What happened to /proc/driver/battery/charge_percentage

I was using it in some of my scripts.
Can I bring it back?
If not, what should be used instead?
I see /proc/driver/battery/sharpsl_main_battery_voltage, but I'm not sure how to convert those numbers to a "percent of full" number for my scripts.
The battery meter must be using something, right? I supposed I should go look at the code.