pinctrl: Add RISC-V Canaan Kendryte K210 FPIOA driver

Add the pinctrl-k210.c pinctrl driver for the Canaan Kendryte K210
field programmable IO array (FPIOA) 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.

The MAINTAINERS file is updated, adding the entry "CANAAN/KENDRYTE K210
SOC FPIOA DRIVER" with myself listed as maintainer for this driver.

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-gpio@vger.kernel.org
Signed-off-by: Sean Anderson <seanga2@gmail.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

Author: damien-lemoal

MAINTAINERS

@@ -3860,6 +3860,13 @@ W:	https://github.com/Cascoda/ca8210-linux.git
 F:	Documentation/devicetree/bindings/net/ieee802154/ca8210.txt
 F:	drivers/net/ieee802154/ca8210.c
 
+CANAAN/KENDRYTE K210 SOC FPIOA DRIVER
+M:	Damien Le Moal <damien.lemoal@wdc.com>
+L:	linux-riscv@lists.infradead.org
+L:	linux-gpio@vger.kernel.org (pinctrl driver)
+F:	Documentation/devicetree/bindings/pinctrl/canaan,k210-fpioa.yaml
+F:	drivers/pinctrl/pinctrl-k210.c
+
 CANAAN/KENDRYTE K210 SOC RESET CONTROLLER DRIVER
 M:	Damien Le Moal <damien.lemoal@wdc.com>
 L:	linux-kernel@vger.kernel.org

arch/riscv/Kconfig.socs

@@ -30,6 +30,7 @@ config SOC_CANAAN
 	select SERIAL_SIFIVE_CONSOLE if TTY
 	select SIFIVE_PLIC
 	select ARCH_HAS_RESET_CONTROLLER
+	select PINCTRL
 	help
 	  This enables support for Canaan Kendryte K210 SoC platform hardware.
 

drivers/pinctrl/Kconfig

@@ -394,6 +394,19 @@ config PINCTRL_MICROCHIP_SGPIO
 	  connect control signals from SFP modules and to act as an
 	  LED controller.
 
+config PINCTRL_K210
+	bool "Pinctrl driver for the Canaan Kendryte K210 SoC"
+	depends on RISCV && SOC_CANAAN && OF
+	select GENERIC_PINMUX_FUNCTIONS
+	select GENERIC_PINCONF
+	select GPIOLIB
+	select OF_GPIO
+	select REGMAP_MMIO
+	default SOC_CANAAN
+	help
+	  Add support for the Canaan Kendryte K210 RISC-V SOC Field
+	  Programmable IO Array (FPIOA) controller.
+
 source "drivers/pinctrl/actions/Kconfig"
 source "drivers/pinctrl/aspeed/Kconfig"
 source "drivers/pinctrl/bcm/Kconfig"

drivers/pinctrl/Makefile

@@ -48,6 +48,7 @@ obj-$(CONFIG_PINCTRL_RK805)	+= pinctrl-rk805.o
 obj-$(CONFIG_PINCTRL_OCELOT)	+= pinctrl-ocelot.o
 obj-$(CONFIG_PINCTRL_MICROCHIP_SGPIO)	+= pinctrl-microchip-sgpio.o
 obj-$(CONFIG_PINCTRL_EQUILIBRIUM)   += pinctrl-equilibrium.o
+obj-$(CONFIG_PINCTRL_K210)	+= pinctrl-k210.o
 
 obj-y				+= actions/
 obj-$(CONFIG_ARCH_ASPEED)	+= aspeed/