Re: [PATCH] alarmtimer: check RTC features instead of ops

[Thomas Gleixner]

On Mon, May 03 2021 at 17:34, Alexandre Belloni wrote:
> On 30/04/2021 10:59:53+0200, Thomas Gleixner wrote:
>> I'm even more confused. So RTC0 does not have .set_alarm() but why does
>> it turn on RTC_FEATURE_ALARM? I'm obviously misinterpreting the above...
>> 
>
> I'm sorry for not being clear.
>
> With RTC0 not having alarms and RTC1 having alarms:
>
> The previous situation was:
>
> The driver for RTC0 didn't have any .set_alarm() to signel it doesn't
> support alarms.
> On registration, alarmtimer_rtc_add_device finds out it doesn't have the
> .set_alarm() callback and doesn't select that RTC.
> On registration of RTC1, alarmtimer_rtc_add_device finds .set_alarm()
> and RTC1 is now the alarmtimer rtcdev.
>
> The new situation is:
>
> The driver for RTC0 always have .set_alarm() but clears
> RTC_FEATURE_ALARM to signal it doesn't support alarms.
> On registration, alarmtimer_rtc_add_device finds .set_alarm() and RTC0
> is now the alarmtimer rtcdev, leading to an error when rtc_timer_start()
> is called.
>
> I hope this is clearer.

Yes, that makes sense now!