Key for tablet rotation?

Many tablet PCs have a button to indicate that the screen should be 
rotated from landscape to portrait mode. There's currently no 
standardisation here - a couple of drivers seem to be using 
KEY_DIRECTION, and others are just being mapped to arbitrary F keys. So:

1) What is KEY_DIRECTION supposed to be for?
2) If it's not suitable, do we still have space for a KEY_ROTATE?

-- 
Matthew Garrett | mjg59@srcf.ucam.org