From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Date: Thu, 01 Apr 2010 15:02:39 +0000 Subject: [lm-sensors] [PATCH] hwmon: (sht15) Fix sht15_calc_temp Message-Id: <20100401170239.3c745577@hyperion.delvare> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lm-sensors@vger.kernel.org From: Jerome Oufella 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(-) --- linux-2.6.34-rc3.orig/drivers/hwmon/sht15.c 2010-04-01 16:24:33.000000000 +0200 +++ linux-2.6.34-rc3/drivers/hwmon/sht15.c 2010-04-01 16:49:45.000000000 +0200 @@ -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; -- Jean Delvare _______________________________________________ lm-sensors mailing list lm-sensors@lm-sensors.org http://lists.lm-sensors.org/mailman/listinfo/lm-sensors