PM / QoS: Add type to dev_pm_qos_add_ancestor_request() arguments

Rework dev_pm_qos_add_ancestor_request() so that device PM QoS type
is passed to it as the third argument and make it support the
DEV_PM_QOS_LATENCY_TOLERANCE device PM QoS type (in addition to
DEV_PM_QOS_RESUME_LATENCY).

That will allow the drivers of devices without latency tolerance
hardware support to use their ancestors having it as proxies for
their latency tolerance requirements.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

4 files changed, 28 insertions, 10 deletions

diff --git a/Documentation/power/pm_qos_interface.txt b/Documentation/power/pm_qos_interface.txt
index ed743bbad87c..a5da5c7e7128 100644
--- a/Documentation/power/pm_qos_interface.txt
+++ b/Documentation/power/pm_qos_interface.txt
@@ -134,9 +134,11 @@ The meaning of the return values is as follows:
         PM_QOS_FLAGS_UNDEFINED: The device's PM QoS structure has not been
                         initialized or the list of requests is empty.
 
-int dev_pm_qos_add_ancestor_request(dev, handle, value)
+int dev_pm_qos_add_ancestor_request(dev, handle, type, value)
 Add a PM QoS request for the first direct ancestor of the given device whose
-power.ignore_children flag is unset.
+power.ignore_children flag is unset (for DEV_PM_QOS_RESUME_LATENCY requests)
+or whose power.set_latency_tolerance callback pointer is not NULL (for
+DEV_PM_QOS_LATENCY_TOLERANCE requests).
 
 int dev_pm_qos_expose_latency_limit(device, value)
 Add a request to the device's PM QoS list of resume latency constraints and
diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
index 84756f7f09d9..36b9eb4862cb 100644
--- a/drivers/base/power/qos.c
+++ b/drivers/base/power/qos.c
@@ -565,20 +565,32 @@ 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.
+ * @type: Type of the request.
  * @value: Constraint latency value.
  */
 int dev_pm_qos_add_ancestor_request(struct device *dev,
-                                    struct dev_pm_qos_request *req, s32 value)
+                                    struct dev_pm_qos_request *req,
+                                    enum dev_pm_qos_req_type type, s32 value)
 {
         struct device *ancestor = dev->parent;
         int ret = -ENODEV;
 
-        while (ancestor && !ancestor->power.ignore_children)
-                ancestor = ancestor->parent;
+        switch (type) {
+        case DEV_PM_QOS_RESUME_LATENCY:
+                while (ancestor && !ancestor->power.ignore_children)
+                        ancestor = ancestor->parent;
 
+                break;
+        case DEV_PM_QOS_LATENCY_TOLERANCE:
+                while (ancestor && !ancestor->power.set_latency_tolerance)
+                        ancestor = ancestor->parent;
+
+                break;
+        default:
+                ancestor = NULL;
+        }
         if (ancestor)
-                ret = dev_pm_qos_add_request(ancestor, req,
-                                             DEV_PM_QOS_RESUME_LATENCY, value);
+                ret = dev_pm_qos_add_request(ancestor, req, type, value);
 
         if (ret < 0)
                 req->dev = NULL;
diff --git a/drivers/input/touchscreen/st1232.c b/drivers/input/touchscreen/st1232.c
index 5c342b3139e8..3c0f57efe7b1 100644
--- a/drivers/input/touchscreen/st1232.c
+++ b/drivers/input/touchscreen/st1232.c
@@ -134,7 +134,8 @@ static irqreturn_t st1232_ts_irq_handler(int irq, void *dev_id)
         } else if (!ts->low_latency_req.dev) {
                 /* First contact, request 100 us latency. */
                 dev_pm_qos_add_ancestor_request(&ts->client->dev,
-                                                &ts->low_latency_req, 100);
+                                                &ts->low_latency_req,
+                                                DEV_PM_QOS_RESUME_LATENCY, 100);
         }
 
         /* SYN_REPORT */
diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h
index 0b476019be55..9ab4bf7c4646 100644
--- a/include/linux/pm_qos.h
+++ b/include/linux/pm_qos.h
@@ -149,7 +149,8 @@ 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);
+                                    struct dev_pm_qos_request *req,
+                                    enum dev_pm_qos_req_type type, s32 value);
 #else
 static inline enum pm_qos_flags_status __dev_pm_qos_flags(struct device *dev,
                                                           s32 mask)
@@ -192,7 +193,9 @@ 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)
+                                                  struct dev_pm_qos_request *req,
+                                                  enum dev_pm_qos_req_type type,
+                                                  s32 value)
                         { return 0; }
 #endif