arm64: dts: mediatek: asurada: Add I2C touchscreen

All machines of the Asurada platform have a touchscreen at address 0x10
in the I2C0 bus, but the devices vary: Spherion has the Elan eKTH3500
touchscreen, while Hayato has a generic HID-over-i2c touchscreen.

Add common support for the touchscreens on the platform and the
specifics in each board file.
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Tested-by: Chen-Yu Tsai <wenst@chromium.org>
Link: https://lore.kernel.org/r/20220629155956.1138955-12-nfraprado@collabora.comSigned-off-by: Matthias Brugger <matthias.bgg@gmail.com>

arch/arm64/boot/dts/mediatek/mt8192-asurada-hayato-r1.dts

@@ -38,3 +38,10 @@ MATRIX_KEY(0x00, 0x04, KEY_VOLUMEUP)
 		CROS_STD_MAIN_KEYMAP
 	>;
 };
+
+&touchscreen {
+	compatible = "hid-over-i2c";
+	post-power-on-delay-ms = <10>;
+	hid-descr-addr = <0x0001>;
+	vdd-supply = <&pp3300_u>;
+};

arch/arm64/boot/dts/mediatek/mt8192-asurada-spherion-r0.dts

@@ -40,3 +40,7 @@ MATRIX_KEY(0x00, 0x04, KEY_VOLUMEUP)
 		CROS_STD_MAIN_KEYMAP
 	>;
 };
+
+&touchscreen {
+	compatible = "elan,ekth3500";
+};

arch/arm64/boot/dts/mediatek/mt8192-asurada.dtsi

@@ -92,6 +92,13 @@ &i2c0 {
 	clock-frequency = <400000>;
 	pinctrl-names = "default";
 	pinctrl-0 = <&i2c0_pins>;
+
+	touchscreen: touchscreen@10 {
+		reg = <0x10>;
+		interrupts-extended = <&pio 21 IRQ_TYPE_LEVEL_LOW>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&touchscreen_pins>;
+	};
 };
 
 &i2c1 {
@@ -454,6 +461,24 @@ pins-int-n {
 			bias-pull-up = <MTK_PUPD_SET_R1R0_11>;
 		};
 	};
+
+	touchscreen_pins: touchscreen-default-pins {
+		pins-irq {
+			pinmux = <PINMUX_GPIO21__FUNC_GPIO21>;
+			input-enable;
+			bias-pull-up;
+		};
+
+		pins-reset {
+			pinmux = <PINMUX_GPIO137__FUNC_GPIO137>;
+			output-high;
+		};
+
+		pins-report-sw {
+			pinmux = <PINMUX_GPIO138__FUNC_GPIO138>;
+			output-low;
+		};
+	};
 };
 
 &spi1 {