Commit 328a2c22 authored Apr 14, 2010 by Jerome Oufella Committed by Jean Delvare Apr 14, 2010

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

parent 2ba3abd8

drivers/hwmon/sht15.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -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;

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