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Subject[patch 2.6.29-rc7 regulator-next] regulator: refcount fixes
Date
From: David Brownell <dbrownell@users.sourceforge.net>

Fix some refcounting issues in the regulator framework, supporting
regulator_disable() for regulators that were enabled at boot time
via machine constraints:

- Update those regulators' usecounts after enabling, so they
can cleanly be disabled at that level.

- Remove the problematic per-consumer usecount, so there's
only one level of enable/disable.

Buggy consumers could notice different bug symptoms. The main
example would be refcounting bugs; also, any (out-of-tree) users
of the experimental regulator_set_optimum_mode() stuff which
don't call it when they're done using a regulator.

This is a net minor codeshrink.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
---
Against the regulator-next tree; mainline has similar issues.
drivers/regulator/core.c | 30 ++++++++----------------------
1 file changed, 8 insertions(+), 22 deletions(-)
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -52,7 +52,6 @@ struct regulator {
int uA_load;
int min_uV;
int max_uV;
- int enabled; /* count of client enables */
char *supply_name;
struct device_attribute dev_attr;
struct regulator_dev *rdev;
@@ -811,6 +810,7 @@ static int set_machine_constraints(struc
rdev->constraints = NULL;
goto out;
}
+ rdev->use_count = 1;
}

print_constraints(rdev);
@@ -1066,10 +1066,6 @@ void regulator_put(struct regulator *reg
mutex_lock(&regulator_list_mutex);
rdev = regulator->rdev;

- if (WARN(regulator->enabled, "Releasing supply %s while enabled\n",
- regulator->supply_name))
- _regulator_disable(rdev);
-
/* remove any sysfs entries */
if (regulator->dev) {
sysfs_remove_link(&rdev->dev.kobj, regulator->supply_name);
@@ -1144,12 +1140,7 @@ int regulator_enable(struct regulator *r
int ret = 0;

mutex_lock(&rdev->mutex);
- if (regulator->enabled == 0)
- ret = _regulator_enable(rdev);
- else if (regulator->enabled < 0)
- ret = -EIO;
- if (ret == 0)
- regulator->enabled++;
+ ret = _regulator_enable(rdev);
mutex_unlock(&rdev->mutex);
return ret;
}
@@ -1160,6 +1151,11 @@ static int _regulator_disable(struct reg
{
int ret = 0;

+ if (WARN(rdev->use_count <= 0,
+ "unbalanced disables for %s\n",
+ rdev->desc->name))
+ return -EIO;
+
/* are we the last user and permitted to disable ? */
if (rdev->use_count == 1 && !rdev->constraints->always_on) {

@@ -1208,16 +1204,7 @@ int regulator_disable(struct regulator *
int ret = 0;

mutex_lock(&rdev->mutex);
- if (regulator->enabled == 1) {
- ret = _regulator_disable(rdev);
- if (ret == 0)
- regulator->uA_load = 0;
- } else if (WARN(regulator->enabled <= 0,
- "unbalanced disables for supply %s\n",
- regulator->supply_name))
- ret = -EIO;
- if (ret == 0)
- regulator->enabled--;
+ ret = _regulator_disable(rdev);
mutex_unlock(&rdev->mutex);
return ret;
}
@@ -1264,7 +1251,6 @@ int regulator_force_disable(struct regul
int ret;

mutex_lock(&regulator->rdev->mutex);
- regulator->enabled = 0;
regulator->uA_load = 0;
ret = _regulator_force_disable(regulator->rdev);
mutex_unlock(&regulator->rdev->mutex);

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