ARM: at91/pio: add new PIO3 features

This patch adds the support for new PIO controller found on some
at91sam SOCs.
- more peripheral multiplexing
- more features to configure on a PIO (pull-down, Schmitt trigger, debouncer)
- support for several IRQ triggering features (type and polarity)

Support for those new features are retrieved from the device tree
compatibility string.

Debugfs at91_gpio file is updated to monitor configuration.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
diff --git a/arch/arm/mach-at91/board-dt.c b/arch/arm/mach-at91/board-dt.c
index acbe23c..583b724 100644
--- a/arch/arm/mach-at91/board-dt.c
+++ b/arch/arm/mach-at91/board-dt.c
@@ -86,6 +86,7 @@
 
 	{ .compatible = "atmel,at91rm9200-aic", .data = at91_aic_of_init },
 	{ .compatible = "atmel,at91rm9200-gpio", .data = at91_gpio_of_irq_setup },
+	{ .compatible = "atmel,at91sam9x5-gpio", .data = at91_gpio_of_irq_setup },
 	{ /*sentinel*/ }
 };