2 files changed, 35 insertions, 6 deletions

diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
index 3b2d5df45e7a..00e667296360 100644
--- a/drivers/power/power_supply_core.c
+++ b/drivers/power/power_supply_core.c
@@ -67,23 +67,42 @@ static int __power_supply_changed_work(struct device *dev, void *data)
 
 static void power_supply_changed_work(struct work_struct *work)
 {
+        unsigned long flags;
         struct power_supply *psy = container_of(work, struct power_supply,
                                                 changed_work);
 
         dev_dbg(psy->dev, "%s\n", __func__);
 
-        class_for_each_device(power_supply_class, NULL, psy,
-                              __power_supply_changed_work);
-
-        power_supply_update_leds(psy);
-
-        kobject_uevent(&psy->dev->kobj, KOBJ_CHANGE);
+        spin_lock_irqsave(&psy->changed_lock, flags);
+        if (psy->changed) {
+                psy->changed = false;
+                spin_unlock_irqrestore(&psy->changed_lock, flags);
+                class_for_each_device(power_supply_class, NULL, psy,
+                                      __power_supply_changed_work);
+                power_supply_update_leds(psy);
+                kobject_uevent(&psy->dev->kobj, KOBJ_CHANGE);
+                spin_lock_irqsave(&psy->changed_lock, flags);
+        }
+        /*
+         * Dependent power supplies (e.g. battery) may have changed state
+         * as a result of this event, so poll again and hold the
+         * wakeup_source until all events are processed.
+         */
+        if (!psy->changed)
+                pm_relax(psy->dev);
+        spin_unlock_irqrestore(&psy->changed_lock, flags);
 }
 
 void power_supply_changed(struct power_supply *psy)
 {
+        unsigned long flags;
+
         dev_dbg(psy->dev, "%s\n", __func__);
 
+        spin_lock_irqsave(&psy->changed_lock, flags);
+        psy->changed = true;
+        pm_stay_awake(psy->dev);
+        spin_unlock_irqrestore(&psy->changed_lock, flags);
         schedule_work(&psy->changed_work);
 }
 EXPORT_SYMBOL_GPL(power_supply_changed);
@@ -500,6 +519,11 @@ int power_supply_register(struct device *parent, struct power_supply *psy)
                 goto check_supplies_failed;
         }
 
+        spin_lock_init(&psy->changed_lock);
+        rc = device_init_wakeup(dev, true);
+        if (rc)
+                goto wakeup_init_failed;
+
         rc = kobject_set_name(&dev->kobj, "%s", psy->name);
         if (rc)
                 goto kobject_set_name_failed;
@@ -529,6 +553,7 @@ create_triggers_failed:
 register_cooler_failed:
         psy_unregister_thermal(psy);
 register_thermal_failed:
+wakeup_init_failed:
         device_del(dev);
 kobject_set_name_failed:
 device_add_failed:
@@ -546,6 +571,7 @@ void power_supply_unregister(struct power_supply *psy)
         power_supply_remove_triggers(psy);
         psy_unregister_cooler(psy);
         psy_unregister_thermal(psy);
+        device_init_wakeup(psy->dev, false);
         device_unregister(psy->dev);
 }
 EXPORT_SYMBOL_GPL(power_supply_unregister);
diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
index 804b90643a85..5c2600630dc9 100644
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -15,6 +15,7 @@
 
 #include <linux/workqueue.h>
 #include <linux/leds.h>
+#include <linux/spinlock.h>
 
 struct device;
 
@@ -194,6 +195,8 @@ struct power_supply {
         /* private */
         struct device *dev;
         struct work_struct changed_work;
+        spinlock_t changed_lock;
+        bool changed;
 #ifdef CONFIG_THERMAL
         struct thermal_zone_device *tzd;
         struct thermal_cooling_device *tcd;