Hi Lorenzo,
On Mon, 2018-04-30 at 09:48 +0200, Lorenzo Bianconi wrote:
> > CTRL1 register (ODR & BDU settings) gets reset after system comes back
> > from suspend, causing subsequent reads from the sensor to fail.
> >
> > This patch restores the CTRL1 register after resume.
> >
>
> Hi Shrirang,
>
> is just CTRL1 reset after suspend/resume or also other registers? are
I have checked, contents of other registers survive the suspend/resume
(both suspend-to-ram & suspend-to-disk)cycle. It's only CTRL1 which resets.
> IIO triggers enabled before the suspend or
No IIO triggers are enabled.
> are you reading data from sysfs?
Yes.
>
> > Based on:
> > git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git iio-for-4.17b
> >
> > Fixes: ffebe74b7c95 (iio: humidity: hts221: avoid useless ODR reconfiguration)
> > Signed-off-by: Shrirang Bagul <shrirang.bagul@xxxxxxxxxxxxx>
> > ---
> > drivers/iio/humidity/hts221_core.c | 13 +++++++------
> > 1 file changed, 7 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/iio/humidity/hts221_core.c b/drivers/iio/humidity/hts221_core.c
> > index 166946d4978d..5d7a652aa6d9 100644
> > --- a/drivers/iio/humidity/hts221_core.c
> > +++ b/drivers/iio/humidity/hts221_core.c
> > @@ -658,12 +658,13 @@ static int __maybe_unused hts221_resume(struct device *dev)
> > struct hts221_hw *hw = iio_priv(iio_dev);
> > int err = 0;
> >
> > - if (hw->enabled)
> > - err = regmap_update_bits(hw->regmap, HTS221_REG_CNTRL1_ADDR,
> > - HTS221_ENABLE_MASK,
> > - FIELD_PREP(HTS221_ENABLE_MASK,
> > - true));
> > - return err;
> > + err = regmap_update_bits(hw->regmap, HTS221_REG_CNTRL1_ADDR,
> > + HTS221_BDU_MASK,
> > + FIELD_PREP(HTS221_BDU_MASK, 1));
> > + if (err < 0)
> > + return err;
> > +
> > + return hts221_update_odr(hw, hw->odr);
> > }
> >
>
> Here you need to re-enable the sensor if it was running before the
> suspend operation.
> Regards,
>
> Lorenzo
>
> > const struct dev_pm_ops hts221_pm_ops = {
> > --
> > 2.14.1
> >
>
>
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