gpio: Kconfig: add CONFIG_AT91_GPIO option

The CONFIG_AT91_GPIO option is used to select AT91 PIO GPIO driver.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Andreas Bießmann <andreas@biessmann.org>

drivers/gpio/Kconfig

@@ -28,6 +28,19 @@ config DWAPB_GPIO
 	help
 	  Support for the Designware APB GPIO driver.
 
+config AT91_GPIO
+	bool "AT91 PIO GPIO driver"
+	depends on DM_GPIO
+	default n
+	help
+	  Say yes here to select AT91 PIO GPIO driver. AT91 PIO
+	  controller manages up to 32 fully programmable input/output
+	  lines. Each I/O line may be dedicated as a general-purpose
+	  I/O or be assigned to a function of an embedded peripheral.
+	  The assignment to a function of an embedded peripheral is
+	  the responsibility of AT91 Pinctrl driver. This driver is
+	  responsible for the general-purpose I/O.
+
 config ATMEL_PIO4
 	bool "ATMEL PIO4 driver"
 	depends on DM_GPIO