[PATCH 4.11 38/78] staging: iio: tsl2x7x_core: Fix standard deviation calculation
From: Greg Kroah-Hartman
Date: Mon Jun 19 2017 - 11:21:13 EST
4.11-stable review patch. If anyone has any objections, please let me know.
From: Eva Rachel Retuya <eraretuya@xxxxxxxxx>
commit cf6c77323a96fc40309cc8a4921ef206cccdd961 upstream.
Standard deviation is calculated as the square root of the variance
where variance is the mean of sample_sum and length. Correct the
computation of statP->stddev in accordance to the proper calculation.
Fixes: 3c97c08b5735 ("staging: iio: add TAOS tsl2x7x driver")
Reported-by: Abhiram Balasubramanian <abhiram@xxxxxxxxxxx>
Signed-off-by: Eva Rachel Retuya <eraretuya@xxxxxxxxx>
Signed-off-by: Jonathan Cameron <jic23@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
drivers/staging/iio/light/tsl2x7x_core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
@@ -854,7 +854,7 @@ void tsl2x7x_prox_calculate(int *data, i
tmp = data[i] - statP->mean;
sample_sum += tmp * tmp;
- statP->stddev = int_sqrt((long)sample_sum) / length;
+ statP->stddev = int_sqrt((long)sample_sum / length);