Re: [RFC PATCH] iio: imu: st_lsm6dsx: filter motion events in driver

[Lorenzo Bianconi <lorenzo@kernel.org>]

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On Sep 16, Sean Nyekjaer wrote:
> 
> 
> On 16/09/2019 13.55, Lorenzo Bianconi wrote:
> > > 
> > > 
> > > On 16/09/2019 11.16, Lorenzo Bianconi wrote:
> > > > > +	if (hw->event_en_mask & BIT(chan->channel2))
> > > > > +		goto out;
> > > > Why do we need this?
> > > > 
> > > 
> > > Guess we need to check if 0 < hw->enable_event before disabling the
> > > sensor...
> > > > > +
> > > > >    	/* do not enable events if they are already enabled */
> > > > >    	if (state && hw->enable_event)
> > > > > -		return 0;
> > > > > +		goto out;
> > > 
> > > static int st_lsm6dsx_write_event_config(struct iio_dev *iio_dev,
> > >                                             const struct iio_chan_spec *chan,
> > >                                             enum iio_event_type type,
> > >                                             enum iio_event_direction dir,
> > >                                             int state)
> > > {
> > >          struct st_lsm6dsx_sensor *sensor = iio_priv(iio_dev);
> > >          struct st_lsm6dsx_hw *hw = sensor->hw;
> > >          u8 _enable_event;
> > 
> > please use enable_event instead of _enable_event
> > 
> > >          int err = 0;
> > > 
> > >          if (type != IIO_EV_TYPE_THRESH)
> > >                  return -EINVAL;
> > > 
> > >          if (state) {
> > >                  _enable_event = hw->enable_event | BIT(chan->channel2);
> > > 
> > >                  /* do not enable events if they are already enabled */
> > >                  if (0 < hw->enable_event)
> > >                          goto out;
> > 
> > we do not need this since there is the check:
> > if (hw->enable_event == enable_event)
> > 	return 0;
> 
> I actually think this is needed as if a channel is enabled and another
> channel is enabled, then 'state' will be 1 and '0 < hw->enable_event' is
> true. Then we don't want to do the event_setup again.

got what you mean here, right..just please do:

if (hw->enable_event)
	goto out;

> 
> > 
> > >          } else {
> > >                  _enable_event = hw->enable_event & ~BIT(chan->channel2);
> > > 
> > >                  /* only turn off sensor if no events is enabled */
> > > 
> > > 
> > > 
> > > 
> > >                  if (0 != _enable_event)
> > >                          goto out;

if (enable_event)
	goto out;

> > 
> > we do not need this as well
> Like wise here, if we don't have this and to channels is enabled, if you
> deactivate one of the channels then enable_event indicates that a channel is
> active but the sensor is disabled.
> Guess that is not what we want :-)
> 
> > 
> > >          }
> > > 
> > >          /* stop here if no changes have been made */
> > >          if (hw->enable_event == _enable_event)
> > >                  return 0;
> > > 
> > >          err = st_lsm6dsx_event_setup(hw, state);
> > >          if (err < 0)
> > >                  return err;
> > > 
> 

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