Lowlevel Backlight controls

modulename: backlight.ko

configname: CONFIG_BACKLIGHT_CLASS_DEVICE

Linux Kernel Configuration
└─>Device Drivers
└─>Graphics support
└─>Backlight & LCD device support
└─>Lowlevel Backlight controls
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
This framework adds support for low-level control of the LCD
backlight. This includes support for brightness and power.

To have support for your specific LCD panel you will have to
select the proper drivers which depend on this option.

source code:
drivers/video/backlight//backlight.c

is selected by
CONFIG_SONY_LAPTOP