diff --git a/drivers/usb/otg/Kconfig b/drivers/usb/otg/Kconfig
index aa884d072f0b..69feeec1628c 100644
--- a/drivers/usb/otg/Kconfig
+++ b/drivers/usb/otg/Kconfig
@@ -59,4 +59,18 @@ config NOP_USB_XCEIV
 	 built-in with usb ip or which are autonomous and doesn't require any
 	 phy programming such as ISP1x04 etc.
 
+config USB_LANGWELL_OTG
+	tristate "Intel Langwell USB OTG dual-role support"
+	depends on USB && MRST
+	select USB_OTG
+	select USB_OTG_UTILS
+	help
+	  Say Y here if you want to build Intel Langwell USB OTG
+	  transciever driver in kernel. This driver implements role
+	  switch between EHCI host driver and Langwell USB OTG
+	  client driver.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called langwell_otg.
+
 endif # USB || OTG
diff --git a/drivers/usb/otg/Makefile b/drivers/usb/otg/Makefile
index 208167856529..6d1abdd3c0ac 100644
--- a/drivers/usb/otg/Makefile
+++ b/drivers/usb/otg/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_USB_OTG_UTILS)	+= otg.o
 obj-$(CONFIG_USB_GPIO_VBUS)	+= gpio_vbus.o
 obj-$(CONFIG_ISP1301_OMAP)	+= isp1301_omap.o
 obj-$(CONFIG_TWL4030_USB)	+= twl4030-usb.o
+obj-$(CONFIG_USB_LANGWELL_OTG)	+= langwell_otg.o
 obj-$(CONFIG_NOP_USB_XCEIV)	+= nop-usb-xceiv.o
 
 ccflags-$(CONFIG_USB_DEBUG)	+= -DDEBUG
diff --git a/drivers/usb/otg/langwell_otg.c b/drivers/usb/otg/langwell_otg.c
new file mode 100644
index 000000000000..6f628d0e9f39
--- /dev/null
+++ b/drivers/usb/otg/langwell_otg.c
@@ -0,0 +1,1915 @@
+/*
+ * Intel Langwell USB OTG transceiver driver
+ * Copyright (C) 2008 - 2009, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+/* This driver helps to switch Langwell OTG controller function between host
+ * and peripheral. It works with EHCI driver and Langwell client controller
+ * driver together.
+ */
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/moduleparam.h>
+#include <linux/usb/ch9.h>
+#include <linux/usb/gadget.h>
+#include <linux/usb.h>
+#include <linux/usb/otg.h>
+#include <linux/notifier.h>
+#include <asm/ipc_defs.h>
+#include <linux/delay.h>
+#include "../core/hcd.h"
+
+#include <linux/usb/langwell_otg.h>
+
+#define	DRIVER_DESC		"Intel Langwell USB OTG transceiver driver"
+#define	DRIVER_VERSION		"3.0.0.32L.0002"
+
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_AUTHOR("Henry Yuan <hang.yuan@intel.com>, Hao Wu <hao.wu@intel.com>");
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_LICENSE("GPL");
+
+static const char driver_name[] = "langwell_otg";
+
+static int langwell_otg_probe(struct pci_dev *pdev,
+			const struct pci_device_id *id);
+static void langwell_otg_remove(struct pci_dev *pdev);
+static int langwell_otg_suspend(struct pci_dev *pdev, pm_message_t message);
+static int langwell_otg_resume(struct pci_dev *pdev);
+
+static int langwell_otg_set_host(struct otg_transceiver *otg,
+				struct usb_bus *host);
+static int langwell_otg_set_peripheral(struct otg_transceiver *otg,
+				struct usb_gadget *gadget);
+static int langwell_otg_start_srp(struct otg_transceiver *otg);
+
+static const struct pci_device_id pci_ids[] = {{
+	.class =        ((PCI_CLASS_SERIAL_USB << 8) | 0xfe),
+	.class_mask =   ~0,
