linux-kernel - Re: [PATCH v2 2/2] iio: bmi323: suspend and resume triggering on relevant pm operations

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Message-ID: <b7e91e68-9f5f-4dd0-aa96-e57983e4a56d@gmail.com>
Date: Sun, 4 Aug 2024 17:40:49 +0200
From: Denis Benato <benato.denis96@...il.com>
To: Jonathan Cameron <jic23@...nel.org>
Cc: 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 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.

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