[PATCH] regulator: Defer lookup of supply to regulator_get

From: Bjorn Andersson
Date: Tue Mar 24 2015 - 21:56:17 EST


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@xxxxxxxxxxxxxx>
---
drivers/regulator/core.c | 92 ++++++++++++++++++++++++----------------
include/linux/regulator/driver.h | 1 +
2 files changed, 57 insertions(+), 36 deletions(-)

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;
--
1.8.2.2

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