diff --git a/board/ryu/board.c b/board/ryu/board.c
index af660017fb..65019c4d2d 100644
--- a/board/ryu/board.c
+++ b/board/ryu/board.c
@@ -7,9 +7,11 @@
 #include "adc.h"
 #include "adc_chip.h"
 #include "battery.h"
+#include "case_closed_debug.h"
 #include "charger.h"
 #include "common.h"
 #include "console.h"
+#include "ec_version.h"
 #include "gpio.h"
 #include "hooks.h"
 #include "host_command.h"
@@ -20,9 +22,12 @@
 #include "power_button.h"
 #include "registers.h"
 #include "task.h"
+#include "usb.h"
 #include "usb_pd.h"
 #include "usb_pd_config.h"
+#include "usb-stm32f3.h"
 #include "util.h"
+#include "pi3usb9281.h"
 
 void vbus_evt(enum gpio_signal signal)
 {
@@ -37,6 +42,15 @@ void unhandled_evt(enum gpio_signal signal)
 
 #include "gpio_list.h"
 
+const void *const usb_strings[] = {
+	[USB_STR_DESC]    = usb_string_desc,
+	[USB_STR_VENDOR]  = USB_STRING_DESC("Google Inc."),
+	[USB_STR_PRODUCT] = USB_STRING_DESC("Ryu - Raiden debug"),
+	[USB_STR_VERSION] = USB_STRING_DESC(CROS_EC_VERSION32),
+};
+
+BUILD_ASSERT(ARRAY_SIZE(usb_strings) == USB_STR_COUNT);
+
 /* Initialize board. */
 static void board_init(void)
 {
@@ -151,3 +165,35 @@ int extpower_is_present(void)
 {
 	return gpio_get_level(GPIO_CHGR_ACOK);
 }
+
+/*
+ * Disconnect the USB lines from the AP, this enables manual control of the
+ * Pericom polarity switch and disconnects the USB 2.0 lines
+ */
+void ccd_board_connect(void)
+{
+	pi3usb9281_set_pins(0, 0x00);
+	pi3usb9281_set_switch_manual(0, 0);
+}
+
+/*
+ * Reconnect the USB lines to the AP re-enabling automatic switching
+ */
+void ccd_board_disconnect(void)
+{
+	pi3usb9281_set_switch_manual(0, 1);
+}
+
+void usb_board_connect(void)
+{
+	/*
+	 * TODO(robotboy): Enable DP pullup for Proto 3, Proto 2 doesn't have
+	 * the DP pullup, so case closed debug will only work on a Proto 2 if
+	 * the board is reworked, and this function is updated.
+	 */
+}
+
+void usb_board_disconnect(void)
+{
+	/* TODO(robotboy): Disable DP pullup for Proto 3 */
+}
diff --git a/board/ryu/board.h b/board/ryu/board.h
index 8e708b97c4..8c21e1b700 100644
--- a/board/ryu/board.h
+++ b/board/ryu/board.h
@@ -25,6 +25,7 @@
 #define CONFIG_USB_PD_DUAL_ROLE
 #define CONFIG_USB_PD_FLASH_ERASE_CHECK
 #define CONFIG_USB_PD_INTERNAL_COMP
+#define CONFIG_USB_SWITCH_PI3USB9281
 #define CONFIG_USBC_SS_MUX
 #define CONFIG_USBC_VCONN
 #define CONFIG_ADC
@@ -82,6 +83,23 @@
 #define CONFIG_HOSTCMD_I2C_SLAVE_ADDR 0x3c
 #endif
 
+/* USB Configuration */
+#define CONFIG_USB
+#define CONFIG_USB_PID 0x500f
+
+/* Prevent the USB driver from initializing at boot */
+#define CONFIG_USB_INHIBIT_INIT
+
+/* USB interface indexes (use define rather than enum to expand them) */
+#define USB_IFACE_COUNT 0
+
+/* USB endpoint indexes (use define rather than enum to expand them) */
+#define USB_EP_CONTROL 0
+#define USB_EP_COUNT   1
+
+/* Enable Case Closed Debugging */
+#define CONFIG_CASE_CLOSED_DEBUG
+
 #ifndef __ASSEMBLER__
 
 /* Timer selection */
@@ -109,6 +127,16 @@ enum adc_channel {
 	ADC_CH_COUNT
 };
 
