enable mcp2515 and the can network drivers as modules and also add a parametrizable overlay #848
Maybe you want to help all the people who still rely on an externally compiled 3.12.X to make CAN-bus work out of the box by including the can drivers for the mcp2515.
What would be needed is:
This is actually a good example of how the device tree works, as it implements a lot of things that may be needed for other overlays as well (GPIOs, Interrupts, Clocks, disable a default spi device, add a new spi device instead,...)
See also raspberrypi/firmware#371