Re: [PATCH v5 1/3] pmdomain: core: introduce dev_pm_genpd_is_on()

Bjorn Andersson
2025-06-18T03:01:37Z

On Tue, Jun 17, 2025 at 04:34:48PM -0300, Hiago De Franco wrote:
> From: Hiago De Franco <hiago.franco@toradex.com>
>
> This helper function returns the current power status of a given generic
> power domain.
>
> As example, remoteproc/imx_rproc.c can now use this function to check
> the power status of the remote core to properly set "attached" or
> "offline" modes.
>
> Suggested-by: Ulf Hansson <ulf.hansson@linaro.org>
> Signed-off-by: Hiago De Franco <hiago.franco@toradex.com>

Reviewed-by: Bjorn Andersson <andersson@kernel.org>

Regards,
Bjorn

> ---
> v4 -> v5:
> - s/dev_pm_genpd_is_on/dev_pm_genpd_is_on()/ in function description.
> - Updated function description to be explicit the function reflects the
> current power status and that this might change after the function
> returns, especially if the genpd is shared.
>
> v3 -> v4:
> - New patch.
> ---
> drivers/pmdomain/core.c | 33 +++++++++++++++++++++++++++++++++
> include/linux/pm_domain.h | 6 ++++++
> 2 files changed, 39 insertions(+)
>
> diff --git a/drivers/pmdomain/core.c b/drivers/pmdomain/core.c
> index ff5c7f2b69ce..2f387e15cb75 100644
> --- a/drivers/pmdomain/core.c
> +++ b/drivers/pmdomain/core.c
> @@ -758,6 +758,39 @@ int dev_pm_genpd_rpm_always_on(struct device *dev, bool on)
> }
> EXPORT_SYMBOL_GPL(dev_pm_genpd_rpm_always_on);
>
> +/**
> + * dev_pm_genpd_is_on() - Get device's current power domain status
> + *
> + * @dev: Device to get the current power status
> + *
> + * This function checks whether the generic power domain associated with the
> + * given device is on or not by verifying if genpd_status_on equals
> + * GENPD_STATE_ON.
> + *
> + * Note: this function returns the power status of the genpd at the time of the
> + * call. The power status may change after due to activity from other devices
> + * sharing the same genpd. Therefore, this information should not be relied for
> + * long-term decisions about the device power state.
> + *
> + * Return: 'true' if the device's power domain is on, 'false' otherwise.
> + */
> +bool dev_pm_genpd_is_on(struct device *dev)
> +{
> + struct generic_pm_domain *genpd;
> + bool is_on;
> +
> + genpd = dev_to_genpd_safe(dev);
> + if (!genpd)
> + return false;
> +
> + genpd_lock(genpd);
> + is_on = genpd_status_on(genpd);
> + genpd_unlock(genpd);
> +
> + return is_on;
> +}
> +EXPORT_SYMBOL_GPL(dev_pm_genpd_is_on);
> +
> /**
> * pm_genpd_inc_rejected() - Adjust the rejected/usage counts for an idle-state.
> *
> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
> index 0b18160901a2..c12580b6579b 100644
> --- a/include/linux/pm_domain.h
> +++ b/include/linux/pm_domain.h
> @@ -301,6 +301,7 @@ void dev_pm_genpd_synced_poweroff(struct device *dev);
> int dev_pm_genpd_set_hwmode(struct device *dev, bool enable);
> bool dev_pm_genpd_get_hwmode(struct device *dev);
> int dev_pm_genpd_rpm_always_on(struct device *dev, bool on);
> +bool dev_pm_genpd_is_on(struct device *dev);
>
> extern struct dev_power_governor simple_qos_governor;
> extern struct dev_power_governor pm_domain_always_on_gov;
> @@ -393,6 +394,11 @@ static inline int dev_pm_genpd_rpm_always_on(struct device *dev, bool on)
> return -EOPNOTSUPP;
> }
>
> +static inline bool dev_pm_genpd_is_on(struct device *dev)
> +{
> + return false;
> +}
> +
> #define simple_qos_governor (*(struct dev_power_governor *)(NULL))
> #define pm_domain_always_on_gov (*(struct dev_power_governor *)(NULL))
> #endif
> --
> 2.39.5
>