iio: adc: meson: add channel labels

Add channel labels to provide human-readable names for the inputs.
Signed-off-by: George Stark <GNStark@sberdevices.ru>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230714114010.293440-6-gnstark@sberdevices.ruSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/meson_saradc.c

@@ -1055,8 +1055,20 @@ static int meson_sar_adc_calib(struct iio_dev *indio_dev)
 	return ret;
 }
 
+static int read_label(struct iio_dev *indio_dev,
+		      struct iio_chan_spec const *chan,
+		      char *label)
+{
+	if (chan->type == IIO_TEMP)
+		return sprintf(label, "temp-sensor\n");
+	if (chan->type == IIO_VOLTAGE)
+		return sprintf(label, "channel-%d\n", chan->channel);
+	return 0;
+}
+
 static const struct iio_info meson_sar_adc_iio_info = {
 	.read_raw = meson_sar_adc_iio_info_read_raw,
+	.read_label = read_label,
 };
 
 static const struct meson_sar_adc_param meson_sar_adc_meson8_param = {