N900 Hardware Battery Charger

The battery charger is the bq24150 charger from TI.

It also features reverse boost mode - which enables power to be supplied to a USB device connected to the N900.

There is no kernel driver for this chip - it is driven over I2C by BME.

BME (Battery Managment Entity) needs replaced with an open-source version in order to allow easy operation in USB host mode.

There are safety implications of software drivers for this chip, the chip can be configured to have an output voltage of up to 4.44V, which is higher than the absolute maximum voltage of 4.2V that li-ion batteries can be safely charged to.