v4.19.13 snapshot.
diff --git a/drivers/media/cec/cec-notifier.c b/drivers/media/cec/cec-notifier.c
new file mode 100644
index 0000000..dd2078b
--- /dev/null
+++ b/drivers/media/cec/cec-notifier.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * cec-notifier.c - notify CEC drivers of physical address changes
+ *
+ * Copyright 2016 Russell King <rmk+kernel@arm.linux.org.uk>
+ * Copyright 2016-2017 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
+ */
+
+#include <linux/export.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/kref.h>
+
+#include <media/cec.h>
+#include <media/cec-notifier.h>
+#include <drm/drm_edid.h>
+
+struct cec_notifier {
+ struct mutex lock;
+ struct list_head head;
+ struct kref kref;
+ struct device *dev;
+ const char *conn;
+ struct cec_adapter *cec_adap;
+ void (*callback)(struct cec_adapter *adap, u16 pa);
+
+ u16 phys_addr;
+};
+
+static LIST_HEAD(cec_notifiers);
+static DEFINE_MUTEX(cec_notifiers_lock);
+
+struct cec_notifier *cec_notifier_get_conn(struct device *dev, const char *conn)
+{
+ struct cec_notifier *n;
+
+ mutex_lock(&cec_notifiers_lock);
+ list_for_each_entry(n, &cec_notifiers, head) {
+ if (n->dev == dev &&
+ (!conn || !strcmp(n->conn, conn))) {
+ kref_get(&n->kref);
+ mutex_unlock(&cec_notifiers_lock);
+ return n;
+ }
+ }
+ n = kzalloc(sizeof(*n), GFP_KERNEL);
+ if (!n)
+ goto unlock;
+ n->dev = dev;
+ if (conn)
+ n->conn = kstrdup(conn, GFP_KERNEL);
+ n->phys_addr = CEC_PHYS_ADDR_INVALID;
+ mutex_init(&n->lock);
+ kref_init(&n->kref);
+ list_add_tail(&n->head, &cec_notifiers);
+unlock:
+ mutex_unlock(&cec_notifiers_lock);
+ return n;
+}
+EXPORT_SYMBOL_GPL(cec_notifier_get_conn);
+
+static void cec_notifier_release(struct kref *kref)
+{
+ struct cec_notifier *n =
+ container_of(kref, struct cec_notifier, kref);
+
+ list_del(&n->head);
+ kfree(n->conn);
+ kfree(n);
+}
+
+void cec_notifier_put(struct cec_notifier *n)
+{
+ mutex_lock(&cec_notifiers_lock);
+ kref_put(&n->kref, cec_notifier_release);
+ mutex_unlock(&cec_notifiers_lock);
+}
+EXPORT_SYMBOL_GPL(cec_notifier_put);
+
+void cec_notifier_set_phys_addr(struct cec_notifier *n, u16 pa)
+{
+ if (n == NULL)
+ return;
+
+ mutex_lock(&n->lock);
+ n->phys_addr = pa;
+ if (n->callback)
+ n->callback(n->cec_adap, n->phys_addr);
+ mutex_unlock(&n->lock);
+}
+EXPORT_SYMBOL_GPL(cec_notifier_set_phys_addr);
+
+void cec_notifier_set_phys_addr_from_edid(struct cec_notifier *n,
+ const struct edid *edid)
+{
+ u16 pa = CEC_PHYS_ADDR_INVALID;
+
+ if (n == NULL)
+ return;
+
+ if (edid && edid->extensions)
+ pa = cec_get_edid_phys_addr((const u8 *)edid,
+ EDID_LENGTH * (edid->extensions + 1), NULL);
+ cec_notifier_set_phys_addr(n, pa);
+}
+EXPORT_SYMBOL_GPL(cec_notifier_set_phys_addr_from_edid);
+
+void cec_notifier_register(struct cec_notifier *n,
+ struct cec_adapter *adap,
+ void (*callback)(struct cec_adapter *adap, u16 pa))
+{
+ kref_get(&n->kref);
+ mutex_lock(&n->lock);
+ n->cec_adap = adap;
+ n->callback = callback;
+ n->callback(adap, n->phys_addr);
+ mutex_unlock(&n->lock);
+}
+EXPORT_SYMBOL_GPL(cec_notifier_register);
+
+void cec_notifier_unregister(struct cec_notifier *n)
+{
+ mutex_lock(&n->lock);
+ n->callback = NULL;
+ mutex_unlock(&n->lock);
+ cec_notifier_put(n);
+}
+EXPORT_SYMBOL_GPL(cec_notifier_unregister);