1 files changed, 44 insertions, 18 deletions

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index ca03d8e70bd1..16114aea099a 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1617,7 +1617,7 @@ static struct regulator *create_regulator(struct regulator_dev *rdev,
 					  const char *supply_name)
 {
 	struct regulator *regulator;
-	int err;
+	int err = 0;
 
 	if (dev) {
 		char buf[REG_STR_SIZE];
@@ -1663,8 +1663,8 @@ static struct regulator *create_regulator(struct regulator_dev *rdev,
 		}
 	}
 
-	regulator->debugfs = debugfs_create_dir(supply_name,
-						rdev->debugfs);
+	if (err != -EEXIST)
+		regulator->debugfs = debugfs_create_dir(supply_name, rdev->debugfs);
 	if (!regulator->debugfs) {
 		rdev_dbg(rdev, "Failed to create debugfs directory\n");
 	} else {
@@ -1813,13 +1813,13 @@ static int regulator_resolve_supply(struct regulator_dev *rdev)
 {
 	struct regulator_dev *r;
 	struct device *dev = rdev->dev.parent;
-	int ret;
+	int ret = 0;
 
 	/* No supply to resolve? */
 	if (!rdev->supply_name)
 		return 0;
 
-	/* Supply already resolved? */
+	/* Supply already resolved? (fast-path without locking contention) */
 	if (rdev->supply)
 		return 0;
 
@@ -1829,7 +1829,7 @@ static int regulator_resolve_supply(struct regulator_dev *rdev)
 
 		/* Did the lookup explicitly defer for us? */
 		if (ret == -EPROBE_DEFER)
-			return ret;
+			goto out;
 
 		if (have_full_constraints()) {
 			r = dummy_regulator_rdev;
@@ -1837,15 +1837,18 @@ static int regulator_resolve_supply(struct regulator_dev *rdev)
 		} else {
 			dev_err(dev, "Failed to resolve %s-supply for %s\n",
 				rdev->supply_name, rdev->desc->name);
-			return -EPROBE_DEFER;
+			ret = -EPROBE_DEFER;
+			goto out;
 		}
 	}
 
 	if (r == rdev) {
 		dev_err(dev, "Supply for %s (%s) resolved to itself\n",
 			rdev->desc->name, rdev->supply_name);
-		if (!have_full_constraints())
-			return -EINVAL;
+		if (!have_full_constraints()) {
+			ret = -EINVAL;
+			goto out;
+		}
 		r = dummy_regulator_rdev;
 		get_device(&r->dev);
 	}
@@ -1859,7 +1862,8 @@ static int regulator_resolve_supply(struct regulator_dev *rdev)
 	if (r->dev.parent && r->dev.parent != rdev->dev.parent) {
 		if (!device_is_bound(r->dev.parent)) {
 			put_device(&r->dev);
-			return -EPROBE_DEFER;
+			ret = -EPROBE_DEFER;
+			goto out;
 		}
 	}
 
@@ -1867,15 +1871,32 @@ static int regulator_resolve_supply(struct regulator_dev *rdev)
 	ret = regulator_resolve_supply(r);
 	if (ret < 0) {
 		put_device(&r->dev);
-		return ret;
+		goto out;
+	}
+
+	/*
+	 * Recheck rdev->supply with rdev->mutex lock held to avoid a race
+	 * between rdev->supply null check and setting rdev->supply in
+	 * set_supply() from concurrent tasks.
+	 */
+	regulator_lock(rdev);
+
+	/* Supply just resolved by a concurrent task? */
+	if (rdev->supply) {
+		regulator_unlock(rdev);
+		put_device(&r->dev);
+		goto out;
 	}
 
 	ret = set_supply(rdev, r);
 	if (ret < 0) {
+		regulator_unlock(rdev);
 		put_device(&r->dev);
-		return ret;
+		goto out;
 	}
 
+	regulator_unlock(rdev);
+
 	/*
 	 * In set_machine_constraints() we may have turned this regulator on
 	 * but we couldn't propagate to the supply if it hadn't been resolved
@@ -1886,11 +1907,12 @@ static int regulator_resolve_supply(struct regulator_dev *rdev)
 		if (ret < 0) {
 			_regulator_put(rdev->supply);
 			rdev->supply = NULL;
-			return ret;
+			goto out;
 		}
 	}
 
-	return 0;
+out:
+	return ret;
 }
 
 /* Internal regulator request function */
@@ -2020,7 +2042,7 @@ struct regulator *_regulator_get(struct device *dev, const char *id,
  * Returns a struct regulator corresponding to the regulator producer,
  * or IS_ERR() condition containing errno.
  *
- * Use of supply names configured via regulator_set_device_supply() is
+ * Use of supply names configured via set_consumer_device_supply() is
  * strongly encouraged.  It is recommended that the supply name used
  * should match the name used for the supply and/or the relevant
  * device pins in the datasheet.
@@ -2047,7 +2069,7 @@ EXPORT_SYMBOL_GPL(regulator_get);
  * regulator off for correct operation of the hardware they are
  * controlling.
  *
- * Use of supply names configured via regulator_set_device_supply() is
+ * Use of supply names configured via set_consumer_device_supply() is
  * strongly encouraged.  It is recommended that the supply name used
  * should match the name used for the supply and/or the relevant
  * device pins in the datasheet.
@@ -2073,7 +2095,7 @@ EXPORT_SYMBOL_GPL(regulator_get_exclusive);
  * disrupting the operation of drivers that can handle absent
  * supplies.
  *
- * Use of supply names configured via regulator_set_device_supply() is
+ * Use of supply names configured via set_consumer_device_supply() is
  * strongly encouraged.  It is recommended that the supply name used
  * should match the name used for the supply and/or the relevant
  * device pins in the datasheet.
@@ -4131,7 +4153,11 @@ int regulator_sync_voltage(struct regulator *regulator)
 	if (ret < 0)
 		goto out;
 
-	ret = _regulator_do_set_voltage(rdev, min_uV, max_uV);
+	/* balance only, if regulator is coupled */
+	if (rdev->coupling_desc.n_coupled > 1)
+		ret = regulator_balance_voltage(rdev, PM_SUSPEND_ON);
+	else
+		ret = _regulator_do_set_voltage(rdev, min_uV, max_uV);
 
 out:
 	regulator_unlock(rdev);