AD7418_CONF
conf = ad7418_read_1(dev, AD7418_CONF);
ad7418_write_1(dev, AD7418_CONF, conf &~ AD7418_CONF_SHUTDOWN);
ad7418_write_1(sc->sc_dev, AD7418_CONF,
(ad7418_read_1(sc->sc_dev, AD7418_CONF) &~ AD7418_CONF_CHAN)|chan);