Re: [PATCH 0/8] IIO: Where dev_pm_ops rework and namespaces meet.

[Paul Cercueil <paul@crapouillou.net>]

Le mer., févr. 23 2022 at 12:13:41 +0000, Jonathan Cameron 
<Jonathan.Cameron@Huawei.com> a écrit :
> On Wed, 23 Feb 2022 11:50:48 +0000
> Paul Cercueil <paul@crapouillou.net> wrote:
> 
>>  Hi Jonathan,
>> 
>>  Le dim., févr. 20 2022 at 18:15:14 +0000, Jonathan Cameron
>>  <jic23@kernel.org> a écrit :
>>  > From: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>>  >
>>  > Hi All,
>>  >
>>  > As these two activities have been ongoing across IIO at the same 
>> time
>>  > it was inevitable that there would be drivers were they both 
>> interact.
>>  > In particularly when we have EXPORT* of struct dev_pm_ops.
>>  >
>>  > This series covers those cases by introducing (in patch 2)
>>  > EXPORT_NS[_GPL]_SIMPLE_DEV_PM_OPS() and
>>  > EXPORT_NS[_GPL]_RUNTIME_DEV_PM_OPS()
>>  > that add a namespace as the final parameter.
>> 
>>  If we now have namespace versions of the macros, I'm starting to 
>> wonder
>>  if the original macros are still useful.
>> 
>>  In which case would we need to export a dev_pm_ops outside the 
>> scope of
>>  a namespace?
> 
> Excellent point. Long term my assumption is that any place where
> a dev_pm_ops is being exported probably should be in a namespace
> because the scope is tightly defined.
> 
> My only thought is it adds a burden to moving over to your new 
> infrastructure
> as it would be odd to move only the dev_pm_ops into a NS without 
> looking
> at the rest of the exports in a driver.
> 
> It was useful to be able to do things in two steps as it allowed 
> separation
> of using the new dev_pm_ops handling from a namespace move, but
> clearly could do that the other way around and not need the non
> namespaced version of this macro.
> So do namespace move first then use the new macros and hence only
> ever need the namespaced one.

I'd be slightly in favor of enforcing namespaces in the PM macros, if 
only to simplify the macro names (as you could just extend the existing 
ones to require a namespace, I don't think anything use them yet).

But I'm fine with keeping the non-namespaced macros as well if it's 
easier. We can always drop them later.

Cheers,
-Paul

> Jonathan
> 
> 
>> 
>>  Cheers,
>>  -Paul
>> 
>>  > In each driver (with the exception of the kxsd9 which was already
>>  > using a IIO_KXSD9 namespace) I first move to the new *_PM_OPS()
>>  > and pm_[sleep_]_ptr() then in a second patch move to the new
>>  > namespaces.  Initially I had these two steps done as one patch
>>  > per driver but that was harder to follow and broke the rule of
>>  > one thing per patch.
>>  >
>>  > All comments welcome.
>>  >
>>  > Thanks,
>>  >
>>  > Jonathan
>>  >
>>  > Jonathan Cameron (8):
>>  >   iio: chemical: scd30: Export dev_pm_ops instead of suspend() and
>>  >     resume()
>>  >   PM: core: Add NS varients of EXPORT[_GPL]_SIMPLE_DEV_PM_OPS and
>>  >     runtime pm equiv
>>  >   iio: chemical: scd30: Move symbol exports into IIO_SCD30 
>> namespace
>>  >   iio:accel:kxsd9: Switch from CONFIG_PM guards to pm_ptr() etc
>>  >   iio: humidity: hts221: Use EXPORT_SIMPLE_DEV_PM_OPS() to allow
>>  >     compiler to remove dead code.
>>  >   iio: humidity: hts221: Move symbol exports into IIO_HTS221 
>> namespace
>>  >   iio: imu: lsm6dsx: Use new pm_sleep_ptr() and
>>  >     EXPORT_SIMPLE_DEV_PM_OPS()
>>  >   iio: imu: lsm6dsx: Move exported symbols to the IIO_LSM6DSX
>>  > namespace
>>  >
>>  >  drivers/iio/accel/kxsd9-i2c.c                |  2 +-
>>  >  drivers/iio/accel/kxsd9-spi.c                |  2 +-
>>  >  drivers/iio/accel/kxsd9.c                    | 11 ++---------
>>  >  drivers/iio/chemical/scd30.h                 |  5 +----
>>  >  drivers/iio/chemical/scd30_core.c            | 10 +++++-----
>>  >  drivers/iio/chemical/scd30_i2c.c             |  3 ++-
>>  >  drivers/iio/chemical/scd30_serial.c          |  3 ++-
>>  >  drivers/iio/humidity/hts221_core.c           | 12 +++++-------
>>  >  drivers/iio/humidity/hts221_i2c.c            |  3 ++-
>>  >  drivers/iio/humidity/hts221_spi.c            |  3 ++-
>>  >  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c | 12 +++++-------
>>  >  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_i2c.c  |  3 ++-
>>  >  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_i3c.c  |  3 ++-
>>  >  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_spi.c  |  3 ++-
>>  >  include/linux/pm.h                           | 14 +++++++++-----
>>  >  include/linux/pm_runtime.h                   | 10 ++++++++--
>>  >  16 files changed, 51 insertions(+), 48 deletions(-)
>>  >
>>  > --
>>  > 2.35.1
>>  >
>> 
>> 
>