These changes are the raw update to linux-4.4.6-rt14. Kernel sources
[kvmfornfv.git] / kernel / drivers / regulator / core.c
index 8a28116..73b7683 100644 (file)
@@ -51,7 +51,6 @@
        pr_debug("%s: " fmt, rdev_get_name(rdev), ##__VA_ARGS__)
 
 static DEFINE_MUTEX(regulator_list_mutex);
-static LIST_HEAD(regulator_list);
 static LIST_HEAD(regulator_map_list);
 static LIST_HEAD(regulator_ena_gpio_list);
 static LIST_HEAD(regulator_supply_alias_list);
@@ -59,6 +58,8 @@ static bool has_full_constraints;
 
 static struct dentry *debugfs_root;
 
+static struct class regulator_class;
+
 /*
  * struct regulator_map
  *
@@ -109,6 +110,12 @@ static int _regulator_do_set_voltage(struct regulator_dev *rdev,
 static struct regulator *create_regulator(struct regulator_dev *rdev,
                                          struct device *dev,
                                          const char *supply_name);
+static void _regulator_put(struct regulator *regulator);
+
+static struct regulator_dev *dev_to_rdev(struct device *dev)
+{
+       return container_of(dev, struct regulator_dev, dev);
+}
 
 static const char *rdev_get_name(struct regulator_dev *rdev)
 {
@@ -125,6 +132,45 @@ static bool have_full_constraints(void)
        return has_full_constraints || of_have_populated_dt();
 }
 
+/**
+ * regulator_lock_supply - lock a regulator and its supplies
+ * @rdev:         regulator source
+ */
+static void regulator_lock_supply(struct regulator_dev *rdev)
+{
+       struct regulator *supply;
+       int i = 0;
+
+       while (1) {
+               mutex_lock_nested(&rdev->mutex, i++);
+               supply = rdev->supply;
+
+               if (!rdev->supply)
+                       return;
+
+               rdev = supply->rdev;
+       }
+}
+
+/**
+ * regulator_unlock_supply - unlock a regulator and its supplies
+ * @rdev:         regulator source
+ */
+static void regulator_unlock_supply(struct regulator_dev *rdev)
+{
+       struct regulator *supply;
+
+       while (1) {
+               mutex_unlock(&rdev->mutex);
+               supply = rdev->supply;
+
+               if (!rdev->supply)
+                       return;
+
+               rdev = supply->rdev;
+       }
+}
+
 /**
  * of_get_regulator - get a regulator device node based on supply name
  * @dev: Device pointer for the consumer (of regulator) device
@@ -174,7 +220,7 @@ static int regulator_check_voltage(struct regulator_dev *rdev,
                return -ENODEV;
        }
        if (!(rdev->constraints->valid_ops_mask & REGULATOR_CHANGE_VOLTAGE)) {
-               rdev_err(rdev, "operation not allowed\n");
+               rdev_err(rdev, "voltage operation not allowed\n");
                return -EPERM;
        }
 
@@ -234,7 +280,7 @@ static int regulator_check_current_limit(struct regulator_dev *rdev,
                return -ENODEV;
        }
        if (!(rdev->constraints->valid_ops_mask & REGULATOR_CHANGE_CURRENT)) {
-               rdev_err(rdev, "operation not allowed\n");
+               rdev_err(rdev, "current operation not allowed\n");
                return -EPERM;
        }
 
@@ -271,7 +317,7 @@ static int regulator_mode_constrain(struct regulator_dev *rdev, int *mode)
                return -ENODEV;
        }
        if (!(rdev->constraints->valid_ops_mask & REGULATOR_CHANGE_MODE)) {
-               rdev_err(rdev, "operation not allowed\n");
+               rdev_err(rdev, "mode operation not allowed\n");
                return -EPERM;
        }
 
@@ -295,7 +341,7 @@ static int regulator_check_drms(struct regulator_dev *rdev)
                return -ENODEV;
        }
        if (!(rdev->constraints->valid_ops_mask & REGULATOR_CHANGE_DRMS)) {
-               rdev_err(rdev, "operation not allowed\n");
+               rdev_dbg(rdev, "drms operation not allowed\n");
                return -EPERM;
        }
        return 0;
@@ -640,6 +686,8 @@ static int drms_uA_update(struct regulator_dev *rdev)
        int current_uA = 0, output_uV, input_uV, err;
        unsigned int mode;
 
+       lockdep_assert_held_once(&rdev->mutex);
+
        /*
         * first check to see if we can set modes at all, otherwise just
         * tell the consumer everything is OK.
@@ -678,6 +726,8 @@ static int drms_uA_update(struct regulator_dev *rdev)
        list_for_each_entry(sibling, &rdev->consumer_list, list)
                current_uA += sibling->uA_load;
 
+       current_uA += rdev->constraints->system_load;
+
        if (rdev->desc->ops->set_load) {
                /* set the optimum mode for our new total regulator load */
                err = rdev->desc->ops->set_load(rdev, current_uA);
@@ -758,6 +808,8 @@ static int suspend_set_state(struct regulator_dev *rdev,
 /* locks held by caller */
 static int suspend_prepare(struct regulator_dev *rdev, suspend_state_t state)
 {
+       lockdep_assert_held_once(&rdev->mutex);
+
        if (!rdev->constraints)
                return -EINVAL;
 
