dm: tegra: Add a GPIO translation function

This deals with the polarity bit and selecting the correct bank device
given a GPIO number.
Signed-off-by: NSimon Glass <sjg@chromium.org>

drivers/gpio/tegra_gpio.c

@@ -21,6 +21,7 @@
 #include <asm/arch/tegra.h>
 #include <asm/gpio.h>
 #include <dm/device-internal.h>
+#include <dt-bindings/gpio/gpio.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -251,6 +252,22 @@ static int tegra_gpio_get_function(struct udevice *dev, unsigned offset)
 		return GPIOF_INPUT;
 }
 
+static int tegra_gpio_xlate(struct udevice *dev, struct gpio_desc *desc,
+			    struct fdtdec_phandle_args *args)
+{
+	int gpio, port, ret;
+
+	gpio = args->args[0];
+	port = gpio / TEGRA_GPIOS_PER_PORT;
+	ret = device_get_child(dev, port, &desc->dev);
+	if (ret)
+		return ret;
+	desc->offset = gpio % TEGRA_GPIOS_PER_PORT;
+	desc->flags = args->args[1] & GPIO_ACTIVE_LOW ? GPIOD_ACTIVE_LOW : 0;
+
+	return 0;
+}
+
 static const struct dm_gpio_ops gpio_tegra_ops = {
 	.request		= tegra_gpio_request,
 	.direction_input	= tegra_gpio_direction_input,
@@ -258,6 +275,7 @@ static const struct dm_gpio_ops gpio_tegra_ops = {
 	.get_value		= tegra_gpio_get_value,
 	.set_value		= tegra_gpio_set_value,
 	.get_function		= tegra_gpio_get_function,
+	.xlate			= tegra_gpio_xlate,
 };
 
 /**