linux-kernel - Re: [PATCH v2 11/15] iio: adc: rzg2l

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Message-ID: <CA+V-a8vHovd7L2bcY61n_Ox_hKvTvhUZMZPKgHFtd5DHQeZNMw@mail.gmail.com>
Date: Sun, 8 Dec 2024 21:35:50 +0000
From: "Lad, Prabhakar" <prabhakar.csengg@...il.com>
To: Claudiu <claudiu.beznea@...on.dev>
Cc: prabhakar.mahadev-lad.rj@...renesas.com, jic23@...nel.org, lars@...afoo.de, 
	robh@...nel.org, krzk+dt@...nel.org, conor+dt@...nel.org, 
	geert+renesas@...der.be, magnus.damm@...il.com, mturquette@...libre.com, 
	sboyd@...nel.org, p.zabel@...gutronix.de, linux-iio@...r.kernel.org, 
	linux-renesas-soc@...r.kernel.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-clk@...r.kernel.org, 
	Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
Subject: Re: [PATCH v2 11/15] iio: adc: rzg2l_adc: Add suspend/resume support

On Fri, Dec 6, 2024 at 11:16 AM Claudiu <claudiu.beznea@...on.dev> wrote:
>
> From: Claudiu Beznea <claudiu.beznea.uj@...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@...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@...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
>
>