NTC build error migrating from nRF Connect v2.4.2 to 2.5

[benoit.gorostidi]

Hello,

We works on a project that use a custom board based on nRF5340 with an NTC. Everything works fine with nRF Connect v2.4.2.

Migrating to v2.5 of the SDK generates error on this project due to NTC.

/home/bgorostidi/Workspace/Toolchains/nrfConnect_SDK/toolchains/7795df4459/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.bfd: app/libapp.a(power_module.c.obj):/home/bgorostidi/Workspace/Projects/Iot/9220Sparklin_NRF53/src/modules/power_module.c:71: undefined reference to `__device_dts_ord_4'
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.
FATAL ERROR: command exited with status 1: /home/bgorostidi/Workspace/Toolchains/nrfConnect_SDK/toolchains/7795df4459/usr/local/bin/cmake --build /home/bgorostidi/Workspace/Projects/Iot/9220Sparklin_NRF53/build

Based on information in build folder, "__device_dts_ord_4" is the NTC node.

/*
 * Generated by gen_defines.py
 *
 * DTS input file:
 *   /home/bgorostidi/Workspace/Projects/Iot/9220Sparklin_NRF53/build/zephyr/zephyr.dts.pre
 *
 * Directories with bindings:
 *   /home/bgorostidi/Workspace/Toolchains/nrfConnect_SDK/v2.5.0/nrf/dts/bindings, /home/bgorostidi/Workspace/Projects/Iot/9220Sparklin_NRF53/dts/bindings, $ZEPHYR_BASE/dts/bindings
 *
 * Node dependency ordering (ordinal and path):
 *   0   /
 *   1   /aliases
 *   2   /chosen
 *   3   /entropy_bt_hci
 *   4   /ntc-thermistor

Extract of our dts:

	table: ntc-thermistor-rt-table {
		compatible = "zephyr,ntc-thermistor-rt-table";
		tr-table = <0 15000>, <10 9760>, <20 6500>, <30 4430>, <40 3090>, <50 2190>, <60 1580>, <70 1160>, <80 870>, <85 750>;

	};

	temp_sensor: ntc-thermistor {
		compatible = "zephyr,ntc-thermistor";
		io-channels = <&adc 6>;
		zephyr,rt-table = <&table>;
		r25-ohm = <5100>;
		pullup-uv = <0>;
		pullup-ohm = <0>;
		pulldown-ohm = <1300>;
		connection-type = "NTC_CONNECTED_POSITIVE";
	};

Does the new SDK version include some changes on NTC part?

Best regards

[helsing]

Hi benoit, sorry for the delay.

According to the release notes for Zephyr v3.5.0 there have been "Various fixes and enhancements in the NTC thermistor and INA23x drivers." The release notes also mentions that, for ntc-thermistor-generic, the property 'r25-ohm' has been removed.

Try removing the r25-ohm property from your code.

For details: https://github.com/zephyrproject-rtos/zephyr/commit/5db05878ab6ef2592281e068b5372d1dd6c62571

[benoit.gorostidi]

Hi Helsing,

I found a working option with ntc-thermistor-generic but r25-ohm is needed to avoid build error.

	 temp_sensor: ntc-thermistor {
		compatible = "ntc-thermistor-generic";
		status = "okay";
		io-channels = <&adc 6>;
		r25-ohm = <5100>;
		pullup-uv = <0>;
		pullup-ohm = <0>;
		pulldown-ohm = < 1300 >;
		connected-positive;
		zephyr,compensation-table = <0 15000>, <10 9760>, <20 6500>, <30 4430>, <40 3090>, <50 2190>, <60 1580>, <70 1160>, <80 870>, <85 750>;	
	};

Thanks for your help.

Best regards.

[helsing]

Great to hear that it is working. Thank you for sharing your solution.