auxbus: New aux_bus_realize(), pairing with aux_bus_init()

aux_bus_init() encapsulates the creation of an aux-bus and its
aux-to-i2c-bridge device.

Create aux_bus_realize() to similarly encapsulate their realization.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200610053247.1583243-33-armbru@redhat.com>

hw/display/xlnx_dp.c

@@ -1266,7 +1266,7 @@ static void xlnx_dp_realize(DeviceState *dev, Error **errp)
     DisplaySurface *surface;
     struct audsettings as;
 
-    qdev_init_nofail(DEVICE(s->aux_bus->bridge));
+    aux_bus_realize(s->aux_bus);
 
     qdev_init_nofail(DEVICE(s->dpcd));
     aux_map_slave(AUX_SLAVE(s->dpcd), 0x0000);

hw/misc/auxbus.c

@@ -81,6 +81,11 @@ AUXBus *aux_bus_init(DeviceState *parent, const char *name)
     return bus;
 }
 
+void aux_bus_realize(AUXBus *bus)
+{
+    qdev_init_nofail(DEVICE(bus->bridge));
+}
+
 void aux_map_slave(AUXSlave *aux_dev, hwaddr addr)
 {
     DeviceState *dev = DEVICE(aux_dev);

include/hw/misc/auxbus.h

@@ -93,6 +93,13 @@ struct AUXSlave {
  */
 AUXBus *aux_bus_init(DeviceState *parent, const char *name);
 
+/**
+ * aux_bus_realize: Realize an AUX bus.
+ *
+ * @bus: The AUX bus.
+ */
+void aux_bus_realize(AUXBus *bus);
+
 /*
  * aux_request: Make a request on the bus.
  *