ad7173_get_ref_voltage_milli
*val = ad7173_get_ref_voltage_milli(st, ch->cfg.ref_sel);
*val = ad7173_get_ref_voltage_milli(st, ch->cfg.ref_sel);
ret = ad7173_get_ref_voltage_milli(st, ref_sel);
/ ad7173_get_ref_voltage_milli(st, chan_st_priv->cfg.ref_sel);