PM / QOS: Pass request type to dev_pm_qos_read_value()

In order to allow dev_pm_qos_read_value() to read values for different
QoS requests, pass request type as a parameter to these routines.

For now, it only supports resume-latency request type but will be
extended to frequency limit (min/max) constraints later on.

Reviewed-by: Matthias Kaehlcke <[e-mail]>
Reviewed-by: Ulf Hansson <[e-mail]>
Signed-off-by: Viresh Kumar <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

Documentation/power/pm_qos_interface.txt

···
 call the notification trees if the target was changed as a result of removing
 the request.
 
-s32 dev_pm_qos_read_value(device):
+s32 dev_pm_qos_read_value(device, type):
 Returns the aggregated value for a given device's constraints list.
 
 enum pm_qos_flags_status dev_pm_qos_flags(device, mask)

drivers/base/power/domain_governor.c

···
 		 * take its current PM QoS constraint (that's the only thing
 		 * known at this point anyway).
 		 */
-		constraint_ns = dev_pm_qos_read_value(dev);
+		constraint_ns = dev_pm_qos_read_value(dev, DEV_PM_QOS_RESUME_LATENCY);
 		constraint_ns *= NSEC_PER_USEC;
 	}
 

drivers/base/power/qos.c

···
 /**
  * dev_pm_qos_read_value - Get PM QoS constraint for a given device (locked).
  * @dev: Device to get the PM QoS constraint value for.
+ * @type: QoS request type.
  */
-s32 dev_pm_qos_read_value(struct device *dev)
+s32 dev_pm_qos_read_value(struct device *dev, enum dev_pm_qos_req_type type)
 {
+	struct dev_pm_qos *qos = dev->power.qos;
 	unsigned long flags;
 	s32 ret;
 
 	spin_lock_irqsave(&dev->power.lock, flags);
 
-	if (IS_ERR_OR_NULL(dev->power.qos))
-		ret = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT;
-	else
-		ret = pm_qos_read_value(&dev->power.qos->resume_latency);
+	switch (type) {
+	case DEV_PM_QOS_RESUME_LATENCY:
+		ret = IS_ERR_OR_NULL(qos) ? PM_QOS_RESUME_LATENCY_NO_CONSTRAINT
+			: pm_qos_read_value(&qos->resume_latency);
+		break;
+	default:
+		WARN_ON(1);
+		ret = 0;
+	}
 
 	spin_unlock_irqrestore(&dev->power.lock, flags);
 

include/linux/pm_qos.h

···
 enum pm_qos_flags_status __dev_pm_qos_flags(struct device *dev, s32 mask);
 enum pm_qos_flags_status dev_pm_qos_flags(struct device *dev, s32 mask);
 s32 __dev_pm_qos_resume_latency(struct device *dev);
-s32 dev_pm_qos_read_value(struct device *dev);
+s32 dev_pm_qos_read_value(struct device *dev, enum dev_pm_qos_req_type type);
 int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
 			   enum dev_pm_qos_req_type type, s32 value);
 int dev_pm_qos_update_request(struct dev_pm_qos_request *req, s32 new_value);
···
 			{ return PM_QOS_FLAGS_UNDEFINED; }
 static inline s32 __dev_pm_qos_resume_latency(struct device *dev)
 			{ return PM_QOS_RESUME_LATENCY_NO_CONSTRAINT; }
-static inline s32 dev_pm_qos_read_value(struct device *dev)
-			{ return PM_QOS_RESUME_LATENCY_NO_CONSTRAINT; }
+static inline s32 dev_pm_qos_read_value(struct device *dev,
+					enum dev_pm_qos_req_type type)
+{
+	switch (type) {
+	case DEV_PM_QOS_RESUME_LATENCY:
+		return PM_QOS_RESUME_LATENCY_NO_CONSTRAINT;
+	default:
+		WARN_ON(1);
+		return 0;
+	}
+}
+
 static inline int dev_pm_qos_add_request(struct device *dev,
 					 struct dev_pm_qos_request *req,
 					 enum dev_pm_qos_req_type type,