+/* USB string indexes */
+enum usb_strings {
+	USB_STR_DESC = 0,
+	USB_STR_VENDOR,
+	USB_STR_PRODUCT,
+	USB_STR_VERSION,
+
+	USB_STR_COUNT
+};
+
 /* Discharge battery when on AC power for factory test. */
 int board_discharge_on_ac(int enable);
 
diff --git a/common/build.mk b/common/build.mk
index acc650522a..e304756895 100644
--- a/common/build.mk
+++ b/common/build.mk
@@ -21,6 +21,7 @@ common-$(CONFIG_BATTERY_BQ27541)+=battery.o
 common-$(CONFIG_BATTERY_SMART)+=battery.o
 common-$(CONFIG_BUTTON_COUNT)+=button.o
 common-$(CONFIG_CAPSENSE)+=capsense.o
+common-$(CONFIG_CASE_CLOSED_DEBUG)+=case_closed_debug.o
 common-$(CONFIG_CHARGE_MANAGER)+=charge_manager.o
 common-$(CONFIG_CHARGER)+=charger.o
 common-$(CONFIG_CHARGER_V1)+=charge_state_v1.o
diff --git a/common/case_closed_debug.c b/common/case_closed_debug.c
new file mode 100644
index 0000000000..08e5e8411d
--- /dev/null
+++ b/common/case_closed_debug.c
@@ -0,0 +1,39 @@
+/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Case Closed Debug common implementation
+ */
+
+#include "case_closed_debug.h"
+
+#include "common.h"
+#include "usb_api.h"
+
+#if !defined(CONFIG_USB_INHIBIT_INIT)
+#error "CONFIG_USB_INHIBIT_INIT must be defined to use Case Closed Debugging"
+#endif
+
+#if !defined(CONFIG_USB)
+#error "CONFIG_USB must be defined to use Case Closed Debugging"
+#endif
+
+static enum ccd_mode current_mode = CCD_MODE_DISABLED;
+
+void ccd_set_mode(enum ccd_mode new_mode)
+{
+	if (new_mode == current_mode)
+		return;
+
+	if (current_mode != CCD_MODE_DISABLED) {
+		usb_release();
+		ccd_board_disconnect();
+	}
+
+	current_mode = new_mode;
+
+	if (new_mode != CCD_MODE_DISABLED) {
+		ccd_board_connect();
+		usb_init();
+	}
+}
diff --git a/include/case_closed_debug.h b/include/case_closed_debug.h
new file mode 100644
index 0000000000..1884e545d9
--- /dev/null
+++ b/include/case_closed_debug.h
@@ -0,0 +1,49 @@
+/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Case Closed Debug interface
+ */
+#ifndef INCLUDE_CASE_CLOSED_DEBUG_H
+#define INCLUDE_CASE_CLOSED_DEBUG_H
+
+enum ccd_mode {
+	/*
+	 * The disabled mode tri-states the DP and DN lines.
+	 */
+	CCD_MODE_DISABLED,
+
+	/*
+	 * The partial mode allows some CCD functionality and is to be set
+	 * when the device is write protected and a CCD cable is detected.
+	 * This mode gives access to the APs console.
+	 */
+	CCD_MODE_PARTIAL,
+
+	/*
+	 * The fully enabled mode is used in factory and test lab
+	 * configurations where it is acceptable to be able to reflash the
+	 * device over CCD.
+	 */
+	CCD_MODE_ENABLED,
+};
+
+/*
+ * Set current CCD mode, this function is idempotent.
+ */
+void ccd_set_mode(enum ccd_mode new_mode);
+
+/*
+ * Board provided function that should ensure that the debug USB port is ready
+ * for use by the case closed debug code.  This could mean updating a MUX or
+ * switch to disconnect USB from the AP.
+ */
+void ccd_board_connect(void);
+
+/*
+ * Board provided function that releases the debug USB port, giving it back
+ * to the AP.
+ */
+void ccd_board_disconnect(void);
+
+#endif /* INCLUDE_CASE_CLOSED_DEBUG_H */
diff --git a/include/config.h b/include/config.h
index 324646f7e0..0cc350bd02 100644
--- a/include/config.h
+++ b/include/config.h
@@ -192,6 +192,11 @@
  */
 #undef CONFIG_BUTTON_COUNT
 
+/*
+ * Enable case close debug (CCD) mode.
+ */
+#undef CONFIG_CASE_CLOSED_DEBUG
+
 /*
  * Capsense chip has buttons, too.
  */