diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/power/runtime_pm.txt | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt index f1937064168..ab00eeddeca 100644 --- a/Documentation/power/runtime_pm.txt +++ b/Documentation/power/runtime_pm.txt @@ -335,6 +335,10 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h: 'power.runtime_error' is set or 'power.disable_depth' is greater than zero) + bool pm_runtime_suspended(struct device *dev); + - return true if the device's runtime PM status is 'suspended', or false + otherwise + void pm_runtime_allow(struct device *dev); - set the power.runtime_auto flag for the device and decrease its usage counter (used by the /sys/devices/.../power/control interface to @@ -459,3 +463,64 @@ The PM core always increments the run-time usage counter before calling the ->prepare() callback and decrements it after calling the ->complete() callback. Hence disabling run-time PM temporarily like this will not cause any run-time suspend callbacks to be lost. + +7. Generic subsystem callbacks + +Subsystems may wish to conserve code space by using the set of generic power +management callbacks provided by the PM core, defined in +driver/base/power/generic_ops.c: + + int pm_generic_runtime_idle(struct device *dev); + - invoke the ->runtime_idle() callback provided by the driver of this + device, if defined, and call pm_runtime_suspend() for this device if the + return value is 0 or the callback is not defined + + int pm_generic_runtime_suspend(struct device *dev); + - invoke the ->runtime_suspend() callback provided by the driver of this + device and return its result, or return -EINVAL if not defined + + int pm_generic_runtime_resume(struct device *dev); + - invoke the ->runtime_resume() callback provided by the driver of this + device and return its result, or return -EINVAL if not defined + + int pm_generic_suspend(struct device *dev); + - if the device has not been suspended at run time, invoke the ->suspend() + callback provided by its driver and return its result, or return 0 if not + defined + + int pm_generic_resume(struct device *dev); + - invoke the ->resume() callback provided by the driver of this device and, + if successful, change the device's runtime PM status to 'active' + + int pm_generic_freeze(struct device *dev); + - if the device has not been suspended at run time, invoke the ->freeze() + callback provided by its driver and return its result, or return 0 if not + defined + + int pm_generic_thaw(struct device *dev); + - if the device has not been suspended at run time, invoke the ->thaw() + callback provided by its driver and return its result, or return 0 if not + defined + + int pm_generic_poweroff(struct device *dev); + - if the device has not been suspended at run time, invoke the ->poweroff() + callback provided by its driver and return its result, or return 0 if not + defined + + int pm_generic_restore(struct device *dev); + - invoke the ->restore() callback provided by the driver of this device and, + if successful, change the device's runtime PM status to 'active' + +These functions can be assigned to the ->runtime_idle(), ->runtime_suspend(), +->runtime_resume(), ->suspend(), ->resume(), ->freeze(), ->thaw(), ->poweroff(), +or ->restore() callback pointers in the subsystem-level dev_pm_ops structures. + +If a subsystem wishes to use all of them at the same time, it can simply assign +the GENERIC_SUBSYS_PM_OPS macro, defined in include/linux/pm.h, to its +dev_pm_ops structure pointer. + +Device drivers that wish to use the same function as a system suspend, freeze, +poweroff and run-time suspend callback, and similarly for system resume, thaw, +restore, and run-time resume, can achieve this with the help of the +UNIVERSAL_DEV_PM_OPS macro defined in include/linux/pm.h (possibly setting its +last argument to NULL). |