diff --git a/include/lib/pmf/pmf.h b/include/lib/pmf/pmf.h
index a3d3226..2320760 100644
--- a/include/lib/pmf/pmf.h
+++ b/include/lib/pmf/pmf.h
@@ -37,8 +37,8 @@
 /*
  * Defines for PMF SMC function ids.
  */
-#define PMF_SMC_GET_TIMESTAMP_32	0x82000010
-#define PMF_SMC_GET_TIMESTAMP_64	0xC2000010
+#define PMF_SMC_GET_TIMESTAMP_32	0x82000010u
+#define PMF_SMC_GET_TIMESTAMP_64	0xC2000010u
 #define PMF_NUM_SMC_CALLS		2
 
 /*