On 22.02.2017 16:07, Mario Six wrote:
Certain boards come in different variations by way of utilizing daughter boards, for example. These boards might contain additional chips, which are added to the main board's busses, e.g. I2C.
The device tree support for such boards would either, quite naturally, employ the overlay mechanism to add such chips to the tree, or would use one large default device tree, and delete the devices that are actually not present.
Regardless of approach, even on the U-Boot level, a modification of the device tree is a prerequisite to have such modular families of boards supported properly.
Therefore, we add an option to make the U-Boot device tree (the actual copy later used by the driver model) writeable, and add a callback method that allows boards to modify the device tree at an early stage, at which, hopefully, also the application of device tree overlays will be possible.
Signed-off-by: Mario Six mario.six@gdsys.cc
Applied to u-boot-marvell/master.
Thanks, Stefan