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    Subject[PATCH 5.15 045/102] hwmon: (f71882fg) Fix negative temperature
    Date
    From: Ji-Ze Hong (Peter Hong) <hpeter@gmail.com>

    [ Upstream commit 4aaaaf0f279836f06d3b9d0ffeec7a1e1a04ceef ]

    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@gmail.com>
    Link: https://lore.kernel.org/r/20220418090706.6339-1-hpeter+linux_kernel@gmail.com
    Signed-off-by: Guenter Roeck <linux@roeck-us.net>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    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 4dec793fd07d..94b35723ee7a 100644
    --- a/drivers/hwmon/f71882fg.c
    +++ b/drivers/hwmon/f71882fg.c
    @@ -1577,8 +1577,9 @@ 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);
    }
    --
    2.35.1


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