USB GadgetFS: Driving Power to Host from Peripheral

Hi,
I have an OMAPL138 ARM processor which I use as a USB bulk device that can be connected to PCs and smart phones, thanks to USB GadgetFS API.
I'm aware that, normally, it is the host side that powers the peripheral; however, I was wondering if it is possible the other way around? Is there a way for the device to supply power to the host (e.g. a smart phone) side and still act as a USB peripheral?
Thanks in advance,
OkCalis

Personally, I wouldn't mess with hardware. I doubt if usb3 runs above 3.3V, USB 1&2 run at 5V, and whereas 3.3V I/O may be 5V tolerant, power lines are not. BTW, my working life was spent in Electronics hardware.