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>
diff --git a/include/linux/iio/consumer.h b/include/linux/iio/consumer.h
index 2752b1f..651f9a0 100644
--- a/include/linux/iio/consumer.h
+++ b/include/linux/iio/consumer.h
@@ -123,6 +123,19 @@
 			 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.
  * @val:		Value read back.