1 files changed, 32 insertions, 29 deletions

diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index 1aadb2ad2cab..bd7e2408bf28 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -2006,16 +2006,15 @@ static int stm32_adc_get_legacy_chan_count(struct iio_dev *indio_dev, struct stm
 	 * to get the *real* number of channels.
 	 */
 	ret = device_property_count_u32(dev, "st,adc-diff-channels");
-	if (ret < 0)
-		return ret;
-
-	ret /= (int)(sizeof(struct stm32_adc_diff_channel) / sizeof(u32));
-	if (ret > adc_info->max_channels) {
-		dev_err(&indio_dev->dev, "Bad st,adc-diff-channels?\n");
-		return -EINVAL;
-	} else if (ret > 0) {
-		adc->num_diff = ret;
-		num_channels += ret;
+	if (ret > 0) {
+		ret /= (int)(sizeof(struct stm32_adc_diff_channel) / sizeof(u32));
+		if (ret > adc_info->max_channels) {
+			dev_err(&indio_dev->dev, "Bad st,adc-diff-channels?\n");
+			return -EINVAL;
+		} else if (ret > 0) {
+			adc->num_diff = ret;
+			num_channels += ret;
+		}
 	}
 
 	/* Optional sample time is provided either for each, or all channels */
@@ -2037,6 +2036,7 @@ static int stm32_adc_legacy_chan_init(struct iio_dev *indio_dev,
 	struct stm32_adc_diff_channel diff[STM32_ADC_CH_MAX];
 	struct device *dev = &indio_dev->dev;
 	u32 num_diff = adc->num_diff;
+	int num_se = nchans - num_diff;
 	int size = num_diff * sizeof(*diff) / sizeof(u32);
 	int scan_index = 0, ret, i, c;
 	u32 smp = 0, smps[STM32_ADC_CH_MAX], chans[STM32_ADC_CH_MAX];
@@ -2063,29 +2063,32 @@ static int stm32_adc_legacy_chan_init(struct iio_dev *indio_dev,
 			scan_index++;
 		}
 	}
-
-	ret = device_property_read_u32_array(dev, "st,adc-channels", chans,
-					     nchans);
-	if (ret)
-		return ret;
-
-	for (c = 0; c < nchans; c++) {
-		if (chans[c] >= adc_info->max_channels) {
-			dev_err(&indio_dev->dev, "Invalid channel %d\n",
-				chans[c]);
-			return -EINVAL;
+	if (num_se > 0) {
+		ret = device_property_read_u32_array(dev, "st,adc-channels", chans, num_se);
+		if (ret) {
+			dev_err(&indio_dev->dev, "Failed to get st,adc-channels %d\n", ret);
+			return ret;
 		}
 
-		/* Channel can't be configured both as single-ended & diff */
-		for (i = 0; i < num_diff; i++) {
-			if (chans[c] == diff[i].vinp) {
-				dev_err(&indio_dev->dev, "channel %d misconfigured\n",	chans[c]);
+		for (c = 0; c < num_se; c++) {
+			if (chans[c] >= adc_info->max_channels) {
+				dev_err(&indio_dev->dev, "Invalid channel %d\n",
+					chans[c]);
 				return -EINVAL;
 			}
+
+			/* Channel can't be configured both as single-ended & diff */
+			for (i = 0; i < num_diff; i++) {
+				if (chans[c] == diff[i].vinp) {
+					dev_err(&indio_dev->dev, "channel %d misconfigured\n",
+						chans[c]);
+					return -EINVAL;
+				}
+			}
+			stm32_adc_chan_init_one(indio_dev, &channels[scan_index],
+						chans[c], 0, scan_index, false);
+			scan_index++;
 		}
-		stm32_adc_chan_init_one(indio_dev, &channels[scan_index],
-					chans[c], 0, scan_index, false);
-		scan_index++;
 	}
 
 	if (adc->nsmps > 0) {
@@ -2306,7 +2309,7 @@ static int stm32_adc_chan_fw_init(struct iio_dev *indio_dev, bool timestamping)
 
 	if (legacy)
 		ret = stm32_adc_legacy_chan_init(indio_dev, adc, channels,
-						 num_channels);
+						 timestamping ? num_channels - 1 : num_channels);
 	else
 		ret = stm32_adc_generic_chan_init(indio_dev, adc, channels);
 	if (ret < 0)