iio: buffer: document iio_push_to_buffers() calling context

Document that iio_push_to_buffers() can be called from any context.

Also document the Return: value while here.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/industrialio-buffer.c

@@ -2372,6 +2372,9 @@ static int iio_push_to_buffer(struct iio_buffer *buffer, const void *data)
  * iio_push_to_buffers() - push to a registered buffer.
  * @indio_dev:		iio_dev structure for device.
  * @data:		Full scan.
+ *
+ * Context: Any context.
+ * Return: 0 on success, negative error code on failure.
  */
 int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data)
 {