ppbus_read
error = ppbus_read(device_parent(dev), sc->sc_outbuf,
error = ppbus_read(dev, &length_field, 1, 0, read);
error = ppbus_read(dev, &length_field, 1, 0, read);
error = ppbus_read(dev, *buffer, msg_sz, 0, read);
return (bus->ppbus_read(device_parent(dev), buf, len, how, cnt));
int ppbus_read(device_t, char *, int, int, size_t *);
ppbus->ppbus_read = sc_link->parport_read;
PARPORT_READ_T ppbus_read;