Nicola Corna schrieb am 23.08.2015 um 09:41: > August 22 2015 11:54 PM, "Hartmut Knaack" <knaack.h@xxxxxx> wrote: >> Hartmut Knaack schrieb am 22.08.2015 um 23:44: >> >>> Nicola Corna schrieb am 22.08.2015 um 20:01: >>>> The maximum possible value for the relative humidity is 55575 (100%RH). >>>> This value, if shifted right by 2 bits, uses 14 bits and masking it with >>>> a 12 bit mask removes 2 meaningful bits. >>>> The masking has been replaced with a range check that sets the minimum >>>> value at 786 (0%RH) and the maximum at 13894 (100%RH). >>>> >>>> Signed-off-by: Nicola Corna <nicola@xxxxxxxxxx> >>> >>> Might be discussable, if we want the upper boundary to be rounded down, >>> so we just barely reach 100% rather than slightly exceeding it (in numbers, >>> that is 99,998 vs 100,006). Using 13893 might be the better value. Other >>> than that (and a typo in the comment) looking good, so: >>> Reviewed-by: Hartmut Knaack <knaack.h@xxxxxx> >> >> On second thought, this is not exactly how clamp_val works. It will return >> a value between the boundaries, so usage is like this: >> *val = clamp_val(*val, 786, 13894) >> > > I've tested clamp_val(*val, 786, 13894) and the minimum returned value is 786 > while the maximum is 13894; shouldn't the line be like this? > *val = clamp_val(*val, 786, 13893) > Now the minimum value is 786 (exactly 0%RH), while the maximum (as you pointed > out) is 13893 (99,998%RH). > > Nicola Corna > Using 13893 as top boundary is my preference, although I would not completely object against 13894. So either way would be fine with me. >> If my suggestions are addressed, you can keep my Reviewed-by tag. >> Thanks, >> >> Hartmut >> >>>> --- >>>> drivers/iio/humidity/si7020.c | 6 +++++- >>>> 1 file changed, 5 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/iio/humidity/si7020.c b/drivers/iio/humidity/si7020.c >>>> index fa3b809..d27e2f2 100644 >>>> --- a/drivers/iio/humidity/si7020.c >>>> +++ b/drivers/iio/humidity/si7020.c >>>> @@ -57,8 +57,12 @@ static int si7020_read_raw(struct iio_dev *indio_dev, >>>> if (ret < 0) >>>> return ret; >>>> *val = ret >> 2; >>>> + /* >>>> + * Humidity values can sligthly exceed the 0-100%RH >>> >>> Typo: slightly >>> >>>> + * range and should be corrected by software >>>> + */ >>>> if (chan->type == IIO_HUMIDITYRELATIVE) >>>> - *val &= GENMASK(11, 0); >>>> + clamp_val(*val, 786, 13894); >>>> return IIO_VAL_INT; >>>> case IIO_CHAN_INFO_SCALE: >>>> if (chan->type == IIO_TEMP) >>> >>> -- >>> 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 > -- > 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 > -- 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
