Re: [PATCH v2 11/15] iio: adc: rzg2l_adc: Add suspend/resume support

[Jonathan Cameron <jic23@kernel.org>]

On Sun, 8 Dec 2024 21:35:50 +0000
"Lad, Prabhakar" <prabhakar.csengg@gmail.com> wrote:

> On Fri, Dec 6, 2024 at 11:16 AM Claudiu <claudiu.beznea@tuxon.dev> wrote:
> >
> > From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
> >
> > The Renesas RZ/G3S SoC features a power-saving mode where power to most of
> > the SoC components is turned off, including the ADC IP.
> >
> > Suspend/resume support has been added to the rzg2l_adc driver to restore
> > functionality after resuming from this power-saving mode. During suspend,
> > the ADC resets are asserted, and the ADC is powered down. On resume, the
> > ADC resets are de-asserted, the hardware is re-initialized, and the ADC
> > power is restored using the runtime PM APIs.
> >
> > Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
> > ---
> >
> > Changes in v2:
> > - none
> >
> >  drivers/iio/adc/rzg2l_adc.c | 70 +++++++++++++++++++++++++++++++++++++
> >  1 file changed, 70 insertions(+)
> >  
> Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Thanks.  I've updated tags.

Jonathan

> 
> Cheers,
> Prabhakar
> 
> > diff --git a/drivers/iio/adc/rzg2l_adc.c b/drivers/iio/adc/rzg2l_adc.c
> > index e8dbc5dfbea1..2a911269a358 100644
> > --- a/drivers/iio/adc/rzg2l_adc.c
> > +++ b/drivers/iio/adc/rzg2l_adc.c
> > @@ -88,6 +88,7 @@ struct rzg2l_adc {
> >         struct completion completion;
> >         struct mutex lock;
> >         u16 last_val[RZG2L_ADC_MAX_CHANNELS];
> > +       bool was_rpm_active;
> >  };
> >
> >  /**
> > @@ -527,8 +528,77 @@ static int rzg2l_adc_pm_runtime_resume(struct device *dev)
> >         return 0;
> >  }
> >
> > +static int rzg2l_adc_suspend(struct device *dev)
> > +{
> > +       struct iio_dev *indio_dev = dev_get_drvdata(dev);
> > +       struct rzg2l_adc *adc = iio_priv(indio_dev);
> > +       struct reset_control_bulk_data resets[] = {
> > +               { .rstc = adc->presetn },
> > +               { .rstc = adc->adrstn },
> > +       };
> > +       int ret;
> > +
> > +       if (pm_runtime_suspended(dev)) {
> > +               adc->was_rpm_active = false;
> > +       } else {
> > +               ret = pm_runtime_force_suspend(dev);
> > +               if (ret)
> > +                       return ret;
> > +               adc->was_rpm_active = true;
> > +       }
> > +
> > +       ret = reset_control_bulk_assert(ARRAY_SIZE(resets), resets);
> > +       if (ret)
> > +               goto rpm_restore;
> > +
> > +       return 0;
> > +
> > +rpm_restore:
> > +       if (adc->was_rpm_active)
> > +               pm_runtime_force_resume(dev);
> > +
> > +       return ret;
> > +}
> > +
> > +static int rzg2l_adc_resume(struct device *dev)
> > +{
> > +       struct iio_dev *indio_dev = dev_get_drvdata(dev);
> > +       struct rzg2l_adc *adc = iio_priv(indio_dev);
> > +       struct reset_control_bulk_data resets[] = {
> > +               { .rstc = adc->adrstn },
> > +               { .rstc = adc->presetn },
> > +       };
> > +       int ret;
> > +
> > +       ret = reset_control_bulk_deassert(ARRAY_SIZE(resets), resets);
> > +       if (ret)
> > +               return ret;
> > +
> > +       if (adc->was_rpm_active) {
> > +               ret = pm_runtime_force_resume(dev);
> > +               if (ret)
> > +                       goto resets_restore;
> > +       }
> > +
> > +       ret = rzg2l_adc_hw_init(dev, adc);
> > +       if (ret)
> > +               goto rpm_restore;
> > +
> > +       return 0;
> > +
> > +rpm_restore:
> > +       if (adc->was_rpm_active) {
> > +               pm_runtime_mark_last_busy(dev);
> > +               pm_runtime_put_autosuspend(dev);
> > +       }
> > +resets_restore:
> > +       reset_control_bulk_assert(ARRAY_SIZE(resets), resets);
> > +       return ret;
> > +}
> > +
> >  static const struct dev_pm_ops rzg2l_adc_pm_ops = {
> >         RUNTIME_PM_OPS(rzg2l_adc_pm_runtime_suspend, rzg2l_adc_pm_runtime_resume, NULL)
> > +       SYSTEM_SLEEP_PM_OPS(rzg2l_adc_suspend, rzg2l_adc_resume)
> >  };
> >
> >  static struct platform_driver rzg2l_adc_driver = {
> > --
> > 2.39.2
> >
> >