Open Source PowerSave Scripts for Linux
sudo ./install
Edit /usr/bin/powerdown as root to add platform's particularities. You can get more info in linux kernel documentation folder. Look for device drivers docs that your platform contain.
Powertop command helps find new customizations mainly on tab Tunables.
Documentation Sources:
https://www.kernel.org/doc/html/latest/
https://www.kernel.org/doc/html/latest/power/index.html