[ Upstream commit 769fc8d4182c1d1875db7859852afeb436714c5c ]
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: 37b918a034fe ("regulator: Add LTC3676 support") 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 --- drivers/regulator/ltc3676.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/regulator/ltc3676.c b/drivers/regulator/ltc3676.c index e6d66e492b851..4be90c78c7209 100644 --- a/drivers/regulator/ltc3676.c +++ b/drivers/regulator/ltc3676.c @@ -285,17 +285,23 @@ static irqreturn_t ltc3676_isr(int irq, void *dev_id) if (irqstat & LTC3676_IRQSTAT_THERMAL_WARN) { dev_warn(dev, "Over-temperature Warning\n"); event = REGULATOR_EVENT_OVER_TEMP; - for (i = 0; i < LTC3676_NUM_REGULATORS; i++) + for (i = 0; i < LTC3676_NUM_REGULATORS; i++) { + regulator_lock(ltc3676->regulators[i]); regulator_notifier_call_chain(ltc3676->regulators[i], event, NULL); + regulator_unlock(ltc3676->regulators[i]); + } }
if (irqstat & LTC3676_IRQSTAT_UNDERVOLT_WARN) { dev_info(dev, "Undervoltage Warning\n"); event = REGULATOR_EVENT_UNDER_VOLTAGE; - for (i = 0; i < LTC3676_NUM_REGULATORS; i++) + for (i = 0; i < LTC3676_NUM_REGULATORS; i++) { + regulator_lock(ltc3676->regulators[i]); regulator_notifier_call_chain(ltc3676->regulators[i], event, NULL); + regulator_unlock(ltc3676->regulators[i]); + } }
/* Clear warning condition */