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

[Amelie Delaunay]

On 5/30/23 16:13, Marek Vasut wrote:
> 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 ?

I didn't find any DTs using STM32 RTC with two interrupts. Did I miss 
something?