Is it possible to force a phone to use USB for data but not charge from it? My plan is to use my phone (Google Pixel) as a screen for a raspberry pi, and I'm worried that my power supply isn't sufficient. Is there a way to prohibit the Pixel from charging while still maintaining data flow? I haven't done much electrical work and I don't know if phones are equipped with this option, let alone if it's even possible. My power source is, if memory serves me, 3000 mWh, capable of 5 volt 2 amp (I can verify later if that turns out to be important). 

UPDATE:

Upon some deeper searching, (not sure how I missed it to begin with), I found some posts suggesting commands such as echo 0 &gt; /sys/class/power_supply/batterycharging_enabled/charging_enabled. My updated question is, then does this actually work? How does it work?
Considering usb C can send power in both directions, I'm assuming you can set the phone to power an external device using in phone settings, and this way you would avoid it pulling power from your source. 

A side note though : 2A is quite a number, unless you're running rpi hot or powering something else my educated guess is that it should be enough for both.