Today I wrote a VX855 southbridge GPIO GPIOLIB driver, which is required by the OLPC DCON display controller.
I've also spammed a queue of 15 patches to linux-fbdev-devel, hoping that the majority of the viafb improvements/extensions can go mainline quite quickly.
What the XO1.5 DCON also needs, is a redesign of how viafb drives its multiple internal I2C busses, but this is not ready for submission yet.
Let's hope that this helps OLPC to get Linux up and running very quickly...