+	.vendor =	0x8086,
+	.device =	0x0811,
+	.subvendor =	PCI_ANY_ID,
+	.subdevice =	PCI_ANY_ID,
+}, { /* end: all zeroes */ }
+};
+
+static struct pci_driver otg_pci_driver = {
+	.name =		(char *) driver_name,
+	.id_table =	pci_ids,
+
+	.probe =	langwell_otg_probe,
+	.remove =	langwell_otg_remove,
+
+	.suspend =	langwell_otg_suspend,
+	.resume =	langwell_otg_resume,
+};
+
+static const char *state_string(enum usb_otg_state state)
+{
+	switch (state) {
+	case OTG_STATE_A_IDLE:
+		return "a_idle";
+	case OTG_STATE_A_WAIT_VRISE:
+		return "a_wait_vrise";
+	case OTG_STATE_A_WAIT_BCON:
+		return "a_wait_bcon";
+	case OTG_STATE_A_HOST:
+		return "a_host";
+	case OTG_STATE_A_SUSPEND:
+		return "a_suspend";
+	case OTG_STATE_A_PERIPHERAL:
+		return "a_peripheral";
+	case OTG_STATE_A_WAIT_VFALL:
+		return "a_wait_vfall";
+	case OTG_STATE_A_VBUS_ERR:
+		return "a_vbus_err";
+	case OTG_STATE_B_IDLE:
+		return "b_idle";
+	case OTG_STATE_B_SRP_INIT:
+		return "b_srp_init";
+	case OTG_STATE_B_PERIPHERAL:
+		return "b_peripheral";
+	case OTG_STATE_B_WAIT_ACON:
+		return "b_wait_acon";
+	case OTG_STATE_B_HOST:
+		return "b_host";
+	default:
+		return "UNDEFINED";
+	}
+}
+
+/* HSM timers */
+static inline struct langwell_otg_timer *otg_timer_initializer
+(void (*function)(unsigned long), unsigned long expires, unsigned long data)
+{
+	struct langwell_otg_timer *timer;
+	timer = kmalloc(sizeof(struct langwell_otg_timer), GFP_KERNEL);
+	timer->function = function;
+	timer->expires = expires;
+	timer->data = data;
+	return timer;
+}
+
+static struct langwell_otg_timer *a_wait_vrise_tmr, *a_wait_bcon_tmr,
+	*a_aidl_bdis_tmr, *b_ase0_brst_tmr, *b_se0_srp_tmr, *b_srp_res_tmr,
+	*b_bus_suspend_tmr;
+
+static struct list_head active_timers;
+
+static struct langwell_otg *the_transceiver;
+
+/* host/client notify transceiver when event affects HNP state */
+void langwell_update_transceiver()
+{
+	otg_dbg("transceiver driver is notified\n");
+	queue_work(the_transceiver->qwork, &the_transceiver->work);
+}
+EXPORT_SYMBOL(langwell_update_transceiver);
+
+static int langwell_otg_set_host(struct otg_transceiver *otg,
+					struct usb_bus *host)
+{
+	otg->host = host;
+
+	return 0;
+}
+
+static int langwell_otg_set_peripheral(struct otg_transceiver *otg,
+					struct usb_gadget *gadget)
+{
+	otg->gadget = gadget;
+
+	return 0;
+}
+
+static int langwell_otg_set_power(struct otg_transceiver *otg,
+				unsigned mA)
+{
+	return 0;
+}
+
+/* A-device drives vbus, controlled through PMIC CHRGCNTL register*/
+static void langwell_otg_drv_vbus(int on)
+{
+	struct ipc_pmic_reg_data	pmic_data = {0};
+	struct ipc_pmic_reg_data	battery_data;
+
+	/* Check if battery is attached or not */
+	battery_data.pmic_reg_data[0].register_address = 0xd2;
+	battery_data.ioc = 0;
+	battery_data.num_entries = 1;
+	if (ipc_pmic_register_read(&battery_data)) {
+		otg_dbg("Failed to read PMIC register 0xd2.\n");
+		return;
+	}
+
+	if ((battery_data.pmic_reg_data[0].value & 0x20) == 0) {
+		otg_dbg("no battery attached\n");
+		return;
+	}
+
+	/* Workaround for battery attachment issue */
+	if (battery_data.pmic_reg_data[0].value == 0x34) {
