usb: gadget: f_tcm: convert to new function interface with backward compatibility

Converting tcm to the new function interface requires converting
USB tcm's function code and its users.

This patch converts the f_tcm.c to the new function interface.

The file can be now compiled into a separate module usb_f_tcm.ko.

The old function interface is provided by means of preprocessor conditional
directives. After all users are converted, the old interface can be
removed.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 50 insertions, 0 deletions

diff --git a/drivers/usb/gadget/function/u_tcm.h b/drivers/usb/gadget/function/u_tcm.h
new file mode 100644
index 000000000000..0bd751e0483f
--- /dev/null
+++ b/drivers/usb/gadget/function/u_tcm.h
@@ -0,0 +1,50 @@
+/*
+ * u_tcm.h
+ *
+ * Utility definitions for the tcm function
+ *
+ * Copyright (c) 2015 Samsung Electronics Co., Ltd.
+ *		http://www.samsung.com
+ *
+ * Author: Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef U_TCM_H
+#define U_TCM_H
+
+#include <linux/usb/composite.h>
+
+/**
+ * @dependent: optional dependent module. Meant for legacy gadget.
+ * If non-null its refcount will be increased when a tpg is created and
+ * decreased when tpg is dropped.
+ * @dep_lock: lock for dependent module operations.
+ * @ready: true if the dependent module information is set.
+ * @can_attach: true a function can be bound to gadget
+ * @has_dep: true if there is a dependent module
+ *
+ */
+struct f_tcm_opts {
+	struct usb_function_instance	func_inst;
+	struct module			*dependent;
+	struct mutex			dep_lock;
+	bool				ready;
+	bool				can_attach;
+	bool				has_dep;
+
+	/*
+	 * Callbacks to be removed when legacy tcm gadget disappears.
+	 *
+	 * If you use the new function registration interface
+	 * programmatically, you MUST set these callbacks to
+	 * something sensible (e.g. probe/remove the composite).
+	 */
+	int (*tcm_register_callback)(struct usb_function_instance *);
+	void (*tcm_unregister_callback)(struct usb_function_instance *);
+};
+
+#endif /* U_TCM_H */