Device Runtime

Device Runtime Power Management API. More...

Functions
int	pm_device_runtime_auto_enable (const struct device *dev)
	Automatically enable device runtime based on devicetree properties.
int	pm_device_runtime_enable (const struct device *dev)
	Enable device runtime PM.
int	pm_device_runtime_disable (const struct device *dev)
	Disable device runtime PM.
int	pm_device_runtime_get (const struct device *dev)
	Resume a device based on usage count.
int	pm_device_runtime_put (const struct device *dev)
	Suspend a device based on usage count.
int	pm_device_runtime_put_async (const struct device *dev, k_timeout_t delay)
	Suspend a device based on usage count (asynchronously).
bool	pm_device_runtime_is_enabled (const struct device *dev)
	Check if device runtime is enabled for a given device.
int	pm_device_runtime_usage (const struct device *dev)
	Return the current device usage counter.

Detailed Description

Device Runtime Power Management API.

Function Documentation

pm_device_runtime_auto_enable()

int pm_device_runtime_auto_enable

(

const struct device *

dev

)

#include <zephyr/pm/device_runtime.h>

Automatically enable device runtime based on devicetree properties.

Note

Must not be called from application code. See the zephyr,pm-device-runtime-auto property in pm.yaml and z_sys_init_run_level.

Parameters

dev	Device instance.

Return values

0	If the device runtime PM is enabled successfully or it has not been requested for this device in devicetree.
-errno	Other negative errno, result of enabled device runtime PM.

pm_device_runtime_disable()

int pm_device_runtime_disable

(

const struct device *

dev

)

#include <zephyr/pm/device_runtime.h>

Disable device runtime PM.

If the device is currently suspended it will be resumed.

Function properties (list may not be complete)

pre-kernel-ok

Parameters

dev	Device instance.

Return values

0	If the device runtime PM is disabled successfully.
-ENOTSUP	If the device does not support PM.
-errno	Other negative errno, result of resuming the device.

pm_device_runtime_enable()

int pm_device_runtime_enable

(

const struct device *

dev

)

#include <zephyr/pm/device_runtime.h>

Enable device runtime PM.

This function will enable runtime PM on the given device. If the device is in PM_DEVICE_STATE_ACTIVE state, the device will be suspended.

Function properties (list may not be complete)

pre-kernel-ok

Parameters

dev	Device instance.

Return values

0	If the device runtime PM is enabled successfully.
-EPERM	If device has power state locked.
-EBUSY	If device is busy.
-ENOTSUP	If the device does not support PM.
-errno	Other negative errno, result of suspending the device.

See also

pm_device_init_suspended()

pm_device_runtime_get()

int pm_device_runtime_get

(

const struct device *

dev

)

#include <zephyr/pm/device_runtime.h>

Resume a device based on usage count.

This function will resume the device if the device is suspended (usage count equal to 0). In case of a resume failure, usage count and device state will be left unchanged. In all other cases, usage count will be incremented.

If the device is still being suspended as a result of calling pm_device_runtime_put_async(), this function will wait for the operation to finish to then resume the device.

Note

It is safe to use this function in contexts where blocking is not allowed, e.g. ISR, provided the device PM implementation does not block.

Function properties (list may not be complete)

pre-kernel-ok

Parameters

dev	Device instance.

Return values

0	If it succeeds. In case device runtime PM is not enabled or not available this function will be a no-op and will also return 0.
-EWOUDBLOCK	If call would block but it is not allowed (e.g. in ISR).
-errno	Other negative errno, result of the PM action callback.

pm_device_runtime_is_enabled()

bool pm_device_runtime_is_enabled

(

const struct device *

dev

)

#include <zephyr/pm/device_runtime.h>

Check if device runtime is enabled for a given device.

Function properties (list may not be complete)

pre-kernel-ok

Parameters

dev	Device instance.

Return values

true	If device has device runtime PM enabled.
false	If the device has device runtime PM disabled.

See also

pm_device_runtime_enable()

pm_device_runtime_put()

int pm_device_runtime_put

(

const struct device *

dev

)

#include <zephyr/pm/device_runtime.h>

Suspend a device based on usage count.

This function will suspend the device if the device is no longer required (usage count equal to 0). In case of suspend failure, usage count and device state will be left unchanged. In all other cases, usage count will be decremented (down to 0).

Function properties (list may not be complete)

pre-kernel-ok

Parameters

dev	Device instance.

Return values

0	If it succeeds. In case device runtime PM is not enabled or not available this function will be a no-op and will also return 0.
-EALREADY	If device is already suspended (can only happen if get/put calls are unbalanced).
-errno	Other negative errno, result of the action callback.

See also

pm_device_runtime_put_async()

pm_device_runtime_put_async()

int pm_device_runtime_put_async	(	const struct device *	dev,
		k_timeout_t	delay
	)

#include <zephyr/pm/device_runtime.h>

Suspend a device based on usage count (asynchronously).

This function will schedule the device suspension if the device is no longer required (usage count equal to 0). In all other cases, usage count will be decremented (down to 0).

Note

Asynchronous operations are not supported when in pre-kernel mode. In this case, the function will be blocking (equivalent to pm_device_runtime_put()).

Function properties (list may not be complete)

pre-kernel-ok , async , isr-ok

Parameters

dev	Device instance.
delay	Minimum amount of time before triggering the action.

Return values

0	If it succeeds. In case device runtime PM is not enabled or not available this function will be a no-op and will also return 0.
-EBUSY	If the device is busy.
-EALREADY	If device is already suspended (can only happen if get/put calls are unbalanced).

See also

pm_device_runtime_put()

pm_device_runtime_usage()

int pm_device_runtime_usage

(

const struct device *

dev

)

#include <zephyr/pm/device_runtime.h>

Return the current device usage counter.

Parameters

dev	Device instance.

Returns

the current usage counter.

Return values

-ENOTSUP	If the device is not using runtime PM.
-ENOSYS	If the runtime PM is not enabled at all.