pinctrl: Add STMFX GPIO expander Pinctrl/GPIO driver

This patch adds pinctrl/GPIO driver for STMicroelectronics
Multi-Function eXpander (STMFX) GPIO expander.
STMFX is an I2C slave controller, offering up to 24 GPIOs.
The driver relies on generic pin config interface to configure the GPIOs.
Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/pinctrl/Kconfig

@@ -265,6 +265,18 @@ config PINCTRL_ST
 	select PINCONF
 	select GPIOLIB_IRQCHIP
 
+config PINCTRL_STMFX
+	tristate "STMicroelectronics STMFX GPIO expander pinctrl driver"
+	select GENERIC_PINCONF
+	select GPIOLIB_IRQCHIP
+	select MFD_STMFX
+	help
+	  Driver for STMicroelectronics Multi-Function eXpander (STMFX)
+	  GPIO expander.
+	  This provides a GPIO interface supporting inputs and outputs,
+	  and configuring push-pull, open-drain, and can also be used as
+	  interrupt-controller.
+
 config PINCTRL_U300
 	bool "U300 pin controller driver"
 	depends on ARCH_U300

drivers/pinctrl/Makefile

@@ -40,6 +40,7 @@ obj-$(CONFIG_PINCTRL_LANTIQ)	+= pinctrl-lantiq.o
 obj-$(CONFIG_PINCTRL_LPC18XX)	+= pinctrl-lpc18xx.o
 obj-$(CONFIG_PINCTRL_TB10X)	+= pinctrl-tb10x.o
 obj-$(CONFIG_PINCTRL_ST) 	+= pinctrl-st.o
+obj-$(CONFIG_PINCTRL_STMFX) 	+= pinctrl-stmfx.o
 obj-$(CONFIG_PINCTRL_ZYNQ)	+= pinctrl-zynq.o
 obj-$(CONFIG_PINCTRL_INGENIC)	+= pinctrl-ingenic.o
 obj-$(CONFIG_PINCTRL_RK805)	+= pinctrl-rk805.o