[PATCH v3] Add "shutdown" to "struct class".

[Josh Zimmerman <joshz@google.com>]

The TPM class has some common shutdown code that must be executed for
all drivers. This adds some needed functionality for that.

Usage example: 'tpm: Issue a TPM2_Shutdown for TPM2 devices.'
(see https://patchwork.kernel.org/patch/9724919/ for v2).

Signed-off-by: Josh Zimmerman <joshz@google.com>

-----
v2: Add Signed-off-by.
v3: Remove logically separate change.
---
 drivers/base/core.c    | 5 +++++
 include/linux/device.h | 2 ++
 2 files changed, 7 insertions(+)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index bbecaf9293be..5c1648875e94 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -2667,6 +2667,11 @@ void device_shutdown(void)
 		pm_runtime_get_noresume(dev);
 		pm_runtime_barrier(dev);
 
+		if (dev->class && dev->class->shutdown) {
+			if (initcall_debug)
+				dev_info(dev, "shutdown\n");
+			dev->class->shutdown(dev);
+		}
 		if (dev->bus && dev->bus->shutdown) {
 			if (initcall_debug)
 				dev_info(dev, "shutdown\n");
diff --git a/include/linux/device.h b/include/linux/device.h
index 9ef518af5515..f240baac2001 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -378,6 +378,7 @@ 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.
@@ -407,6 +408,7 @@ 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);
-- 
2.13.0.rc2.291.g57267f2277-goog