power_supply: Hold a wake_lock while power supply change notifications are pending

When connecting usb or the charger the device would often go back to sleep
before the charge led and screen turned on.

Change-Id: I01def6d86ddece0d4e31d2a91d176ed0975b6b9d
Signed-off-by: Arve Hjønnevåg <arve@android.com>

2 files changed, 30 insertions, 4 deletions

diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
index 329b46b..03810ce 100644
--- a/drivers/power/power_supply_core.c
+++ b/drivers/power/power_supply_core.c
@@ -41,23 +41,40 @@ 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);
+	spin_lock_irqsave(&psy->changed_lock, flags);
+	if (psy->changed) {
+		psy->changed = false;
+		spin_unlock_irqrestore(&psy->changed_lock, flags);
 
-	power_supply_update_leds(psy);
+		class_for_each_device(power_supply_class, NULL, psy,
+				      __power_supply_changed_work);
 
-	kobject_uevent(&psy->dev->kobj, KOBJ_CHANGE);
+		power_supply_update_leds(psy);
+
+		kobject_uevent(&psy->dev->kobj, KOBJ_CHANGE);
+		spin_lock_irqsave(&psy->changed_lock, flags);
+	}
+	if (!psy->changed)
+		wake_unlock(&psy->work_wake_lock);
+	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;
+	wake_lock(&psy->work_wake_lock);
+	spin_unlock_irqrestore(&psy->changed_lock, flags);
 	schedule_work(&psy->changed_work);
 }
 EXPORT_SYMBOL_GPL(power_supply_changed);
@@ -181,6 +198,9 @@ int power_supply_register(struct device *parent, struct power_supply *psy)
 	if (rc)
 		goto device_add_failed;
 
+	spin_lock_init(&psy->changed_lock);
+	wake_lock_init(&psy->work_wake_lock, WAKE_LOCK_SUSPEND, "power-supply");
+
 	rc = power_supply_create_triggers(psy);
 	if (rc)
 		goto create_triggers_failed;
@@ -190,6 +210,7 @@ int power_supply_register(struct device *parent, struct power_supply *psy)
 	goto success;
 
 create_triggers_failed:
+	wake_lock_destroy(&psy->work_wake_lock);
 	device_del(dev);
 kobject_set_name_failed:
 device_add_failed:
@@ -203,6 +224,7 @@ void power_supply_unregister(struct power_supply *psy)
 {
 	cancel_work_sync(&psy->changed_work);
 	power_supply_remove_triggers(psy);
+	wake_lock_destroy(&psy->work_wake_lock);
 	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 204c18d..2287c321 100644
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -14,6 +14,7 @@
 #define __LINUX_POWER_SUPPLY_H__
 
 #include <linux/device.h>
+#include <linux/wakelock.h>
 #include <linux/workqueue.h>
 #include <linux/leds.h>
 
@@ -163,6 +164,9 @@ struct power_supply {
 	/* private */
 	struct device *dev;
 	struct work_struct changed_work;
+	spinlock_t changed_lock;
+	bool changed;
+	struct wake_lock work_wake_lock;
 
 #ifdef CONFIG_LEDS_TRIGGERS
 	struct led_trigger *charging_full_trig;