[PATCH 09/13] regulator: pv88080: Fix notifier mutex lock warning

[Steve Twiss]

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.opensou...@diasemi.com>
Signed-off-by: Steve Twiss <stwiss.opensou...@diasemi.com>
---
 drivers/regulator/pv88080-regulator.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/regulator/pv88080-regulator.c 
b/drivers/regulator/pv88080-regulator.c
index 9a08cb2..d99f1b9 100644
--- 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]);
                        }
                }
 
-- 
1.9.3