Re: [PATCH v1 2/2] rtc: cmos: Do not require IRQ if ACPI alarm is used

["Mario Limonciello (AMD) (kernel.org)" <superm1@kernel.org>]

On 3/20/2026 1:00 PM, Alexandre Belloni wrote:
> On 14/03/2026 13:12:44+0100, Rafael J. Wysocki wrote:
>> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>>
>> If the ACPI RTC fixed event is used, a dedicated IRQ is not required
>> for the CMOS RTC alarm to work, so allow the driver to use the alarm
>> without a valid IRQ in that case.
>>
>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>

> 
>> ---
>>   drivers/rtc/rtc-cmos.c |   15 ++++++++++-----
>>   1 file changed, 10 insertions(+), 5 deletions(-)
>>
>> --- a/drivers/rtc/rtc-cmos.c
>> +++ b/drivers/rtc/rtc-cmos.c
>> @@ -216,6 +216,11 @@ static inline void cmos_write_bank2(unsi
>>   
>>   /*----------------------------------------------------------------*/
>>   
>> +static bool cmos_no_alarm(struct cmos_rtc *cmos)
>> +{
>> +	return !is_valid_irq(cmos->irq) && !cmos_use_acpi_alarm();
>> +}
>> +
>>   static int cmos_read_time(struct device *dev, struct rtc_time *t)
>>   {
>>   	int ret;
>> @@ -287,7 +292,7 @@ static int cmos_read_alarm(struct device
>>   	};
>>   
>>   	/* This not only a rtc_op, but also called directly */
>> -	if (!is_valid_irq(cmos->irq))
>> +	if (cmos_no_alarm(cmos))
>>   		return -ETIMEDOUT;
>>   
>>   	/* Basic alarms only support hour, minute, and seconds fields.
>> @@ -520,7 +525,7 @@ static int cmos_set_alarm(struct device
>>   	int ret;
>>   
>>   	/* This not only a rtc_op, but also called directly */
>> -	if (!is_valid_irq(cmos->irq))
>> +	if (cmos_no_alarm(cmos))
>>   		return -EIO;
>>   
>>   	ret = cmos_validate_alarm(dev, t);
>> @@ -1096,7 +1101,7 @@ cmos_do_probe(struct device *dev, struct
>>   			dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
>>   			goto cleanup1;
>>   		}
>> -	} else {
>> +	} else if (!cmos_use_acpi_alarm()) {
>>   		clear_bit(RTC_FEATURE_ALARM, cmos_rtc.rtc->features);
>>   	}
>>   
>> @@ -1121,7 +1126,7 @@ cmos_do_probe(struct device *dev, struct
>>   		acpi_rtc_event_setup(dev);
>>   
>>   	dev_info(dev, "%s%s, %d bytes nvram%s\n",
>> -		 !is_valid_irq(rtc_irq) ? "no alarms" :
>> +		 cmos_no_alarm(&cmos_rtc) ? "no alarms" :
>>   		 cmos_rtc.mon_alrm ? "alarms up to one year" :
>>   		 cmos_rtc.day_alrm ? "alarms up to one month" :
>>   		 "alarms up to one day",
>> @@ -1147,7 +1152,7 @@ cleanup0:
>>   static void cmos_do_shutdown(int rtc_irq)
>>   {
>>   	spin_lock_irq(&rtc_lock);
>> -	if (is_valid_irq(rtc_irq))
>> +	if (!cmos_no_alarm(&cmos_rtc))
>>   		cmos_irq_disable(&cmos_rtc, RTC_IRQMASK);
>>   	spin_unlock_irq(&rtc_lock);
>>   }
>>
>>
>>
>