diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index 33bbbae..cc76b3e 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -332,6 +332,7 @@
 #define xlate_dev_kmem_ptr(p)	p
 #define xlate_dev_mem_ptr(p)	__va(p)
 
+#ifdef CONFIG_VIRT_TO_BUS
 #ifndef virt_to_bus
 static inline unsigned long virt_to_bus(volatile void *address)
 {
@@ -343,6 +344,7 @@
 	return (void *) address;
 }
 #endif
+#endif
 
 #ifndef memset_io
 #define memset_io(a, b, c)	memset(__io_virt(a), (b), (c))