linux-kernel - [PATCH AUTOSEL 4.19 03/22] power: supply: max17042: Do not enforce (incorrect) interrupt trigger type

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Message-Id: <20210710235143.3222129-3-sashal@kernel.org>
Date:   Sat, 10 Jul 2021 19:51:24 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Krzysztof Kozlowski <krzk@...nel.org>,
        Sebastian Reichel <sebastian.reichel@...labora.com>,
        Sasha Levin <sashal@...nel.org>, linux-pm@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19 03/22] power: supply: max17042: Do not enforce (incorrect) interrupt trigger type

From: Krzysztof Kozlowski <krzk@...nel.org>

[ Upstream commit 7fbf6b731bca347700e460d94b130f9d734b33e9 ]

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 17047/77693 datasheets describe 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@...nel.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@...labora.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/power/supply/max17042_battery.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/power/supply/max17042_battery.c b/drivers/power/supply/max17042_battery.c
index 1a568df383db..00a3a581e079 100644
--- a/drivers/power/supply/max17042_battery.c
+++ b/drivers/power/supply/max17042_battery.c
@@ -1083,7 +1083,7 @@ static int max17042_probe(struct i2c_client *client,
 	}

 	if (client->irq) {
-		unsigned int flags = IRQF_TRIGGER_FALLING | IRQF_ONESHOT;
+		unsigned int flags = IRQF_ONESHOT;

 		/*
 		 * On ACPI systems the IRQ may be handled by ACPI-event code,
-- 
2.30.2