diff --git a/api/mraa/spi.hpp b/api/mraa/spi.hpp
index 7ab1f9f..fa586d9 100644
--- a/api/mraa/spi.hpp
+++ b/api/mraa/spi.hpp
@@ -111,8 +111,8 @@ class Spi {
 
         /**
          * Write buffer of bytes to SPI device The pointer return has to be
-	 * free'd by the caller. It will return a NULL pointer in cases of
-	 * error
+         * free'd by the caller. It will return a NULL pointer in cases of
+         * error
          *
          * @param txBuf buffer to send
          * @param length size of buffer to send