diff --git a/include/asm-sparc/mostek.h b/include/asm-sparc/mostek.h
index bd92a78f49379f5e9b339552b9081f6072c33cbe..958d0513a6d4151eecd78c0acdc22b0bb4f71510 100644
--- a/include/asm-sparc/mostek.h
+++ b/include/asm-sparc/mostek.h
@@ -87,7 +87,7 @@ extern void __iomem *mstk48t02_regs;
 #define	MSTK_DOW_MASK	0x07
 #define	MSTK_DOM_MASK	0x3f
 #define	MSTK_MONTH_MASK	0x1f
-#define	MSTK_YEAR_MASK	0xff
+#define	MSTK_YEAR_MASK	0xffU
 
 /* Binary coded decimal conversion macros. */
 #define MSTK_REGVAL_TO_DECIMAL(x)  (((x) & 0x0F) + 0x0A * ((x) >> 0x04))
diff --git a/include/asm-sparc64/mostek.h b/include/asm-sparc64/mostek.h
index 09b5aba6678aee24cc16064401644e38cc4657e5..d14dd8988161fd05f14258bf34fd618f656d5d40 100644
--- a/include/asm-sparc64/mostek.h
+++ b/include/asm-sparc64/mostek.h
@@ -89,7 +89,7 @@ extern void __iomem *mstk48t02_regs;
 #define	MSTK_DOW_MASK	0x07
 #define	MSTK_DOM_MASK	0x3f
 #define	MSTK_MONTH_MASK	0x1f
-#define	MSTK_YEAR_MASK	0xff
+#define	MSTK_YEAR_MASK	0xffU
 
 /* Binary coded decimal conversion macros. */
 #define MSTK_REGVAL_TO_DECIMAL(x)  (((x) & 0x0F) + 0x0A * ((x) >> 0x04))