diff --git a/drivers/net/smc91x.h b/drivers/net/smc91x.h
index a9b06b8..ac9ce65 100644
--- a/drivers/net/smc91x.h
+++ b/drivers/net/smc91x.h
@@ -986,7 +986,7 @@
 	})
 #endif
 
-#if SMC_CAN_USE_DATACS
+#ifdef SMC_CAN_USE_DATACS
 #define SMC_PUSH_DATA(p, l)						\
 	if ( lp->datacs ) {						\
 		unsigned char *__ptr = (p);				\