regulator: da9211: Fix notifier mutex lock warning

BugLink: https://bugs.launchpad.net/bugs/1837517
[ Upstream commit 65378de3359d30ebce44762d8b8027f372b5b1c4 ]

The mutex for the regulator_dev must be controlled by the caller of
the regulator_notifier_call_chain(), as described in the comment
for that function.

Failure to mutex lock and unlock surrounding the notifier call results
in a kernel WARN_ON_ONCE() which will dump a backtrace for the
regulator_notifier_call_chain() when that function call is first made.
The mutex can be controlled using the regulator_lock/unlock() API.

Fixes: 1028a37daa14 ("regulator: da9211: new regulator driver")
Suggested-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
Signed-off-by: Steve Twiss <stwiss.opensource@diasemi.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/drivers/regulator/da9211-regulator.c b/drivers/regulator/da9211-regulator.c
index 109ee12d43626ce2822ba872c252000bf3e7cea1..4d7fe4819c1ce056c3cc8b09069a98f20e1ad2f2 100644 (file)
--- a/drivers/regulator/da9211-regulator.c
+++ b/drivers/regulator/da9211-regulator.c
@@ -322,8 +322,10 @@ static irqreturn_t da9211_irq_handler(int irq, void *data)
                goto error_i2c;
 
        if (reg_val & DA9211_E_OV_CURR_A) {
+               regulator_lock(chip->rdev[0]);
                regulator_notifier_call_chain(chip->rdev[0],
                        REGULATOR_EVENT_OVER_CURRENT, NULL);
+               regulator_unlock(chip->rdev[0]);
 
                err = regmap_write(chip->regmap, DA9211_REG_EVENT_B,
                        DA9211_E_OV_CURR_A);
@@ -334,8 +336,10 @@ static irqreturn_t da9211_irq_handler(int irq, void *data)
        }
 
        if (reg_val & DA9211_E_OV_CURR_B) {
+               regulator_lock(chip->rdev[1]);
                regulator_notifier_call_chain(chip->rdev[1],
                        REGULATOR_EVENT_OVER_CURRENT, NULL);
+               regulator_unlock(chip->rdev[1]);
 
                err = regmap_write(chip->regmap, DA9211_REG_EVENT_B,
                        DA9211_E_OV_CURR_B);