ARM: tegra: add USB ULPI PHY reset GPIO to device tree

ULPI PHYs have a reset signal, and different boards use a different GPIO
for this task. Add a property to device tree to represent this.

I'm not sure if adding this property to the EHCI controller node is
entirely correct; perhaps eventually we should have explicit separate
nodes for the various PHYs. However, we don't have that right now, so this
binding seems like a reasonable choice.

Cc: <devicetree-discuss@lists.ozlabs.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <linux-usb@vger.kernel.org>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
diff --git a/arch/arm/mach-tegra/usb_phy.c b/arch/arm/mach-tegra/usb_phy.c
index d71d2fe..54e353c 100644
--- a/arch/arm/mach-tegra/usb_phy.c
+++ b/arch/arm/mach-tegra/usb_phy.c
@@ -26,6 +26,7 @@
 #include <linux/platform_device.h>
 #include <linux/io.h>
 #include <linux/gpio.h>
+#include <linux/of_gpio.h>
 #include <linux/usb/otg.h>
 #include <linux/usb/ulpi.h>
 #include <asm/mach-types.h>
@@ -654,8 +655,8 @@
 	clk_disable(phy->clk);
 }
 
-struct tegra_usb_phy *tegra_usb_phy_open(int instance, void __iomem *regs,
-			void *config, enum tegra_usb_phy_mode phy_mode)
+struct tegra_usb_phy *tegra_usb_phy_open(struct device *dev, int instance,
+	void __iomem *regs, void *config, enum tegra_usb_phy_mode phy_mode)
 {
 	struct tegra_usb_phy *phy;
 	struct tegra_ulpi_config *ulpi_config;
@@ -711,6 +712,16 @@
 			err = -ENXIO;
 			goto err1;
 		}
+		if (!gpio_is_valid(ulpi_config->reset_gpio))
+			ulpi_config->reset_gpio =
+				of_get_named_gpio(dev->of_node,
+						  "nvidia,phy-reset-gpio", 0);
+		if (!gpio_is_valid(ulpi_config->reset_gpio)) {
+			pr_err("%s: invalid reset gpio: %d\n", __func__,
+			       ulpi_config->reset_gpio);
+			err = -EINVAL;
+			goto err1;
+		}
 		gpio_request(ulpi_config->reset_gpio, "ulpi_phy_reset_b");
 		gpio_direction_output(ulpi_config->reset_gpio, 0);
 		phy->ulpi = otg_ulpi_create(&ulpi_viewport_access_ops, 0);