media: cec-notifier: debounce callback setting invalid phys addr

drivers/media/cec/cec-notifier.c

@@ -11,6 +11,7 @@
 #include <linux/slab.h>
 #include <linux/list.h>
 #include <linux/kref.h>
+#include <linux/workqueue.h>
 
 #include <media/cec.h>
 #include <media/cec-notifier.h>
@@ -26,11 +27,23 @@ struct cec_notifier {
 	void (*callback)(struct cec_adapter *adap, u16 pa);
 
 	u16 phys_addr;
+	struct delayed_work work;
 };
 
 static LIST_HEAD(cec_notifiers);
 static DEFINE_MUTEX(cec_notifiers_lock);
 
+static void cec_notifier_delayed_work(struct work_struct *work)
+{
+	struct cec_notifier *n =
+		container_of(to_delayed_work(work), struct cec_notifier, work);
+
+	mutex_lock(&n->lock);
+	if (n->callback)
+		n->callback(n->cec_adap, n->phys_addr);
+	mutex_unlock(&n->lock);
+}
+
 struct cec_notifier *cec_notifier_get_conn(struct device *dev, const char *conn)
 {
 	struct cec_notifier *n;
@@ -51,6 +64,7 @@ struct cec_notifier *cec_notifier_get_conn(struct device *dev, const char *conn)
 	if (conn)
 		n->conn = kstrdup(conn, GFP_KERNEL);
 	n->phys_addr = CEC_PHYS_ADDR_INVALID;
+	INIT_DELAYED_WORK(&n->work, cec_notifier_delayed_work);
 	mutex_init(&n->lock);
 	kref_init(&n->kref);
 	list_add_tail(&n->head, &cec_notifiers);
@@ -83,9 +97,12 @@ void cec_notifier_set_phys_addr(struct cec_notifier *n, u16 pa)
 	if (n == NULL)
 		return;
 
+	cancel_delayed_work_sync(&n->work);
 	mutex_lock(&n->lock);
 	n->phys_addr = pa;
-	if (n->callback)
+	if (pa == CEC_PHYS_ADDR_INVALID)
+		schedule_delayed_work(&n->work, msecs_to_jiffies(1100));
+	else if (n->callback)
 		n->callback(n->cec_adap, n->phys_addr);
 	mutex_unlock(&n->lock);
 }