iio: adc: stm32-dfsdm: enable hw consumer

Optionally enable IIO hw consumer, when provided (e.g. for DFSDM_IIO type).
This is precursor patch to introduce buffer modes.
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/stm32-dfsdm-adc.c

@@ -630,9 +630,15 @@ static int stm32_dfsdm_postenable(struct iio_dev *indio_dev)
 	/* Reset adc buffer index */
 	adc->bufi = 0;
 
+	if (adc->hwc) {
+		ret = iio_hw_consumer_enable(adc->hwc);
+		if (ret < 0)
+			return ret;
+	}
+
 	ret = stm32_dfsdm_start_dfsdm(adc->dfsdm);
 	if (ret < 0)
-		return ret;
+		goto err_stop_hwc;
 
 	ret = stm32_dfsdm_adc_dma_start(indio_dev);
 	if (ret) {
@@ -652,6 +658,9 @@ static int stm32_dfsdm_postenable(struct iio_dev *indio_dev)
 	stm32_dfsdm_adc_dma_stop(indio_dev);
 stop_dfsdm:
 	stm32_dfsdm_stop_dfsdm(adc->dfsdm);
+err_stop_hwc:
+	if (adc->hwc)
+		iio_hw_consumer_disable(adc->hwc);
 
 	return ret;
 }
@@ -667,6 +676,9 @@ static int stm32_dfsdm_predisable(struct iio_dev *indio_dev)
 
 	stm32_dfsdm_stop_dfsdm(adc->dfsdm);
 
+	if (adc->hwc)
+		iio_hw_consumer_disable(adc->hwc);
+
 	return 0;
 }