PMIC_BBAT output - pin functionality (for RTC usage)

I have a question about TX2 NX PMIC_BBAT
From SOM Datasheet i understand that PMIC_BBAT (pin235) is set as bidir with 1.65-5.5V

Super cap or coin cell is
source when system is disconnected from power.

Does it means that PBMIC_BBAT can funtion as output, and can charge the Super capacitor for the RTC? if so, do i need to enable it somehow ?
Except adding below section to my device-tree ?

    backup-battery {
              backup-battery-charging-current = <100>;
              backup-battery-charging-voltage = <3300000>;
              backup-battery-output-resister = <100>;
              status = "okay";

I have custom board connected with TX2 NX , and BCAP0005 P300 X11 super-capacitor connected like below sketch, and no output detected from SOM the capacitor, anyone have any suggestion ?

Thanks in advanced.
Siri (Paul)

Yes, need adding backup-battery in device tree.
Also the driver is located …/kernel/kernel-4.9/drivers/mfd/max77620.c to handle the backup-battery-*