diff --git a/include/asm-powerpc/prom.h b/include/asm-powerpc/prom.h
index 920b75620f74..925e2d384bb3 100644
--- a/include/asm-powerpc/prom.h
+++ b/include/asm-powerpc/prom.h
@@ -24,7 +24,7 @@
 #define OF_ROOT_NODE_ADDR_CELLS_DEFAULT	1
 #define OF_ROOT_NODE_SIZE_CELLS_DEFAULT	1
 
-#define of_compat_cmp(s1, s2, l)	strncasecmp((s1), (s2), (l))
+#define of_compat_cmp(s1, s2, l)	strcasecmp((s1), (s2))
 #define of_prop_cmp(s1, s2)		strcmp((s1), (s2))
 #define of_node_cmp(s1, s2)		strcasecmp((s1), (s2))