Re: [PATCH v2] rtc: pcf2127: arm the alarm IRQ as a wake IRQ

[sashiko-bot@kernel.org]

> When an alarm IRQ is available, the driver calls device_init_wakeup(),
> so the RTC shows up as wakeup capable and enabled, but it never marks
> the IRQ itself as a wakeup interrupt. The PM core therefore disables
> the IRQ for the whole system suspend, and the alarm cannot wake the
> system: "rtcwake -m mem" on this RTC only resumes once another wakeup
> source fires.
> 
> On the i.MX93 11x11 FRDM board the PCF2131 alarm is routed through a
> PCAL6524 GPIO expander. Without a wakeup request on the expander pin,
> the expander's own interrupt is not armed for wakeup either, so the
> alarm never reaches the CPU. The BBNSM RTC on the same board uses
> devm_pm_set_wake_irq() and wakes the system as expected.
> 
> Register the alarm IRQ with devm_pm_set_wake_irq() so that the PM core
> arms it whenever the device may wake the system. A failure is not
> fatal: the RTC keeps working, only wakeup from it is unavailable.
> 
> The I2C core already sets up the wake IRQ before probe for clients
> flagged I2C_CLIENT_WAKE, which a "wakeup-source" DT property or a
> wake-capable ACPI interrupt sets. Those boards can already wake from
> the alarm, so skip the call for them: a second registration would only
> trigger a "wake irq already initialized" warning.
> 
> Fixes: 8a914bac44be ("rtc: pcf2127: add alarm support")
> Assisted-by: LLM
> Signed-off-by: Aristo Chen <aristo.chen@canonical.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261021064432.551943-1-aristo.chen@canonical.com?part=1