The fact that the phone is charging obviously means that there is power getting to the port. Have you got any other USB peripherals that you can test, to make sure the port is fully functional?
You can also try connecting your iPhone to another usb port on your new macbook and test if you havent already. If not try other devices via usb that require usb 2.0. If that doesnt work a reinstall of iTunes or software updates may need to be done.