Messages in this thread | | | Date | Mon, 8 Aug 2022 11:43:31 +0100 | Subject | Re: [PATCH 20/28] mfd: arizona: Remove #ifdef guards for PM related functions | From | Richard Fitzgerald <> |
| |
On 08/08/2022 11:06, Paul Cercueil wrote: > Hi Richard, > > Le lun., août 8 2022 at 10:53:54 +0100, Richard Fitzgerald > <rf@opensource.cirrus.com> a écrit : >> On 07/08/2022 15:52, Paul Cercueil wrote: >>> Only export the arizona_pm_ops if CONFIG_PM is set, but leave the >>> suspend/resume functions (and related code) outside #ifdef guards. >>> >>> If CONFIG_PM is not set, the arizona_pm_ops will be defined as >>> "static __maybe_unused", and the structure plus all the callbacks will >>> be automatically dropped by the compiler. >>> >>> The advantage is then that these functions are now always compiled >>> independently of any Kconfig option, and thanks to that bugs and >>> regressions are easier to catch. >>> >>> Signed-off-by: Paul Cercueil <paul@crapouillou.net> >>> Cc: patches@opensource.cirrus.com >>> --- >>> drivers/mfd/arizona-core.c | 21 +++++++++++---------- >>> drivers/mfd/arizona-i2c.c | 2 +- >>> drivers/mfd/arizona-spi.c | 2 +- >>> 3 files changed, 13 insertions(+), 12 deletions(-) >>> >>> diff --git a/drivers/mfd/arizona-core.c b/drivers/mfd/arizona-core.c >>> index cbf1dd90b70d..c1acc9521f83 100644 >>> --- a/drivers/mfd/arizona-core.c >>> +++ b/drivers/mfd/arizona-core.c >>> @@ -480,7 +480,6 @@ static int wm5102_clear_write_sequencer(struct >>> arizona *arizona) >>> return 0; >>> } >>> -#ifdef CONFIG_PM >>> static int arizona_isolate_dcvdd(struct arizona *arizona) >> >> __maybe_unused? > > No need. The symbols are always referenced. > >>> { >>> int ret; >>> @@ -742,9 +741,7 @@ static int arizona_runtime_suspend(struct device >>> *dev) >> >> __maybe_unused? >> >>> return 0; >>> } >>> -#endif >>> -#ifdef CONFIG_PM_SLEEP >>> static int arizona_suspend(struct device *dev) >> >> __maybe_unused? >> >>> { >>> struct arizona *arizona = dev_get_drvdata(dev); >>> @@ -784,17 +781,21 @@ static int arizona_resume(struct device *dev) >> >> __maybe_unused? >> >>> return 0; >>> } >>> -#endif >>> +#ifndef CONFIG_PM >>> +static __maybe_unused >>> +#endif >> >> No need to ifdef a __maybe_unused. > > Yes, it is needed, because the symbol is conditionally exported. If
Why conditionally export it?
> !CONFIG_PM, we want the compiler to discard the dev_pm_ops and all the > callbacks, hence the "static __maybe_unused". That's the same trick used > in _EXPORT_DEV_PM_OPS(). > > (note that this patch is broken as it does not change the struct name, > in the !PM case, which causes conflicts with the .h. I'll fix in v2) > >>> const struct dev_pm_ops arizona_pm_ops = { >>> - SET_RUNTIME_PM_OPS(arizona_runtime_suspend, >>> - arizona_runtime_resume, >>> - NULL) >>> - SET_SYSTEM_SLEEP_PM_OPS(arizona_suspend, arizona_resume) >>> - SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(arizona_suspend_noirq, >>> - arizona_resume_noirq) >>> + RUNTIME_PM_OPS(arizona_runtime_suspend, >>> + arizona_runtime_resume, >>> + NULL) >>> + SYSTEM_SLEEP_PM_OPS(arizona_suspend, arizona_resume) >>> + NOIRQ_SYSTEM_SLEEP_PM_OPS(arizona_suspend_noirq, >>> + arizona_resume_noirq) >>> }; >>> +#ifdef CONFIG_PM >>> EXPORT_SYMBOL_GPL(arizona_pm_ops); >>> +#endif >> >> This ifdeffing is ugly. Why must the structure only be exported if >> CONFIG_PM is set? > > So that all the PM code is garbage-collected by the compiler if !CONFIG_PM.
The functions will be dropped if they are not referenced. That doesn't answer why the struct must not be exported.
What is the aim of omitting the struct export?
> > Ideally I would use something like EXPORT_SIMPLE_DEV_PM_OPS() which > would make the patch much cleaner, but it doesn't support noirq > callbacks - and that's why I suggested in the cover letter that maybe a > new PM macro can be added if this patch is deemed too messy. > > Cheers, > -Paul > >>> #ifdef CONFIG_OF >>> static int arizona_of_get_core_pdata(struct arizona *arizona) >>> diff --git a/drivers/mfd/arizona-i2c.c b/drivers/mfd/arizona-i2c.c >>> index 6d83e6b9a692..8799d9183bee 100644 >>> --- a/drivers/mfd/arizona-i2c.c >>> +++ b/drivers/mfd/arizona-i2c.c >>> @@ -119,7 +119,7 @@ static const struct of_device_id >>> arizona_i2c_of_match[] = { >>> static struct i2c_driver arizona_i2c_driver = { >>> .driver = { >>> .name = "arizona", >>> - .pm = &arizona_pm_ops, >>> + .pm = pm_ptr(&arizona_pm_ops), >>> .of_match_table = of_match_ptr(arizona_i2c_of_match), >>> }, >>> .probe = arizona_i2c_probe, >>> diff --git a/drivers/mfd/arizona-spi.c b/drivers/mfd/arizona-spi.c >>> index 941b0267d09d..da05b966d48c 100644 >>> --- a/drivers/mfd/arizona-spi.c >>> +++ b/drivers/mfd/arizona-spi.c >>> @@ -282,7 +282,7 @@ static const struct of_device_id >>> arizona_spi_of_match[] = { >>> static struct spi_driver arizona_spi_driver = { >>> .driver = { >>> .name = "arizona", >>> - .pm = &arizona_pm_ops, >>> + .pm = pm_ptr(&arizona_pm_ops), >>> .of_match_table = of_match_ptr(arizona_spi_of_match), >>> .acpi_match_table = ACPI_PTR(arizona_acpi_match), >>> }, > >
| |