regulator: core: Use ww_mutex for regulators locking

Wait/wound mutex shall be used in order to avoid lockups on locking of
coupled regulators.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Suggested-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/da9210-regulator.c

@@ -131,7 +131,7 @@ static irqreturn_t da9210_irq_handler(int irq, void *data)
 	if (error < 0)
 		goto error_i2c;
 
-	mutex_lock(&chip->rdev->mutex);
+	regulator_lock(chip->rdev);
 
 	if (val & DA9210_E_OVCURR) {
 		regulator_notifier_call_chain(chip->rdev,
@@ -157,7 +157,7 @@ static irqreturn_t da9210_irq_handler(int irq, void *data)
 		handled |= DA9210_E_VMAX;
 	}
 
-	mutex_unlock(&chip->rdev->mutex);
+	regulator_unlock(chip->rdev);
 
 	if (handled) {
 		/* Clear handled events */

drivers/regulator/stpmic1_regulator.c

@@ -489,14 +489,14 @@ static irqreturn_t stpmic1_curlim_irq_handler(int irq, void *data)
 {
 	struct regulator_dev *rdev = (struct regulator_dev *)data;
 
-	mutex_lock(&rdev->mutex);
+	regulator_lock(rdev, NULL);
 
 	/* Send an overcurrent notification */
 	regulator_notifier_call_chain(rdev,
 				      REGULATOR_EVENT_OVER_CURRENT,
 				      NULL);
 
-	mutex_unlock(&rdev->mutex);
+	regulator_unlock(rdev);
 
 	return IRQ_HANDLED;
 }

drivers/regulator/wm8350-regulator.c

@@ -1153,7 +1153,7 @@ static irqreturn_t pmic_uv_handler(int irq, void *data)
 {
 	struct regulator_dev *rdev = (struct regulator_dev *)data;
 
-	mutex_lock(&rdev->mutex);
+	regulator_lock(rdev);
 	if (irq == WM8350_IRQ_CS1 || irq == WM8350_IRQ_CS2)
 		regulator_notifier_call_chain(rdev,
 					      REGULATOR_EVENT_REGULATION_OUT,
@@ -1162,7 +1162,7 @@ static irqreturn_t pmic_uv_handler(int irq, void *data)
 		regulator_notifier_call_chain(rdev,
 					      REGULATOR_EVENT_UNDER_VOLTAGE,
 					      NULL);
-	mutex_unlock(&rdev->mutex);
+	regulator_unlock(rdev);
 
 	return IRQ_HANDLED;
 }

include/linux/regulator/driver.h

@@ -20,6 +20,7 @@
 #include <linux/device.h>
 #include <linux/notifier.h>
 #include <linux/regulator/consumer.h>
+#include <linux/ww_mutex.h>
 
 struct gpio_desc;
 struct regmap;
@@ -462,7 +463,7 @@ struct regulator_dev {
 	struct coupling_desc coupling_desc;
 
 	struct blocking_notifier_head notifier;
-	struct mutex mutex; /* consumer lock */
+	struct ww_mutex mutex; /* consumer lock */
 	struct task_struct *mutex_owner;
 	int ref_cnt;
 	struct module *owner;
@@ -545,4 +546,7 @@ int regulator_set_active_discharge_regmap(struct regulator_dev *rdev,
 					  bool enable);
 void *regulator_get_init_drvdata(struct regulator_init_data *reg_init_data);
 
+void regulator_lock(struct regulator_dev *rdev);
+void regulator_unlock(struct regulator_dev *rdev);
+
 #endif