Hi guys,
I have a smart6818 and nanopi fire 3 motherboard. I am writing a GPIO kernel module to control the GPI O pins, but I am not compiling the module. I am creating a Makefile but the device is giving the following error.

make -C /lib/modules/4.4.172-s5p6818/build M=/home/pi/kernel_deneme/GPIO_REG_ACCESS modules
make[1]: *** /lib/modules/4.4.172-s5p6818/build: No such file or directory. Stop.
Makefile:3: recipe for target 'all' failed
make: *** [all] Error 2

I guess the kernel module couldn't find the build file. Where can I find this file and integrate it into the system?