linux-kernel - [PATCH v2 1/2] power: supply: max17042_battery: Clear status bits in interrupt handler

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Date:   Tue, 14 Sep 2021 14:18:05 +0200
From:   Sebastian Krzyszkowiak <sebastian.krzyszkowiak@...i.sm>
To:     Sebastian Reichel <sre@...nel.org>, linux-pm@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Dirk Brandewie <dirk.brandewie@...il.com>, kernel@...i.sm,
        Sebastian Krzyszkowiak <sebastian.krzyszkowiak@...i.sm>,
        stable@...r.kernel.org
Subject: [PATCH v2 1/2] power: supply: max17042_battery: Clear status bits in interrupt handler

The gauge requires us to clear the status bits manually for some alerts
to be properly dismissed. Previously the IRQ was configured to react only
on falling edge, which wasn't technically correct (the ALRT line is active
low), but it had a happy side-effect of preventing interrupt storms
on uncleared alerts from happening.

Fixes: 7fbf6b731bca ("power: supply: max17042: Do not enforce (incorrect) interrupt trigger type")
Cc: <stable@...r.kernel.org>
Signed-off-by: Sebastian Krzyszkowiak <sebastian.krzyszkowiak@...i.sm>
---
v2: added a comment on why it clears all alert bits
---
 drivers/power/supply/max17042_battery.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/power/supply/max17042_battery.c b/drivers/power/supply/max17042_battery.c
index 8dffae76b6a3..da78ffe6a3ec 100644
--- a/drivers/power/supply/max17042_battery.c
+++ b/drivers/power/supply/max17042_battery.c
@@ -876,6 +876,10 @@ static irqreturn_t max17042_thread_handler(int id, void *dev)
 		max17042_set_soc_threshold(chip, 1);
 	}
 
+	/* we implicitly handle all alerts via power_supply_changed */
+	regmap_clear_bits(chip->regmap, MAX17042_STATUS,
+			  0xFFFF & ~(STATUS_POR_BIT | STATUS_BST_BIT));
+
 	power_supply_changed(chip->battery);
 	return IRQ_HANDLED;
 }
-- 
2.33.0