board: asus: grouper: add Google Nexus 7 (2012) support

Nexus 7 is a mini tablet computer co-developed by Google and Asus
that runs the Android operating system. The Nexus 7 features a 7"
display, an Nvidia Tegra 3 quad-core chip, 1 GB of RAM and 8/16 GB
of internal storage.

This patch brings support for all 3 known ASUS/Google devices:
- Nexus 7 (2012) E1565
- Nexus 7 (2012) PM269
- Nexus 7 (2012) 3G - tilapia

Tested-by: Andreas Westman Dorcsak <hedmoo@yahoo.com> # ASUS Grouper E1565
Tested-by: Svyatoslav Ryhel <clamor95@gmail.com> # ASUS Grouper E1565
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
diff --git a/arch/arm/dts/tegra30-asus-grouper-common.dtsi b/arch/arm/dts/tegra30-asus-grouper-common.dtsi
new file mode 100644
index 0000000..4fa980f
--- /dev/null
+++ b/arch/arm/dts/tegra30-asus-grouper-common.dtsi
@@ -0,0 +1,157 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <dt-bindings/input/input.h>
+
+#include "tegra30.dtsi"
+
+/ {
+	chosen {
+		stdout-path = &uarta;
+	};
+
+	aliases {
+		i2c0 = &pwr_i2c;
+
+		mmc0 = &sdmmc4;	/* eMMC */
+
+		rtc0 = &pmic;
+		rtc1 = "/rtc@7000e000";
+
+		usb0 = &usb1;
+	};
+
+	memory {
+		device_type = "memory";
+		reg = <0x80000000 0x40000000>;
+	};
+
+	host1x@50000000 {
+		dc@54200000 {
+			nvidia,180-rotation;
+			rgb {
+				status = "okay";
+
+				nvidia,panel = <&panel>;
+			};
+		};
+	};
+
+	gpio@6000d000 {
+		volume-buttons-hog {
+			gpio-hog;
+			gpios = <TEGRA_GPIO(R, 0) GPIO_ACTIVE_HIGH>,
+				<TEGRA_GPIO(Q, 0) GPIO_ACTIVE_HIGH>;
+			output-low;
+		};
+	};
+
+	uarta: serial@70006000 {
+		status = "okay";
+	};
+
+	pwm: pwm@7000a000 {
+		status = "okay";
+	};
+
+	pwr_i2c: i2c@7000d000 {
+		status = "okay";
+		clock-frequency = <400000>;
+	};
+
+	sdmmc4: sdhci@78000600 {
+		status = "okay";
+		bus-width = <8>;
+		non-removable;
+	};
+
+	usb1: usb@7d000000 {
+		status = "okay";
+		dr_mode = "otg";
+	};
+
+	backlight: backlight {
+		compatible = "pwm-backlight";
+
+		enable-gpios = <&gpio TEGRA_GPIO(H, 2) GPIO_ACTIVE_HIGH>;
+		power-supply = <&vdd_5v0_bl>;
+		pwms = <&pwm 0 50000>;
+
+		brightness-levels = <1 35 70 105 140 175 210 255>;
+		default-brightness-level = <5>;
+	};
+
+	/* PMIC has a built-in 32KHz oscillator which is used by PMC */
+	clk32k_in: clock-32k {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <32768>;
+		clock-output-names = "pmic-oscillator";
+	};
+
+	gpio-keys {
+		compatible = "gpio-keys";
+
+		key-power {
+			label = "Power";
+			gpios = <&gpio TEGRA_GPIO(V, 0) GPIO_ACTIVE_LOW>;
+			linux,code = <KEY_ENTER>;
+		};
+
+		key-volume-up {
+			label = "Volume Up";
+			gpios = <&gpio TEGRA_GPIO(Q, 2) GPIO_ACTIVE_LOW>;
+			linux,code = <KEY_UP>;
+		};
+
+		key-volume-down {
+			label = "Volume Down";
+			gpios = <&gpio TEGRA_GPIO(Q, 3) GPIO_ACTIVE_LOW>;
+			linux,code = <KEY_DOWN>;
+		};
+	};
+
+	panel: panel {
+		compatible = "simple-panel";
+
+		power-supply = <&vdd_pnl_reg>;
+		enable-gpios = <&gpio TEGRA_GPIO(N, 6) GPIO_ACTIVE_HIGH>;
+
+		backlight = <&backlight>;
+
+		display-timings {
+			timing@0 {
+				/* 1280x800@60Hz */
+				clock-frequency = <68000000>;
+
+				hactive = <800>;
+				hfront-porch = <24>;
+				hback-porch = <32>;
+				hsync-len = <24>;
+
+				vactive = <1280>;
+				vfront-porch = <5>;
+				vback-porch = <32>;
+				vsync-len = <1>;
+			};
+		};
+	};
+
+	vdd_pnl_reg: regulator-pnl {
+		compatible = "regulator-fixed";
+		regulator-name = "vdd_panel";
+		regulator-min-microvolt = <3300000>;
+		regulator-max-microvolt = <3300000>;
+		gpio = <&gpio TEGRA_GPIO(W, 1) GPIO_ACTIVE_HIGH>;
+		enable-active-high;
+	};
+
+	vdd_5v0_bl: regulator-bl {
+		compatible = "regulator-fixed";
+		regulator-name = "vdd_5v0_bl";
+		regulator-min-microvolt = <5000000>;
+		regulator-max-microvolt = <5000000>;
+		regulator-boot-on;
+		gpio = <&gpio TEGRA_GPIO(H, 3) GPIO_ACTIVE_HIGH>;
+		enable-active-high;
+	};
+};