iio: buffer: document iio_push_to_buffers_with_ts()

Document the iio_push_to_buffers_with_ts() function.

This is copied and slightly cleaned up from
iio_push_to_buffers_with_timestamp().

Signed-off-by: David Lechner <[e-mail]>
Signed-off-by: Jonathan Cameron <[e-mail]>

include/linux/iio/buffer.h

···
 	return iio_push_to_buffers(indio_dev, data);
 }
 
+/**
+ * iio_push_to_buffers_with_ts() - push data and timestamp to buffers
+ * @indio_dev:		iio_dev structure for device.
+ * @data:		Pointer to sample data buffer.
+ * @data_total_len:	The size of @data in bytes.
+ * @timestamp:		Timestamp for the sample data.
+ *
+ * Pushes data to the IIO device's buffers. If timestamps are enabled for the
+ * device the function will store the supplied timestamp as the last element in
+ * the sample data buffer before pushing it to the device buffers. The sample
+ * data buffer needs to be large enough to hold the additional timestamp
+ * (usually the buffer should be at least indio->scan_bytes bytes large).
+ *
+ * Context: Any context.
+ * Return: 0 on success, a negative error code otherwise.
+ */
 static inline int iio_push_to_buffers_with_ts(struct iio_dev *indio_dev,
 					      void *data, size_t data_total_len,
 					      s64 timestamp)