@@ -780,58 +832,63 @@ static void print_constraints(struct regulator_dev *rdev)
 {
        struct regulation_constraints *constraints = rdev->constraints;
        char buf[160] = "";
+       size_t len = sizeof(buf) - 1;
        int count = 0;
        int ret;
 
        if (constraints->min_uV && constraints->max_uV) {
                if (constraints->min_uV == constraints->max_uV)
-                       count += sprintf(buf + count, "%d mV ",
-                                        constraints->min_uV / 1000);
+                       count += scnprintf(buf + count, len - count, "%d mV ",
+                                          constraints->min_uV / 1000);
                else
-                       count += sprintf(buf + count, "%d <--> %d mV ",
-                                        constraints->min_uV / 1000,
-                                        constraints->max_uV / 1000);
+                       count += scnprintf(buf + count, len - count,
+                                          "%d <--> %d mV ",
+                                          constraints->min_uV / 1000,
+                                          constraints->max_uV / 1000);
        }
 
        if (!constraints->min_uV ||
            constraints->min_uV != constraints->max_uV) {
                ret = _regulator_get_voltage(rdev);
                if (ret > 0)
-                       count += sprintf(buf + count, "at %d mV ", ret / 1000);
+                       count += scnprintf(buf + count, len - count,
+                                          "at %d mV ", ret / 1000);
        }
 
        if (constraints->uV_offset)
-               count += sprintf(buf, "%dmV offset ",
-                                constraints->uV_offset / 1000);
+               count += scnprintf(buf + count, len - count, "%dmV offset ",
+                                  constraints->uV_offset / 1000);
 
        if (constraints->min_uA && constraints->max_uA) {
                if (constraints->min_uA == constraints->max_uA)
-                       count += sprintf(buf + count, "%d mA ",
-                                        constraints->min_uA / 1000);
+                       count += scnprintf(buf + count, len - count, "%d mA ",
+                                          constraints->min_uA / 1000);
                else
-                       count += sprintf(buf + count, "%d <--> %d mA ",
-                                        constraints->min_uA / 1000,
-                                        constraints->max_uA / 1000);
+                       count += scnprintf(buf + count, len - count,
+                                          "%d <--> %d mA ",
+                                          constraints->min_uA / 1000,
+                                          constraints->max_uA / 1000);
        }
 
        if (!constraints->min_uA ||
            constraints->min_uA != constraints->max_uA) {
                ret = _regulator_get_current_limit(rdev);
                if (ret > 0)
-                       count += sprintf(buf + count, "at %d mA ", ret / 1000);
+                       count += scnprintf(buf + count, len - count,
+                                          "at %d mA ", ret / 1000);
        }
 
        if (constraints->valid_modes_mask & REGULATOR_MODE_FAST)
-               count += sprintf(buf + count, "fast ");
+               count += scnprintf(buf + count, len - count, "fast ");
        if (constraints->valid_modes_mask & REGULATOR_MODE_NORMAL)
-               count += sprintf(buf + count, "normal ");
+               count += scnprintf(buf + count, len - count, "normal ");
        if (constraints->valid_modes_mask & REGULATOR_MODE_IDLE)
-               count += sprintf(buf + count, "idle ");
+               count += scnprintf(buf + count, len - count, "idle ");
        if (constraints->valid_modes_mask & REGULATOR_MODE_STANDBY)
-               count += sprintf(buf + count, "standby");
+               count += scnprintf(buf + count, len - count, "standby");
 
        if (!count)
-               sprintf(buf, "no parameters");
+               scnprintf(buf, len, "no parameters");
 
        rdev_dbg(rdev, "%s\n", buf);
 
@@ -1006,6 +1063,15 @@ static int set_machine_constraints(struct regulator_dev *rdev,
        if (ret != 0)
                goto out;
 
+       if (rdev->constraints->ilim_uA && ops->set_input_current_limit) {
+               ret = ops->set_input_current_limit(rdev,
+                                                  rdev->constraints->ilim_uA);
+               if (ret < 0) {
+                       rdev_err(rdev, "failed to set input limit\n");
+                       goto out;
+               }
+       }
+
        /* do we need to setup our suspend state */
        if (rdev->constraints->initial_state) {
                ret = suspend_prepare(rdev, rdev->constraints->initial_state);
@@ -1049,6 +1115,31 @@ static int set_machine_constraints(struct regulator_dev *rdev,
                }
        }
 
+       if (rdev->constraints->pull_down && ops->set_pull_down) {
+               ret = ops->set_pull_down(rdev);
+               if (ret < 0) {
+                       rdev_err(rdev, "failed to set pull down\n");
+                       goto out;
+               }
+       }
+
+       if (rdev->constraints->soft_start && ops->set_soft_start) {
+               ret = ops->set_soft_start(rdev);
+               if (ret < 0) {
+                       rdev_err(rdev, "failed to set soft start\n");
+                       goto out;
+               }
+       }
+
+       if (rdev->constraints->over_current_protection
+               && ops->set_over_current_protection) {
+               ret = ops->set_over_current_protection(rdev);
+               if (ret < 0) {
+                       rdev_err(rdev, "failed to set over current protection\n");
+                       goto out;
+               }
+       }
+
        print_constraints(rdev);
        return 0;
 out:
@@ -1073,6 +1164,9 @@ static int set_supply(struct regulator_dev *rdev,
 
        rdev_info(rdev, "supplied by %s\n", rdev_get_name(supply_rdev));
 
+       if (!try_module_get(supply_rdev->owner))
+               return -ENODEV;
+
        rdev->supply = create_regulator(supply_rdev, &rdev->dev, "SUPPLY");
        if (rdev->supply == NULL) {
                err = -ENOMEM;
@@ -1192,10 +1286,10 @@ static struct regulator *create_regulator(struct regulator_dev *rdev,
                if (regulator->supply_name == NULL)
                        goto overflow_err;
 
