Re: [PATCH 1/3] iio:humidity:si7020: replaced bitmask on humidity values with range check

[Hartmut Knaack <knaack.h@gmx.de>]

Nicola Corna schrieb am 20.08.2015 um 23:57:
> August 20 2015 10:49 PM, "Hartmut Knaack" <knaack.h@gmx.de> wrote:
>> Nicola Corna schrieb am 20.08.2015 um 16:11:
>>
>>> 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 3194 (0%RH) and the maximum at 55575 (100%RH).
>>
>> Hmm, I guess the mask should have been applied for bits 13:2, but your
>> solution confirms better to the data sheet. Just one essential detail:
>> The raw sensor data has already been divided by 4 when you do the boundary
>> check. So, you need to divide the boundaries, as well.
>> Btw, you can make this a one-liner using clamp_val, check it out: [1]
>>
>> [1]http://lxr.free-electrons.com/source/include/linux/kernel.h#L795
>>
> 
> Yes, you're right. Thanks.
> Forgive me for my ignorance, but do I have now to upload the [PATCH v2] for
> all the three patches?
> 

That's what we usually do. And since your third patch depends on this one,
it needs to be updated as well.

>>> Signed-off-by: Nicola Corna <nicola@corna.info>
>>> ---
>>> drivers/iio/humidity/si7020.c | 12 ++++++++++--
>>> 1 file changed, 10 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/iio/humidity/si7020.c b/drivers/iio/humidity/si7020.c
>>> index fa3b809..62fdbcf 100644
>>> --- a/drivers/iio/humidity/si7020.c
>>> +++ b/drivers/iio/humidity/si7020.c
>>> @@ -57,8 +57,16 @@ static int si7020_read_raw(struct iio_dev *indio_dev,
>>> if (ret < 0)
>>> return ret;
>>> *val = ret >> 2;
>>> - if (chan->type == IIO_HUMIDITYRELATIVE)
>>> - *val &= GENMASK(11, 0);
>>> + /*
>>> + * Humidity values can sligthly exceed the 0-100%RH
>>> + * range and should be corrected by software
>>> + */
>>> + if (chan->type == IIO_HUMIDITYRELATIVE) {
>>> + if (*val < 3194) /* 0%RH */
>>> + *val = 3194;
>>> + else if (*val > 55575) /* 100%RH */
>>> + *val = 55575;
>>> + }
>>> return IIO_VAL_INT;
>>> case IIO_CHAN_INFO_SCALE:
>>> if (chan->type == IIO_TEMP)
> --
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