Hi,
The driver register a "Power Present" control that can be queried to get the current state of whether a cable is connected or not.
If you want to the driver to send a notification when the status of that control changes you need to implement a IRQ handler in your board driver that is triggered when the INT signal of the ADV7611 is asserted. In this interrupt handler you need to call the interrupt_service_routine callback of the ADV7611 subdevice. E.g.
v4l2_subdev_call(dev->sd, core, interrupt_service_routine, 0, &handled);
- Lars