-               err = sysfs_create_link(&rdev->dev.kobj, &dev->kobj,
+               err = sysfs_create_link_nowarn(&rdev->dev.kobj, &dev->kobj,
                                        buf);
                if (err) {
-                       rdev_warn(rdev, "could not add device link %s err %d\n",
+                       rdev_dbg(rdev, "could not add device link %s err %d\n",
                                  dev->kobj.name, err);
                        /* non-fatal */
                }
@@ -1208,7 +1302,7 @@ static struct regulator *create_regulator(struct regulator_dev *rdev,
        regulator->debugfs = debugfs_create_dir(regulator->supply_name,
                                                rdev->debugfs);
        if (!regulator->debugfs) {
-               rdev_warn(rdev, "Failed to create debugfs directory\n");
+               rdev_dbg(rdev, "Failed to create debugfs directory\n");
        } else {
                debugfs_create_u32("uA_load", 0444, regulator->debugfs,
                                   &regulator->uA_load);
@@ -1271,6 +1365,47 @@ static void regulator_supply_alias(struct device **dev, const char **supply)
        }
 }
 
+static int of_node_match(struct device *dev, const void *data)
+{
+       return dev->of_node == data;
+}
+
+static struct regulator_dev *of_find_regulator_by_node(struct device_node *np)
+{
+       struct device *dev;
+
+       dev = class_find_device(&regulator_class, NULL, np, of_node_match);
+
+       return dev ? dev_to_rdev(dev) : NULL;
+}
+
+static int regulator_match(struct device *dev, const void *data)
+{
+       struct regulator_dev *r = dev_to_rdev(dev);
+
+       return strcmp(rdev_get_name(r), data) == 0;
+}
+
+static struct regulator_dev *regulator_lookup_by_name(const char *name)
+{
+       struct device *dev;
+
+       dev = class_find_device(&regulator_class, NULL, name, regulator_match);
+
+       return dev ? dev_to_rdev(dev) : NULL;
+}
+
+/**
+ * regulator_dev_lookup - lookup a regulator device.
+ * @dev: device for regulator "consumer".
+ * @supply: Supply name or regulator ID.
+ * @ret: 0 on success, -ENODEV if lookup fails permanently, -EPROBE_DEFER if
+ * 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().
+ */
 static struct regulator_dev *regulator_dev_lookup(struct device *dev,
                                                  const char *supply,
                                                  int *ret)
@@ -1286,10 +1421,9 @@ static struct regulator_dev *regulator_dev_lookup(struct device *dev,
        if (dev && dev->of_node) {
                node = of_get_regulator(dev, supply);
                if (node) {
-                       list_for_each_entry(r, &regulator_list, list)
-                               if (r->dev.parent &&
-                                       node == r->dev.of_node)
-                                       return r;
+                       r = of_find_regulator_by_node(node);
+                       if (r)
+                               return r;
                        *ret = -EPROBE_DEFER;
                        return NULL;
                } else {
@@ -1307,20 +1441,24 @@ static struct regulator_dev *regulator_dev_lookup(struct device *dev,
        if (dev)
                devname = dev_name(dev);
 
-       list_for_each_entry(r, &regulator_list, list)
-               if (strcmp(rdev_get_name(r), supply) == 0)
-                       return r;
+       r = regulator_lookup_by_name(supply);
+       if (r)
+               return r;
 
+       mutex_lock(&regulator_list_mutex);
        list_for_each_entry(map, &regulator_map_list, list) {
                /* If the mapping has a device set up it must match */
                if (map->dev_name &&
                    (!devname || strcmp(map->dev_name, devname)))
                        continue;
 
-               if (strcmp(map->supply, supply) == 0)
+               if (strcmp(map->supply, supply) == 0 &&
+                   get_device(&map->regulator->dev)) {
+                       mutex_unlock(&regulator_list_mutex);
                        return map->regulator;
+               }
        }
-
+       mutex_unlock(&regulator_list_mutex);
 
        return NULL;
 }
@@ -1340,34 +1478,49 @@ static int regulator_resolve_supply(struct regulator_dev *rdev)
                return 0;
 
        r = regulator_dev_lookup(dev, rdev->supply_name, &ret);
-       if (ret == -ENODEV) {
-               /*
-                * No supply was specified for this regulator and
-                * there will never be one.
-                */
-               return 0;
-       }
-
        if (!r) {
-               dev_err(dev, "Failed to resolve %s-supply for %s\n",
-                       rdev->supply_name, rdev->desc->name);
-               return -EPROBE_DEFER;
+               if (ret == -ENODEV) {
+                       /*
+                        * No supply was specified for this regulator and
+                        * there will never be one.
+                        */
+                       return 0;
+               }
+
+               /* Did the lookup explicitly defer for us? */
+               if (ret == -EPROBE_DEFER)
+                       return ret;
+
+               if (have_full_constraints()) {
+                       r = dummy_regulator_rdev;
+                       get_device(&r->dev);
+               } else {
+                       dev_err(dev, "Failed to resolve %s-supply for %s\n",
+                               rdev->supply_name, rdev->desc->name);
+                       return -EPROBE_DEFER;
+               }
        }
 
        /* Recursively resolve the supply of the supply */
        ret = regulator_resolve_supply(r);
-       if (ret < 0)
+       if (ret < 0) {
+               put_device(&r->dev);
                return ret;
+       }
 
        ret = set_supply(rdev, r);
-       if (ret < 0)
+       if (ret < 0) {
+               put_device(&r->dev);
                return ret;
+       }
 
        /* Cascade always-on state to supply */
-       if (_regulator_is_enabled(rdev)) {
+       if (_regulator_is_enabled(rdev) && rdev->supply) {
                ret = regulator_enable(rdev->supply);
-               if (ret < 0)
+               if (ret < 0) {
+                       _regulator_put(rdev->supply);
                        return ret;
+               }
        }
 
        return 0;
@@ -1395,8 +1548,6 @@ static struct regulator *_regulator_get(struct device *dev, const char *id,
        else
                ret = -EPROBE_DEFER;
 
