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Subject[patch 2.6.28-rc5] regulator: enable/disable refcounting
Date
From: David Brownell <dbrownell@users.sourceforge.net>

Make the <linux/regulator.h> framework treat enable/disable call
pairs like the <linux/clk.h> and <linux/interrupt.h> frameworks do:
they're refcounted, so that different parts of a driver don't need
to put work into coordination that frameworks normally handle.
It's a minor object code shrink.

It also makes the regulator_is_disabled() kerneldoc say what it's
actually returning: return value is not a refcount, and may report
an error (e.g. I/O error from I2C).

It also fixes some minor regulator_put() goofage: removing unlocked
access to the enable state. (But still not making regulator put/get
match the refcounting pattern they invoke.)

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
---
drivers/regulator/core.c | 71 ++++++++++++++++++++++-----------------------
1 file changed, 36 insertions(+), 35 deletions(-)

--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -79,7 +79,7 @@ struct regulator {
int uA_load;
int min_uV;
int max_uV;
- int enabled; /* client has called enabled */
+ int enabled; /* count of client enables */
char *supply_name;
struct device_attribute dev_attr;
struct regulator_dev *rdev;
@@ -933,16 +933,13 @@ void regulator_put(struct regulator *reg
if (regulator == NULL || IS_ERR(regulator))
return;

- if (regulator->enabled) {
- printk(KERN_WARNING "Releasing supply %s while enabled\n",
- regulator->supply_name);
- WARN_ON(regulator->enabled);
- regulator_disable(regulator);
- }
-
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);
@@ -1012,21 +1009,17 @@ static int _regulator_enable(struct regu
*/
int regulator_enable(struct regulator *regulator)
{
- int ret;
-
- if (regulator->enabled) {
- printk(KERN_CRIT "Regulator %s already enabled\n",
- regulator->supply_name);
- WARN_ON(regulator->enabled);
- return 0;
- }
+ struct regulator_dev *rdev = regulator->rdev;
+ int ret = 0;

- mutex_lock(&regulator->rdev->mutex);
- regulator->enabled = 1;
- ret = _regulator_enable(regulator->rdev);
- if (ret != 0)
- regulator->enabled = 0;
- mutex_unlock(&regulator->rdev->mutex);
+ mutex_lock(&rdev->mutex);
+ if (regulator->enabled == 0)
+ ret = _regulator_enable(rdev);
+ else if (regulator->enabled < 0)
+ ret = -EIO;
+ if (ret == 0)
+ regulator->enabled++;
+ mutex_unlock(&rdev->mutex);
return ret;
}
EXPORT_SYMBOL_GPL(regulator_enable);
@@ -1078,19 +1071,21 @@ static int _regulator_disable(struct reg
*/
int regulator_disable(struct regulator *regulator)
{
- int ret;
-
- if (!regulator->enabled) {
- printk(KERN_ERR "%s: not in use by this consumer\n",
- __func__);
- return 0;
- }
+ struct regulator_dev *rdev = regulator->rdev;
+ int ret = 0;

- mutex_lock(&regulator->rdev->mutex);
- regulator->enabled = 0;
- regulator->uA_load = 0;
- ret = _regulator_disable(regulator->rdev);
- mutex_unlock(&regulator->rdev->mutex);
+ 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--;
+ mutex_unlock(&rdev->mutex);
return ret;
}
EXPORT_SYMBOL_GPL(regulator_disable);
@@ -1166,7 +1161,13 @@ out:
* regulator_is_enabled - is the regulator output enabled
* @regulator: regulator source
*
- * Returns zero for disabled otherwise return number of enable requests.
+ * Returns positive if the regulator driver backing the source/client
+ * has requested that the device be enabled, zero if it hasn't, else a
+ * negative errno code.
+ *
+ * Note that the device backing this regulator handle can have multiple
+ * users, so it might be enabled even if regulator_enable() was never
+ * called for this particular source.
*/
int regulator_is_enabled(struct regulator *regulator)
{

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