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

[Marek Vasut]

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)
-- 
2.39.2