-       mutex_lock(&regulator_list_mutex);
-
        rdev = regulator_dev_lookup(dev, id, &ret);
        if (rdev)
                goto found;
@@ -1408,7 +1559,7 @@ static struct regulator *_regulator_get(struct device *dev, const char *id,
         * succeed, so, quit with appropriate error value
         */
        if (ret && ret != -ENODEV)
-               goto out;
+               return regulator;
 
        if (!devname)
                devname = "deviceless";
@@ -1422,40 +1573,46 @@ static struct regulator *_regulator_get(struct device *dev, const char *id,
                        devname, id);
 
                rdev = dummy_regulator_rdev;
+               get_device(&rdev->dev);
                goto found;
        /* Don't log an error when called from regulator_get_optional() */
        } else if (!have_full_constraints() || exclusive) {
                dev_warn(dev, "dummy supplies not allowed\n");
        }
 
-       mutex_unlock(&regulator_list_mutex);
        return regulator;
 
 found:
        if (rdev->exclusive) {
                regulator = ERR_PTR(-EPERM);
-               goto out;
+               put_device(&rdev->dev);
+               return regulator;
        }
 
        if (exclusive && rdev->open_count) {
                regulator = ERR_PTR(-EBUSY);
-               goto out;
+               put_device(&rdev->dev);
+               return regulator;
        }
 
        ret = regulator_resolve_supply(rdev);
        if (ret < 0) {
                regulator = ERR_PTR(ret);
-               goto out;
+               put_device(&rdev->dev);
+               return regulator;
        }
 
-       if (!try_module_get(rdev->owner))
-               goto out;
+       if (!try_module_get(rdev->owner)) {
+               put_device(&rdev->dev);
+               return regulator;
+       }
 
        regulator = create_regulator(rdev, dev, id);
        if (regulator == NULL) {
                regulator = ERR_PTR(-ENOMEM);
+               put_device(&rdev->dev);
                module_put(rdev->owner);
-               goto out;
+               return regulator;
        }
 
        rdev->open_count++;
@@ -1469,9 +1626,6 @@ found:
                        rdev->use_count = 0;
        }
 
-out:
-       mutex_unlock(&regulator_list_mutex);
-
        return regulator;
 }
 
@@ -1552,9 +1706,11 @@ static void _regulator_put(struct regulator *regulator)
 {
        struct regulator_dev *rdev;
 
-       if (regulator == NULL || IS_ERR(regulator))
+       if (IS_ERR_OR_NULL(regulator))
                return;
 
+       lockdep_assert_held_once(&regulator_list_mutex);
+
        rdev = regulator->rdev;
 
        debugfs_remove_recursive(regulator->debugfs);
@@ -1563,14 +1719,16 @@ static void _regulator_put(struct regulator *regulator)
        if (regulator->dev)
                sysfs_remove_link(&rdev->dev.kobj, regulator->supply_name);
        mutex_lock(&rdev->mutex);
-       kfree(regulator->supply_name);
        list_del(&regulator->list);
-       kfree(regulator);
 
        rdev->open_count--;
        rdev->exclusive = 0;
+       put_device(&rdev->dev);
        mutex_unlock(&rdev->mutex);
 
+       kfree(regulator->supply_name);
+       kfree(regulator);
+
        module_put(rdev->owner);
 }
 
@@ -1933,6 +2091,8 @@ static int _regulator_enable(struct regulator_dev *rdev)
 {
        int ret;
 
+       lockdep_assert_held_once(&rdev->mutex);
+
        /* check voltage and requested load before enabling */
        if (rdev->constraints &&
            (rdev->constraints->valid_ops_mask & REGULATOR_CHANGE_DRMS))
@@ -2033,6 +2193,8 @@ static int _regulator_disable(struct regulator_dev *rdev)
 {
        int ret = 0;
 
+       lockdep_assert_held_once(&rdev->mutex);
+
        if (WARN(rdev->use_count <= 0,
                 "unbalanced disables for %s\n", rdev_get_name(rdev)))
                return -EIO;
@@ -2111,6 +2273,8 @@ static int _regulator_force_disable(struct regulator_dev *rdev)
 {
        int ret = 0;
 
+       lockdep_assert_held_once(&rdev->mutex);
+
        ret = _notifier_call_chain(rdev, REGULATOR_EVENT_FORCE_DISABLE |
                        REGULATOR_EVENT_PRE_DISABLE, NULL);
        if (ret & NOTIFY_STOP_MASK)
@@ -2239,6 +2403,40 @@ static int _regulator_is_enabled(struct regulator_dev *rdev)
        return rdev->desc->ops->is_enabled(rdev);
 }
 
