arm64: tegra: Add VDD_GPU regulator to Jetson TX1

Add the VDD_GPU regulator (a GPIO-enabled PWM regulator) to the Jetson
TX1 board. This addition allows the GPU to be used provided the
bootloader properly enabled the GPU node.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
[as pointed out by Thierry on IRC, nobody has reported a bug
 in the field, but using a new bootloader with a .dtb that
 has the incorrect data, it will crash on boot]
Fixes: 336f79c7 ("arm64: tegra: Add NVIDIA Jetson TX1 Developer Kit support")
Cc: stable@vger.kernel.org #v4.5+
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm64/boot/dts/nvidia/tegra210-p2180.dtsi

@@ -21,6 +21,10 @@ memory {
 		reg = <0x0 0x80000000 0x1 0x0>;
 	};
 
+	gpu@57000000 {
+		vdd-supply = <&vdd_gpu>;
+	};
+
 	/* debug port */
 	serial@70006000 {
 		status = "okay";
@@ -291,4 +295,18 @@ clk32k_in: clock@0 {
 			clock-frequency = <32768>;
 		};
 	};
+
+	regulators {
+		vdd_gpu: regulator@100 {
+			compatible = "pwm-regulator";
+			reg = <100>;
+			pwms = <&pwm 1 4880>;
+			regulator-name = "VDD_GPU";
+			regulator-min-microvolt = <710000>;
+			regulator-max-microvolt = <1320000>;
+			enable-gpios = <&pmic 6 GPIO_ACTIVE_HIGH>;
+			regulator-ramp-delay = <80>;
+			regulator-enable-ramp-delay = <1000>;
+		};
+	};
 };