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authorDavid Brownell <dbrownell@users.sourceforge.net>2008-11-16 11:44:46 -0800
committerLiam Girdwood <lrg@slimlogic.co.uk>2009-01-08 20:10:29 +0000
commit412aec610559bdb602a0a21ce149ba8ffbb6f983 (patch)
treeddc1e45080b94fdd791c244ab6f9cada712a52e5
parent812460a927c1d0dc1fbdbec9aa07de1b04043d83 (diff)
regulator: enable/disable refcounting
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> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
-rw-r--r--drivers/regulator/core.c71
1 files changed, 36 insertions, 35 deletions
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 9a644d41b81..c2b7ec90103 100644
--- 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;
@@ -963,16 +963,13 @@ void regulator_put(struct regulator *regulator)
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);
@@ -1042,21 +1039,17 @@ static int _regulator_enable(struct regulator_dev *rdev)
*/
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);
@@ -1108,19 +1101,21 @@ static int _regulator_disable(struct regulator_dev *rdev)
*/
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);
@@ -1196,7 +1191,13 @@ 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)
{