register_chrdev,register_chrdev_region,alloc_chrdev_region---udev class bus driver device
3.4.2.TheOlderWayIfyoudigthroughmuchdrivercodeinthe2.6kernel,youmaynoticethatquiteafewchardriversdonotusethecdevinterfacethatwehavejustdescribed.Whatyouareseeingisoldercodethathasnotyetbeenupgradedtot