There is the only [techincal] thread about Paperwhite in Developer's Corner at the moment, so I leave this information here:
/usr/bin/powerd in Kindle Touch firmware already knows about magnetic sensor. To see it:
Code:
strings /usr/bin/powerd | grep -i mag
So there is another trace of Paperwhite hardware support (sensor for going to sleep on cover closing) in current Kindle Touch software.