linux-kernel - Re: [PATCH v6 1/2] power: domain: handle genpd correctly when needing interrupts

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Message-ID: <CAPDyKFrLLw=y9+t3f_bOH2mw2NVDGJxKE5=+XHY7C6SUzLzUDg@mail.gmail.com>
Date:   Tue, 26 Jul 2022 17:07:04 +0200
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Martin Kepplinger <martin.kepplinger@...i.sm>
Cc:     rafael@...nel.org, khilman@...nel.org, robh@...nel.org,
        krzysztof.kozlowski@...aro.org, shawnguo@...nel.org,
        s.hauer@...gutronix.de, festevam@...il.com, pavel@....cz,
        kernel@...i.sm, linux-imx@....com, broonie@...nel.org,
        l.stach@...gutronix.de, aford173@...il.com,
        linux-pm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v6 1/2] power: domain: handle genpd correctly when needing interrupts

On Tue, 26 Jul 2022 at 10:33, Martin Kepplinger
<martin.kepplinger@...i.sm> wrote:
>
> If for example the power-domains' power-supply node (regulator) needs
> interrupts to work, the current setup with noirq callbacks cannot
> work; for example a pmic regulator on i2c, when suspending, usually already
> times out during suspend_noirq:
>
> [   41.024193] buck4: failed to disable: -ETIMEDOUT
>
> So fix system suspend and resume for these power-domains by using the
> "outer" suspend/resume callbacks instead. Tested on the imx8mq-librem5 board,
> but by looking at the dts, this will fix imx8mq-evk and possibly many other
> boards too.
>
> This is designed so that genpd providers just say "this genpd needs
> interrupts" (by setting the flag) - without implying an implementation.
>
> Initially system suspend problems had been discussed at
> https://lore.kernel.org/linux-arm-kernel/20211002005954.1367653-8-l.stach@pengutronix.de/
> which led to discussing the pmic that contains the regulators which
> serve as power-domain power-supplies:
> https://lore.kernel.org/linux-pm/573166b75e524517782471c2b7f96e03fd93d175.camel@puri.sm/T/
>
> Signed-off-by: Martin Kepplinger <martin.kepplinger@...i.sm>
> ---
>  drivers/base/power/domain.c | 13 +++++++++++--
>  include/linux/pm_domain.h   |  5 +++++
>  2 files changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 5a2e0232862e..58376752a4de 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -130,6 +130,7 @@ static const struct genpd_lock_ops genpd_spin_ops = {
>  #define genpd_is_active_wakeup(genpd)  (genpd->flags & GENPD_FLAG_ACTIVE_WAKEUP)
>  #define genpd_is_cpu_domain(genpd)     (genpd->flags & GENPD_FLAG_CPU_DOMAIN)
>  #define genpd_is_rpm_always_on(genpd)  (genpd->flags & GENPD_FLAG_RPM_ALWAYS_ON)
> +#define genpd_irq_on(genpd)            (genpd->flags & GENPD_FLAG_IRQ_ON)
>
>  static inline bool irq_safe_dev_in_sleep_domain(struct device *dev,
>                 const struct generic_pm_domain *genpd)
> @@ -2065,8 +2066,15 @@ int pm_genpd_init(struct generic_pm_domain *genpd,
>         genpd->domain.ops.runtime_suspend = genpd_runtime_suspend;
>         genpd->domain.ops.runtime_resume = genpd_runtime_resume;
>         genpd->domain.ops.prepare = genpd_prepare;
> -       genpd->domain.ops.suspend_noirq = genpd_suspend_noirq;
> -       genpd->domain.ops.resume_noirq = genpd_resume_noirq;
> +
> +       if (genpd_irq_on(genpd)) {
> +               genpd->domain.ops.suspend = genpd_suspend_noirq;
> +               genpd->domain.ops.resume = genpd_resume_noirq;
> +       } else {
> +               genpd->domain.ops.suspend_noirq = genpd_suspend_noirq;
> +               genpd->domain.ops.resume_noirq = genpd_resume_noirq;

As we discussed previously, I am thinking that it may be better to
move to using genpd->domain.ops.suspend_late and
genpd->domain.ops.resume_early instead.

Beside this, I think the $subject patch looks good to me.

[...]

Kind regards
Uffe