diff --git a/arch/powerpc/include/asm/vio.h b/arch/powerpc/include/asm/vio.h
index cc9b787627ad..6faf2a931755 100644
--- a/arch/powerpc/include/asm/vio.h
+++ b/arch/powerpc/include/asm/vio.h
@@ -39,7 +39,7 @@
  */
 #define VIO_CMO_MIN_ENT 1562624
 
-extern struct bus_type vio_bus_type;
+extern const struct bus_type vio_bus_type;
 
 struct iommu_table;
 
diff --git a/arch/powerpc/platforms/pseries/vio.c b/arch/powerpc/platforms/pseries/vio.c
index 6c58824190a2..90ff85c879bf 100644
--- a/arch/powerpc/platforms/pseries/vio.c
+++ b/arch/powerpc/platforms/pseries/vio.c
@@ -1615,7 +1615,7 @@ static struct attribute *vio_cmo_dev_attrs[] = {
 };
 ATTRIBUTE_GROUPS(vio_cmo_dev);
 
-struct bus_type vio_bus_type = {
+const struct bus_type vio_bus_type = {
 	.name = "vio",
 	.dev_groups = vio_cmo_dev_groups,
 	.bus_groups = vio_bus_groups,
@@ -1634,7 +1634,7 @@ static struct attribute *vio_dev_attrs[] = {
 };
 ATTRIBUTE_GROUPS(vio_dev);
 
-struct bus_type vio_bus_type = {
+const struct bus_type vio_bus_type = {
 	.name = "vio",
 	.dev_groups = vio_dev_groups,
 	.uevent = vio_hotplug,