De1-soc valid KERNEL SRC path

hii i am running linux on de1-soc

and i am writhing a make file to compile ad device driver for the module , and i saw an example for a make file where in the beginning of the make file there is a path for the kernel source

KERNEL_LOCATION=~/programs/others/linux-socfpga

and my question is how do i find the valid src path for my project

i have build my own qsys system and compiled it in Quartus , thanks for help