How to driver GPIO pin reset the network port

The demo 8168 board use system reposition to reset  network port before to initialize the  network port.But, our coustom board try to use GPIO pin  to reset network port, the circuit illustrate as follow:

we want to set GP1[28] pin as reposition function to reset network port instead of system reposition.But, I do not know how to achieve this function in u-boot and kernel.  Please tell me how to solve the problem? The GP1[28] pin datasheet as follow:

Thanks,

Chen