Introduction:
This section deals with adding new driver onto the Linux source tree,I have added Lumidigm Venus Driver as character driver.
step 1: copy the driver source code(vcom.c) and into character folder of Linux source tree. 
step 2: Edit the Kconfig file in the char folder and add the following line.
config LUMIDIGM
        bool "Limidigm fingerprint USB driver" 
        depends on ARCH_S3C2440
        default m if ARCH_S3C2440
        help
         say Y here to select,otherwise say N.
The Above configuration will give the option to the user for select/deselect Lumidigm driver,for S3C2440 Architecture with default as driver selected.
And help will display "say Y here to select,otherwise say N."
step 3: Edit Makefile in the char folder and add the following line
obj-$(CONFIG_LUMIDIGM)          += vcom.o
prefix "CONFIG_" before "LUMIDIGM" flag as set in KConfig file. 
save the configuration and do a menuconfig to verify the changes.
on menuconfig we will see the "[*] Limidigm fingerprint USB driver" in  Device Drivers  ---> Character devices  --->
