arm64: dts: qcom: x1e80100-t14s: add EC

Describe ThinkPad Embedded Controller in the T14s device tree,
which adds LED and special key support.

Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on Thinkpad T14S OLED
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Link: https://patch.msgid.link/20250918-thinkpad-t14s-ec-v5-3-ac0bc6382c5c@collabora.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

Author: sre

arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi

@@ -887,6 +887,24 @@
 	};
 };
 
+&i2c6 {
+	clock-frequency = <400000>;
+
+	status = "okay";
+
+	embedded-controller@28 {
+		compatible = "lenovo,thinkpad-t14s-ec";
+		reg = <0x28>;
+
+		interrupts-extended = <&tlmm 66 IRQ_TYPE_LEVEL_LOW>;
+
+		pinctrl-0 = <&ec_int_n_default>;
+		pinctrl-names = "default";
+
+		wakeup-source;
+	};
+};
+
 &i2c7 {
 	clock-frequency = <400000>;
 
@@ -1267,6 +1285,12 @@
 			       <72 2>, /* Secure EC I2C connection (?) */
 			       <238 1>; /* UFS Reset */
 
+	ec_int_n_default: ec-int-n-state {
+		pins = "gpio66";
+		function = "gpio";
+		bias-disable;
+	};
+
 	eusb3_reset_n: eusb3-reset-n-state {
 		pins = "gpio6";
 		function = "gpio";