pinctrl: nuvoton: Add driver for WPCM450

This driver is based on the one for NPCM7xx, because the WPCM450 is a
predecessor of those SoCs. Notable differences:

- WPCM450, the GPIO registers are not organized in multiple banks, but
  rather placed continually into the same register block. This affects
  how register offsets are computed.
- Pinmux nodes can explicitly select GPIO mode, whereas, in the npcm7xx
  driver, this happens automatically when a GPIO is requested.

Some functionality implemented in the hardware was (for now) left unused
in the driver, specifically blinking and pull-up/down.

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>

MAINTAINERS

@@ -2343,6 +2343,7 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/*/*wpcm*
 F:	arch/arm/boot/dts/nuvoton-wpcm450*
 F:	arch/arm/mach-npcm/wpcm450.c
+F:	drivers/*/*/*wpcm*
 F:	drivers/*/*wpcm*
 
 ARM/NXP S32G ARCHITECTURE

drivers/pinctrl/Makefile

@@ -58,7 +58,7 @@ obj-y				+= freescale/
 obj-$(CONFIG_X86)		+= intel/
 obj-y				+= mvebu/
 obj-y				+= nomadik/
-obj-$(CONFIG_ARCH_NPCM7XX)	+= nuvoton/
+obj-y				+= nuvoton/
 obj-$(CONFIG_PINCTRL_PXA)	+= pxa/
 obj-$(CONFIG_ARCH_QCOM)		+= qcom/
 obj-$(CONFIG_PINCTRL_RALINK)	+= ralink/

drivers/pinctrl/nuvoton/Kconfig

@@ -1,4 +1,22 @@
 # SPDX-License-Identifier: GPL-2.0-only
+
+config PINCTRL_WPCM450
+	tristate "Pinctrl and GPIO driver for Nuvoton WPCM450"
+	depends on ARCH_WPCM450 || COMPILE_TEST
+	select PINMUX
+	select PINCONF
+	select GENERIC_PINCONF
+	select GPIOLIB
+	select GPIO_GENERIC
+	select GPIOLIB_IRQCHIP
+	help
+	  Say Y or M here to enable pin controller and GPIO support for
+	  the Nuvoton WPCM450 SoC. This is strongly recommended when
+	  building a kernel that will run on this chip.
+
+	  If this driver is compiled as a module, it will be named
+	  pinctrl-wpcm450.
+
 config PINCTRL_NPCM7XX
 	bool "Pinctrl and GPIO driver for Nuvoton NPCM7XX"
 	depends on (ARCH_NPCM7XX || COMPILE_TEST) && OF

drivers/pinctrl/nuvoton/Makefile

@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
 # Nuvoton pinctrl support
 
+obj-$(CONFIG_PINCTRL_WPCM450)	+= pinctrl-wpcm450.o
 obj-$(CONFIG_PINCTRL_NPCM7XX)	+= pinctrl-npcm7xx.o