From: Maud Spierings Date: Fri, 7 Mar 2025 08:10:43 +0000 (+0100) Subject: hwmon: (ntc_thermistor) return error instead of clipping on OOB X-Git-Tag: v6.15-rc1~180^2~14 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7953605976f55acd4f297d310e6b0b2944f4bdc8;p=thirdparty%2Fkernel%2Fstable.git hwmon: (ntc_thermistor) return error instead of clipping on OOB When the ntc is reading Out Of Bounds instead of clipping to the nearest limit (min/max) return -ENODATA. This prevents malfunctioning sensors from sending a device into a shutdown loop due to a critical trip. This implementation will only work for ntc type thermistors if a ptc type is to be implemented the min/max ohm calculation must be adjusted to take that into account. Signed-off-by: Maud Spierings Link: https://lore.kernel.org/r/20250307-ntc_oob-v2-1-bba2d32b1a8e@gocontroll.com Signed-off-by: Guenter Roeck --- diff --git a/drivers/hwmon/ntc_thermistor.c b/drivers/hwmon/ntc_thermistor.c index b5352900463fb..7c759669b26fa 100644 --- a/drivers/hwmon/ntc_thermistor.c +++ b/drivers/hwmon/ntc_thermistor.c @@ -387,12 +387,9 @@ static int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uv) puo = data->pullup_ohm; pdo = data->pulldown_ohm; - if (uv == 0) - return (data->connect == NTC_CONNECTED_POSITIVE) ? - INT_MAX : 0; - if (uv >= puv) - return (data->connect == NTC_CONNECTED_POSITIVE) ? - 0 : INT_MAX; + /* faulty adc value */ + if (uv == 0 || uv >= puv) + return -ENODATA; if (data->connect == NTC_CONNECTED_POSITIVE && puo == 0) n = div_u64(pdo * (puv - uv), uv); @@ -404,8 +401,10 @@ static int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uv) else n = div64_u64_safe(pdo * puo * uv, pdo * (puv - uv) - puo * uv); - if (n > INT_MAX) - n = INT_MAX; + /* sensor out of bounds */ + if (n > data->comp[0].ohm || n < data->comp[data->n_comp - 1].ohm) + return -ENODATA; + return n; }