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| author | Jerome Oufella <jerome.oufella@savoirfairelinux.com> | 2010-04-14 16:14:07 +0200 |
|---|---|---|
| committer | Jean Delvare <khali@linux-fr.org> | 2010-04-14 16:14:07 +0200 |
| commit | 328a2c22abd08911e37fa66f1358f829cecd72e9 (patch) | |
| tree | 31f33c7b72b522eed0ab4d5da9904cc726471937 /drivers/hwmon/sht15.c | |
| parent | 2ba3abd8186f24c7fb418927025b4e2120e3a362 (diff) | |
| download | lwn-328a2c22abd08911e37fa66f1358f829cecd72e9.tar.gz lwn-328a2c22abd08911e37fa66f1358f829cecd72e9.zip | |
hwmon: (sht15) Fix sht15_calc_temp interpolation function
I discovered two issues.
First the previous sht15_calc_temp() loop did not iterate through the
temppoints array since the (data->supply_uV > temppoints[i - 1].vdd)
test is always true in this direction.
Also the two-points linear interpolation function was returning biased
values due to a stray division by 1000 which shouldn't be there.
[JD: Also change the default value for d1 from 0 to something saner.]
Signed-off-by: Jerome Oufella <jerome.oufella@savoirfairelinux.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: stable@kernel.org
Diffstat (limited to 'drivers/hwmon/sht15.c')
| -rw-r--r-- | drivers/hwmon/sht15.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/hwmon/sht15.c b/drivers/hwmon/sht15.c index 6b2d8ae64fe1..9a15b1af1f11 100644 --- a/drivers/hwmon/sht15.c +++ b/drivers/hwmon/sht15.c @@ -303,13 +303,13 @@ error_ret: **/ static inline int sht15_calc_temp(struct sht15_data *data) { - int d1 = 0; + int d1 = temppoints[0].d1; int i; - for (i = 1; i < ARRAY_SIZE(temppoints); i++) + for (i = ARRAY_SIZE(temppoints) - 1; i > 0; i--) /* Find pointer to interpolate */ if (data->supply_uV > temppoints[i - 1].vdd) { - d1 = (data->supply_uV/1000 - temppoints[i - 1].vdd) + d1 = (data->supply_uV - temppoints[i - 1].vdd) * (temppoints[i].d1 - temppoints[i - 1].d1) / (temppoints[i].vdd - temppoints[i - 1].vdd) + temppoints[i - 1].d1; |