iio: Add new operating mode for non triggered sw buffers

There was a need for non triggered software buffer type.  It can be used when
triggered model does not fit and INDIO_BUFFER_HARDWARE causes confusion because
the data stream can be obtained not directly form hardware backend.

Suggested-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Karol Wrona <k.wrona@samsung.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index 878d861..5902020 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -286,10 +286,11 @@
 /* Device operating modes */
 #define INDIO_DIRECT_MODE		0x01
 #define INDIO_BUFFER_TRIGGERED		0x02
+#define INDIO_BUFFER_SOFTWARE		0x04
 #define INDIO_BUFFER_HARDWARE		0x08
 
 #define INDIO_ALL_BUFFER_MODES					\
-	(INDIO_BUFFER_TRIGGERED | INDIO_BUFFER_HARDWARE)
+	(INDIO_BUFFER_TRIGGERED | INDIO_BUFFER_HARDWARE | INDIO_BUFFER_SOFTWARE)
 
 #define INDIO_MAX_RAW_ELEMENTS		4
 
@@ -593,7 +594,8 @@
 static inline bool iio_buffer_enabled(struct iio_dev *indio_dev)
 {
 	return indio_dev->currentmode
-		& (INDIO_BUFFER_TRIGGERED | INDIO_BUFFER_HARDWARE);
+		& (INDIO_BUFFER_TRIGGERED | INDIO_BUFFER_HARDWARE |
+		   INDIO_BUFFER_SOFTWARE);
 }
 
 /**