+		otg_dbg("battery \n");
+		return;
+	}
+
+	otg_dbg("battery attached\n");
+
+	pmic_data.ioc = 0;
+	pmic_data.pmic_reg_data[0].register_address = 0xD4;
+	pmic_data.num_entries = 1;
+	if (on)
+		pmic_data.pmic_reg_data[0].value = 0x20;
+	else
+		pmic_data.pmic_reg_data[0].value = 0xc0;
+
+	if (ipc_pmic_register_write(&pmic_data, TRUE))
+		otg_dbg("Failed to write PMIC.\n");
+
+}
+
+/* charge vbus or discharge vbus through a resistor to ground */
+static void langwell_otg_chrg_vbus(int on)
+{
+
+	u32	val;
+
+	val = readl(the_transceiver->regs + CI_OTGSC);
+
+	if (on)
+		writel((val & ~OTGSC_INTSTS_MASK) | OTGSC_VC,
+				the_transceiver->regs + CI_OTGSC);
+	else
+		writel((val & ~OTGSC_INTSTS_MASK) | OTGSC_VD,
+				the_transceiver->regs + CI_OTGSC);
+
+}
+
+/* Start SRP */
+static int langwell_otg_start_srp(struct otg_transceiver *otg)
+{
+	u32	val;
+
+	otg_dbg("Start SRP ->\n");
+
+	val = readl(the_transceiver->regs + CI_OTGSC);
+
+	writel((val & ~OTGSC_INTSTS_MASK) | OTGSC_HADP,
+		the_transceiver->regs + CI_OTGSC);
+
+	/* Check if the data plus is finished or not */
+	msleep(8);
+	val = readl(the_transceiver->regs + CI_OTGSC);
+	if (val & (OTGSC_HADP | OTGSC_DP))
+		otg_dbg("DataLine SRP Error\n");
+
+	/* FIXME: VBus SRP */
+
+	return 0;
+}
+
+
+/* stop SOF via bus_suspend */
+static void langwell_otg_loc_sof(int on)
+{
+	struct usb_hcd	*hcd;
+	int		err;
+
+	otg_dbg("loc_sof -> %d\n", on);
+
+	hcd = bus_to_hcd(the_transceiver->otg.host);
+	if (on)
+		err = hcd->driver->bus_resume(hcd);
+	else
+		err = hcd->driver->bus_suspend(hcd);
+
+	if (err)
+		otg_dbg("Failed to resume/suspend bus - %d\n", err);
+}
+
+static void langwell_otg_phy_low_power(int on)
+{
+	u32	val;
+
+	otg_dbg("phy low power mode-> %d\n", on);
+
+	val = readl(the_transceiver->regs + CI_HOSTPC1);
+	if (on)
+		writel(val | HOSTPC1_PHCD, the_transceiver->regs + CI_HOSTPC1);
+	else
+		writel(val & ~HOSTPC1_PHCD, the_transceiver->regs + CI_HOSTPC1);
+}
+
+/* Enable/Disable OTG interrupt */
+static void langwell_otg_intr(int on)
+{
+	u32 val;
+
+	otg_dbg("interrupt -> %d\n", on);
+
+	val = readl(the_transceiver->regs + CI_OTGSC);
+	if (on) {
+		val = val | (OTGSC_INTEN_MASK | OTGSC_IDPU);
+		writel(val, the_transceiver->regs + CI_OTGSC);
+	} else {
+		val = val & ~(OTGSC_INTEN_MASK | OTGSC_IDPU);
+		writel(val, the_transceiver->regs + CI_OTGSC);
+	}
+}
+
+/* set HAAR: Hardware Assist Auto-Reset */
+static void langwell_otg_HAAR(int on)
+{
+	u32	val;
+
+	otg_dbg("HAAR -> %d\n", on);
+
+	val = readl(the_transceiver->regs + CI_OTGSC);
+	if (on)
+		writel((val & ~OTGSC_INTSTS_MASK) | OTGSC_HAAR,
+				the_transceiver->regs + CI_OTGSC);
+	else
+		writel((val & ~OTGSC_INTSTS_MASK) & ~OTGSC_HAAR,
+				the_transceiver->regs + CI_OTGSC);
+}
+
+/* set HABA: Hardware Assist B-Disconnect to A-Connect */
+static void langwell_otg_HABA(int on)
+{
+	u32	val;
+
+	otg_dbg("HABA -> %d\n", on);
+
+	val = readl(the_transceiver->regs + CI_OTGSC);
+	if (on)
+		writel((val & ~OTGSC_INTSTS_MASK) | OTGSC_HABA,
+				the_transceiver->regs + CI_OTGSC);
+	else
+		writel((val & ~OTGSC_INTSTS_MASK) & ~OTGSC_HABA,
+				the_transceiver->regs + CI_OTGSC);
