regulator: core: have regulator_dev_lookup() return ERR_PTR-encoded errors

Instead of returning both regulator_dev structure as return value and
auxiliary error code in 'ret' argument, let's switch to using ERR_PTR
encoded values. This makes it more obvious what is going on at call sites.

Also, let's not unlock the mutex in the middle of a loop, but rather break
out and have single unlock path.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 23 insertions, 19 deletions

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 867756651544..3e246c82939d 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1455,12 +1455,14 @@ static struct regulator_dev *regulator_lookup_by_name(const char *name)
  * lookup could succeed in the future.
  *
  * If successful, returns a struct regulator_dev that corresponds to the name
- * @supply and with the embedded struct device refcount incremented by one,
- * or NULL on failure. The refcount must be dropped by calling put_device().
+ * @supply and with the embedded struct device refcount incremented by one.
+ * The refcount must be dropped by calling put_device().
+ * On failure one of the following ERR-PTR-encoded values is returned:
+ * -ENODEV if lookup fails permanently, -EPROBE_DEFER if lookup could succeed
+ * in the future.
  */
 static struct regulator_dev *regulator_dev_lookup(struct device *dev,
-                                                  const char *supply,
-                                                  int *ret)
+                                                  const char *supply)
 {
         struct regulator_dev *r;
         struct device_node *node;
@@ -1476,16 +1478,12 @@ static struct regulator_dev *regulator_dev_lookup(struct device *dev,
                         r = of_find_regulator_by_node(node);
                         if (r)
                                 return r;
-                        *ret = -EPROBE_DEFER;
-                        return NULL;
-                } else {
+
                         /*
-                         * If we couldn't even get the node then it's
-                         * not just that the device didn't register
-                         * yet, there's no node and we'll never
-                         * succeed.
+                         * We have a node, but there is no device.
+                         * assume it has not registered yet.
                          */
-                        *ret = -ENODEV;
+                        return ERR_PTR(-EPROBE_DEFER);
                 }
         }
 
@@ -1506,13 +1504,16 @@ static struct regulator_dev *regulator_dev_lookup(struct device *dev,
 
                 if (strcmp(map->supply, supply) == 0 &&
                     get_device(&map->regulator->dev)) {
-                        mutex_unlock(&regulator_list_mutex);
-                        return map->regulator;
+                        r = map->regulator;
+                        break;
                 }
         }
         mutex_unlock(&regulator_list_mutex);
 
-        return NULL;
+        if (r)
+                return r;
+
+        return ERR_PTR(-ENODEV);
 }
 
 static int regulator_resolve_supply(struct regulator_dev *rdev)
@@ -1529,8 +1530,10 @@ static int regulator_resolve_supply(struct regulator_dev *rdev)
         if (rdev->supply)
                 return 0;
 
-        r = regulator_dev_lookup(dev, rdev->supply_name, &ret);
-        if (!r) {
+        r = regulator_dev_lookup(dev, rdev->supply_name);
+        if (IS_ERR(r)) {
+                ret = PTR_ERR(r);
+
                 if (ret == -ENODEV) {
                         /*
                          * No supply was specified for this regulator and
@@ -1601,10 +1604,11 @@ struct regulator *_regulator_get(struct device *dev, const char *id,
         if (dev)
                 devname = dev_name(dev);
 
-        rdev = regulator_dev_lookup(dev, id, &ret);
-        if (rdev)
+        rdev = regulator_dev_lookup(dev, id);
+        if (!IS_ERR(rdev))
                 goto found;
 
+        ret = PTR_ERR(rdev);
         regulator = ERR_PTR(ret);
 
         /*