Messages in this thread Patch in this message | | | From | Ulf Hansson <> | Subject | [PATCH 1/5] PM / Sleep: Add pm_generic functions to re-use runtime PM callbacks | Date | Wed, 27 Nov 2013 16:34:56 +0100 |
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To put devices into low power state during sleep, it sometimes makes sense at subsystem-level to re-use the runtime PM callbacks.
The PM core will at device_suspend_late disable runtime PM, after that we can safely operate on these callbacks. At suspend_late the device will be put into low power state by invoking the runtime_suspend callbacks, unless the runtime status is already suspended. At resume_early the state is restored by invoking the runtime_resume callbacks. Soon after the PM core will re-enable runtime PM before returning from device_resume_early.
The new pm_generic functions are named pm_generic_suspend_late_runtime and pm_generic_resume_early_runtime, they are supposed to be used in pairs.
Do note that these new generic callbacks will work smothly even with and without CONFIG_PM_RUNTIME, as long as the runtime PM callbacks are implemented inside CONFIG_PM instead of CONFIG_PM_RUNTIME.
A special thanks to Alan Stern who came up with this idea.
Cc: Kevin Hilman <khilman@linaro.org> Cc: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> --- drivers/base/power/generic_ops.c | 86 ++++++++++++++++++++++++++++++++++++++ include/linux/pm.h | 2 + 2 files changed, 88 insertions(+)
diff --git a/drivers/base/power/generic_ops.c b/drivers/base/power/generic_ops.c index 5ee030a..8e78ad1 100644 --- a/drivers/base/power/generic_ops.c +++ b/drivers/base/power/generic_ops.c @@ -93,6 +93,49 @@ int pm_generic_suspend_late(struct device *dev) EXPORT_SYMBOL_GPL(pm_generic_suspend_late); /** + * pm_generic_suspend_late_runtime - Generic suspend_late callback for drivers + * @dev: Device to suspend. + * Use to invoke runtime_suspend callbacks at suspend_late. + */ +int pm_generic_suspend_late_runtime(struct device *dev) +{ + int (*callback)(struct device *); + int ret = 0; + + /* + * PM core has disabled runtime PM in device_suspend_late, thus we can + * safely check the device's runtime status and decide whether + * additional actions are needed to put the device into low power state. + * If so, we invoke the runtime_suspend callbacks. + * For the !CONFIG_PM_RUNTIME case, pm_runtime_status_suspended() always + * returns false and therefore the runtime_suspend callback will be + * invoked. + */ + if (pm_runtime_status_suspended(dev)) + return 0; + + if (dev->pm_domain) + callback = dev->pm_domain->ops.runtime_suspend; + else if (dev->type && dev->type->pm) + callback = dev->type->pm->runtime_suspend; + else if (dev->class && dev->class->pm) + callback = dev->class->pm->runtime_suspend; + else if (dev->bus && dev->bus->pm) + callback = dev->bus->pm->runtime_suspend; + else + callback = NULL; + + if (!callback && dev->driver && dev->driver->pm) + callback = dev->driver->pm->runtime_suspend; + + if (callback) + ret = callback(dev); + + return ret; +} +EXPORT_SYMBOL_GPL(pm_generic_suspend_late_runtime); + +/** * pm_generic_suspend - Generic suspend callback for subsystems. * @dev: Device to suspend. */ @@ -237,6 +280,49 @@ int pm_generic_resume_early(struct device *dev) EXPORT_SYMBOL_GPL(pm_generic_resume_early); /** + * pm_generic_resume_early_runtime - Generic resume_early callback for drivers + * @dev: Device to resume. + * Use to invoke runtime_resume callbacks at resume_early. + */ +int pm_generic_resume_early_runtime(struct device *dev) +{ + int (*callback)(struct device *); + int ret = 0; + + /* + * PM core has not yet enabled runtime PM in device_resume_early, + * thus we can safely check the device's runtime status and restore the + * previous state we had in device_suspend_late. If restore is needed + * we invoke the runtime_resume callbacks. + * For the !CONFIG_PM_RUNTIME case, pm_runtime_status_suspended() always + * returns false and therefore the runtime_resume callback will be + * invoked. + */ + if (pm_runtime_status_suspended(dev)) + return 0; + + if (dev->pm_domain) + callback = dev->pm_domain->ops.runtime_resume; + else if (dev->type && dev->type->pm) + callback = dev->type->pm->runtime_resume; + else if (dev->class && dev->class->pm) + callback = dev->class->pm->runtime_resume; + else if (dev->bus && dev->bus->pm) + callback = dev->bus->pm->runtime_resume; + else + callback = NULL; + + if (!callback && dev->driver && dev->driver->pm) + callback = dev->driver->pm->runtime_resume; + + if (callback) + ret = callback(dev); + + return ret; +} +EXPORT_SYMBOL_GPL(pm_generic_resume_early_runtime); + +/** * pm_generic_resume - Generic resume callback for subsystems. * @dev: Device to resume. */ diff --git a/include/linux/pm.h b/include/linux/pm.h index a224c7f..5bce0d4 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -656,9 +656,11 @@ extern void dpm_for_each_dev(void *data, void (*fn)(struct device *, void *)); extern int pm_generic_prepare(struct device *dev); extern int pm_generic_suspend_late(struct device *dev); +extern int pm_generic_suspend_late_runtime(struct device *dev); extern int pm_generic_suspend_noirq(struct device *dev); extern int pm_generic_suspend(struct device *dev); extern int pm_generic_resume_early(struct device *dev); +extern int pm_generic_resume_early_runtime(struct device *dev); extern int pm_generic_resume_noirq(struct device *dev); extern int pm_generic_resume(struct device *dev); extern int pm_generic_freeze_noirq(struct device *dev); -- 1.7.9.5
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