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. Changes in v2: - cast also constants to signed; otherwise calculation is not correct I removed the Acked-By of Linus Walleij because of another change in the calculation. Don't know how it should be treated. Signed-off-by: Andreas Klinger <ak@xxxxxxxxxxxxx> --- drivers/iio/pressure/bmp280-core.c | 11 ++++++----- 1 file 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; }; -- 2.1.4 -- -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
