[PATCH v1 3/4] Add "shutdown" to "struct class".'

Backport of commit f77af15165847406b15d8f70c382c4cb15846b2a upstream.

The TPM class has some common shutdown code that must be executed for
all drivers. This adds some needed functionality for that.
---
 drivers/base/core.c    | 6 +++++-
 include/linux/device.h | 2 ++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index f18856f5954b..afe045792796 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -2094,7 +2094,11 @@ void device_shutdown(void)
 		pm_runtime_get_noresume(dev);
 		pm_runtime_barrier(dev);
 
-		if (dev->bus && dev->bus->shutdown) {
+		if (dev->class && dev->class->shutdown) {
+			if (initcall_debug)
+				dev_info(dev, "shutdown\n");
+			dev->class->shutdown(dev);
+		} else if (dev->bus && dev->bus->shutdown) {
 			if (initcall_debug)
 				dev_info(dev, "shutdown\n");
 			dev->bus->shutdown(dev);
diff --git a/include/linux/device.h b/include/linux/device.h
index b8f411b57dcb..3656df6cf638 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -368,6 +368,7 @@ int subsys_virtual_register(struct bus_type *subsys,
  * @suspend:	Used to put the device to sleep mode, usually to a low power
  *		state.
  * @resume:	Used to bring the device from the sleep mode.
+ * @shutdown:  Called at shut-down time to quiesce the device.
  * @ns_type:	Callbacks so sysfs can detemine namespaces.
  * @namespace:	Namespace of the device belongs to this class.
  * @pm:		The default device power management operations of this class.
@@ -396,6 +397,7 @@ struct class {
 
 	int (*suspend)(struct device *dev, pm_message_t state);
 	int (*resume)(struct device *dev);
+	int (*shutdown)(struct device *dev);
 
 	const struct kobj_ns_type_operations *ns_type;
 	const void *(*namespace)(struct device *dev);
-- 
2.13.2.932.g7449e964c-goog