+}
+
+static int langwell_otg_check_se0_srp(int on)
+{
+	u32 val;
+
+	int delay_time = TB_SE0_SRP * 10; /* step is 100us */
+
+	otg_dbg("check_se0_srp -> \n");
+
+	do {
+		udelay(100);
+		if (!delay_time--)
+			break;
+		val = readl(the_transceiver->regs + CI_PORTSC1);
+		val &= PORTSC_LS;
+	} while (!val);
+
+	otg_dbg("check_se0_srp <- \n");
+	return val;
+}
+
+/* The timeout callback function to set time out bit */
+static void set_tmout(unsigned long indicator)
+{
+	*(int *)indicator = 1;
+}
+
+void langwell_otg_nsf_msg(unsigned long indicator)
+{
+	switch (indicator) {
+	case 2:
+	case 4:
+	case 6:
+	case 7:
+		printk(KERN_ERR "OTG:NSF-%lu - deivce not responding\n",
+				indicator);
+		break;
+	case 3:
+		printk(KERN_ERR "OTG:NSF-%lu - deivce not supported\n",
+				indicator);
+		break;
+	default:
+		printk(KERN_ERR "Do not have this kind of NSF\n");
+		break;
+	}
+}
+
+/* Initialize timers */
+static void langwell_otg_init_timers(struct otg_hsm *hsm)
+{
+	/* HSM used timers */
+	a_wait_vrise_tmr = otg_timer_initializer(&set_tmout, TA_WAIT_VRISE,
+				(unsigned long)&hsm->a_wait_vrise_tmout);
+	a_wait_bcon_tmr = otg_timer_initializer(&set_tmout, TA_WAIT_BCON,
+				(unsigned long)&hsm->a_wait_bcon_tmout);
+	a_aidl_bdis_tmr = otg_timer_initializer(&set_tmout, TA_AIDL_BDIS,
+				(unsigned long)&hsm->a_aidl_bdis_tmout);
+	b_ase0_brst_tmr = otg_timer_initializer(&set_tmout, TB_ASE0_BRST,
+				(unsigned long)&hsm->b_ase0_brst_tmout);
+	b_se0_srp_tmr = otg_timer_initializer(&set_tmout, TB_SE0_SRP,
+				(unsigned long)&hsm->b_se0_srp);
+	b_srp_res_tmr = otg_timer_initializer(&set_tmout, TB_SRP_RES,
+				(unsigned long)&hsm->b_srp_res_tmout);
+	b_bus_suspend_tmr = otg_timer_initializer(&set_tmout, TB_BUS_SUSPEND,
+				(unsigned long)&hsm->b_bus_suspend_tmout);
+}
+
+/* Free timers */
+static void langwell_otg_free_timers(void)
+{
+	kfree(a_wait_vrise_tmr);
+	kfree(a_wait_bcon_tmr);
+	kfree(a_aidl_bdis_tmr);
+	kfree(b_ase0_brst_tmr);
+	kfree(b_se0_srp_tmr);
+	kfree(b_srp_res_tmr);
+	kfree(b_bus_suspend_tmr);
+}
+
+/* Add timer to timer list */
+static void langwell_otg_add_timer(void *gtimer)
+{
+	struct langwell_otg_timer *timer = (struct langwell_otg_timer *)gtimer;
+	struct langwell_otg_timer *tmp_timer;
+	u32	val32;
+
+	/* Check if the timer is already in the active list,
+	 * if so update timer count
+	 */
+	list_for_each_entry(tmp_timer, &active_timers, list)
+		if (tmp_timer == timer) {
+			timer->count = timer->expires;
+			return;
+		}
+	timer->count = timer->expires;
+
+	if (list_empty(&active_timers)) {
+		val32 = readl(the_transceiver->regs + CI_OTGSC);
+		writel(val32 | OTGSC_1MSE, the_transceiver->regs + CI_OTGSC);
+	}
+
+	list_add_tail(&timer->list, &active_timers);
+}
+
+/* Remove timer from the timer list; clear timeout status */
+static void langwell_otg_del_timer(void *gtimer)
+{
+	struct langwell_otg_timer *timer = (struct langwell_otg_timer *)gtimer;
+	struct langwell_otg_timer *tmp_timer, *del_tmp;
+	u32 val32;
+
+	list_for_each_entry_safe(tmp_timer, del_tmp, &active_timers, list)
+		if (tmp_timer == timer)
+			list_del(&timer->list);
+
