sunxi: add gpio driver

This patch enables CONFIG_CMD_GPIO for the Allwinner (sunxi) platform as well
as providing the common gpio API (gpio_request/free, direction in/out, get/set
etc).

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ma Haijun <mahaijuns@gmail.com>
Signed-off-by: Oliver Schinagl <oliver@schinagl.nl>
Signed-off-by: Ian Campbell <ijc@hellion.org.uk>
Cc: Henrik Nordström <henrik@henriknordstrom.net>
Cc: Tom Cubie <Mr.hipboi@gmail.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
diff --git a/arch/arm/include/asm/arch-sunxi/gpio.h b/arch/arm/include/asm/arch-sunxi/gpio.h
index 892479c..f7f3d8c 100644
--- a/arch/arm/include/asm/arch-sunxi/gpio.h
+++ b/arch/arm/include/asm/arch-sunxi/gpio.h
@@ -143,5 +143,7 @@
 int sunxi_gpio_get_cfgpin(u32 pin);
 int sunxi_gpio_set_drv(u32 pin, u32 val);
 int sunxi_gpio_set_pull(u32 pin, u32 val);
+int sunxi_name_to_gpio(const char *name);
+#define name_to_gpio(name) sunxi_name_to_gpio(name)
 
 #endif /* _SUNXI_GPIO_H */