i2c: virtio: mark device ready before registering the adapter

virtio_i2c_probe() synchronously probes child i2c drivers on the bus,
but peripherals may use the bus at probe for tasks like reading a chip
id. The vhost-user-i2c backend stalls at such probes unless DRIVER_OK
is already set before the virtqueue is first kicked.

Set DRIVER_OK explicitly before i2c_add_adapter(), as done for the
same reason in commit f5866db ("virtio_console: enable VQs
early") and commit 71e4b8b ("virtio_rpmsg: set DRIVER_OK before
using device").

Signed-off-by: Alexis Bouzigues <BouziguesAlexis@JohnDeere.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Author: Alexis Bouzigues

drivers/i2c/busses/i2c-virtio.c

@@ -222,6 +222,8 @@ static int virtio_i2c_probe(struct virtio_device *vdev)
 	 */
 	ACPI_COMPANION_SET(&vi->adap.dev, ACPI_COMPANION(vdev->dev.parent));
 
+	virtio_device_ready(vdev);
+
 	ret = i2c_add_adapter(&vi->adap);
 	if (ret)
 		virtio_i2c_del_vqs(vdev);