centos man page for device_register

DEVICE_REGISTER(9)					   Device drivers infrastructure					DEVICE_REGISTER(9)

NAME
       device_register - register a device with the system.

SYNOPSIS
       int device_register(struct device * dev);

ARGUMENTS
       dev
	   pointer to the device structure

DESCRIPTION
       This happens in two clean steps - initialize the device and add it to the system. The two steps can be called separately, but this is the
       easiest and most common. I.e. you should only call the two helpers separately if have a clearly defined need to use and refcount the device
       before it is added to the hierarchy.

       For more information, see the kerneldoc for device_initialize and device_add.

NOTE
       _Never_ directly free dev after calling this function, even if it returned an error! Always use put_device to give up the reference
       initialized in this function instead.

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014							DEVICE_REGISTER(9)