On 31/05/16 18:45, Alison Schofield wrote:
> On Sun, May 29, 2016 at 07:53:08PM -0700, Matt Ranostay wrote:
>> Alison,
>>
>> Can you give a Tested-by: since I don't own this sensor anymore.
>>
>> Thanks,
>>
>> Matt
>
> Tested it. Verified temp & humidty calcs. Looks great!
Ideally please give an explicit tag.
Tested-by: Alison Schofield <amsfield22@xxxxxxxxx>
(I've add this time on the basis you meant that I think...)
Applied to fixes-togreg and marked for stable. Thanks,
Jonathan
>
> And, (seeing a pattern here ;)) this comes with another question,
> probably directed a Jonathan...
>
> with regards to temperature calculations:
>
> Datasheets give numbers for this method:
> temp = ((raw * scale) + offset)
> IIO drivers report numbers for this method:
> temp = ((raw + offset) * scale)
>
> I've figured out the math for translating between them and creating
> the offset for the driver to report in sysfs, but don't know why we
> are doing that. 'Our' way seems kind of ugly. For example, for HDC1008
> the offset is -40. It's the minimum expected temp value. But, we munge
> it to be -15887.515151 so we can apply it before scaling.
>
> Why do we do it this way in IIO?
>
> alisons
>
>>
>> On Sun, May 29, 2016 at 7:52 PM, Matt Ranostay <mranostay@xxxxxxxxx> wrote:
>>> Shifting sensor data to the right 2 bits was incorrect and caused the
>>> scaling values + offsets to be invalid.
>>>
>>> Reported-by: Alison Schofield <amsfield22@xxxxxxxxx>
>>> Signed-off-by: Matt Ranostay <mranostay@xxxxxxxxx>
>>> ---
>>> drivers/iio/humidity/hdc100x.c | 16 ++++++++--------
>>> 1 file changed, 8 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/drivers/iio/humidity/hdc100x.c b/drivers/iio/humidity/hdc100x.c
>>> index 3070983..a03832a 100644
>>> --- a/drivers/iio/humidity/hdc100x.c
>>> +++ b/drivers/iio/humidity/hdc100x.c
>>> @@ -164,14 +164,14 @@ static int hdc100x_get_measurement(struct hdc100x_data *data,
>>> dev_err(&client->dev, "cannot read high byte measurement");
>>> return ret;
>>> }
>>> - val = ret << 6;
>>> + val = ret << 8;
>>>
>>> ret = i2c_smbus_read_byte(client);
>>> if (ret < 0) {
>>> dev_err(&client->dev, "cannot read low byte measurement");
>>> return ret;
>>> }
>>> - val |= ret >> 2;
>>> + val |= ret;
>>>
>>> return val;
>>> }
>>> @@ -212,17 +212,17 @@ static int hdc100x_read_raw(struct iio_dev *indio_dev,
>>> case IIO_CHAN_INFO_SCALE:
>>> if (chan->type == IIO_TEMP) {
>>> *val = 165000;
>>> - *val2 = 65536 >> 2;
>>> + *val2 = 65536;
>>> return IIO_VAL_FRACTIONAL;
>>> } else {
>>> - *val = 0;
>>> - *val2 = 10000;
>>> - return IIO_VAL_INT_PLUS_MICRO;
>>> + *val = 100;
>>> + *val2 = 65536;
>>> + return IIO_VAL_FRACTIONAL;
>>> }
>>> break;
>>> case IIO_CHAN_INFO_OFFSET:
>>> - *val = -3971;
>>> - *val2 = 879096;
>>> + *val = -15887;
>>> + *val2 = 515151;
>>> return IIO_VAL_INT_PLUS_MICRO;
>>> default:
>>> return -EINVAL;
>>> --
>>> 2.7.4
>>>
--
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
