If you want them all, you either need to find a common standard or implement them all.

It would be nice if Qt would provide cross platform and cross vendor api's to everything and the kitchen sink. However, this is not doable.
The problem is that A uses their own protocols and api's, B uses their own. Hope for some standardisation.

Maybe there's a generic usb driver for such devices. Try searching for that.

In the end, this is a question that doesn't have a lot to do with Qt itself but more with the devices you want to use.