Re: [PATCH 3/4] iio: adc: mediatek: SET_LATE_SYSTEM_SLEEP_PM_OPS support

[Chun-Hung Wu]

Hi Matthias:

  Thanks for your suggestion, I think device_links is a good way to
make dependency of module's suspend/resume order.

Hi Jonathan:

  Is it ok to keep using late_suspend and early_resume, or do you think
it's better to use device_links?

Thanks,
Chun-Hung
On Wed, 2019-05-22 at 18:28 +0200, Matthias Brugger wrote:
> 
> On 20/05/2019 08:03, Chun-Hung Wu wrote:
> > Hi Jonathan:
> > 
> >   Thanks for the prompt reply,
> > 
> > On Sat, 2019-05-18 at 11:35 +0100, Jonathan Cameron wrote:
> >> On Thu, 16 May 2019 16:10:46 +0800
> >> Chun-Hung Wu <chun-hung.wu@xxxxxxxxxxxx> wrote:
> >>
> >>>   Move suspend/resume to late_suspend and
> >>> early_resume to gurantee users can use auxadc
> >> guarantee
> >>
> > will fix it in next version.
> >>> driver at suspend/resume stage.
> >> No problem with the patch content, but we need a reason why they may
> >> want to do so?
> > Our thermal drivers uses auxadc at suspend/resume stage.
> > In order to avoid auxadc suspended prior to thermal driver,
> > we move auxadc to late_suspend and early_resume.
> > 
> 
> That sounds like a user of device_links [1] to me.
> 
> [1] https://www.kernel.org/doc/html/latest/driver-api/device_link.html
> 
> > Thanks,
> > Chun-Hung
> >>
> >> Thanks,
> >>
> >> Jonathan
> >>>
> >>> Signed-off-by: Chun-Hung Wu <chun-hung.wu@xxxxxxxxxxxx>
> >>> ---
> >>>  drivers/iio/adc/mt6577_auxadc.c | 7 ++++---
> >>>  1 file changed, 4 insertions(+), 3 deletions(-)
> >>>
> >>> diff --git a/drivers/iio/adc/mt6577_auxadc.c b/drivers/iio/adc/mt6577_auxadc.c
> >>> index e1bdcc0..58d7cb2 100644
> >>> --- a/drivers/iio/adc/mt6577_auxadc.c
> >>> +++ b/drivers/iio/adc/mt6577_auxadc.c
> >>> @@ -326,9 +326,10 @@ static int mt6577_auxadc_remove(struct platform_device *pdev)
> >>>  	return 0;
> >>>  }
> >>>  
> >>> -static SIMPLE_DEV_PM_OPS(mt6577_auxadc_pm_ops,
> >>> -			 mt6577_auxadc_suspend,
> >>> -			 mt6577_auxadc_resume);
> >>> +static const struct dev_pm_ops mt6577_auxadc_pm_ops = {
> >>> +	SET_LATE_SYSTEM_SLEEP_PM_OPS(mt6577_auxadc_suspend,
> >>> +				     mt6577_auxadc_resume)
> >>> +};
> >>>  
> >>>  static const struct of_device_id mt6577_auxadc_of_match[] = {
> >>>  	{ .compatible = "mediatek,mt2701-auxadc", .data = &mt8173_compat},
> >>
> > 
> >