Commit ed3730c4 authored by Andreas Klinger's avatar Andreas Klinger Committed by Jonathan Cameron

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: default avatarAndreas Klinger <ak@it-klinger.de>
Acked-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: default avatarMatt Ranostay <matt.ranostay@konsulko.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent 84ca8e36
...@@ -175,11 +175,12 @@ static u32 bmp280_compensate_humidity(struct bmp280_data *data, ...@@ -175,11 +175,12 @@ static u32 bmp280_compensate_humidity(struct bmp280_data *data,
} }
H6 = sign_extend32(tmp, 7); H6 = sign_extend32(tmp, 7);
var = ((s32)data->t_fine) - 76800; var = ((s32)data->t_fine) - (s32)76800;
var = ((((adc_humidity << 14) - (H4 << 20) - (H5 * var)) + 16384) >> 15) var = ((((adc_humidity << 14) - (H4 << 20) - (H5 * var))
* (((((((var * H6) >> 10) * (((var * H3) >> 11) + 32768)) >> 10) + (s32)16384) >> 15) * (((((((var * H6) >> 10)
+ 2097152) * H2 + 8192) >> 14); * (((var * (s32)H3) >> 11) + (s32)32768)) >> 10)
var -= ((((var >> 15) * (var >> 15)) >> 7) * H1) >> 4; + (s32)2097152) * H2 + 8192) >> 14);
var -= ((((var >> 15) * (var >> 15)) >> 7) * (s32)H1) >> 4;
return var >> 12; return var >> 12;
}; };
......
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