[PATCH v3 1/3] PM: runtime: add devm_pm_runtime_enable helper

[Dmitry Baryshkov <dmitry.baryshkov@linaro.org>]

A typical code pattern for pm_runtime_enable() call is to call it in the
_probe function and to call pm_runtime_disable() both from _probe error
path and from _remove function. For some drivers the whole remove
function would consist of the call to pm_remove_disable().

Add helper function to replace this bolierplate piece of code. Calling
devm_pm_runtime_enable() removes the need for calling
pm_runtime_disable() both in the probe()'s error path and in the
remove() function.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 drivers/base/power/runtime.c | 17 +++++++++++++++++
 include/linux/pm_runtime.h   |  4 ++++
 2 files changed, 21 insertions(+)

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 8a66eaf731e4..ec94049442b9 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -1447,6 +1447,23 @@ void pm_runtime_enable(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(pm_runtime_enable);
 
+static void pm_runtime_disable_action(void *data)
+{
+	pm_runtime_disable(data);
+}
+
+/**
+ * devm_pm_runtime_enable - devres-enabled version of pm_runtime_enable.
+ * @dev: Device to handle.
+ */
+int devm_pm_runtime_enable(struct device *dev)
+{
+	pm_runtime_enable(dev);
+
+	return devm_add_action_or_reset(dev, pm_runtime_disable_action, dev);
+}
+EXPORT_SYMBOL_GPL(devm_pm_runtime_enable);
+
 /**
  * pm_runtime_forbid - Block runtime PM of a device.
  * @dev: Device to handle.
diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h
index aab8b35e9f8a..222da43b7096 100644
--- a/include/linux/pm_runtime.h
+++ b/include/linux/pm_runtime.h
@@ -59,6 +59,8 @@ extern void pm_runtime_put_suppliers(struct device *dev);
 extern void pm_runtime_new_link(struct device *dev);
 extern void pm_runtime_drop_link(struct device_link *link);
 
+extern int devm_pm_runtime_enable(struct device *dev);
+
 /**
  * pm_runtime_get_if_in_use - Conditionally bump up runtime PM usage counter.
  * @dev: Target device.
@@ -253,6 +255,8 @@ static inline void __pm_runtime_disable(struct device *dev, bool c) {}
 static inline void pm_runtime_allow(struct device *dev) {}
 static inline void pm_runtime_forbid(struct device *dev) {}
 
+static inline int devm_pm_runtime_enable(struct device *dev) { return 0; }
+
 static inline void pm_suspend_ignore_children(struct device *dev, bool enable) {}
 static inline void pm_runtime_get_noresume(struct device *dev) {}
 static inline void pm_runtime_put_noidle(struct device *dev) {}
-- 
2.30.2