You should generally set the PMIC settings such as input volage, input current limit, charge current, and charge termination voltage using the Power Manager API, above. If you directly set the PMIC, the settings will likely be overridden by the system.
Note: This is advanced IO and for experienced users. This controls the LiPo battery management system and is handled automatically by the Device OS.
Power Management is available on the Boron, B Series SoM, Tracker SoM (Gen 3), Electron, and E Series (Gen 2).
It is not available on the P2, Photon 2, Argon (Gen 3), Photon, or P1 (Gen 2).