From 54784ffa5b267f57161eb8fbb811499f22a0a0bf Mon Sep 17 00:00:00 2001
From: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Date: Mon, 16 Aug 2021 10:27:14 +0200
Subject: [PATCH] power: supply: max17042: handle fails of reading status register
Git-commit: 54784ffa5b267f57161eb8fbb811499f22a0a0bf
Patch-mainline: v5.15-rc1
References: git-fixes

Reading status register can fail in the interrupt handler.  In such
case, the regmap_read() will not store anything useful under passed
'val' variable and random stack value will be used to determine type of
interrupt.

Handle the regmap_read() failure to avoid handling interrupt type and
triggering changed power supply event based on random stack value.

Fixes: 39e7213edc4f ("max17042_battery: Support regmap to access device's registers")
Cc: <stable@vger.kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/power/supply/max17042_battery.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/power/supply/max17042_battery.c b/drivers/power/supply/max17042_battery.c
index f28c90ea41b4..62eb5ae36bb0 100644
--- a/drivers/power/supply/max17042_battery.c
+++ b/drivers/power/supply/max17042_battery.c
@@ -869,8 +869,12 @@ static irqreturn_t max17042_thread_handler(int id, void *dev)
 {
 	struct max17042_chip *chip = dev;
 	u32 val;
+	int ret;
+
+	ret = regmap_read(chip->regmap, MAX17042_STATUS, &val);
+	if (ret)
+		return IRQ_HANDLED;
 
-	regmap_read(chip->regmap, MAX17042_STATUS, &val);
 	if ((val & STATUS_INTR_SOCMIN_BIT) ||
 		(val & STATUS_INTR_SOCMAX_BIT)) {
 		dev_info(&chip->client->dev, "SOC threshold INTR\n");
-- 
2.26.2