riscv: Add Kendryte K210 FPIOA pinctrl driver

Add the pinctrl-k210.c pinctrl driver for the Kendryte K210 FPIOA
(fully programmable IO array) to allow configuring the SoC pin
functions. The K210 has 48 programmable pins which can take any of 256
possible functions.

This patch is inspired from the k210 pinctrl driver for the u-boot
project and contains many direct contributions from Sean Anderson.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>

arch/riscv/Kconfig.socs

@@ -34,6 +34,8 @@ config SOC_KENDRYTE
 	select ARCH_HAS_RESET_CONTROLLER
 	select RESET_CONTROLLER
 	select RESET_K210
+	select PINCTRL
+	select PINCTRL_K210
 	help
 	  This enables support for Kendryte K210 SoC platform hardware.
 

drivers/pinctrl/Kconfig

@@ -374,6 +374,21 @@ config PINCTRL_OCELOT
 	select OF_GPIO
 	select REGMAP_MMIO
 
+config PINCTRL_K210
+	bool "Pinctrl driver for the Kendryte K210 SoC"
+	depends on RISCV && SOC_KENDRYTE
+	depends on OF && HAS_IOMEM
+	select PINMUX
+	select GENERIC_PINCONF
+	select GPIOLIB
+	select OF_GPIO
+	select REGMAP_MMIO
+	help
+	  Add support for the Kendryte K210 RISC-V SOC Field Programmable
+	  IO Array (FPIOA) controller. Support for this controller is
+	  automatically selected when the SOC_KENDRYTE option is selected
+	  in the "SOC selection" menu.
+
 source "drivers/pinctrl/actions/Kconfig"
 source "drivers/pinctrl/aspeed/Kconfig"
 source "drivers/pinctrl/bcm/Kconfig"

drivers/pinctrl/Makefile

@@ -47,6 +47,7 @@ obj-$(CONFIG_PINCTRL_INGENIC)	+= pinctrl-ingenic.o
 obj-$(CONFIG_PINCTRL_RK805)	+= pinctrl-rk805.o
 obj-$(CONFIG_PINCTRL_OCELOT)	+= pinctrl-ocelot.o
 obj-$(CONFIG_PINCTRL_EQUILIBRIUM)   += pinctrl-equilibrium.o
+obj-$(CONFIG_PINCTRL_K210)	+= pinctrl-k210.o
 
 obj-y				+= actions/
 obj-$(CONFIG_ARCH_ASPEED)	+= aspeed/