stm32h7: ADC acquisition time not set

[geblerg]

Describe the bug

The macro ADC_ACQ_TIME is used in adc_stm32.c, adc_stm32_sampling_time_check() to pick the index of sampling_time_table:

for (int i = 0; i < STM32_NB_SAMPLING_TIME; i++) { if (acq_time == ADC_ACQ_TIME(ADC_ACQ_TIME_TICKS, config->sampling_time_table[i])) { return i; }

This is useful for setting the "zephyr,acquisition-time" property but not for retrieving the value at an index
Using the raw value at current index of sampling_time_table leads to picking the correct index:

for (int i = 0; i < STM32_NB_SAMPLING_TIME; i++) { if (acq_time == config->sampling_time_table[i]) { return i; } }

Regression

• This is a regression.

Steps to reproduce

Use adc_stm32.c, adc_stm32_sampling_time_check(const struct device *dev, uint16_t acq_time) with any parameter.

Relevant log output

Impact

Functional Limitation – Some features not working as expected, but system usable.

Environment

• Zephyr 4.1

Additional Context

No response

[etienne-lms]

Hi @geblerg,
adc_stm32_sampling_time_check() is called only from adc_stm32_sampling_time_setup() itself called only from adc_stm32_channel_setup() that sets acq_time from channel_cfg->acquisition_time (4.1.0 ref here). As per const struct adc_channel_cfg description, field acquisition_time is expected to be encoded with ADC_ACQ_TIME(), not raw. I think the current driver implementation is fine. Could you give some details on the usecases/samples with which you found this issue?