[PATCH v2 9/9] arm64: dts: mediatek: Add Xiaomi Poco X4 GT

[Alexander Letuchiy <asalde.le1@gmail.com>]

Add a device tree for the Xiaomi xaga board, which is sold as Xiaomi
Poco X4 GT, Redmi Note 11T Pro/Pro+ and Redmi K50i. It enables a serial
console on UART0 and the volume down key on the SoC keypad. The power
and volume up keys are connected to the MT6363 PMIC, which isn't
supported yet.

The DT only describes the memory that Linux itself uses, which is the
ramoops region. The bootloader updates the /memory node and adds the
firmware carveouts to /reserved-memory, so their addresses are not
hardcoded here. This DT must not be booted with a bootloader that does
not do this, as Linux would then use memory owned by the firmware.

The ramoops zone sizes place the console zone at the offset where the
bootloader expects to find it.

Signed-off-by: Alexander Letuchiy <asalde.le1@gmail.com>
---
 arch/arm64/boot/dts/mediatek/Makefile              |  1 +
 .../arm64/boot/dts/mediatek/mt6895-xiaomi-xaga.dts | 87 ++++++++++++++++++++++
 2 files changed, 88 insertions(+)

diff --git a/arch/arm64/boot/dts/mediatek/Makefile b/arch/arm64/boot/dts/mediatek/Makefile
index a86fb313b1a9..d73489149ab5 100644
--- a/arch/arm64/boot/dts/mediatek/Makefile
+++ b/arch/arm64/boot/dts/mediatek/Makefile
@@ -6,6 +6,7 @@ dtb-$(CONFIG_ARCH_MEDIATEK) += mt6795-evb.dtb
 dtb-$(CONFIG_ARCH_MEDIATEK) += mt6795-sony-xperia-m5.dtb
 dtb-$(CONFIG_ARCH_MEDIATEK) += mt6797-evb.dtb
 dtb-$(CONFIG_ARCH_MEDIATEK) += mt6797-x20-dev.dtb
+dtb-$(CONFIG_ARCH_MEDIATEK) += mt6895-xiaomi-xaga.dtb
 dtb-$(CONFIG_ARCH_MEDIATEK) += mt7622-rfb1.dtb
 dtb-$(CONFIG_ARCH_MEDIATEK) += mt7622-bananapi-bpi-r64.dtb
 dtb-$(CONFIG_ARCH_MEDIATEK) += mt7981b-cudy-wr3000-v1.dtb
diff --git a/arch/arm64/boot/dts/mediatek/mt6895-xiaomi-xaga.dts b/arch/arm64/boot/dts/mediatek/mt6895-xiaomi-xaga.dts
new file mode 100644
index 000000000000..8d529062eea1
--- /dev/null
+++ b/arch/arm64/boot/dts/mediatek/mt6895-xiaomi-xaga.dts
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: (GPL-2.0 OR MIT)
+/*
+ * Copyright (C) 2026 Alexander Letuchiy <asalde.le1@gmail.com>
+ */
+
+/dts-v1/;
+#include <dt-bindings/input/input.h>
+
+#include "mt6895.dtsi"
+
+/ {
+	model = "Xiaomi Poco X4 GT";
+	compatible = "xiaomi,xaga", "mediatek,mt6895";
+	chassis-type = "handset";
+
+	aliases {
+		serial0 = &uart0;
+	};
+
+	chosen {
+		stdout-path = "serial0:921600n8";
+	};
+
+	memory@40000000 {
+		device_type = "memory";
+		/* The size is updated by the bootloader. */
+		reg = <0x0 0x40000000 0x2 0x0>;
+	};
+
+	reserved-memory {
+		ranges;
+		#address-cells = <2>;
+		#size-cells = <2>;
+
+		/* The firmware carveouts are added by the bootloader. */
+
+		ramoops@48090000 {
+			compatible = "ramoops";
+			reg = <0 0x48090000 0 0xe0000>;
+			no-map;
+			record-size = <0x10000>;
+			console-size = <0x40000>;
+			ftrace-size = <0x10000>;
+			pmsg-size = <0x10000>;
+		};
+	};
+};
+
+&keypad {
+	pinctrl-0 = <&keypad_pins>;
+	pinctrl-names = "default";
+	debounce-delay-ms = <32>;
+	keypad,num-columns = <1>;
+	keypad,num-rows = <1>;
+	linux,keymap = <MATRIX_KEY(0, 0, KEY_VOLUMEDOWN)>;
+
+	status = "okay";
+};
+
+&pio {
+	keypad_pins: keypad-pins {
+		pins-col {
+			pinmux = <PINMUX_GPIO107__FUNC_KPCOL0>;
+			bias-pull-up = <MTK_PUPD_SET_R1R0_01>;
+			input-enable;
+		};
+	};
+
+	uart0_pins: uart0-pins {
+		pins-rx {
+			pinmux = <PINMUX_GPIO88__FUNC_URXD0>;
+			bias-pull-up;
+			input-enable;
+		};
+
+		pins-tx {
+			pinmux = <PINMUX_GPIO89__FUNC_UTXD0>;
+		};
+	};
+};
+
+&uart0 {
+	pinctrl-0 = <&uart0_pins>;
+	pinctrl-names = "default";
+
+	status = "okay";
+};

-- 
2.56.0