regulator: Defer lookup of supply to regulator_get

Commit Message

Bjorn Andersson March 25, 2015, 1:56 a.m. UTC

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 <[e-mail]>
---
 drivers/regulator/core.c         | 92 ++++++++++++++++++++++++----------------
 include/linux/regulator/driver.h |  1 +
 2 files changed, 57 insertions(+), 36 deletions(-)

Comments

Mark Brown March 25, 2015, 4:50 a.m. UTC | #1

On Tue, Mar 24, 2015 at 06:56:05PM -0700, Bjorn Andersson wrote:
> 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.

This looks basically sensible (as we discussed in person) - I'd like to
poke at this on some systems I've got back home to make sure I'm happy
with the debugging output and so on but I'm not expecting any problems.

Patch

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index f245214..52ddb73 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1325,6 +1325,54 @@  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)
@@ -1394,6 +1442,12 @@  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;
 
@@ -3545,7 +3599,6 @@  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);
@@ -3659,41 +3712,10 @@  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++) {
@@ -3720,8 +3742,6 @@  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 0f86a182..a15c59d 100644
--- a/include/linux/regulator/driver.h
+++ b/include/linux/regulator/driver.h
@@ -371,6 +371,7 @@  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;