+static int _regulator_list_voltage(struct regulator *regulator,
+                                   unsigned selector, int lock)
+{
+       struct regulator_dev *rdev = regulator->rdev;
+       const struct regulator_ops *ops = rdev->desc->ops;
+       int ret;
+
+       if (rdev->desc->fixed_uV && rdev->desc->n_voltages == 1 && !selector)
+               return rdev->desc->fixed_uV;
+
+       if (ops->list_voltage) {
+               if (selector >= rdev->desc->n_voltages)
+                       return -EINVAL;
+               if (lock)
+                       mutex_lock(&rdev->mutex);
+               ret = ops->list_voltage(rdev, selector);
+               if (lock)
+                       mutex_unlock(&rdev->mutex);
+       } else if (rdev->supply) {
+               ret = _regulator_list_voltage(rdev->supply, selector, lock);
+       } else {
+               return -EINVAL;
+       }
+
+       if (ret > 0) {
+               if (ret < rdev->constraints->min_uV)
+                       ret = 0;
+               else if (ret > rdev->constraints->max_uV)
+                       ret = 0;
+       }
+
+       return ret;
+}
+
 /**
  * regulator_is_enabled - is the regulator output enabled
  * @regulator: regulator source
@@ -2328,33 +2526,7 @@ EXPORT_SYMBOL_GPL(regulator_count_voltages);
  */
 int regulator_list_voltage(struct regulator *regulator, unsigned selector)
 {
-       struct regulator_dev *rdev = regulator->rdev;
-       const struct regulator_ops *ops = rdev->desc->ops;
-       int ret;
-
-       if (rdev->desc->fixed_uV && rdev->desc->n_voltages == 1 && !selector)
-               return rdev->desc->fixed_uV;
-
-       if (ops->list_voltage) {
-               if (selector >= rdev->desc->n_voltages)
-                       return -EINVAL;
-               mutex_lock(&rdev->mutex);
-               ret = ops->list_voltage(rdev, selector);
-               mutex_unlock(&rdev->mutex);
-       } else if (rdev->supply) {
-               ret = regulator_list_voltage(rdev->supply, selector);
-       } else {
-               return -EINVAL;
-       }
-
-       if (ret > 0) {
-               if (ret < rdev->constraints->min_uV)
-                       ret = 0;
-               else if (ret > rdev->constraints->max_uV)
-                       ret = 0;
-       }
-
-       return ret;
+       return _regulator_list_voltage(regulator, selector, 1);
 }
 EXPORT_SYMBOL_GPL(regulator_list_voltage);
 
@@ -2489,6 +2661,23 @@ int regulator_is_supported_voltage(struct regulator *regulator,
 }
 EXPORT_SYMBOL_GPL(regulator_is_supported_voltage);
 
+static int regulator_map_voltage(struct regulator_dev *rdev, int min_uV,
+                                int max_uV)
+{
+       const struct regulator_desc *desc = rdev->desc;
+
+       if (desc->ops->map_voltage)
+               return desc->ops->map_voltage(rdev, min_uV, max_uV);
+
+       if (desc->ops->list_voltage == regulator_list_voltage_linear)
+               return regulator_map_voltage_linear(rdev, min_uV, max_uV);
+
+       if (desc->ops->list_voltage == regulator_list_voltage_linear_range)
+               return regulator_map_voltage_linear_range(rdev, min_uV, max_uV);
+
+       return regulator_map_voltage_iterate(rdev, min_uV, max_uV);
+}
+
 static int _regulator_call_set_voltage(struct regulator_dev *rdev,
                                       int min_uV, int max_uV,
                                       unsigned *selector)
@@ -2577,23 +2766,7 @@ static int _regulator_do_set_voltage(struct regulator_dev *rdev,
                }
 
        } else if (rdev->desc->ops->set_voltage_sel) {
-               if (rdev->desc->ops->map_voltage) {
-                       ret = rdev->desc->ops->map_voltage(rdev, min_uV,
-                                                          max_uV);
-               } else {
-                       if (rdev->desc->ops->list_voltage ==
-                           regulator_list_voltage_linear)
-                               ret = regulator_map_voltage_linear(rdev,
-                                                               min_uV, max_uV);
-                       else if (rdev->desc->ops->list_voltage ==
-                                regulator_list_voltage_linear_range)
-                               ret = regulator_map_voltage_linear_range(rdev,
-                                                               min_uV, max_uV);
-                       else
-                               ret = regulator_map_voltage_iterate(rdev,
-                                                               min_uV, max_uV);
-               }
-
+               ret = regulator_map_voltage(rdev, min_uV, max_uV);
                if (ret >= 0) {
                        best_val = rdev->desc->ops->list_voltage(rdev, ret);
                        if (min_uV <= best_val && max_uV >= best_val) {
@@ -2644,32 +2817,15 @@ static int _regulator_do_set_voltage(struct regulator_dev *rdev,
        return ret;
 }
 
-/**
- * regulator_set_voltage - set regulator output voltage
- * @regulator: regulator source
- * @min_uV: Minimum required voltage in uV
- * @max_uV: Maximum acceptable voltage in uV
- *
- * Sets a voltage regulator to the desired output voltage. This can be set
- * during any regulator state. IOW, regulator can be disabled or enabled.
- *
- * If the regulator is enabled then the voltage will change to the new value
- * immediately otherwise if the regulator is disabled the regulator will
- * output at the new voltage when enabled.
- *
- * NOTE: If the regulator is shared between several devices then the lowest
- * request voltage that meets the system constraints will be used.
- * Regulator system constraints must be set for this regulator before
- * calling this function otherwise this call will fail.
- */
-int regulator_set_voltage(struct regulator *regulator, int min_uV, int max_uV)
+static int regulator_set_voltage_unlocked(struct regulator *regulator,
+                                         int min_uV, int max_uV)
 {
        struct regulator_dev *rdev = regulator->rdev;
        int ret = 0;
        int old_min_uV, old_max_uV;
        int current_uV;
-
-       mutex_lock(&rdev->mutex);
+       int best_supply_uV = 0;
+       int supply_change_uV = 0;
 
        /* If we're setting the same range as last time the change
         * should be a noop (some cpufreq implementations use the same
@@ -2679,7 +2835,7 @@ int regulator_set_voltage(struct regulator *regulator, int min_uV, int max_uV)
                goto out;
 
        /* If we're trying to set a range that overlaps the current voltage,
-        * return succesfully even though the regulator does not support
+        * return successfully even though the regulator does not support
         * changing the voltage.
         */
        if (!(rdev->constraints->valid_ops_mask & REGULATOR_CHANGE_VOLTAGE)) {
@@ -2713,17 +2869,95 @@ int regulator_set_voltage(struct regulator *regulator, int min_uV, int max_uV)
        if (ret < 0)
                goto out2;
 
