gpio: add flags to export GPIOs when requesting

Introduce new flags to automatically export GPIOs when using the convenience
functions gpio_request_one() or gpio_request_array(). This eases support for
custom boards where lots of GPIOs need to be exported for customer
applications.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/include/linux/gpio.h b/include/linux/gpio.h
index 6155ecf..af511a6 100644
--- a/include/linux/gpio.h
+++ b/include/linux/gpio.h
@@ -20,6 +20,11 @@
 /* Gpio pin is open source */
 #define GPIOF_OPEN_SOURCE	(1 << 3)
 
+#define GPIOF_EXPORT		(1 << 2)
+#define GPIOF_EXPORT_CHANGEABLE	(1 << 3)
+#define GPIOF_EXPORT_DIR_FIXED	(GPIOF_EXPORT)
+#define GPIOF_EXPORT_DIR_CHANGEABLE (GPIOF_EXPORT | GPIOF_EXPORT_CHANGEABLE)
+
 /**
  * struct gpio - a structure describing a GPIO with configuration
  * @gpio:	the GPIO number