@gcondra I don't have anymore the prototype with the sensors but I think that tonight I should receive a pcb. When I will have something to connect to the Edison I will try it and let you know. You are interested in the patch with the code or the whole image to be flashed.
Yes would be better to compile it as a module and not was a built in, first I also tried to do this but I got into some compilation errors and didn't had time to investigate them and as I needed a solution for the day I just went for the quick and dirty.
The ADXL345 I checked it using the breakout from sparkfun if I remember well and after that a PCB made by us.
@facepalent yes it's true the according to the specs ADXL345 should run at 400kHz probably dropping the clock to 100KHz is just a workaround to another problem, if the clock is slower are less chances that the things go wrong and as we needed a working prototype for this week was the only thing that occurred to me.