4.3 jelly bean - Where is the current_now measurement generated

If you go into the adb shell, you can check what the amount of current the battery is discharging by using the following command

cat /sys/class/power_supply/battery/current_now

When the current is discharged it shows it as a negative value. I am wondering where in the kernel this current_now file is generated. I am using a nexus 7(flo) and I am using 4.3 jelly bean.

An app I am using (trepn) doesn't like negative measurements. So it shows current values as 0. I am trying to find where the current now file is generated and replace the sign