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authorAndreas Klinger <ak@it-klinger.de>2017-04-10 19:00:01 +0200
committerJonathan Cameron <jic23@kernel.org>2017-04-14 16:54:49 +0100
commited3730c435f1a9f9559ed7762035d22d8a95adfe (patch)
tree677e87223f1e19d556faec1d463da4d1af834f29 /drivers/iio
parent84ca8e364acb26aba3292bc113ca8ed4335380fd (diff)
IIO: bmp280-core.c: fix error in humidity calculation
While calculating the compensation of the humidity there are negative values interpreted as unsigned because of unsigned variables used. These values as well as the constants need to be casted to signed as indicated by the documentation of the sensor. Signed-off-by: Andreas Klinger <ak@it-klinger.de> Acked-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Matt Ranostay <matt.ranostay@konsulko.com> Cc: <Stable@vger.kernel.org> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Diffstat (limited to 'drivers/iio')
-rw-r--r--drivers/iio/pressure/bmp280-core.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/drivers/iio/pressure/bmp280-core.c b/drivers/iio/pressure/bmp280-core.c
index 4d18826ac63c..d82b788374b6 100644
--- a/drivers/iio/pressure/bmp280-core.c
+++ b/drivers/iio/pressure/bmp280-core.c
@@ -175,11 +175,12 @@ static u32 bmp280_compensate_humidity(struct bmp280_data *data,
}
H6 = sign_extend32(tmp, 7);
- var = ((s32)data->t_fine) - 76800;
- var = ((((adc_humidity << 14) - (H4 << 20) - (H5 * var)) + 16384) >> 15)
- * (((((((var * H6) >> 10) * (((var * H3) >> 11) + 32768)) >> 10)
- + 2097152) * H2 + 8192) >> 14);
- var -= ((((var >> 15) * (var >> 15)) >> 7) * H1) >> 4;
+ var = ((s32)data->t_fine) - (s32)76800;
+ var = ((((adc_humidity << 14) - (H4 << 20) - (H5 * var))
+ + (s32)16384) >> 15) * (((((((var * H6) >> 10)
+ * (((var * (s32)H3) >> 11) + (s32)32768)) >> 10)
+ + (s32)2097152) * H2 + 8192) >> 14);
+ var -= ((((var >> 15) * (var >> 15)) >> 7) * (s32)H1) >> 4;
return var >> 12;
};