greybus: introduce a connection abstraction

Within a UniPro network a pair of CPorts can be linked to form a
UniPro Connection.  This patch creates a new abstraction to
represent an AP CPort that is connected with a CPort used by a
function within a Greybus module.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
diff --git a/drivers/staging/greybus/connection.h b/drivers/staging/greybus/connection.h
new file mode 100644
index 0000000..79b3b07
--- /dev/null
+++ b/drivers/staging/greybus/connection.h
@@ -0,0 +1,29 @@
+/*
+ * Greybus connections
+ *
+ * Copyright 2014 Google Inc.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#ifndef __CONNECTION_H
+#define __CONNECTION_H
+
+#include <linux/list.h>
+
+#include "greybus.h"
+#include "function.h"
+
+struct gb_connection {
+	struct gb_function		*function;
+	struct greybus_host_device	*hd;
+	u16				cport_id;	/* Host side */
+
+	struct list_head		host_links;
+};
+
+bool gb_connection_setup(struct greybus_host_device *hd, u16 cport_id,
+				struct gb_function *function);
+void gb_connection_teardown(struct gb_connection *connection);
+
+#endif /* __CONNECTION_H */