Returns current in mA

def battery_charge_current(self):
        """ Returns current in mA """
        msb = self.bus.read_byte_data(AXP209_ADDRESS, BATTERY_CHARGE_CURRENT_MSB_REG)
        lsb = self.bus.read_byte_data(AXP209_ADDRESS, BATTERY_CHARGE_CURRENT_LSB_REG)
        # (12 bits)
        charge_bin = msb << 4 | lsb & 0x0f
        # 0 mV -> 000h,	0.5 mA/bit	FFFh -> 1800 mA
        return charge_bin * 0.5