[PATCH v7 1/3] pmdomain: core: introduce dev_pm_genpd_is_on()

Hiago De Franco
2025-06-29T17:32:03Z

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>
Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Hiago De Franco <hiago.franco@toradex.com>
---
v6 -> v7:
- Added Peng reviewed-by.
v5 -> v6:
- Added Bjorn reviewed-by.
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