bluetooth: classic: add role changed callback

add `role_changed` to `struct bt_conn_cb` to notify the HCI_Role_Change
event to application.

Signed-off-by: Mark Wang <[email protected]>

Author: MarkWangChinese

include/zephyr/bluetooth/conn.h

@@ -1975,6 +1975,17 @@ struct bt_conn_cb {
 
 #endif
 
+#if defined(CONFIG_BT_CLASSIC)
+	/** @brief The role of the connection has changed.
+	 *
+	 *  This callback notifies the application that the role switch procedure has completed.
+	 *
+	 *  @param conn Connection object.
+	 *  @param status HCI status of role change event.
+	 */
+	void (*role_changed)(struct bt_conn *conn, uint8_t status);
+#endif
+
 	/** @internal Internally used field for list handling */
 	sys_snode_t _node;
 };

subsys/bluetooth/host/classic/br.c

@@ -681,22 +681,22 @@ void bt_hci_role_change(struct net_buf *buf)
 
 	LOG_DBG("status 0x%02x role %u addr %s", evt->status, evt->role, bt_addr_str(&evt->bdaddr));
 
-	if (evt->status) {
-		return;
-	}
-
 	conn = bt_conn_lookup_addr_br(&evt->bdaddr);
 	if (!conn) {
 		LOG_ERR("Can't find conn for %s", bt_addr_str(&evt->bdaddr));
 		return;
 	}
 
-	if (evt->role) {
-		conn->role = BT_CONN_ROLE_PERIPHERAL;
-	} else {
-		conn->role = BT_CONN_ROLE_CENTRAL;
+	if (!evt->status) {
+		if (evt->role) {
+			conn->role = BT_CONN_ROLE_PERIPHERAL;
+		} else {
+			conn->role = BT_CONN_ROLE_CENTRAL;
+		}
 	}
 
+	bt_conn_role_changed(conn, evt->status);
+
 	bt_conn_unref(conn);
 }
 

subsys/bluetooth/host/conn.c

@@ -1844,6 +1844,25 @@ void bt_conn_connected(struct bt_conn *conn)
 	notify_connected(conn);
 }
 
+#if defined(CONFIG_BT_CLASSIC)
+void bt_conn_role_changed(struct bt_conn *conn, uint8_t status)
+{
+	struct bt_conn_cb *callback;
+
+	SYS_SLIST_FOR_EACH_CONTAINER(&conn_cbs, callback, _node) {
+		if (callback->role_changed) {
+			callback->role_changed(conn, status);
+		}
+	}
+
+	STRUCT_SECTION_FOREACH(bt_conn_cb, cb) {
+		if (cb->role_changed) {
+			cb->role_changed(conn, status);
+		}
+	}
+}
+#endif
+
 static int conn_disconnect(struct bt_conn *conn, uint8_t reason)
 {
 	int err;

subsys/bluetooth/host/conn_internal.h

@@ -478,6 +478,8 @@ void bt_conn_set_state(struct bt_conn *conn, bt_conn_state_t state);
 
 void bt_conn_connected(struct bt_conn *conn);
 
+void bt_conn_role_changed(struct bt_conn *conn, uint8_t status);
+
 int bt_conn_le_conn_update(struct bt_conn *conn,
 			   const struct bt_le_conn_param *param);