ppbus_get_mode
ppbdev->ctx.mode = ppbus_get_mode(parent);
ppbus_dev->ctx.mode = ppbus_get_mode(ppbus);
switch (ppbus_get_mode(device_parent(dev))) {
old_mode = ppbus_get_mode(dev);
int ppbus_get_mode(device_t);
#define PPBUS_IN_EPP_MODE(bus) (PPBUS_IS_EPP(ppbus_get_mode(bus)))
#define PPBUS_IN_NIBBLE_MODE(bus) (ppbus_get_mode(bus) & PPBUS_NIBBLE)
#define PPBUS_IN_PS2_MODE(bus) (ppbus_get_mode(bus) & PPBUS_PS2)