2 files changed, 30 insertions, 0 deletions

diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
index 86de6c50fc41..edf7687615e8 100644
--- a/drivers/base/power/qos.c
+++ b/drivers/base/power/qos.c
@@ -412,3 +412,28 @@ int dev_pm_qos_remove_global_notifier(struct notifier_block *notifier)
         return blocking_notifier_chain_unregister(&dev_pm_notifiers, notifier);
 }
 EXPORT_SYMBOL_GPL(dev_pm_qos_remove_global_notifier);
+
+/**
+ * dev_pm_qos_add_ancestor_request - Add PM QoS request for device's ancestor.
+ * @dev: Device whose ancestor to add the request for.
+ * @req: Pointer to the preallocated handle.
+ * @value: Constraint latency value.
+ */
+int dev_pm_qos_add_ancestor_request(struct device *dev,
+                                    struct dev_pm_qos_request *req, s32 value)
+{
+        struct device *ancestor = dev->parent;
+        int error = -ENODEV;
+
+        while (ancestor && !ancestor->power.ignore_children)
+                ancestor = ancestor->parent;
+
+        if (ancestor)
+                error = dev_pm_qos_add_request(ancestor, req, value);
+
+        if (error)
+                req->dev = NULL;
+
+        return error;
+}
+EXPORT_SYMBOL_GPL(dev_pm_qos_add_ancestor_request);
diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h
index 83b0ea302a80..fe247b33652d 100644
--- a/include/linux/pm_qos.h
+++ b/include/linux/pm_qos.h
@@ -91,6 +91,8 @@ int dev_pm_qos_add_global_notifier(struct notifier_block *notifier);
 int dev_pm_qos_remove_global_notifier(struct notifier_block *notifier);
 void dev_pm_qos_constraints_init(struct device *dev);
 void dev_pm_qos_constraints_destroy(struct device *dev);
+int dev_pm_qos_add_ancestor_request(struct device *dev,
+                                    struct dev_pm_qos_request *req, s32 value);
 #else
 static inline int pm_qos_update_target(struct pm_qos_constraints *c,
                                        struct plist_node *node,
@@ -150,6 +152,9 @@ static inline void dev_pm_qos_constraints_destroy(struct device *dev)
 {
         dev->power.power_state = PMSG_INVALID;
 }
+static inline int dev_pm_qos_add_ancestor_request(struct device *dev,
+                                    struct dev_pm_qos_request *req, s32 value)
+                        { return 0; }
 #endif
 
 #endif