greybus: bundle: create GB_DEVICE_ID_BAD

Use a "name" for when we don't have a valid device id yet, instead of a
magic value of 0xff.
Reported-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
Reviewed-by: Alex Elder <elder@linaro.org>

drivers/staging/greybus/bundle.c

@@ -91,9 +91,11 @@ struct gb_bundle *gb_bundle_create(struct gb_interface *intf, u8 interface_id)
 
 	bundle->intf = intf;
 	bundle->id = interface_id;
-	bundle->device_id = 0xff;	/* Invalid device id to start with */
 	INIT_LIST_HEAD(&bundle->connections);
 
+	/* Invalid device id to start with */
+	bundle->device_id = GB_DEVICE_ID_BAD;
+
 	/* Build up the bundle device structures and register it with the
 	 * driver core */
 	bundle->dev.parent = &intf->dev;

drivers/staging/greybus/bundle.h

@@ -24,6 +24,8 @@ struct gb_bundle {
 };
 #define to_gb_bundle(d) container_of(d, struct gb_bundle, dev)
 
+#define GB_DEVICE_ID_BAD	0xff
+
 /* Greybus "private" definitions" */
 struct gb_bundle *gb_bundle_create(struct gb_interface *intf, u8 module_id);
 void gb_bundle_destroy(struct gb_interface *intf);

drivers/staging/greybus/connection.c

@@ -146,7 +146,7 @@ void gb_connection_bind_protocol(struct gb_connection *connection)
 	 * device, so bring up the connection at the same time.
 	 * */
 	bundle = connection->bundle;
-	if (bundle->device_id != 0xff)
+	if (bundle->device_id != GB_DEVICE_ID_BAD)
 		gb_connection_init(connection);
 }