pushpull
smaster->pushpull = siox_gpio_pushpull;
smaster->pushpull(smaster, smaster->setbuf_len, smaster->buf,
if (!smaster->pushpull)
int (*pushpull)(struct siox_master *smaster,
struct pushpull pp;
static inline void init_pushpull(struct pushpull *pp, char *buf,
static inline int pushbit(struct pushpull *pp, int bit, int use_reserved)
static inline int pushedbits(struct pushpull *pp)
static inline int pullbit(struct pushpull *pp)