rtc: max77686: Do not enforce (incorrect) interrupt trigger type

BugLink: https://bugs.launchpad.net/bugs/1939442
[ Upstream commit 742b0d7e15c333303daad4856de0764f4bc83601 ]

Interrupt line can be configured on different hardware in different way,
even inverted.  Therefore driver should not enforce specific trigger
type - edge falling - but instead rely on Devicetree to configure it.

The Maxim 77686 datasheet describes the interrupt line as active low
with a requirement of acknowledge from the CPU therefore the edge
falling is not correct.

The interrupt line is shared between PMIC and RTC driver, so using level
sensitive interrupt is here especially important to avoid races.  With
an edge configuration in case if first PMIC signals interrupt followed
shortly after by the RTC, the interrupt might not be yet cleared/acked
thus the second one would not be noticed.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210526172036.183223-6-krzysztof.kozlowski@canonical.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

diff --git a/drivers/rtc/rtc-max77686.c b/drivers/rtc/rtc-max77686.c
index d5a0e27dd0a08e57331efb9cb860a145185bf56d..9e27f5a011975b92eac1a1d3190bd9f8bd8d4f57 100644 (file)
--- a/drivers/rtc/rtc-max77686.c
+++ b/drivers/rtc/rtc-max77686.c
@@ -707,8 +707,8 @@ static int max77686_init_rtc_regmap(struct max77686_rtc_info *info)
 
 add_rtc_irq:
        ret = regmap_add_irq_chip(info->rtc_regmap, info->rtc_irq,
-                                 IRQF_TRIGGER_FALLING | IRQF_ONESHOT |
-                                 IRQF_SHARED, 0, info->drv_data->rtc_irq_chip,
+                                 IRQF_ONESHOT | IRQF_SHARED,
+                                 0, info->drv_data->rtc_irq_chip,
                                  &info->rtc_irq_data);
        if (ret < 0) {
                dev_err(info->dev, "Failed to add RTC irq chip: %d\n", ret);