[PATCH] rtc: stm32: Handle single EXTI IRQ as wake up source

[Marek Vasut]

On 5/30/23 16:02, Amelie Delaunay wrote:
> Hi Marek,

Hello Amelie,

> On 5/18/23 02:33, Marek Vasut wrote:
>> The arch/arm/boot/dts/stm32mp151.dtsi specifies one interrupt for the
>> RTC node, while the expectation of the RTC driver is two interrupts on
>> STM32MP15xx SoC, one connected to GIC interrupt controller and another
>> one to EXTI. Per STM32MP15xx reference manual, the two interrupts serve
>> the same purpose, except the EXTI one can also wake the system up. The
>> EXTI driver already internally handles this GIC and EXTI duality and
>> maps the EXTI interrupt onto GIC during runtime, and only uses the EXTI
>> for wake up functionality.
>>
>> Therefore, fix the driver such that if on STM32MP15xx there is only one
>> interrupt specified in the DT, use that interrupt as EXTI interrupt and
>> set it as wake up source.
>>
>> This fixes the following warning in the kernel log on STM32MP15xx:
>> "
>> stm32_rtc 5c004000.rtc: error -ENXIO: IRQ index 1 not found
>> stm32_rtc 5c004000.rtc: alarm can't wake up the system: -6
>> "
>>
>> This also fixes the system wake up via built-in RTC using e.g.:
>> $ rtcwake -s 5 -m mem
>>
>> Fixes: b72252b6580c ("rtc: stm32: add stm32mp1 rtc support")
>> Signed-off-by: Marek Vasut <marex at denx.de>
>> ---
>> Cc: Alessandro Zummo <a.zummo at towertech.it>
>> Cc: Alexandre Belloni <alexandre.belloni at bootlin.com>
>> Cc: Alexandre Torgue <alexandre.torgue at foss.st.com>
>> Cc: Amelie DELAUNAY <amelie.delaunay at foss.st.com>
>> Cc: Maxime Coquelin <mcoquelin.stm32 at gmail.com>
>> Cc: linux-arm-kernel at lists.infradead.org
>> Cc: linux-rtc at vger.kernel.org
>> Cc: linux-stm32 at st-md-mailman.stormreply.com
>> ---
>>   drivers/rtc/rtc-stm32.c | 9 +++++----
>>   1 file changed, 5 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/rtc/rtc-stm32.c b/drivers/rtc/rtc-stm32.c
>> index 229cb2847cc48..72994b9f95319 100644
>> --- a/drivers/rtc/rtc-stm32.c
>> +++ b/drivers/rtc/rtc-stm32.c
>> @@ -780,14 +780,15 @@ static int stm32_rtc_probe(struct 
>> platform_device *pdev)
>>       ret = device_init_wakeup(&pdev->dev, true);
>>       if (rtc->data->has_wakeirq) {
>> -        rtc->wakeirq_alarm = platform_get_irq(pdev, 1);
>> +        rtc->wakeirq_alarm = platform_get_irq_optional(pdev, 1);
>>           if (rtc->wakeirq_alarm > 0) {
>>               ret = dev_pm_set_dedicated_wake_irq(&pdev->dev,
>>                                   rtc->wakeirq_alarm);
>> -        } else {
>> +        } else if (rtc->wakeirq_alarm == -EPROBE_DEFER) {
>>               ret = rtc->wakeirq_alarm;
>> -            if (rtc->wakeirq_alarm == -EPROBE_DEFER)
>> -                goto err;
>> +            goto err;
>> +        } else {
>> +            ret = dev_pm_set_wake_irq(&pdev->dev, rtc->irq_alarm);
>>           }
>>       }
>>       if (ret)
> 
> In our downstream [1], dedicated wakeup irq management is dropped: it is 
> neither described in st,stm32-rtc bindings nor used in STM32Fx, STM32Hx, 
> STM32MP1x device trees.
> The pointed patch is going to be upstreamed.
> 
> [1] 
> https://github.com/STMicroelectronics/linux/commit/5a45e1f100d59c33b6b50fe98c0f62862bd6f3d2

Won't that break compatibility with DTs which do use two interrupts 
entries ?