linux-kernel - [PATCH 03/13] regulator: da9063: Fix notifier mutex lock warning

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Message-ID: <1215fdadbb4fceb0a500102dbcc69df79e685875.1551808797.git.stwiss.opensource@diasemi.com>
Date:   Tue, 26 Feb 2019 15:23:02 +0000
From:   Steve Twiss <stwiss.opensource@...semi.com>
To:     Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>
CC:     Support Opensource <support.opensource@...semi.com>,
        LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 03/13] regulator: da9063: Fix notifier mutex lock warning

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: 69ca3e58d178 ("regulator: da9063: Add Dialog DA9063 voltage regulators support.")
Suggested-by: Adam Thomson <Adam.Thomson.Opensource@...semi.com>
Signed-off-by: Steve Twiss <stwiss.opensource@...semi.com>
---
 drivers/regulator/da9063-regulator.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/regulator/da9063-regulator.c b/drivers/regulator/da9063-regulator.c
index 8cbcd2a..d3ea73a 100644
--- a/drivers/regulator/da9063-regulator.c
+++ b/drivers/regulator/da9063-regulator.c
@@ -615,9 +615,12 @@ static irqreturn_t da9063_ldo_lim_event(int irq, void *data)
 		if (regl->info->oc_event.reg != DA9063_REG_STATUS_D)
 			continue;
 
-		if (BIT(regl->info->oc_event.lsb) & bits)
+		if (BIT(regl->info->oc_event.lsb) & bits) {
+		        regulator_lock(regl->rdev);
 			regulator_notifier_call_chain(regl->rdev,
 					REGULATOR_EVENT_OVER_CURRENT, NULL);
+		        regulator_unlock(regl->rdev);
+		}
 	}
 
 	return IRQ_HANDLED;
-- 
1.9.3