pinctrl: at91: add pinctrl driver

AT91 PIO controller is a combined gpio-controller, pin-mux and
pin-config module. The peripheral's pins are assigned through
per-pin based muxing logic.

Each SoC will have to describe the its limitation and pin
configuration via device tree. This will allow to do not need
to touch the C code when adding new SoC if the IP version is
supported.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/include/dt-bindings/pinctrl/at91.h b/include/dt-bindings/pinctrl/at91.h
index bbca3d0..2732d6c 100644
--- a/include/dt-bindings/pinctrl/at91.h
+++ b/include/dt-bindings/pinctrl/at91.h
@@ -15,6 +15,8 @@
 #define AT91_PINCTRL_DEGLITCH		(1 << 2)
 #define AT91_PINCTRL_PULL_DOWN		(1 << 3)
 #define AT91_PINCTRL_DIS_SCHMIT		(1 << 4)
+#define AT91_PINCTRL_OUTPUT		(1 << 7)
+#define AT91_PINCTRL_OUTPUT_VAL(x)	((x & 0x1) << 8)
 #define AT91_PINCTRL_DEBOUNCE		(1 << 16)
 #define AT91_PINCTRL_DEBOUNCE_VAL(x)	(x << 17)