All temperature of Fintek superio hwmonitor that using 1-byte reg will use 2's complement. In show_temp() temp = data->temp[nr] * 1000; When data->temp[nr] read as 255, it indicate -1C, but this code will report 255C to userspace. It'll be ok when change to: temp = ((s8)data->temp[nr]) * 1000; Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@xxxxxxxxx> --- drivers/hwmon/f71882fg.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/hwmon/f71882fg.c b/drivers/hwmon/f71882fg.c index 938a8b9ec70d..6830e029995d 100644 --- a/drivers/hwmon/f71882fg.c +++ b/drivers/hwmon/f71882fg.c @@ -1578,8 +1578,9 @@ static ssize_t show_temp(struct device *dev, struct device_attribute *devattr, temp *= 125; if (sign) temp -= 128000; - } else - temp = data->temp[nr] * 1000; + } else { + temp = ((s8)data->temp[nr]) * 1000; + } return sprintf(buf, "%d\n", temp); } -- 2.17.1