nixos-config/config/devterm/devterm-misc-overlay.dts

/dts-v1/;
/plugin/;

/{
	compatible = "brcm,bcm2711";
	
	fragment@0 {
		target = <&i2c1>;
		__overlay__ {
			#address-cells = <1>;
			#size-cells = <0>;
			pinctrl-names = "default";
			pinctrl-0 = <&i2c1_pins>;
			status = "okay";
			
			adc101c: adc@54 {
				reg = <0x54>;
				compatible = "ti,adc101c";
				status = "okay";
			};
		};
	};
	
	fragment@1 {
		target = <&spi4>;
		__overlay__ {
			pinctrl-names = "default";
			pinctrl-0 = <&spi4_pins &spi4_cs_pins>;
			cs-gpios = <&gpio 4 1>;
			status = "okay";
			
			spidev4_0: spidev@0 {
				compatible = "spidev";
				reg = <0>;      /* CE0 */
				#address-cells = <1>;
				#size-cells = <0>;
				spi-max-frequency = <125000000>;
				status = "okay";
			};
		};
	};
	
	fragment@2 {
		target = <&uart1>;
		__overlay__ {
			pinctrl-names = "default";
			pinctrl-0 = <&uart1_pins>;
			status = "okay";
		};
	};
	
	fragment@3 {
		target = <&gpio>;
		__overlay__ {
			
			i2c1_pins: i2c1 {
				brcm,pins = <44 45>;
				brcm,function = <6>;
			};
			
			spi4_pins: spi4_pins {
				brcm,pins = <6 7>;
				brcm,function = <7>;
			};
			
			spi4_cs_pins: spi0_cs_pins {
				brcm,pins = <4>;
				brcm,function = <1>;
			};
			
			uart1_pins: uart1_pins {
				brcm,pins = <14 15>;
				brcm,function = <2>;
				brcm,pull = <0 2>;
			};
			
		};
	};
	
};