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authorVivien Didelot <vivien.didelot@savoirfairelinux.com>2011-03-21 17:59:35 +0100
committerGreg Kroah-Hartman <gregkh@suse.de>2011-03-23 13:16:59 -0700
commitd79a1f96cc0d512e8198d463d5ee7b3ebf06f023 (patch)
tree088c292c233cca1130d9f249c11765662b9b41d0
parentd3dd00569dfcc9fa732f16e832ddcb75f1e52186 (diff)
hwmon: (sht15) Fix integer overflow in humidity calculation
commit ccd32e735de7a941906e093f8dca924bb05c5794 upstream. An integer overflow occurs in the calculation of RHlinear when the relative humidity is greater than around 30%. The consequence is a subtle (but noticeable) error in the resulting humidity measurement. Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com> Signed-off-by: Jean Delvare <khali@linux-fr.org> Cc: Jonathan Cameron <jic23@cam.ac.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--drivers/hwmon/sht15.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/hwmon/sht15.c b/drivers/hwmon/sht15.c
index fbc997ee67d9..204050720efb 100644
--- a/drivers/hwmon/sht15.c
+++ b/drivers/hwmon/sht15.c
@@ -332,11 +332,11 @@ static inline int sht15_calc_humid(struct sht15_data *data)
const int c1 = -4;
const int c2 = 40500; /* x 10 ^ -6 */
- const int c3 = -2800; /* x10 ^ -9 */
+ const int c3 = -28; /* x 10 ^ -7 */
RHlinear = c1*1000
+ c2 * data->val_humid/1000
- + (data->val_humid * data->val_humid * c3)/1000000;
+ + (data->val_humid * data->val_humid * c3) / 10000;
return (temp - 25000) * (10000 + 80 * data->val_humid)
/ 1000000 + RHlinear;
}