iio: inkern: add iio_read_channel_average_raw

Add iio_read_channel_average_raw to support reading
averaged raw values in consumer drivers.
Signed-off-by: Sebastian Reichel <sre@debian.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/inkern.c

@@ -443,6 +443,24 @@ int iio_read_channel_raw(struct iio_channel *chan, int *val)
 }
 EXPORT_SYMBOL_GPL(iio_read_channel_raw);
 
+int iio_read_channel_average_raw(struct iio_channel *chan, int *val)
+{
+	int ret;
+
+	mutex_lock(&chan->indio_dev->info_exist_lock);
+	if (chan->indio_dev->info == NULL) {
+		ret = -ENODEV;
+		goto err_unlock;
+	}
+
+	ret = iio_channel_read(chan, val, NULL, IIO_CHAN_INFO_AVERAGE_RAW);
+err_unlock:
+	mutex_unlock(&chan->indio_dev->info_exist_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iio_read_channel_average_raw);
+
 static int iio_convert_raw_to_processed_unlocked(struct iio_channel *chan,
 	int raw, int *processed, unsigned int scale)
 {

include/linux/iio/consumer.h

@@ -122,6 +122,19 @@ struct iio_channel
 int iio_read_channel_raw(struct iio_channel *chan,
 			 int *val);
 
+/**
+ * iio_read_channel_average_raw() - read from a given channel
+ * @chan:		The channel being queried.
+ * @val:		Value read back.
+ *
+ * Note raw reads from iio channels are in adc counts and hence
+ * scale will need to be applied if standard units required.
+ *
+ * In opposit to the normal iio_read_channel_raw this function
+ * returns the average of multiple reads.
+ */
+int iio_read_channel_average_raw(struct iio_channel *chan, int *val);
+
 /**
  * iio_read_channel_processed() - read processed value from a given channel
  * @chan:		The channel being queried.