power: supply: max17042: handle fails of reading status register

BugLink: https://bugs.launchpad.net/bugs/1947781
commit 54784ffa5b267f57161eb8fbb811499f22a0a0bf upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

diff --git a/drivers/power/supply/max17042_battery.c b/drivers/power/supply/max17042_battery.c
index b52fa4d79046d417371da3167d503c435d992449..3136856b0ef9ac972f0f646c228cdb7567046cde 100644 (file)
--- 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");