+       if (rdev->supply && (rdev->desc->min_dropout_uV ||
+                               !rdev->desc->ops->get_voltage)) {
+               int current_supply_uV;
+               int selector;
+
+               selector = regulator_map_voltage(rdev, min_uV, max_uV);
+               if (selector < 0) {
+                       ret = selector;
+                       goto out2;
+               }
+
+               best_supply_uV = _regulator_list_voltage(regulator, selector, 0);
+               if (best_supply_uV < 0) {
+                       ret = best_supply_uV;
+                       goto out2;
+               }
+
+               best_supply_uV += rdev->desc->min_dropout_uV;
+
+               current_supply_uV = _regulator_get_voltage(rdev->supply->rdev);
+               if (current_supply_uV < 0) {
+                       ret = current_supply_uV;
+                       goto out2;
+               }
+
+               supply_change_uV = best_supply_uV - current_supply_uV;
+       }
+
+       if (supply_change_uV > 0) {
+               ret = regulator_set_voltage_unlocked(rdev->supply,
+                               best_supply_uV, INT_MAX);
+               if (ret) {
+                       dev_err(&rdev->dev, "Failed to increase supply voltage: %d\n",
+                                       ret);
+                       goto out2;
+               }
+       }
+
        ret = _regulator_do_set_voltage(rdev, min_uV, max_uV);
        if (ret < 0)
                goto out2;
 
+       if (supply_change_uV < 0) {
+               ret = regulator_set_voltage_unlocked(rdev->supply,
+                               best_supply_uV, INT_MAX);
+               if (ret)
+                       dev_warn(&rdev->dev, "Failed to decrease supply voltage: %d\n",
+                                       ret);
+               /* No need to fail here */
+               ret = 0;
+       }
+
 out:
-       mutex_unlock(&rdev->mutex);
        return ret;
 out2:
        regulator->min_uV = old_min_uV;
        regulator->max_uV = old_max_uV;
-       mutex_unlock(&rdev->mutex);
+
+       return ret;
+}
+
+/**
+ * regulator_set_voltage - set regulator output voltage
+ * @regulator: regulator source
+ * @min_uV: Minimum required voltage in uV
+ * @max_uV: Maximum acceptable voltage in uV
+ *
+ * Sets a voltage regulator to the desired output voltage. This can be set
+ * during any regulator state. IOW, regulator can be disabled or enabled.
+ *
+ * If the regulator is enabled then the voltage will change to the new value
+ * immediately otherwise if the regulator is disabled the regulator will
+ * output at the new voltage when enabled.
+ *
+ * NOTE: If the regulator is shared between several devices then the lowest
+ * request voltage that meets the system constraints will be used.
+ * Regulator system constraints must be set for this regulator before
+ * calling this function otherwise this call will fail.
+ */
+int regulator_set_voltage(struct regulator *regulator, int min_uV, int max_uV)
+{
+       int ret = 0;
+
+       regulator_lock_supply(regulator->rdev);
+
+       ret = regulator_set_voltage_unlocked(regulator, min_uV, max_uV);
+
+       regulator_unlock_supply(regulator->rdev);
+
        return ret;
 }
 EXPORT_SYMBOL_GPL(regulator_set_voltage);
@@ -2876,7 +3110,7 @@ static int _regulator_get_voltage(struct regulator_dev *rdev)
        } else if (rdev->desc->fixed_uV && (rdev->desc->n_voltages == 1)) {
                ret = rdev->desc->fixed_uV;
        } else if (rdev->supply) {
-               ret = regulator_get_voltage(rdev->supply);
+               ret = _regulator_get_voltage(rdev->supply->rdev);
        } else {
                return -EINVAL;
        }
@@ -2899,11 +3133,11 @@ int regulator_get_voltage(struct regulator *regulator)
 {
        int ret;
 
-       mutex_lock(&regulator->rdev->mutex);
+       regulator_lock_supply(regulator->rdev);
 
        ret = _regulator_get_voltage(regulator->rdev);
 
-       mutex_unlock(&regulator->rdev->mutex);
+       regulator_unlock_supply(regulator->rdev);
 
        return ret;
 }
@@ -3407,6 +3641,8 @@ EXPORT_SYMBOL_GPL(regulator_bulk_free);
 int regulator_notifier_call_chain(struct regulator_dev *rdev,
                                  unsigned long event, void *data)
 {
+       lockdep_assert_held_once(&rdev->mutex);
+
        _notifier_call_chain(rdev, event, data);
        return NOTIFY_DONE;
 
@@ -3551,6 +3787,9 @@ static const struct attribute_group *regulator_dev_groups[] = {
 static void regulator_dev_release(struct device *dev)
 {
        struct regulator_dev *rdev = dev_get_drvdata(dev);
+
+       kfree(rdev->constraints);
+       of_node_put(rdev->dev.of_node);
        kfree(rdev);
 }
 
@@ -3732,8 +3971,6 @@ regulator_register(const struct regulator_desc *regulator_desc,
                }
        }
 
-       list_add(&rdev->list, &regulator_list);
-
        rdev_init_debugfs(rdev);
 out:
        mutex_unlock(&regulator_list_mutex);
@@ -3781,14 +4018,25 @@ void regulator_unregister(struct regulator_dev *rdev)
        WARN_ON(rdev->open_count);
        unset_regulator_supplies(rdev);
        list_del(&rdev->list);
-       kfree(rdev->constraints);
+       mutex_unlock(&regulator_list_mutex);
        regulator_ena_gpio_free(rdev);
-       of_node_put(rdev->dev.of_node);
        device_unregister(&rdev->dev);
-       mutex_unlock(&regulator_list_mutex);
 }
 EXPORT_SYMBOL_GPL(regulator_unregister);
 
