i2c_mux_disc_nports
len = snprintf(buf, buflen, "%u", i2c_mux_disc_nports(disc));
extern uint32_t i2c_mux_disc_nports(const i2c_mux_disc_t *);
if (i2c_mux_disc_nports(disc) != 8) {
path, i2c_mux_disc_nports(disc));