diff --git a/extensions/openpower-pels/bcd_time.cpp b/extensions/openpower-pels/bcd_time.cpp
index 24de908..c5dd0d8 100644
--- a/extensions/openpower-pels/bcd_time.cpp
+++ b/extensions/openpower-pels/bcd_time.cpp
@@ -73,7 +73,7 @@
     return s;
 }
 
-Stream& operator<<(Stream& s, BCDTime& time)
+Stream& operator<<(Stream& s, const BCDTime& time)
 {
     s << time.yearMSB << time.yearLSB << time.month << time.day << time.hour;
     s << time.minutes << time.seconds << time.hundredths;
diff --git a/extensions/openpower-pels/bcd_time.hpp b/extensions/openpower-pels/bcd_time.hpp
index 86d9f4e..72c5755 100644
--- a/extensions/openpower-pels/bcd_time.hpp
+++ b/extensions/openpower-pels/bcd_time.hpp
@@ -90,7 +90,7 @@
  *
  * @return Stream&
  */
-Stream& operator<<(Stream& s, BCDTime& time);
+Stream& operator<<(Stream& s, const BCDTime& time);
 
 } // namespace pels
 } // namespace openpower