diff --git a/drivers/iio/adc/stm32-adc-core.c b/drivers/iio/adc/stm32-adc-core.c
index 74f3a2be17a6..14d6a537289c 100644
--- a/drivers/iio/adc/stm32-adc-core.c
+++ b/drivers/iio/adc/stm32-adc-core.c
@@ -780,6 +780,13 @@ static int stm32_adc_core_runtime_resume(struct device *dev)
 {
 	return stm32_adc_core_hw_start(dev);
 }
+
+static int stm32_adc_core_runtime_idle(struct device *dev)
+{
+	pm_runtime_mark_last_busy(dev);
+
+	return 0;
+}
 #endif
 
 static const struct dev_pm_ops stm32_adc_core_pm_ops = {
@@ -787,7 +794,7 @@ static const struct dev_pm_ops stm32_adc_core_pm_ops = {
 				pm_runtime_force_resume)
 	SET_RUNTIME_PM_OPS(stm32_adc_core_runtime_suspend,
 			   stm32_adc_core_runtime_resume,
-			   NULL)
+			   stm32_adc_core_runtime_idle)
 };
 
 static const struct stm32_adc_priv_cfg stm32f4_adc_priv_cfg = {