dm: exynos: Add a GPIO translation function

This deals with the polarity bit. It also changes the GPIO devices so that
the correct device tree node is linked to each one. This allows us to use
the new uclass phandle functionality to implement a proper GPIO binding.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/gpio/s5p_gpio.c b/drivers/gpio/s5p_gpio.c
index 6c41a42..0a245ba 100644
--- a/drivers/gpio/s5p_gpio.c
+++ b/drivers/gpio/s5p_gpio.c
@@ -13,6 +13,7 @@
 #include <asm/io.h>
 #include <asm/gpio.h>
 #include <dm/device-internal.h>
+#include <dt-bindings/gpio/gpio.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -275,12 +276,22 @@
 		return GPIOF_FUNC;
 }
 
+static int exynos_gpio_xlate(struct udevice *dev, struct gpio_desc *desc,
+			     struct fdtdec_phandle_args *args)
+{
+	desc->offset = args->args[0];
+	desc->flags = args->args[1] & GPIO_ACTIVE_LOW ? GPIOD_ACTIVE_LOW : 0;
+
+	return 0;
+}
+
 static const struct dm_gpio_ops gpio_exynos_ops = {
 	.direction_input	= exynos_gpio_direction_input,
 	.direction_output	= exynos_gpio_direction_output,
 	.get_value		= exynos_gpio_get_value,
 	.set_value		= exynos_gpio_set_value,
 	.get_function		= exynos_gpio_get_function,
+	.xlate			= exynos_gpio_xlate,
 };
 
 static int gpio_exynos_probe(struct udevice *dev)
@@ -342,7 +353,7 @@
 					plat->bank_name, plat, -1, &dev);
 		if (ret)
 			return ret;
-		dev->of_offset = parent->of_offset;
+		dev->of_offset = node;
 	}
 
 	return 0;