How to write a Linux driver

1. wrote driver function file(s) .
2. stored in the proper folder, eg: character driver stored in folder  drivers/char/
3. modified Makefile in this folder(eg: drivers/char/)
        -added configuration at somewhere: type like that "obj-$(CONFIG_TESTDRIVER) += testdriver.o"
4. modified config.in in the same folder
        -added configuration at somewhere: type like that "bool 'Mytestdriver' CONFIG_TESTDRIVER"
5. modified mem.c in the same folder
        -added initial function of my driver into mem.c with same rule within it.
5. added device node in Makefile in folder vendors/Samsung/4510B
        -added parameters(same as command mknod's parameters) in DEVICES section, eg: test, c, 254, 0, which stands for the register driver name, device type(char), major device number, minor device number
6. used command make menuconfig at linux root folder(eg: uClinux-dist) to let my driver choice available
7. re-compiled linux with some commands
That's all!