Message-ID: <20240807135731.0000320f@Huawei.com>
Date: Wed, 7 Aug 2024 13:57:31 +0100
From: Jonathan Cameron <Jonathan.Cameron@...wei.com>
To: Denis Benato <benato.denis96@...il.com>
CC: Jonathan Cameron <jic23@...nel.org>, Lars-Peter Clausen <lars@...afoo.de>,
	Jagath Jog J <jagathjog1996@...il.com>, <linux-iio@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, "Luke D . Jones" <luke@...nes.dev>, Jonathan
 LoBue <jlobue10@...il.com>
Subject: Re: [PATCH v2 2/2] iio: bmi323: suspend and resume triggering on
 relevant pm operations

On Sun, 4 Aug 2024 17:40:49 +0200
Denis Benato <benato.denis96@...il.com> wrote:

> On 03/08/24 17:44, Jonathan Cameron wrote:
> > On Sat, 27 Jul 2024 14:30:34 +0200
> > Denis Benato <benato.denis96@...il.com> wrote:
> >   
> >> Prevent triggers from stop working after the device has entered sleep:
> >> use iio_device_suspend_triggering and iio_device_resume_triggering helpers.  
> > 
> > Hi Denis,
> >   
> Hello Jonathan,
> > I'd got it into my head this was about main suspend / resume, but
> > it's runtime PM. I assume the s2idle uses only that level which is
> > interesting.
> >   
> I have catched the problem with s2idle, but I don-t fully understand
> it will manifest outside of said scenario, nor if it will at all and
> only s2idle is affected.
> 
> > Anyhow, solution seems safe. We might be able to do something nicer
> > in the long run as potentially we could have the trigger driver
> > notified when all consumers have entered this state at which point it
> > could stop generating triggers at all.
> > Totally agree.
> > Anyhow, that's a job for when we actually care about it.
> > 
> > Applied to the togreg branch of iio.git and pushed out as testing
> > for 0-day to poke at it.
> >   
> I have made a mistake while cleaning up patch 1/2 for submission and lost a piece:
> the pollfunc->irq=0 you suggested in your first mail.
> 
> I would be more than happy to provide a v3, but if you prefer I can also send
> a separate patch.
Send a v3. I'll try and remember to drop the v2 before sending a pull request
upstream.

> 
> I am sorry about that and I would like guidance on what to do in cases like this.

Not a problem, we all do stuff like this from time to time!

> > For now I'm not keen to see this pushed into drivers where we don't
> > know if anyone is running into this particular situation.  We can
> > reevaluate that if we start getting lots of reports of this.
> >   
> I catched the issue while developing an application for a handheld PC.
> 
> As the application will target these kind of devices we can apply the fix
> to every relevant driver (bmi260 comes to mind) and have that well-tested
> on multiple drivers.

Ok. Let's see how it goes with a few drivers.

