gpio: winbond: Add driver

This commit adds GPIO driver for Winbond Super I/Os.

Currently, only W83627UHG model (also known as Nuvoton NCT6627UD)
is supported but in the future a support for other Winbond models,
too, can be added to the driver.

A module parameter "gpios" sets a bitmask of GPIO ports to enable
(bit 0 is GPIO1, bit 1 is GPIO2, etc.).

One should be careful which ports one tinkers with since some
might be managed by the firmware (for functions like powering on and
off, sleeping, BIOS recovery, etc.) and some of GPIO port pins are
physically shared with other devices included in the Super I/O chip.
Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/Kconfig

@@ -698,6 +698,22 @@ config GPIO_TS5500
 	  blocks of the TS-5500: DIO1, DIO2 and the LCD port, and the TS-5600
 	  LCD port.
 
+config GPIO_WINBOND
+	tristate "Winbond Super I/O GPIO support"
+	select ISA_BUS_API
+	help
+	  This option enables support for GPIOs found on Winbond Super I/O
+	  chips.
+	  Currently, only W83627UHG (also known as Nuvoton NCT6627UD) is
+	  supported.
+
+	  You will need to provide a module parameter "gpios", or a
+	  boot-time parameter "gpio_winbond.gpios" with a bitmask of GPIO
+	  ports to enable (bit 0 is GPIO1, bit 1 is GPIO2, etc.).
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called gpio-winbond.
+
 config GPIO_WS16C48
 	tristate "WinSystems WS16C48 GPIO support"
 	depends on ISA_BUS_API

drivers/gpio/Makefile

@@ -139,6 +139,7 @@ obj-$(CONFIG_GPIO_VIPERBOARD)	+= gpio-viperboard.o
 obj-$(CONFIG_GPIO_VR41XX)	+= gpio-vr41xx.o
 obj-$(CONFIG_GPIO_VX855)	+= gpio-vx855.o
 obj-$(CONFIG_GPIO_WHISKEY_COVE)	+= gpio-wcove.o
+obj-$(CONFIG_GPIO_WINBOND)	+= gpio-winbond.o
 obj-$(CONFIG_GPIO_WM831X)	+= gpio-wm831x.o
 obj-$(CONFIG_GPIO_WM8350)	+= gpio-wm8350.o
 obj-$(CONFIG_GPIO_WM8994)	+= gpio-wm8994.o