Automatic wake-up from system-level sleep modes

[pizi-nordic]

At the moment, the system-level power management assumes that system timer is always able trigger exit from sleep modes. Unfortunately this is not true for most of the SoCs. Only few dedicated peripherals could wake-up the system from most of the sleep modes and options are even more limited for deep-sleep modes where many SoCs need external device for wake-up.

Things needed:

• API allowing to assign a counter device (RTC/Timer) which will be used to wake-up source from given power mode(s).
• Ability to switch system clock device to the one selected for given power mode at suspend and restoring it back to the default on resume (Use counter drivers as a system clock source #12068 might help here)

[wentongwu]

Not only counter device can do the wakeup, it highly depends on soc design

[pizi-nordic]

Yes, but the kernel could automatically handle only timers.

[gmarull]

Closing as obsolete, open new issue with more details if needed.