+static int _regulator_suspend_prepare(struct device *dev, void *data)
+{
+       struct regulator_dev *rdev = dev_to_rdev(dev);
+       const suspend_state_t *state = data;
+       int ret;
+
+       mutex_lock(&rdev->mutex);
+       ret = suspend_prepare(rdev, *state);
+       mutex_unlock(&rdev->mutex);
+
+       return ret;
+}
+
 /**
  * regulator_suspend_prepare - prepare regulators for system wide suspend
  * @state: system suspend state
@@ -3798,30 +4046,45 @@ EXPORT_SYMBOL_GPL(regulator_unregister);
  */
 int regulator_suspend_prepare(suspend_state_t state)
 {
-       struct regulator_dev *rdev;
-       int ret = 0;
-
        /* ON is handled by regulator active state */
        if (state == PM_SUSPEND_ON)
                return -EINVAL;
 
-       mutex_lock(&regulator_list_mutex);
-       list_for_each_entry(rdev, &regulator_list, list) {
+       return class_for_each_device(&regulator_class, NULL, &state,
+                                    _regulator_suspend_prepare);
+}
+EXPORT_SYMBOL_GPL(regulator_suspend_prepare);
 
-               mutex_lock(&rdev->mutex);
-               ret = suspend_prepare(rdev, state);
-               mutex_unlock(&rdev->mutex);
+static int _regulator_suspend_finish(struct device *dev, void *data)
+{
+       struct regulator_dev *rdev = dev_to_rdev(dev);
+       int ret;
 
-               if (ret < 0) {
-                       rdev_err(rdev, "failed to prepare\n");
-                       goto out;
+       mutex_lock(&rdev->mutex);
+       if (rdev->use_count > 0  || rdev->constraints->always_on) {
+               if (!_regulator_is_enabled(rdev)) {
+                       ret = _regulator_do_enable(rdev);
+                       if (ret)
+                               dev_err(dev,
+                                       "Failed to resume regulator %d\n",
+                                       ret);
                }
+       } else {
+               if (!have_full_constraints())
+                       goto unlock;
+               if (!_regulator_is_enabled(rdev))
+                       goto unlock;
+
+               ret = _regulator_do_disable(rdev);
+               if (ret)
+                       dev_err(dev, "Failed to suspend regulator %d\n", ret);
        }
-out:
-       mutex_unlock(&regulator_list_mutex);
-       return ret;
+unlock:
+       mutex_unlock(&rdev->mutex);
+
+       /* Keep processing regulators in spite of any errors */
+       return 0;
 }
-EXPORT_SYMBOL_GPL(regulator_suspend_prepare);
 
 /**
  * regulator_suspend_finish - resume regulators from system wide suspend
@@ -3831,33 +4094,8 @@ EXPORT_SYMBOL_GPL(regulator_suspend_prepare);
  */
 int regulator_suspend_finish(void)
 {
-       struct regulator_dev *rdev;
-       int ret = 0, error;
-
-       mutex_lock(&regulator_list_mutex);
-       list_for_each_entry(rdev, &regulator_list, list) {
-               mutex_lock(&rdev->mutex);
-               if (rdev->use_count > 0  || rdev->constraints->always_on) {
-                       if (!_regulator_is_enabled(rdev)) {
-                               error = _regulator_do_enable(rdev);
-                               if (error)
-                                       ret = error;
-                       }
-               } else {
-                       if (!have_full_constraints())
-                               goto unlock;
-                       if (!_regulator_is_enabled(rdev))
-                               goto unlock;
-
-                       error = _regulator_do_disable(rdev);
-                       if (error)
-                               ret = error;
-               }
-unlock:
-               mutex_unlock(&rdev->mutex);
-       }
-       mutex_unlock(&regulator_list_mutex);
-       return ret;
+       return class_for_each_device(&regulator_class, NULL, NULL,
+                                    _regulator_suspend_finish);
 }
 EXPORT_SYMBOL_GPL(regulator_suspend_finish);
 
@@ -3977,14 +4215,35 @@ static const struct file_operations supply_map_fops = {
 };
 
 #ifdef CONFIG_DEBUG_FS
+struct summary_data {
+       struct seq_file *s;
+       struct regulator_dev *parent;
+       int level;
+};
+
+static void regulator_summary_show_subtree(struct seq_file *s,
+                                          struct regulator_dev *rdev,
+                                          int level);
+
+static int regulator_summary_show_children(struct device *dev, void *data)
+{
+       struct regulator_dev *rdev = dev_to_rdev(dev);
+       struct summary_data *summary_data = data;
+
+       if (rdev->supply && rdev->supply->rdev == summary_data->parent)
+               regulator_summary_show_subtree(summary_data->s, rdev,
+                                              summary_data->level + 1);
+
+       return 0;
+}
+
 static void regulator_summary_show_subtree(struct seq_file *s,
                                           struct regulator_dev *rdev,
                                           int level)
 {
-       struct list_head *list = s->private;
-       struct regulator_dev *child;
        struct regulation_constraints *c;
        struct regulator *consumer;
+       struct summary_data summary_data;
 
        if (!rdev)
                return;
@@ -4034,33 +4293,32 @@ static void regulator_summary_show_subtree(struct seq_file *s,
                seq_puts(s, "\n");
        }
 
-       list_for_each_entry(child, list, list) {
-               /* handle only non-root regulators supplied by current rdev */
-               if (!child->supply || child->supply->rdev != rdev)
-                       continue;
+       summary_data.s = s;
+       summary_data.level = level;
+       summary_data.parent = rdev;
 