Jonathan

> > I'm also not going to rush this in as a fix. We can consider backporting
> > it once it's been in mainline for a bit and no side effects have
> > shown up.
> > 
> > Thanks,
> > 
> > Jonathan
> >   
> Thanks,
> 
> Denis
> >>
> >> Signed-off-by: Denis Benato <benato.denis96@...il.com>
> >> ---
> >>  drivers/iio/imu/bmi323/bmi323.h      |  1 +
> >>  drivers/iio/imu/bmi323/bmi323_core.c | 23 +++++++++++++++++++++++
> >>  drivers/iio/imu/bmi323/bmi323_i2c.c  |  1 +
> >>  drivers/iio/imu/bmi323/bmi323_spi.c  |  1 +
> >>  4 files changed, 26 insertions(+)
> >>
> >> diff --git a/drivers/iio/imu/bmi323/bmi323.h b/drivers/iio/imu/bmi323/bmi323.h
> >> index dff126d41658..209bccb1f335 100644
> >> --- a/drivers/iio/imu/bmi323/bmi323.h
> >> +++ b/drivers/iio/imu/bmi323/bmi323.h
> >> @@ -205,5 +205,6 @@
> >>  struct device;
> >>  int bmi323_core_probe(struct device *dev);
> >>  extern const struct regmap_config bmi323_regmap_config;
> >> +extern const struct dev_pm_ops bmi323_core_pm_ops;
> >>  
> >>  #endif
> >> diff --git a/drivers/iio/imu/bmi323/bmi323_core.c b/drivers/iio/imu/bmi323/bmi323_core.c
> >> index d708d1fe3e42..4b2b211a3e88 100644
> >> --- a/drivers/iio/imu/bmi323/bmi323_core.c
> >> +++ b/drivers/iio/imu/bmi323/bmi323_core.c
> >> @@ -2121,6 +2121,29 @@ int bmi323_core_probe(struct device *dev)
> >>  }
> >>  EXPORT_SYMBOL_NS_GPL(bmi323_core_probe, IIO_BMI323);
> >>  
> >> +#if defined(CONFIG_PM)
> >> +static int bmi323_core_runtime_suspend(struct device *dev)
> >> +{
> >> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> >> +
> >> +	return iio_device_suspend_triggering(indio_dev);
> >> +}
> >> +
> >> +static int bmi323_core_runtime_resume(struct device *dev)
> >> +{
> >> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> >> +
> >> +	return iio_device_resume_triggering(indio_dev);
> >> +}
> >> +
> >> +#endif
> >> +
> >> +const struct dev_pm_ops bmi323_core_pm_ops = {
> >> +	SET_RUNTIME_PM_OPS(bmi323_core_runtime_suspend,
> >> +			   bmi323_core_runtime_resume, NULL)
> >> +};
> >> +EXPORT_SYMBOL_NS_GPL(bmi323_core_pm_ops, IIO_BMI323);
> >> +
> >>  MODULE_DESCRIPTION("Bosch BMI323 IMU driver");
> >>  MODULE_AUTHOR("Jagath Jog J <jagathjog1996@...il.com>");
> >>  MODULE_LICENSE("GPL");
> >> diff --git a/drivers/iio/imu/bmi323/bmi323_i2c.c b/drivers/iio/imu/bmi323/bmi323_i2c.c
> >> index 52140bf05765..057342f4f816 100644
> >> --- a/drivers/iio/imu/bmi323/bmi323_i2c.c
> >> +++ b/drivers/iio/imu/bmi323/bmi323_i2c.c
> >> @@ -128,6 +128,7 @@ MODULE_DEVICE_TABLE(of, bmi323_of_i2c_match);
> >>  static struct i2c_driver bmi323_i2c_driver = {
> >>  	.driver = {
> >>  		.name = "bmi323",
> >> +		.pm = pm_ptr(&bmi323_core_pm_ops),
> >>  		.of_match_table = bmi323_of_i2c_match,
> >>  		.acpi_match_table = bmi323_acpi_match,
> >>  	},
> >> diff --git a/drivers/iio/imu/bmi323/bmi323_spi.c b/drivers/iio/imu/bmi323/bmi323_spi.c
> >> index 7b1e8127d0dd..487d4ee05246 100644
> >> --- a/drivers/iio/imu/bmi323/bmi323_spi.c
> >> +++ b/drivers/iio/imu/bmi323/bmi323_spi.c
> >> @@ -79,6 +79,7 @@ MODULE_DEVICE_TABLE(of, bmi323_of_spi_match);
> >>  static struct spi_driver bmi323_spi_driver = {
> >>  	.driver = {
> >>  		.name = "bmi323",
> >> +		.pm = pm_ptr(&bmi323_core_pm_ops),
> >>  		.of_match_table = bmi323_of_spi_match,
> >>  	},
> >>  	.probe = bmi323_spi_probe,  
> >   
> 
> 

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