+	if (list_empty(&active_timers)) {
+		val32 = readl(the_transceiver->regs + CI_OTGSC);
+		writel(val32 & ~OTGSC_1MSE, the_transceiver->regs + CI_OTGSC);
+	}
+}
+
+/* Reduce timer count by 1, and find timeout conditions.*/
+static int langwell_otg_tick_timer(u32 *int_sts)
+{
+	struct langwell_otg_timer *tmp_timer, *del_tmp;
+	int expired = 0;
+
+	list_for_each_entry_safe(tmp_timer, del_tmp, &active_timers, list) {
+		tmp_timer->count--;
+		/* check if timer expires */
+		if (!tmp_timer->count) {
+			list_del(&tmp_timer->list);
+			tmp_timer->function(tmp_timer->data);
+			expired = 1;
+		}
+	}
+
+	if (list_empty(&active_timers)) {
+		otg_dbg("tick timer: disable 1ms int\n");
+		*int_sts = *int_sts & ~OTGSC_1MSE;
+	}
+	return expired;
+}
+
+static void reset_otg(void)
+{
+	u32	val;
+	int	delay_time = 1000;
+
+	otg_dbg("reseting OTG controller ...\n");
+	val = readl(the_transceiver->regs + CI_USBCMD);
+	writel(val | USBCMD_RST, the_transceiver->regs + CI_USBCMD);
+	do {
+		udelay(100);
+		if (!delay_time--)
+			otg_dbg("reset timeout\n");
+		val = readl(the_transceiver->regs + CI_USBCMD);
+		val &= USBCMD_RST;
+	} while (val != 0);
+	otg_dbg("reset done.\n");
+}
+
+static void set_host_mode(void)
+{
+	u32 	val;
+
+	reset_otg();
+	val = readl(the_transceiver->regs + CI_USBMODE);
+	val = (val & (~USBMODE_CM)) | USBMODE_HOST;
+	writel(val, the_transceiver->regs + CI_USBMODE);
+}
+
+static void set_client_mode(void)
+{
+	u32 	val;
+
+	reset_otg();
+	val = readl(the_transceiver->regs + CI_USBMODE);
+	val = (val & (~USBMODE_CM)) | USBMODE_DEVICE;
+	writel(val, the_transceiver->regs + CI_USBMODE);
+}
+
+static void init_hsm(void)
+{
+	struct langwell_otg	*langwell = the_transceiver;
+	u32			val32;
+
+	/* read OTGSC after reset */
+	val32 = readl(langwell->regs + CI_OTGSC);
+	otg_dbg("%s: OTGSC init value = 0x%x\n", __func__, val32);
+
+	/* set init state */
+	if (val32 & OTGSC_ID) {
+		langwell->hsm.id = 1;
+		langwell->otg.default_a = 0;
+		set_client_mode();
+		langwell->otg.state = OTG_STATE_B_IDLE;
+		langwell_otg_drv_vbus(0);
+	} else {
+		langwell->hsm.id = 0;
+		langwell->otg.default_a = 1;
+		set_host_mode();
+		langwell->otg.state = OTG_STATE_A_IDLE;
+	}
+
+	/* set session indicator */
+	if (val32 & OTGSC_BSE)
+		langwell->hsm.b_sess_end = 1;
+	if (val32 & OTGSC_BSV)
+		langwell->hsm.b_sess_vld = 1;
+	if (val32 & OTGSC_ASV)
+		langwell->hsm.a_sess_vld = 1;
+	if (val32 & OTGSC_AVV)
+		langwell->hsm.a_vbus_vld = 1;
+
+	/* defautly power the bus */
+	langwell->hsm.a_bus_req = 1;
+	langwell->hsm.a_bus_drop = 0;
+	/* defautly don't request bus as B device */
+	langwell->hsm.b_bus_req = 0;
+	/* no system error */
+	langwell->hsm.a_clr_err = 0;
+}
+
+static irqreturn_t otg_dummy_irq(int irq, void *_dev)
+{
+	void __iomem	*reg_base = _dev;
+	u32	val;
+	u32	int_mask = 0;
+
+	val = readl(reg_base + CI_USBMODE);
+	if ((val & USBMODE_CM) != USBMODE_DEVICE)
+		return IRQ_NONE;
+
+	val = readl(reg_base + CI_USBSTS);
+	int_mask = val & INTR_DUMMY_MASK;
+
+	if (int_mask == 0)
+		return IRQ_NONE;
+
+	/* clear hsm.b_conn here since host driver can't detect it
+	*  otg_dummy_irq called means B-disconnect happened.
