regulator: pv88080: Fix notifier mutex lock warning

BugLink: https://bugs.launchpad.net/bugs/1837517
[ Upstream commit 1867af94cfdf37fc70fe67b3d522e78352800196 ]

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: 99cf3af5e2d5 ("regulator: pv88080: 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/pv88080-regulator.c b/drivers/regulator/pv88080-regulator.c
index 9a08cb2de501e95175fe4f56168ec0bfe123b08a..d99f1b9fa075654d31738d563ad801010ec8d1ce 100644 (file)
--- a/drivers/regulator/pv88080-regulator.c
+++ b/drivers/regulator/pv88080-regulator.c
@@ -384,9 +384,11 @@ static irqreturn_t pv88080_irq_handler(int irq, void *data)
        if (reg_val & PV88080_E_VDD_FLT) {
                for (i = 0; i < PV88080_MAX_REGULATORS; i++) {
                        if (chip->rdev[i] != NULL) {
+                               regulator_lock(chip->rdev[i]);
                                regulator_notifier_call_chain(chip->rdev[i],
                                        REGULATOR_EVENT_UNDER_VOLTAGE,
                                        NULL);
+                               regulator_unlock(chip->rdev[i]);
                        }
                }
 
@@ -401,9 +403,11 @@ static irqreturn_t pv88080_irq_handler(int irq, void *data)
        if (reg_val & PV88080_E_OVER_TEMP) {
                for (i = 0; i < PV88080_MAX_REGULATORS; i++) {
                        if (chip->rdev[i] != NULL) {
+                               regulator_lock(chip->rdev[i]);
                                regulator_notifier_call_chain(chip->rdev[i],
                                        REGULATOR_EVENT_OVER_TEMP,
                                        NULL);
+                               regulator_unlock(chip->rdev[i]);
                        }
                }