linux-kernel - [PATCH v2 6/7] power: supply: max17042: Do not enforce (incorrect) interrupt trigger type

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Message-Id: <20210526172036.183223-7-krzysztof.kozlowski@canonical.com>
Date:   Wed, 26 May 2021 13:20:35 -0400
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>
To:     Chanwoo Choi <cw00.choi@...sung.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Lee Jones <lee.jones@...aro.org>,
        Sebastian Reichel <sre@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Alessandro Zummo <a.zummo@...ertech.it>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        linux-kernel@...r.kernel.org, linux-clk@...r.kernel.org,
        devicetree@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-samsung-soc@...r.kernel.org, linux-rtc@...r.kernel.org
Cc:     Krzysztof Kozlowski <krzk@...nel.org>
Subject: [PATCH v2 6/7] power: supply: max17042: Do not enforce (incorrect) interrupt trigger type

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

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>

---

Changes since v1:
1. None
---
 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 1d7326cd8fc6..ce2041b30a06 100644
--- a/drivers/power/supply/max17042_battery.c
+++ b/drivers/power/supply/max17042_battery.c
@@ -1104,7 +1104,7 @@ 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,
-- 
2.27.0