ISL1208_SR
status = islrtc_reg_read(sc, ISL1208_SR);
reg = islrtc_reg_read(sc, ISL1208_SR);
islrtc_reg_write(sc, ISL1208_SR, reg | ISL1208_SR_WRTC);
islrtc_reg_write(sc, ISL1208_SR, reg & ~ISL1208_SR_WRTC);