• Guenter Roeck's avatar
    hwmon: (tmp102) Fix first temperature reading · d0725439
    Guenter Roeck authored
    Commit 3d8f7a89 ("hwmon: (tmp102) Improve handling of initial read
    delay") reduced the initial temperature read delay and made it dependent
    on the chip's shutdown mode. If the chip was not in shutdown mode at probe,
    the read delay no longer applies.
    
    This ignores the fact that the chip initialization changes the temperature
    sensor resolution, and that the temperature register values change when
    the resolution is changed. As a result, the reported temperature is twice
    as high as the real temperature until the first temperature conversion
    after the configuration change is complete. This can result in unexpected
    behavior and, worst case, in a system shutdown. To fix the problem,
    let's just always wait for a conversion to complete before reporting
    a temperature.
    
    Fixes: 3d8f7a89 ("hwmon: (tmp102) Improve handling of initial read delay")
    Link: https://bugzilla.kernel.org/show_bug.cgi?id=197167Reported-by: default avatarRalf Goebel <ralf.goebel@imago-technologies.com>
    Cc: Ralf Goebel <ralf.goebel@imago-technologies.com>
    Reviewed-by: default avatarJean Delvare <jdelvare@suse.de>
    Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
    d0725439
tmp102.c 8.23 KB