powerpc: Add a shutdown member to vio_driver

Add a shutdown member to struct vio_driver. We also need vio_bus_shutdown()
which converts from struct device to struct vio_dev and knows how to extract
the struct vio_driver.

Original patch adjusted for different location of vio.c.

Signed-off-by: Michael Ellerman <[e-mail]>
Signed-off-by: Stephen Rothwell <[e-mail]>

arch/powerpc/kernel/vio.c

···
 	return 1;
 }
 
+/* convert from struct device to struct vio_dev and pass to driver. */
+static void vio_bus_shutdown(struct device *dev)
+{
+	struct vio_dev *viodev = to_vio_dev(dev);
+	struct vio_driver *viodrv = to_vio_driver(dev->driver);
+
+	if (viodrv->shutdown)
+		viodrv->shutdown(viodev);
+}
+
 /**
  * vio_register_driver: - Register a new vio driver
  * @drv:	The vio_driver structure to be registered.
···
 	viodrv->driver.bus = &vio_bus_type;
 	viodrv->driver.probe = vio_bus_probe;
 	viodrv->driver.remove = vio_bus_remove;
+	viodrv->driver.shutdown = vio_bus_shutdown;
 
 	return driver_register(&viodrv->driver);
 }

include/asm-powerpc/vio.h

···
 	const struct vio_device_id *id_table;
 	int (*probe)(struct vio_dev *dev, const struct vio_device_id *id);
 	int (*remove)(struct vio_dev *dev);
+	void (*shutdown)(struct vio_dev *dev);
 	unsigned long driver_data;
 	struct device_driver driver;
 };