[patch 2.6.29-rc7 regulator-next] regulator: refcount fixes

[David Brownell]

From: David Brownell <dbrown...@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 <dbrown...@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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