On Thu, 8 Dec 2016, Rob Herring wrote:

quoted

And if tomorrow there is Elan device that is drop-in compatible (same 
connector, etc) with Wacom i2c-hid, will you ask for Elan-specific 
binding? Atmel? Weida? They all need to be powered up ultimately.

Yes, I will. 

What advantage does that bring?

That in no way means the OS driver has to know about each and every one. 
If they can all claim compatibility with Wacom (including power 
control), then they can have a Wacom compatible string too. Or you can 
just never tell me that there's a different manufacturer and I won't 
care as long you don't need different control. But soon as a device 
needs another power rail, GPIO or different timing, then you'd better 
have a new compatible string.

Again, I simply don't understand what advantage does the aproach you are 
trying to use bring.

HID over I2C is a generic protocol. Sure, we need to have quirks for 
device-specific bugs, and in such cases enumerate particular devices. But 
we don't need DT for that at all.

-- 
Jiri Kosina
SUSE Labs