate "Renesas R-Car Gen3 & RZ/N1 NAND controller"
+	depends on ARCH_RENESAS || COMPILE_TEST
+	help
+	  Enables support for the NAND controller found on Renesas R-Car
+	  Gen3 and RZ/N1 SoC families.
+
 comment "Misc"
 
 config MTD_SM_COMMON

drivers/mtd/nand/raw/Makefile

@@ -58,6 +58,7 @@ obj-$(CONFIG_MTD_NAND_ARASAN)		+= arasan-nand-controller.o
 obj-$(CONFIG_MTD_NAND_INTEL_LGM)	+= intel-nand-controller.o
 obj-$(CONFIG_MTD_NAND_ROCKCHIP)		+= rockchip-nand-controller.o
 obj-$(CONFIG_MTD_NAND_PL35X)		+= pl35x-nand-controller.o
+obj-$(CONFIG_MTD_NAND_RENESAS)		+= renesas-nand-controller.o
 
 nand-objs := nand_base.o nand_legacy.o nand_bbt.o nand_timings.o nand_ids.o
 nand-objs += nand_onfi.o