Currently Displaylink devices using evdi subsystem live in /sys/devices/platform/evdi.N/...

This is not helpful if they are multi-function devices (such as external display with touchscreen connected via USB), as we need to associate the display and the touchscreen and one of the ways would be to use common sysfs hierarchy (such as both devices connected to the same USB HUB).

An option is to pass path to the parent (such as USB interface) as argument when writing into "add" attribute of evdi and have kernel traverse proper bus and locate device with given path, then use it as the parent of evdi device.