arm64: dts: allwinner: anbernic-rg35xx-h: Add ADC joysticks

Add support for the ADC joysticks found on the Anbernic RG35XX-H. The
joysticks use one channel of the GPADC which is muxed 4 ways by an ADC
mux.

Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
Link: https://lore.kernel.org/r/20240605172049.231108-5-macroalpha82@gmail.com
Signed-off-by: Chen-Yu Tsai <wens@csie.org>

Author: macromorgan

arch/arm64/boot/dts/allwinner/sun50i-h700-anbernic-rg35xx-h.dts

@@ -9,6 +9,78 @@
 / {
 	model = "Anbernic RG35XX H";
 	compatible = "anbernic,rg35xx-h", "allwinner,sun50i-h700";
+
+	adc-joystick {
+		compatible = "adc-joystick";
+		io-channels = <&adc_mux 0>,
+			      <&adc_mux 1>,
+			      <&adc_mux 2>,
+			      <&adc_mux 3>;
+		pinctrl-0 = <&joy_mux_pin>;
+		pinctrl-names = "default";
+		poll-interval = <60>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		axis@0 {
+			reg = <0>;
+			abs-flat = <32>;
+			abs-fuzz = <32>;
+			abs-range = <4096 0>;
+			linux,code = <ABS_X>;
+		};
+
+		axis@1 {
+			reg = <1>;
+			abs-flat = <32>;
+			abs-fuzz = <32>;
+			abs-range = <0 4096>;
+			linux,code = <ABS_Y>;
+		};
+
+		axis@2 {
+			reg = <2>;
+			abs-flat = <32>;
+			abs-fuzz = <32>;
+			abs-range = <0 4096>;
+			linux,code = <ABS_RX>;
+		};
+
+		axis@3 {
+			reg = <3>;
+			abs-flat = <32>;
+			abs-fuzz = <32>;
+			abs-range = <4096 0>;
+			linux,code = <ABS_RY>;
+		};
+	};
+
+	adc_mux: adc-mux {
+		compatible = "io-channel-mux";
+		channels = "left_x", "left_y", "right_x", "right_y";
+		#io-channel-cells = <1>;
+		io-channels = <&gpadc 0>;
+		io-channel-names = "parent";
+		mux-controls = <&gpio_mux>;
+		settle-time-us = <100>;
+	};
+
+	gpio_mux: mux-controller {
+		compatible = "gpio-mux";
+		mux-gpios = <&pio 8 1 GPIO_ACTIVE_LOW>,
+			    <&pio 8 2 GPIO_ACTIVE_LOW>;
+		#mux-control-cells = <0>;
+	};
+};
+
+&gpadc {
+	#address-cells = <1>;
+	#size-cells = <0>;
+	status = "okay";
+
+	channel@0 {
+		reg = <0>;
+	};
 };
 
 &gpio_keys_gamepad {
@@ -34,3 +106,10 @@
 &ohci1 {
 	status = "okay";
 };
+
+&pio {
+	joy_mux_pin: joy-mux-pin {
+		pins = "PI0";
+		function = "gpio_out";
+	};
+};