Controlling LCD backlight with mini2440v2 (markII)

Hi, I'm trying to use mini2440v2 with 3.5 W35 display(from Sharp), but
display is so bright it make any text unreadable. Mini2440v2 contains
ATMega48PA MCU for brightness setting but I didn't find out how to control
it. Changing /sys/class/leds/backlight/brightness works only discretly -
setting it to 1 has same effect as to 255.
Using the same kernel and rootfs images on classic mini2440 (not mark II)
works as intended and the brighness is correct.
I've tried latest vanilla kernel and OSELAS BSP for mini2440 with same
result
Any help would be appreciated

This is interesting.  Could you point me an electronic copy of the
schematic for the mini2440v2?

Does it still use the S3C2410? 
The AT series usually use ISP (In System Programming) via a 6pin header. 
See www.avrfreaks.net and WinAVR.

Ah, found it.  Looks like it is the display controller.  I suspect it does
more than control brightness.
***
The display includes an ATMega uProcessor that controls back light
brightness with I2C signals. On Linux it is a simple Linux device. For
example, to set the brightness to 50%

echo 50 > /dev/backlight/
***
So, that doesn't work?

Hi, unfortunately there is no such device, I guess the default config for
mini2440 doesn't includes this controller..

I do not understand.  Someone supplies this board and doesn't tell you how
to perform the above action. And the product does not perform in a
reasonable manner, ie the brightness of the display.

Dave,

any hints for me to include something not yet supported in my Mini2440 BSP?
Where did you found the schematics?

Juergen,

Didn't find any schematics only the text between the *** and the ***.

There are many sites out there selling these things.  Ashen doesn't seem to
have any documentation on this variant.

Suggestions:
- seeing as you have done quite a bit with the touchscreens how about
interfacing a capacitive touchscreen to the mini.  Seems sourcing them is
not easy.  Just a thought.
- does something need to written up on partitioning the SD card in section
6.3? Setting up the kernel partition was new to me.  

Dave

Only documentation for v2 I've found so far resides here >
http://www.hiteg.com/downloads/mini2440v2/
Juergen, is there anything I can help with? Would complete dmesg be any
help?

Ashen,

you should talk to HITEG and ask for the Linux kernel sources that are the
base of their shipped binary kernels. Nothing else would help.

Ashen,

I tried the kernel from their
ttp://www.hiteg.com/downloads/buildroot.tar.bz2, but there seems no
additional device driver to talk to the ATMega48PA via I2C. No idea what
has to be sent to the MCU to make it change the brightness.