From 328a2c22abd08911e37fa66f1358f829cecd72e9 Mon Sep 17 00:00:00 2001 From: Jerome Oufella Date: Wed, 14 Apr 2010 16:14:07 +0200 Subject: [PATCH] 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 Acked-by: Jonathan Cameron Signed-off-by: Jean Delvare Cc: stable@kernel.org --- drivers/hwmon/sht15.c | 6 +++--- 1 file 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;