Similar to the dev_set_drv_sync_state() helper, let's add another one to
allow subsystem level code to set the ->queue_sync_state() callback for a
driver that has not already set it.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 include/linux/device.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/linux/device.h b/include/linux/device.h
index 0be95294b6e6..eeb18548ea4f 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -940,6 +940,18 @@ static inline int dev_set_drv_sync_state(struct device *dev,
 	return 0;
 }
 
+static inline int dev_set_drv_queue_sync_state(struct device *dev,
+					       void (*fn)(struct device *dev))
+{
+	if (!dev || !dev->driver)
+		return 0;
+	if (dev->driver->queue_sync_state && dev->driver->queue_sync_state != fn)
+		return -EBUSY;
+	if (!dev->driver->queue_sync_state)
+		dev->driver->queue_sync_state = fn;
+	return 0;
+}
+
 static inline void dev_set_removable(struct device *dev,
 				     enum device_removable removable)
 {
-- 
2.43.0