device_getprop_data
if (device_getprop_data(sc->sc_dev, "shared-pins",
if (device_getprop_data(dev, "mac-address", enaddr,
device_getprop_data(dev, "local-mac-address", enaddr,
ssize_t device_getprop_data(device_t, const char *, void *, size_t);