| From 328a2c22abd08911e37fa66f1358f829cecd72e9 Mon Sep 17 00:00:00 2001 |
| From: Jerome Oufella <jerome.oufella@savoirfairelinux.com> |
| Date: Wed, 14 Apr 2010 16:14:07 +0200 |
| Subject: hwmon: (sht15) Fix sht15_calc_temp interpolation function |
| |
| From: Jerome Oufella <jerome.oufella@savoirfairelinux.com> |
| |
| commit 328a2c22abd08911e37fa66f1358f829cecd72e9 upstream. |
| |
| 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> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| |
| --- |
| drivers/hwmon/sht15.c | 6 +++--- |
| 1 file changed, 3 insertions(+), 3 deletions(-) |
| |
| --- a/drivers/hwmon/sht15.c |
| +++ b/drivers/hwmon/sht15.c |
| @@ -302,13 +302,13 @@ 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; |
