USB: otg: add otg id notifier utiltiies

Add a otg_id notifier to allow multiple drivers to cooperate to
determine the type of cable connected to a USB connector without
requiring direct calls between the drivers.

Change-Id: Ic5675f1a89daf85b17336765de24e4bdb6df6348
Signed-off-by: Colin Cross <ccross@android.com>

1 files changed, 50 insertions, 0 deletions

diff --git a/include/linux/usb/otg_id.h b/include/linux/usb/otg_id.h
new file mode 100644
index 000000000000..b686ab067957
--- /dev/null
+++ b/include/linux/usb/otg_id.h
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2011 Google, Inc.
+ *
+ * Author:
+ *	Colin Cross <ccross@android.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef __LINUX_USB_OTG_ID_H
+#define __LINUX_USB_OTG_ID_H
+
+#include <linux/notifier.h>
+#include <linux/plist.h>
+
+/**
+ * otg_id_notifier_block
+ *
+ * @priority: Order the notifications will be called in.  Higher numbers
+ *    get called first.
+ * @detect: Called during otg_id_notify.  Return OTG_ID_HANDLED if the USB cable
+ *    has been identified
+ * @cancel: Called after detect has returned OTG_ID_HANDLED to ask it to
+ *    release detection resources to allow a new identification to occur.
+ */
+
+struct otg_id_notifier_block {
+	int priority;
+	int (*detect)(struct otg_id_notifier_block *otg_id_nb);
+	void (*cancel)(struct otg_id_notifier_block *otg_id_nb);
+	struct plist_node p;
+};
+
+#define OTG_ID_HANDLED 1
+#define OTG_ID_UNHANDLED 0
+
+int otg_id_register_notifier(struct otg_id_notifier_block *otg_id_nb);
+void otg_id_unregister_notifier(struct otg_id_notifier_block *otg_id_nb);
+
+void otg_id_notify(void);
+
+#endif /* __LINUX_USB_OTG_ID_H */