Regulator: Push lock out of _notifier_call_chain + add voltage change event.

Regulator: Push lock out of _notifier_call_chain and into caller functions
(side effect of fixing deadlock in regulator_force_disable)
+ Add a voltage changed event.
Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>

drivers/regulator/core.c

@@ -1284,6 +1284,7 @@ int regulator_set_voltage(struct regulator *regulator, int min_uV, int max_uV)
 	ret = rdev->desc->ops->set_voltage(rdev, min_uV, max_uV);
 
 out:
+	_notifier_call_chain(rdev, REGULATOR_EVENT_VOLTAGE_CHANGE, NULL);
 	mutex_unlock(&rdev->mutex);
 	return ret;
 }
@@ -1584,20 +1585,23 @@ int regulator_unregister_notifier(struct regulator *regulator,
 }
 EXPORT_SYMBOL_GPL(regulator_unregister_notifier);
 
-/* notify regulator consumers and downstream regulator consumers */
+/* notify regulator consumers and downstream regulator consumers.
+ * Note mutex must be held by caller.
+ */
 static void _notifier_call_chain(struct regulator_dev *rdev,
 				  unsigned long event, void *data)
 {
 	struct regulator_dev *_rdev;
 
 	/* call rdev chain first */
-	mutex_lock(&rdev->mutex);
 	blocking_notifier_call_chain(&rdev->notifier, event, NULL);
-	mutex_unlock(&rdev->mutex);
 
 	/* now notify regulator we supply */
-	list_for_each_entry(_rdev, &rdev->supply_list, slist)
-		_notifier_call_chain(_rdev, event, data);
+	list_for_each_entry(_rdev, &rdev->supply_list, slist) {
+	  mutex_lock(&_rdev->mutex);
+	  _notifier_call_chain(_rdev, event, data);
+	  mutex_unlock(&_rdev->mutex);
+	}
 }
 
 /**
@@ -1744,6 +1748,7 @@ EXPORT_SYMBOL_GPL(regulator_bulk_free);
  *
  * Called by regulator drivers to notify clients a regulator event has
  * occurred. We also notify regulator clients downstream.
+ * Note lock must be held by caller.
  */
 int regulator_notifier_call_chain(struct regulator_dev *rdev,
 				  unsigned long event, void *data)

drivers/regulator/wm8350-regulator.c

@@ -1293,6 +1293,7 @@ static void pmic_uv_handler(struct wm8350 *wm8350, int irq, void *data)
 {
 	struct regulator_dev *rdev = (struct regulator_dev *)data;
 
+	mutex_lock(&rdev->mutex);
 	if (irq == WM8350_IRQ_CS1 || irq == WM8350_IRQ_CS2)
 		regulator_notifier_call_chain(rdev,
 					      REGULATOR_EVENT_REGULATION_OUT,
@@ -1301,6 +1302,7 @@ static void pmic_uv_handler(struct wm8350 *wm8350, int irq, void *data)
 		regulator_notifier_call_chain(rdev,
 					      REGULATOR_EVENT_UNDER_VOLTAGE,
 					      wm8350);
+	mutex_unlock(&rdev->mutex);
 }
 
 static int wm8350_regulator_probe(struct platform_device *pdev)

include/linux/regulator/consumer.h

@@ -88,6 +88,7 @@
  * FAIL           Regulator output has failed.
  * OVER_TEMP      Regulator over temp.
  * FORCE_DISABLE  Regulator shut down by software.
+ * VOLTAGE_CHANGE Regulator voltage changed.
  *
  * NOTE: These events can be OR'ed together when passed into handler.
  */
@@ -98,6 +99,7 @@
 #define REGULATOR_EVENT_FAIL			0x08
 #define REGULATOR_EVENT_OVER_TEMP		0x10
 #define REGULATOR_EVENT_FORCE_DISABLE		0x20
+#define REGULATOR_EVENT_VOLTAGE_CHANGE		0x40
 
 struct regulator;