NPCM_I2CST_NEGACK
if (NPCM_I2CST_NEGACK & i2cst) {
iowrite8(NPCM_I2CST_NEGACK, bus->reg + NPCM_I2CST);
if (FIELD_GET(NPCM_I2CST_NEGACK, i2cst)) {
val = NPCM_I2CST_BER | NPCM_I2CST_NEGACK | NPCM_I2CST_STASTR;