AD7192_CONF_CHAN_MASK
conf &= ~AD7192_CONF_CHAN_MASK;
conf |= FIELD_PREP(AD7192_CONF_CHAN_MASK, BIT(i));
st->conf &= ~AD7192_CONF_CHAN_MASK;
st->conf |= FIELD_PREP(AD7192_CONF_CHAN_MASK, channel);
conf &= ~AD7192_CONF_CHAN_MASK;