rtc: pcf2127: use IRQ flags obtained from device tree if available

If the interrupt pin of the PCF2127 is routed to the input of a GPIO
expander using the pca953x driver, the later will only accept an IRQ
of type IRQ_TYPE_EDGE_FALLING or IRQ_TYPE_EDGE_RISING, and the IRQ
request will fail.

Therefore, allow the IRQ type to be passed from the device tree data
if available.
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220117225742.1252362-1-hugo@hugovil.com

drivers/rtc/rtc-pcf2127.c

@@ -659,9 +659,20 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
 	clear_bit(RTC_FEATURE_ALARM, pcf2127->rtc->features);
 
 	if (alarm_irq > 0) {
+		unsigned long flags;
+
+		/*
+		 * If flags = 0, devm_request_threaded_irq() will use IRQ flags
+		 * obtained from device tree.
+		 */
+		if (dev_fwnode(dev))
+			flags = 0;
+		else
+			flags = IRQF_TRIGGER_LOW;
+
 		ret = devm_request_threaded_irq(dev, alarm_irq, NULL,
 						pcf2127_rtc_irq,
-						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+						flags | IRQF_ONESHOT,
 						dev_name(dev), dev);
 		if (ret) {
 			dev_err(dev, "failed to request alarm irq\n");