finger print scanner - Completely disable the fingerprint sensor

I don't really like all the hype about the fingerprint sensor, I'd rather like to have it killed down, so that it doesn't register any fingerprints.

On a desktop Linux I'd simply modprobe -r the relevant kernel module. Can I do something like that on Android? I don't want to simply disable it in the settings - then I have to trust the system that nothing really uses it.

Answer

On Linux (and Android) it is possible to disconnect a device from its driver^[1]. The fingerprint driver (denoted as fpc) on my LG G5 has the name fpc1020. Searching in the /sys path gave me the folder /sys/bus/spi/drivers/fpc1020/. This folder has four files: bind, unbind, uevent AND spi8.1. What we do is to unbind the device spi8.1 from the driver fpc1020.

Now how to disable the sensor:

1. 
   

   we need to find the driver name:
   Try this command: find /sys/bus -name 'fpc*'
   For me it's: /sys/bus/spi/drivers/fpc1020/

   
   



2. 
   

   we need to find the device name:
   The device name is the fourth file in this folder.
   ls /sys/bus/spi/drivers/fpc1020/ (depends on your result from 1.)
   For me it's: spi8.1

   
   


3. 
   

   unbind this device:
   echo spi8.1 > /sys/bus/spi/drivers/fpc1020/unbind (depends on your result from 1. & 2.)
   Now you are not able to use the fingerprint sensor until the next restart.

   
   
   


4. 
   

   unbind on every system boot:
   We want/need to execute this command on every boot. Currently I'm not sure what's the best way to do it.

   
   

Requirements:

• Root Access


• Terminal App (or adb shell from PC)

References:
1. https://lwn.net/Articles/143397/