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>

1 files changed, 56 insertions, 36 deletions

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index b899947d839d..a291a6b9cd44 100644
--- 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: