Using Display eith custom linux

[mx_mos]

The display is working fine with the OLinuXino-Lime image,
but i would like to use the LCD-OLinuXino-7CTS with the STMP157-OLinuXino-LIME2 with a self build linux image.
The image is build with buildroot using the configuration provided for the board. I know there is no graphical
stack and user interface in this configuration, but i thought that at least the display can be activated by using
the kernel modules, so that the kernel can detect the display.

I have tried to load the right kernel modules, but the display did not show anything. It is also not in the
i have tried to use the devictree from the working OLinuXino image, but the same.

Can you give me a hint where the problem is located