+	*/
+	if (the_transceiver->hsm.b_conn) {
+		the_transceiver->hsm.b_conn = 0;
+		if (spin_trylock(&the_transceiver->wq_lock)) {
+			queue_work(the_transceiver->qwork,
+				&the_transceiver->work);
+			spin_unlock(&the_transceiver->wq_lock);
+		}
+	}
+	/* Clear interrupts */
+	writel(int_mask, reg_base + CI_USBSTS);
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t otg_irq(int irq, void *_dev)
+{
+	struct	langwell_otg *langwell = _dev;
+	u32	int_sts, int_en;
+	u32	int_mask = 0;
+	int	flag = 0;
+
+	int_sts = readl(langwell->regs + CI_OTGSC);
+	int_en = (int_sts & OTGSC_INTEN_MASK) >> 8;
+	int_mask = int_sts & int_en;
+	if (int_mask == 0)
+		return IRQ_NONE;
+
+	if (int_mask & OTGSC_IDIS) {
+		otg_dbg("%s: id change int\n", __func__);
+		langwell->hsm.id = (int_sts & OTGSC_ID) ? 1 : 0;
+		flag = 1;
+	}
+	if (int_mask & OTGSC_DPIS) {
+		otg_dbg("%s: data pulse int\n", __func__);
+		langwell->hsm.a_srp_det = (int_sts & OTGSC_DPS) ? 1 : 0;
+		flag = 1;
+	}
+	if (int_mask & OTGSC_BSEIS) {
+		otg_dbg("%s: b session end int\n", __func__);
+		langwell->hsm.b_sess_end = (int_sts & OTGSC_BSE) ? 1 : 0;
+		flag = 1;
+	}
+	if (int_mask & OTGSC_BSVIS) {
+		otg_dbg("%s: b session valid int\n", __func__);
+		langwell->hsm.b_sess_vld = (int_sts & OTGSC_BSV) ? 1 : 0;
+		flag = 1;
+	}
+	if (int_mask & OTGSC_ASVIS) {
+		otg_dbg("%s: a session valid int\n", __func__);
+		langwell->hsm.a_sess_vld = (int_sts & OTGSC_ASV) ? 1 : 0;
+		flag = 1;
+	}
+	if (int_mask & OTGSC_AVVIS) {
+		otg_dbg("%s: a vbus valid int\n", __func__);
+		langwell->hsm.a_vbus_vld = (int_sts & OTGSC_AVV) ? 1 : 0;
+		flag = 1;
+	}
+
+	if (int_mask & OTGSC_1MSS) {
+		/* need to schedule otg_work if any timer is expired */
+		if (langwell_otg_tick_timer(&int_sts))
+			flag = 1;
+	}
+
+	writel((int_sts & ~OTGSC_INTSTS_MASK) | int_mask,
+			langwell->regs + CI_OTGSC);
+	if (flag)
+		queue_work(langwell->qwork, &langwell->work);
+
+	return IRQ_HANDLED;
+}
+
+static void langwell_otg_work(struct work_struct *work)
+{
+	struct langwell_otg *langwell = container_of(work,
+					struct langwell_otg, work);
+	int	retval;
+
+	otg_dbg("%s: old state = %s\n", __func__,
+			state_string(langwell->otg.state));
+
+	switch (langwell->otg.state) {
+	case OTG_STATE_UNDEFINED:
+	case OTG_STATE_B_IDLE:
+		if (!langwell->hsm.id) {
+			langwell_otg_del_timer(b_srp_res_tmr);
+			langwell->otg.default_a = 1;
+			langwell->hsm.a_srp_det = 0;
+
+			langwell_otg_chrg_vbus(0);
+			langwell_otg_drv_vbus(0);
+
+			set_host_mode();
+			langwell->otg.state = OTG_STATE_A_IDLE;
+			queue_work(langwell->qwork, &langwell->work);
