Man page 9 : __unregister_chrdev

__unregister_chrdev - unregister and destroy a cdev

void __unregister_chrdev(unsigned int  major , unsigned int  baseminor , unsigned int  count , const char *  name );

major
    major device number

baseminor
    first of the range of minor numbers

count
    the number of minor numbers this cdev is occupying

name
    name of this range of devices

Unregister and destroy the cdev occupying the region described by major, baseminor and count. This function undoes what __register_chrdev did.