Re: [PATCH RFC 2/3] alarmtimer: Choose the wakeup RTC by sleep state and priority

[sashiko-bot@kernel.org]

> From: Igor Velkov <iav@iav.lv>
> 
> alarmtimer_rtc_add_device() registers a platform device under the first
> RTC that has an alarm and a wakeup-capable parent, and alarmtimer_suspend()
> programs that RTC. On ODROID-HC4 it is meson-vrtc, a register the firmware
> reads when the application processors suspend, with no interrupt in
> Linux, so an alarm set on it does not wake the board from s2idle; the
> board's pcf8563 registers later and is never used.
> 
> Keep each such RTC that no earlier registered one with at least the same
> priority already covers, each with its own platform device, and read
> linux,wakeup-states and linux,alarmtimer-priority from its parent. In
> alarmtimer_suspend() choose, among the RTCs whose linux,wakeup-states
> contains pm_suspend_target_state, the one with the highest priority,
> registered first among equals, and program the alarm from its platform
> device only. That platform device is a child of its RTC, so the driver
> core suspends it before the RTC. alarmtimer_resume() cancels the timer
> from the platform device that started it.
> 
> An RTC without linux,wakeup-states qualifies for every state; without
> linux,alarmtimer-priority its priority is 0. An RTC that an earlier
> registered one with at least the same priority beats for every state gets
> no platform device, so without the properties only the first RTC is kept.
> alarmtimer does not use an RTC that lists no suspend state, as with
> "none". hibernate and off count as no suspend state; nothing in this
> series acts on them.
> 
> alarmtimer_get_rtcdev() returns the RTC with the highest priority.
> 
> Signed-off-by: Igor Velkov <iav@iav.lv>

Sashiko has reviewed this patch and found no issues.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261104-b4-alarmtimer-rtc-priority-v1-0-e996681b8086@iav.lv?part=2