DA9053 USB charging questions

I use a DA9053 inside a mobile device containing a li-ion battery. I'd like to be able to charge the main battery from the VBUS input and the datasheet claims this is possible "...while maintaining USB power specification compliance", however I cannot find any description or app note on how to do this.

DA9053 USB D +和D -销,所以应该capable of identifying whether the upstream charging device provides a "standard downstream port" (100mA or 500mA charge current), a "charging downstream port" (up to 1.5A), or a "dedicated charging port" (up to 1.5A), but the datasheet is silent on this point.

I note that the DA9053 contains the "ISET_USB" field of the ISET register, which defines a USB charging current. How this value combines with the charging port handshake to set charging current isn't clear.

Another factor is that my mobile device uses the USB data lines for other comms purposes and a question is whether that would be affected by also connecting the DA9053 to them.

Thanks for any help you may provide.