adc channel config error in custom board and devicetree config

[billywalton]

Hi,

I have a custom board, i enable the adc peripheral, and it generates:

	zephyr,user {

		io-channels = <&adc 4>;
	};

		adc: adc@40007000 {
			compatible = "nordic,nrf-saadc";
			reg = <0x40007000 0x1000>;
			interrupts = <7 NRF_DEFAULT_IRQ_PRIORITY>;
			status = "disabled";
			#io-channel-cells = <1>;
		};

then i connect the AIN4 channel and it generates:

&adc {
	status = "okay";
	channel@4 {
		reg = <4>;
		zephyr,gain = "ADC_GAIN_1_6";
		zephyr,reference = "ADC_REF_VDD_1";
		zephyr,acquisition-time = <0>;
	};
};

but when i build i get the following error:

devicetree error: 'reg' property in <Node /soc/adc@40007000/channel@4 in '/home/billy/ncs/v2.9.1/zephyr/misc/empty_file.c'> has length 4, which is not evenly divisible by 12 (= 4*(<#address-cells> (= 2) + <#size-cells> (= 1))). Note that #*-cells properties come either from the parent node or from the controller (in the case of 'interrupts').

What should this channel reg property be set to? 4 * <something>?

[billywalton]

changing the &adc entry to the following allows the build to complete

&adc {
	status = "okay";
	#address-cells = <1>;
	#size-cells = <0>;
	channel@4 {
		reg = <4>;
		zephyr,gain = "ADC_GAIN_1_6";
		zephyr,reference = "ADC_REF_VDD_1";
		zephyr,acquisition-time = <0>;
	};

	#io-channel-cells = <1>;
};

adding the address-cells and size-cells proerties, are these the correct values?

[Sigurd Hellesvik]

Looks like what for example nrf5340_audio_dk_nrf5340_cpuapp_common.dtsi is doing, so I guess that should be right. Well, the boardfile example use reg=0 instead. And in my experience, the first "group" under a DTS node starts at reg 0 as well, so I suggest that you try to use 0.