gpio: add GPIO support for SMSC SCH311x

This patch adds support for the GPIOs found on the SMSC "Super I/
SCH311x.

The chip detection and I/O functions are copied from sch311x_wdt.
Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/Kconfig

@@ -244,6 +244,15 @@ config GPIO_SAMSUNG
 	  Legacy GPIO support. Use only for platforms without support for
 	  pinctrl.
 
+config GPIO_SCH311X
+	tristate "SMSC SCH311x SuperI/O GPIO"
+	help
+	  Driver to enable the GPIOs found on SMSC SMSC SCH3112, SCH3114 and
+	  SCH3116 "Super I/O" chipsets.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called gpio-sch311x.
+
 config GPIO_SPEAR_SPICS
 	bool "ST SPEAr13xx SPI Chip Select as GPIO support"
 	depends on PLAT_SPEAR

drivers/gpio/Makefile

@@ -68,6 +68,7 @@ obj-$(CONFIG_GPIO_RCAR)		+= gpio-rcar.o
 obj-$(CONFIG_GPIO_SAMSUNG)	+= gpio-samsung.o
 obj-$(CONFIG_ARCH_SA1100)	+= gpio-sa1100.o
 obj-$(CONFIG_GPIO_SCH)		+= gpio-sch.o
+obj-$(CONFIG_GPIO_SCH311X)	+= gpio-sch311x.o
 obj-$(CONFIG_GPIO_SODAVILLE)	+= gpio-sodaville.o
 obj-$(CONFIG_GPIO_SPEAR_SPICS)	+= gpio-spear-spics.o
 obj-$(CONFIG_GPIO_STA2X11)	+= gpio-sta2x11.o