Compiling Linux kernel module !!!!!!

This is one the essential and important task. Many time we upgrade our kernel and some precompiled drivers won't work with Linux. Especially if you have weird hardware; then vendor may send you driver code aka C files to compile. Or even you can write your own Linux kernel driver. Compiling kernel driver is easy. Kernel 2.6.xx makes it even much more easier. Following steps are required to compile driver as module:

1) You need running kernel source code; if you don't have a source code download it from kernel.org. Untar kernel source code (tar ball) in /usr/src using tar command:

$ tar -zxvf kernel* -C /usr/src

2) Next go to your kernel module source code directory and simply create the Makefile file as follows (assuming your kernel module name is foo):

$ vi Makefile

3) Add following text to it:
obj-m = foo.o
KVERSION = $(shell uname -r)
all:
make -C /lib/modules/$(KVERSION)/build M=$(PWD) modules
clean:
make -C /lib/modules/$(KVERSION)/build M=$(PWD) clean

4) Compile module using make command (module build can be done by any user) :
$ make
It will finally creates the foo.ko module in current directory. You can see all actual compile command stored in .foo* files in same directory.

5) Once module compiled successfully, load it using insmod or modprobe command. You need to be root user or privileged user to run insmod:
# insmod foo.ko