[PATCH] regulator: core: Add devres versions of regulator_enable/disable

[Chuhong Yuan]

I wrote a coccinelle script to detect possible chances
of utilizing devm_() APIs to simplify the driver.
The script found 147 drivers in total and 22 of them
have be patched.

Within the 125 left ones, at least 31 of them (24.8%)
are hindered from benefiting from devm_() APIs because
of lack of a devres version of regulator_enable().

Therefore I implemented devm_regulator_enable/disable()
to make more drivers possible to use devm_() APIs.

Signed-off-by: Chuhong Yuan <hslester96@xxxxxxxxx>
---
 drivers/regulator/devres.c | 55 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/drivers/regulator/devres.c b/drivers/regulator/devres.c
index 3ea1c170f840..507151a71fd3 100644
--- a/drivers/regulator/devres.c
+++ b/drivers/regulator/devres.c
@@ -115,6 +115,61 @@ void devm_regulator_put(struct regulator *regulator)
 }
 EXPORT_SYMBOL_GPL(devm_regulator_put);
 
+static void devm_regulator_off(struct device *dev, void *res)
+{
+	regulator_disable(*(struct regulator **)res);
+}
+
+/**
+ * devm_regulator_enable - Resource managed regulator_enable()
+ * @regulator: regulator to enable
+ *
+ * Managed regulator_enable(). Regulator enabled is automatically
+ * disabled on driver detach. See regulator_enable() for more
+ * information.
+ */
+int devm_regulator_enable(struct device *dev, struct regulator *regulator)
+{
+	struct regulator **ptr;
+	int ret;
+
+	ptr = devres_alloc(devm_regulator_off, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	ret = regulator_enable(regulator);
+	if (!ret) {
+		*ptr = regulator;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devm_regulator_enable);
+
+/**
+ * devm_regulator_disable - Resource managed regulator_disable()
+ * @regulator: regulator to disable
+ *
+ * Disable a regulator enabled by devm_regulator_enable().
+ * Normally this function will not need to be called and the
+ * resource management code will ensure that the regulator is
+ * disabled.
+ */
+void devm_regulator_disable(struct regulator *regulator)
+{
+	int rc;
+
+	rc = devres_release(regulator->dev, devm_regulator_off,
+			    devm_regulator_match, regulator);
+
+	if (rc != 0)
+		WARN_ON(rc);
+}
+EXPORT_SYMBOL_GPL(devm_regulator_disable);
+
 struct regulator_bulk_devres {
 	struct regulator_bulk_data *consumers;
 	int num_consumers;
-- 
2.20.1