Battery Sample - runtime error "voltage: setup: -134"

Question

Hello, I'm building the sample Measure battery voltage on a custom board, and I have an error voltage: setup: -134 at runtime. SEGGER J-Link V7.94i - Real time terminal output SEGGER J-Link (unknown) V1.0, SN=1050264300 Process: JLink.exe [00:00:00.390,777] voltage: setup: -134 *** Booting nRF Connect SDK v2.9.0-7787b2649840 *** *** Using Zephyr OS v3.7.99-1f8f3dc29142 *** [00:00:04.254,882] BATTERY: Setup AIN2 got 0 [00:00:04.254,882] BATTERY: Battery setup: 0 1 [00:00:04.262,878] BATTERY: raw 1348 ~ 296 mV => 3256 mV The overlay file is configure as explained in the sample: /{ vbatt { compatible = "voltage-divider"; io-channels = <&adc 2>; output-ohms = <100000>; // 100k full-ohms = <(100000 + 1000000)>; // 100k + 1M power-gpios = <&gpio0 11 GPIO_ACTIVE_HIGH>; }; }; &adc { status = "okay"; }; And the code in the sample has not been changed. I use the SDK v2.9.0 From what I can trace, the compatible = "voltage-divider " ; will configure the .config with DT_HAS_VOLTAGE_DIVIDER_ENABLED , therefore enabling the "voltage_divider" folder located in < zephyr/drivers/sensors/voltage_divider> . The error comes from the file voltage.c , more specifically the initialisation function called by the macro DT_INST_FOREACH_STATUS_OKAY(VOLTAGE_INIT) static int voltage_init(const struct device *dev) { const struct voltage_config *config = dev->config; struct voltage_data *data = dev->data; int ret; if (!adc_is_ready_dt(&config->voltage.port)) { LOG_ERR("ADC is not ready"); return -ENODEV; } if (config->gpio_power.port != NULL) { if (!gpio_is_ready_dt(&config->gpio_power)) { LOG_ERR("Power GPIO is not ready"); return -ENODEV; } } ret = adc_channel_setup_dt(&config->voltage.port); if (ret != 0) { LOG_ERR("setup: %d", ret); return ret; } ret = adc_sequence_init_dt(&config->voltage.port, &data->sequence); if (ret != 0) { LOG_ERR("sequence init: %d", ret); return ret; } data->sequence.buffer = &data->raw; data->sequence.buffer_size = sizeof(data->raw); return pm_device_driver_init(dev, pm_action); } #define VOLTAGE_INIT(inst) \ static struct voltage_data voltage_##inst##_data; \ \ static const struct voltage_config voltage_##inst##_config = { \ .voltage = VOLTAGE_DIVIDER_DT_SPEC_GET(DT_DRV_INST(inst)), \ .gpio_power = GPIO_DT_SPEC_INST_GET_OR(inst, power_gpios, {0}), \ }; \ \ PM_DEVICE_DT_INST_DEFINE(inst, pm_action); \ \ SENSOR_DEVICE_DT_INST_DEFINE(inst, &voltage_init, PM_DEVICE_DT_INST_GET(inst), \ &voltage_##inst##_data, &voltage_##inst##_config, POST_KERNEL, \ CONFIG_SENSOR_INIT_PRIORITY, &voltage_api); DT_INST_FOREACH_STATUS_OKAY(VOLTAGE_INIT) The function adc_channel_setup_dt(&config->voltage.port) will fail as it is called POST_KERNEL and the parameters of the ADC are not configured yet . The driver for adc is and the function: /* Implementation of the ADC driver API function: adc_channel_setup. */ static int adc_nrfx_channel_setup(const struct device *dev, const struct adc_channel_cfg *channel_cfg) { ... } implement the adc_channel_setup . I'm not sure where the error is coming from next, but I guess from int ret = adc_convert_acq_time(channel_cfg->acquisition_time, &config.acq_time); as the acquisition time of the ADC has never been defined, and is done at run time in the sample (therefore at APPLICATION level and not POST_KERNEL ). Could you tell me why the ADC is not configured in the overlay file for something similar as: &adc { #address-cells = <1>; #size-cells = <0>; status = "okay"; channel@0 { reg = <0>; zephyr,gain = "ADC_GAIN_1_6"; zephyr,reference = "ADC_REF_INTERNAL"; zephyr,acquisition-time = ; zephyr,input-positive = ; zephyr,resolution = <12>; }; }; I checked as well the board definiton for the Nordic Thingy52 and there is not definition for the ADC, therefore I guess the error is happening as well. Please, let me know how to get rid of that error, and correct the sample if necessay. Thank you.