Linux Device Drivers Development

In the kernel tree

Before you can build your driver in the kernel tree, you should first identify which directory in drivers should host your .c file. Given your file name mychardev.c, which contains the source code of your special character driver, it should be placed in the drivers/char directory in the kernel source. Every subdirectory in drivers has both Makefile and Kconfig files.

Add the following content to the Kconfig of that directory:

config PACKT_MYCDEV 
   tristate "Our packtpub special Character driver" 
   default m 
   help 
     Say Y here if you want to support the /dev/mycdev device. 
     The /dev/mycdev device is used to access packtpub. 

In the makefile of that same directory, add the following:

obj-$(CONFIG_PACKT_MYCDEV)   += mychardev.o 

Be ...