On Mon, 2018-04-30 at 17:12 +0800, Shrirang Bagul wrote:
> On Mon, 2018-04-30 at 11:05 +0200, Lorenzo Bianconi wrote:
> > > 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
> > > > IIO triggers enabled before the suspend or
> > > > are you reading data from sysfs?
> > > >
> > > > > 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);
> > > > > }
> > > > >
> > >
> > > No need to re-enable the sensor here. hts221_read_oneshot() [called from hts221_read_raw()] does that every time before read:
> > >
> >
> > Could please try to change other registers (e.g. rh or temp gain) and
> > double check values are properly configured resuming the sensor?
Further testing revealed that the contents of AV_CONF register value gets
overwritten (set to 0x3F) every time system comes out of suspend.
> > It is necessary to re-enable the sensor if you use IIO triggers and
> > the sensor was enabled before the suspend operation
Yes, I understand this is required, will handle this and restoring the AV_CONF
register in the next version.
I've tried using sysfs_trig_iio to test reading the sensor output from devfs
(using iio_generic_buffer) but looks like this is not supported in the current
driver. HW interrupts cannot be used on my system.
Please suggest if there are other alternatives?
>
> Sure. I'll do some more testing and share the results.
> >
> > > static int hts221_read_oneshot(struct hts221_hw *hw, u8 addr, int *val)
> > > {
> > > __le16 data;
> > > int err;
> > >
> > > err = hts221_set_enable(hw, true);
> > > if (err < 0)
> > > return err;
> > >
> > > msleep(50);
> > >
> > > err = regmap_bulk_read(hw->regmap, addr, &data, sizeof(data));
> > > if (err < 0)
> > > return err;
> > >
> > > hts221_set_enable(hw, false);
> > >
> > > Regards,
> > > Shrirang
> > > >
> > > > 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
> > > > >
> > > >
> > > >
> > > >
> >
> > Attachment:
signature.asc
Description: This is a digitally signed message part
