ACPI / PM: Make acpi_bus_type use driver struct dev_pm_ops callbacks

Modify acpi_bus_type so that it executes PM callbacks provided
by drivers through their struct dev_pm_ops objects, if present,
while still allowing the legacy ACPI PM callbacks to take precedence.
This will make it possible to convert ACPI drivers one by one to
handling PM through struct dev_pm_ops instead of the legacy way.

The code added by this change is temporary and will be removed
when all of the drivers in question have been switched over to
the PM handling based on struct dev_pm_ops.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

drivers/acpi/scan.c

@@ -290,27 +290,61 @@ static void acpi_device_release(struct device *dev)
 	kfree(acpi_dev);
 }
 
-static int acpi_device_suspend(struct device *dev)
+#define ACPI_DEV_PM_CALLBACK(dev, callback, legacy_cb)		\
+({								\
+	struct acpi_device *__acpi_dev = to_acpi_device(dev);	\
+	struct acpi_driver *__acpi_drv = __acpi_dev->driver;	\
+	struct device_driver *__drv = dev->driver;		\
+	int __ret;						\
+								\
+	if (__acpi_drv && __acpi_drv->ops.legacy_cb)		\
+		__ret = __acpi_drv->ops.legacy_cb(__acpi_dev);	\
+	else if (__drv && __drv->pm && __drv->pm->callback)	\
+		__ret = __drv->pm->callback(dev);		\
+	else							\
+		__ret = 0;					\
+								\
+	__ret;							\
+})
+
+static int acpi_pm_suspend(struct device *dev)
 {
-	struct acpi_device *acpi_dev = to_acpi_device(dev);
-	struct acpi_driver *acpi_drv = acpi_dev->driver;
+	return ACPI_DEV_PM_CALLBACK(dev, suspend, suspend);
+}
 
-	if (acpi_drv && acpi_drv->ops.suspend)
-		return acpi_drv->ops.suspend(acpi_dev);
-	return 0;
+static int acpi_pm_resume(struct device *dev)
+{
+	return ACPI_DEV_PM_CALLBACK(dev, resume, resume);
 }
 
-static int acpi_device_resume(struct device *dev)
+static int acpi_pm_freeze(struct device *dev)
 {
-	struct acpi_device *acpi_dev = to_acpi_device(dev);
-	struct acpi_driver *acpi_drv = acpi_dev->driver;
+	return ACPI_DEV_PM_CALLBACK(dev, freeze, suspend);
+}
 
-	if (acpi_drv && acpi_drv->ops.resume)
-		return acpi_drv->ops.resume(acpi_dev);
-	return 0;
+static int acpi_pm_thaw(struct device *dev)
+{
+	return ACPI_DEV_PM_CALLBACK(dev, thaw, resume);
+}
+
+static int acpi_pm_poweroff(struct device *dev)
+{
+	return ACPI_DEV_PM_CALLBACK(dev, poweroff, suspend);
 }
 
-static SIMPLE_DEV_PM_OPS(acpi_bus_pm, acpi_device_suspend, acpi_device_resume);
+static int acpi_pm_restore(struct device *dev)
+{
+	return ACPI_DEV_PM_CALLBACK(dev, restore, resume);
+}
+
+static const struct dev_pm_ops acpi_bus_pm = {
+	.suspend = acpi_pm_suspend,
+	.resume = acpi_pm_resume,
+	.freeze = acpi_pm_freeze,
+	.thaw = acpi_pm_thaw,
+	.poweroff = acpi_pm_poweroff,
+	.restore = acpi_pm_restore,
+};
 
 static int acpi_bus_match(struct device *dev, struct device_driver *drv)
 {