Export kernel source directory a KSRC variable before building the driver and fix the building command to use $KSRC and M=$PWD to perform single kernel module build inside the out-of-tree kernel module directory.
Also add a reference link to official kbuild/modules documentations.
Export kernel source directory a KSRC variable before building the driver and fix the building command to use $KSRC and M=$PWD to perform single kernel module build inside the out-of-tree kernel module directory.
Also add a reference link to official kbuild/modules documentations.