regulator: Defer lookup of supply to regulator_get

Instead of resolving regulator supplies during registration move this to
the time of a consumer retrieving a handle. The benefit is that it's
possible for one driver to register regulators with internal
dependencies out of order.

Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index b899947d839d87b03608d1f9bf4b4208cf57aa01..a291a6b9cd44815daeb77f90836d524396c50a61 100644 (file)
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1316,6 +1316,54 @@ static struct regulator_dev *regulator_dev_lookup(struct device *dev,
        return NULL;
 }
 
+static int regulator_resolve_supply(struct regulator_dev *rdev)
+{
+       struct regulator_dev *r;
+       struct device *dev = rdev->dev.parent;
+       int ret;
+
+       /* No supply to resovle? */
+       if (!rdev->supply_name)
+               return 0;
+
+       /* Supply already resolved? */
+       if (rdev->supply)
+               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;
+       }
+
+       /* Recursively resolve the supply of the supply */
+       ret = regulator_resolve_supply(r);
+       if (ret < 0)
+               return ret;
+
+       ret = set_supply(rdev, r);
+       if (ret < 0)
+               return ret;
+
+       /* Cascade always-on state to supply */
+       if (_regulator_is_enabled(rdev)) {
+               ret = regulator_enable(rdev->supply);
+               if (ret < 0)
+                       return ret;
+       }
+
+       return 0;
+}
+
 /* Internal regulator request function */
 static struct regulator *_regulator_get(struct device *dev, const char *id,
                                        bool exclusive, bool allow_dummy)
@@ -1385,6 +1433,12 @@ found:
                goto out;
        }
 
+       ret = regulator_resolve_supply(rdev);
+       if (ret < 0) {
+               regulator = ERR_PTR(ret);
+               goto out;
+       }
+
        if (!try_module_get(rdev->owner))
                goto out;
 
@@ -3536,7 +3590,6 @@ regulator_register(const struct regulator_desc *regulator_desc,
        struct regulator_dev *rdev;
        struct device *dev;
        int ret, i;
-       const char *supply = NULL;
 
        if (regulator_desc == NULL || cfg == NULL)
                return ERR_PTR(-EINVAL);
@@ -3650,41 +3703,10 @@ regulator_register(const struct regulator_desc *regulator_desc,
                goto scrub;
 
        if (init_data && init_data->supply_regulator)
-               supply = init_data->supply_regulator;
+               rdev->supply_name = init_data->supply_regulator;
        else if (regulator_desc->supply_name)
-               supply = regulator_desc->supply_name;
-
-       if (supply) {
-               struct regulator_dev *r;
-
-               r = regulator_dev_lookup(dev, supply, &ret);
+               rdev->supply_name = regulator_desc->supply_name;
 
-               if (ret == -ENODEV) {
-                       /*
-                        * No supply was specified for this regulator and
-                        * there will never be one.
-                        */
-                       ret = 0;
-                       goto add_dev;
-               } else if (!r) {
-                       dev_err(dev, "Failed to find supply %s\n", supply);
-                       ret = -EPROBE_DEFER;
-                       goto scrub;
-               }
-
-               ret = set_supply(rdev, r);
-               if (ret < 0)
-                       goto scrub;
-
-               /* Enable supply if rail is enabled */
-               if (_regulator_is_enabled(rdev)) {
-                       ret = regulator_enable(rdev->supply);
-                       if (ret < 0)
-                               goto scrub;
-               }
-       }
-
-add_dev:
        /* add consumers devices */
        if (init_data) {
                for (i = 0; i < init_data->num_consumer_supplies; i++) {
@@ -3711,8 +3733,6 @@ unset_supplies:
        unset_regulator_supplies(rdev);
 
 scrub:
-       if (rdev->supply)
-               _regulator_put(rdev->supply);
        regulator_ena_gpio_free(rdev);
        kfree(rdev->constraints);
 wash:

diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h
index d4ad5b5a02bb478a422b349406efba00997bab76..6d9fcd0c33d66e07e9d494c5d7275933dcb7a1f3 100644 (file)
--- a/include/linux/regulator/driver.h
+++ b/include/linux/regulator/driver.h
@@ -367,6 +367,7 @@ struct regulator_dev {
        struct device dev;
        struct regulation_constraints *constraints;
        struct regulator *supply;       /* for tree */
+       const char *supply_name;
        struct regmap *regmap;
 
        struct delayed_work disable_work;