@sgjava, could you describe how to install Linux headers for the raspberry-CM3 target, I am running the latest kernel, built and install, I cloned the kernel from "git clone --depth=1 https://github.com/raspberrypi/linux " which falls to be a kernel version 4.4.21-v7+ , I have even tried installing the header from the kernel build directory using the command "make headers_install" but still it is not installing all the required include file like "linux/gpio.h" for building the libgpiod. I noticed you were successfull in building the libgpiod on raspberry. please give some tips I am literally blocked. Appreciate your help. regards,Srini