Dell Laptop Extras

modulename: dell-laptop.ko

configname: CONFIG_DELL_LAPTOP

Linux Kernel Configuration
└─>Device Drivers
└─>X86 Platform Specific Device Drivers
└─>Dell Laptop Extras
In linux kernel since version 2.6.29 (release Date: 2009-03-23)  
This driver adds support for rfkill and backlight control to Dell
laptops (except for some models covered by the Compal driver).

source code:
drivers/platform/x86/dell-laptop.c