I am compiling linux kernel for raspberry pi and I have everything custom except linux kernel. I have my own init, own commands implementation like cat, mkdir etc. Problem is that /dev/video0 doesnot exist even though I enabled v4l2 driver etc while compiling kernel. I am using devtmpfs for creating device files.
(mount("devtmpfs", "/dev", "devtmpfs", 0, NULL)
I have many device files properly but not /dev/video0 for my CSI camera. I use raspberry pi v2.1 camera. I assume that I am missing some configuration from kernel configuration. My final point is having /dev/video0 and using v4l2 to capture a frame from a camera.
I have tried many different configurations option from kernel configuration but not success, I also have start_x=1 and gpu_mem options in config.txt file and I have required firmware files in boot folder. it boots properly but camera file does not exist.