Enabling OTG in SC20

Hi all,
how can i enable otg in sc20.

this is our hardware design.
where otg_en is connected to gpio_8
(correction in hardware usb_id is directly connected directly to sc20 pin )
please support

which charging desige do you adopt? internal or external ?

hi Rooney,
we are using external charging circuit

Whether charging function is ok,now? If ok,OTG should can work as default.