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

Lad, Prabhakar
2024-12-08T21:36:16Z

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>

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
>
>