Re: [PATCH v5 3/7] pmdomain: core: Introduce dev_pm_genpd_rpm_always_on()

Ulf Hansson
2024-11-12T14:36:47Z

On Fri, 8 Nov 2024 at 07:57, Shawn Lin <shawn.lin@rock-chips.com> wrote:
>
> From: Ulf Hansson <ulf.hansson@linaro.org>
>
> For some usecases a consumer driver requires its device to remain power-on
> from the PM domain perspective during runtime. Using dev PM qos along with
> the genpd governors, doesn't work for this case as would potentially
> prevent the device from being runtime suspended too.
>
> To support these usecases, let's introduce dev_pm_genpd_rpm_always_on() to
> allow consumers drivers to dynamically control the behaviour in genpd for a
> device that is attached to it.
>
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
> ---
>
> Changes in v5: None
> Changes in v4: None
> Changes in v3: None
> Changes in v2: None
>
> drivers/pmdomain/core.c | 34 ++++++++++++++++++++++++++++++++++
> include/linux/pm_domain.h | 7 +++++++
> 2 files changed, 41 insertions(+)
>
> diff --git a/drivers/pmdomain/core.c b/drivers/pmdomain/core.c
> index 5ede0f7..2ccfcb7 100644
> --- a/drivers/pmdomain/core.c
> +++ b/drivers/pmdomain/core.c
> @@ -692,6 +692,36 @@ bool dev_pm_genpd_get_hwmode(struct device *dev)
> }
> EXPORT_SYMBOL_GPL(dev_pm_genpd_get_hwmode);
>
> +/**
> + * dev_pm_genpd_rpm_always_on() - Control if the PM domain can be powered off.
> + *
> + * @dev: Device for which the PM domain may need to stay on for.
> + * @on: Value to set or unset for the condition.
> + *
> + * For some usecases a consumer driver requires its device to remain power-on
> + * from the PM domain perspective during runtime. This function allows the
> + * behaviour to be dynamically controlled for a device attached to a genpd.
> + *
> + * It is assumed that the users guarantee that the genpd wouldn't be detached
> + * while this routine is getting called.
> + *
> + * Return: Returns 0 on success and negative error values on failures.
> + */
> +int dev_pm_genpd_rpm_always_on(struct device *dev, bool on)
> +{
> + struct generic_pm_domain *genpd;
> +
> + genpd = dev_to_genpd_safe(dev);
> + if (!genpd)
> + return -ENODEV;
> +
> + genpd_lock(genpd);
> + dev_gpd_data(dev)->rpm_always_on = on;
> + genpd_unlock(genpd);
> +
> + return 0;
> +}

We need and EXPORT_SYMBOL_GPL() here too.

[...]

Kind regards
Uffe