[ Upstream commit 8be64b6d87bd47d81753b60ddafe70102ebfd76b ]
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: d1c6b4fe668b ("regulator: Add WM831x LDO support") Suggested-by: Adam Thomson Adam.Thomson.Opensource@diasemi.com Signed-off-by: Steve Twiss stwiss.opensource@diasemi.com Acked-by: Charles Keepax ckeepax@opensource.cirrus.com Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/regulator/wm831x-ldo.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/regulator/wm831x-ldo.c b/drivers/regulator/wm831x-ldo.c index e4a6f888484ec..fcd038e7cd803 100644 --- a/drivers/regulator/wm831x-ldo.c +++ b/drivers/regulator/wm831x-ldo.c @@ -51,9 +51,11 @@ static irqreturn_t wm831x_ldo_uv_irq(int irq, void *data) { struct wm831x_ldo *ldo = data;
+ regulator_lock(ldo->regulator); regulator_notifier_call_chain(ldo->regulator, REGULATOR_EVENT_UNDER_VOLTAGE, NULL); + regulator_unlock(ldo->regulator);
return IRQ_HANDLED; }