Ambient Light Sensor

From WebOS Internals

Showing up as an input is something identified as a temt6200_light.

That's probably something doing an a2d conversion of Vishay Semiconductors TEMT 6200 ambient light sensor

You can read the ambient light value from /sys/class/input/input4/result

Putting the pre in complete darkness:

root@castle:/sys/class/input/input4# cat result 
4

Exposing it to low light levels

root@castle:/sys/class/input/input4# cat result 
11