-               regulator_summary_show_subtree(s, child, level + 1);
-       }
+       class_for_each_device(&regulator_class, NULL, &summary_data,
+                             regulator_summary_show_children);
 }
 
-static int regulator_summary_show(struct seq_file *s, void *data)
+static int regulator_summary_show_roots(struct device *dev, void *data)
 {
-       struct list_head *list = s->private;
-       struct regulator_dev *rdev;
+       struct regulator_dev *rdev = dev_to_rdev(dev);
+       struct seq_file *s = data;
 
-       seq_puts(s, " regulator                      use open bypass voltage current     min     max\n");
-       seq_puts(s, "-------------------------------------------------------------------------------\n");
-
-       mutex_lock(&regulator_list_mutex);
+       if (!rdev->supply)
+               regulator_summary_show_subtree(s, rdev, 0);
 
-       list_for_each_entry(rdev, list, list) {
-               if (rdev->supply)
-                       continue;
+       return 0;
+}
 
-               regulator_summary_show_subtree(s, rdev, 0);
-       }
+static int regulator_summary_show(struct seq_file *s, void *data)
+{
+       seq_puts(s, " regulator                      use open bypass voltage current     min     max\n");
+       seq_puts(s, "-------------------------------------------------------------------------------\n");
 
-       mutex_unlock(&regulator_list_mutex);
+       class_for_each_device(&regulator_class, NULL, s,
+                             regulator_summary_show_roots);
 
        return 0;
 }
@@ -4094,7 +4352,7 @@ static int __init regulator_init(void)
                            &supply_map_fops);
 
        debugfs_create_file("regulator_summary", 0444, debugfs_root,
-                           &regulator_list, &regulator_summary_fops);
+                           NULL, &regulator_summary_fops);
 
        regulator_dummy_init();
 
@@ -4104,13 +4362,57 @@ static int __init regulator_init(void)
 /* init early to allow our consumers to complete system booting */
 core_initcall(regulator_init);
 
-static int __init regulator_init_complete(void)
+static int __init regulator_late_cleanup(struct device *dev, void *data)
 {
-       struct regulator_dev *rdev;
-       const struct regulator_ops *ops;
-       struct regulation_constraints *c;
+       struct regulator_dev *rdev = dev_to_rdev(dev);
+       const struct regulator_ops *ops = rdev->desc->ops;
+       struct regulation_constraints *c = rdev->constraints;
        int enabled, ret;
 
+       if (c && c->always_on)
+               return 0;
+
+       if (c && !(c->valid_ops_mask & REGULATOR_CHANGE_STATUS))
+               return 0;
+
+       mutex_lock(&rdev->mutex);
+
+       if (rdev->use_count)
+               goto unlock;
+
+       /* If we can't read the status assume it's on. */
+       if (ops->is_enabled)
+               enabled = ops->is_enabled(rdev);
+       else
+               enabled = 1;
+
+       if (!enabled)
+               goto unlock;
+
+       if (have_full_constraints()) {
+               /* We log since this may kill the system if it goes
+                * wrong. */
+               rdev_info(rdev, "disabling\n");
+               ret = _regulator_do_disable(rdev);
+               if (ret != 0)
+                       rdev_err(rdev, "couldn't disable: %d\n", ret);
+       } else {
+               /* The intention is that in future we will
+                * assume that full constraints are provided
+                * so warn even if we aren't going to do
+                * anything here.
+                */
+               rdev_warn(rdev, "incomplete constraints, leaving on\n");
+       }
+
+unlock:
+       mutex_unlock(&rdev->mutex);
+
+       return 0;
+}
+
+static int __init regulator_init_complete(void)
+{
        /*
         * Since DT doesn't provide an idiomatic mechanism for
         * enabling full constraints and since it's much more natural
@@ -4120,58 +4422,13 @@ static int __init regulator_init_complete(void)
        if (of_have_populated_dt())
                has_full_constraints = true;
 
-       mutex_lock(&regulator_list_mutex);
-
        /* If we have a full configuration then disable any regulators
         * we have permission to change the status for and which are
         * not in use or always_on.  This is effectively the default
         * for DT and ACPI as they have full constraints.
         */
-       list_for_each_entry(rdev, &regulator_list, list) {
-               ops = rdev->desc->ops;
-               c = rdev->constraints;
-
-               if (c && c->always_on)
-                       continue;
-
-               if (c && !(c->valid_ops_mask & REGULATOR_CHANGE_STATUS))
-                       continue;
-
-               mutex_lock(&rdev->mutex);
-
-               if (rdev->use_count)
-                       goto unlock;
-
-               /* If we can't read the status assume it's on. */
-               if (ops->is_enabled)
-                       enabled = ops->is_enabled(rdev);
-               else
-                       enabled = 1;
-
-               if (!enabled)
-                       goto unlock;
-
-               if (have_full_constraints()) {
-                       /* We log since this may kill the system if it
-                        * goes wrong. */
-                       rdev_info(rdev, "disabling\n");
-                       ret = _regulator_do_disable(rdev);
-                       if (ret != 0)
-                               rdev_err(rdev, "couldn't disable: %d\n", ret);
-               } else {
-                       /* The intention is that in future we will
-                        * assume that full constraints are provided
-                        * so warn even if we aren't going to do
-                        * anything here.
-                        */
-                       rdev_warn(rdev, "incomplete constraints, leaving on\n");
-               }
-
-unlock:
-               mutex_unlock(&rdev->mutex);
-       }
-
-       mutex_unlock(&regulator_list_mutex);
+       class_for_each_device(&regulator_class, NULL, NULL,
+                             regulator_late_cleanup);
 
        return 0;
 }