PM / runtime: Fetch runtime PM callbacks using a macro

While fetching the proper runtime PM callback, we walk the hierarchy of
device's power domains, subsystems and drivers.

This is common for rpm_suspend(), rpm_idle() and rpm_resume(). Let's
clean up the code by using a macro that handles this.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/base/power/runtime.c

@@ -13,6 +13,42 @@
 #include <trace/events/rpm.h>
 #include "power.h"
 
+#define RPM_GET_CALLBACK(dev, cb)				\
+({								\
+	int (*__rpm_cb)(struct device *__d);			\
+								\
+	if (dev->pm_domain)					\
+		__rpm_cb = dev->pm_domain->ops.cb;		\
+	else if (dev->type && dev->type->pm)			\
+		__rpm_cb = dev->type->pm->cb;			\
+	else if (dev->class && dev->class->pm)			\
+		__rpm_cb = dev->class->pm->cb;			\
+	else if (dev->bus && dev->bus->pm)			\
+		__rpm_cb = dev->bus->pm->cb;			\
+	else							\
+		__rpm_cb = NULL;				\
+								\
+	if (!__rpm_cb && dev->driver && dev->driver->pm)	\
+		__rpm_cb = dev->driver->pm->cb;			\
+								\
+	__rpm_cb;						\
+})
+
+static int (*rpm_get_suspend_cb(struct device *dev))(struct device *)
+{
+	return RPM_GET_CALLBACK(dev, runtime_suspend);
+}
+
+static int (*rpm_get_resume_cb(struct device *dev))(struct device *)
+{
+	return RPM_GET_CALLBACK(dev, runtime_resume);
+}
+
+static int (*rpm_get_idle_cb(struct device *dev))(struct device *)
+{
+	return RPM_GET_CALLBACK(dev, runtime_idle);
+}
+
 static int rpm_resume(struct device *dev, int rpmflags);
 static int rpm_suspend(struct device *dev, int rpmflags);
 
@@ -310,19 +346,7 @@ static int rpm_idle(struct device *dev, int rpmflags)
 
 	dev->power.idle_notification = true;
 
-	if (dev->pm_domain)
-		callback = dev->pm_domain->ops.runtime_idle;
-	else if (dev->type && dev->type->pm)
-		callback = dev->type->pm->runtime_idle;
-	else if (dev->class && dev->class->pm)
-		callback = dev->class->pm->runtime_idle;
-	else if (dev->bus && dev->bus->pm)
-		callback = dev->bus->pm->runtime_idle;
-	else
-		callback = NULL;
-
-	if (!callback && dev->driver && dev->driver->pm)
-		callback = dev->driver->pm->runtime_idle;
+	callback = rpm_get_idle_cb(dev);
 
 	if (callback)
 		retval = __rpm_callback(callback, dev);
@@ -492,19 +516,7 @@ static int rpm_suspend(struct device *dev, int rpmflags)
 
 	__update_runtime_status(dev, RPM_SUSPENDING);
 
-	if (dev->pm_domain)
-		callback = dev->pm_domain->ops.runtime_suspend;
-	else if (dev->type && dev->type->pm)
-		callback = dev->type->pm->runtime_suspend;
-	else if (dev->class && dev->class->pm)
-		callback = dev->class->pm->runtime_suspend;
-	else if (dev->bus && dev->bus->pm)
-		callback = dev->bus->pm->runtime_suspend;
-	else
-		callback = NULL;
-
-	if (!callback && dev->driver && dev->driver->pm)
-		callback = dev->driver->pm->runtime_suspend;
+	callback = rpm_get_suspend_cb(dev);
 
 	retval = rpm_callback(callback, dev);
 	if (retval)
@@ -724,19 +736,7 @@ static int rpm_resume(struct device *dev, int rpmflags)
 
 	__update_runtime_status(dev, RPM_RESUMING);
 
-	if (dev->pm_domain)
-		callback = dev->pm_domain->ops.runtime_resume;
-	else if (dev->type && dev->type->pm)
-		callback = dev->type->pm->runtime_resume;
-	else if (dev->class && dev->class->pm)
-		callback = dev->class->pm->runtime_resume;
-	else if (dev->bus && dev->bus->pm)
-		callback = dev->bus->pm->runtime_resume;
-	else
-		callback = NULL;
-
-	if (!callback && dev->driver && dev->driver->pm)
-		callback = dev->driver->pm->runtime_resume;
+	callback = rpm_get_resume_cb(dev);
 
 	retval = rpm_callback(callback, dev);
 	if (retval) {