+		} else if (langwell->hsm.b_srp_res_tmout) {
+			langwell->hsm.b_srp_res_tmout = 0;
+			langwell->hsm.b_bus_req = 0;
+			langwell_otg_nsf_msg(6);
+		} else if (langwell->hsm.b_sess_vld) {
+			langwell_otg_del_timer(b_srp_res_tmr);
+			langwell->hsm.b_sess_end = 0;
+			langwell->hsm.a_bus_suspend = 0;
+
+			langwell_otg_chrg_vbus(0);
+			if (langwell->client_ops) {
+				langwell->client_ops->resume(langwell->pdev);
+				langwell->otg.state = OTG_STATE_B_PERIPHERAL;
+			} else
+				otg_dbg("client driver not loaded.\n");
+
+		} else if (langwell->hsm.b_bus_req &&
+				(langwell->hsm.b_sess_end)) {
+			/* workaround for b_se0_srp detection */
+			retval = langwell_otg_check_se0_srp(0);
+			if (retval) {
+				langwell->hsm.b_bus_req = 0;
+				otg_dbg("LS is not SE0, try again later\n");
+			} else {
+				/* Start SRP */
+				langwell_otg_start_srp(&langwell->otg);
+				langwell_otg_add_timer(b_srp_res_tmr);
+			}
+		}
+		break;
+	case OTG_STATE_B_SRP_INIT:
+		if (!langwell->hsm.id) {
+			langwell->otg.default_a = 1;
+			langwell->hsm.a_srp_det = 0;
+
+			langwell_otg_drv_vbus(0);
+			langwell_otg_chrg_vbus(0);
+
+			langwell->otg.state = OTG_STATE_A_IDLE;
+			queue_work(langwell->qwork, &langwell->work);
+		} else if (langwell->hsm.b_sess_vld) {
+			langwell_otg_chrg_vbus(0);
+			if (langwell->client_ops) {
+				langwell->client_ops->resume(langwell->pdev);
+				langwell->otg.state = OTG_STATE_B_PERIPHERAL;
+			} else
+				otg_dbg("client driver not loaded.\n");
+		}
+		break;
+	case OTG_STATE_B_PERIPHERAL:
+		if (!langwell->hsm.id) {
+			langwell->otg.default_a = 1;
+			langwell->hsm.a_srp_det = 0;
+
+			langwell_otg_drv_vbus(0);
+			langwell_otg_chrg_vbus(0);
+			set_host_mode();
+
+			if (langwell->client_ops) {
+				langwell->client_ops->suspend(langwell->pdev,
+					PMSG_FREEZE);
+			} else
+				otg_dbg("client driver has been removed.\n");
+
+			langwell->otg.state = OTG_STATE_A_IDLE;
+			queue_work(langwell->qwork, &langwell->work);
+		} else if (!langwell->hsm.b_sess_vld) {
+			langwell->hsm.b_hnp_enable = 0;
+
+			if (langwell->client_ops) {
+				langwell->client_ops->suspend(langwell->pdev,
+					PMSG_FREEZE);
+			} else
+				otg_dbg("client driver has been removed.\n");
+
+			langwell->otg.state = OTG_STATE_B_IDLE;
+		} else if (langwell->hsm.b_bus_req && langwell->hsm.b_hnp_enable
+			&& langwell->hsm.a_bus_suspend) {
+
+			if (langwell->client_ops) {
+				langwell->client_ops->suspend(langwell->pdev,
+					PMSG_FREEZE);
+			} else
+				otg_dbg("client driver has been removed.\n");
+
+			langwell_otg_HAAR(1);
+			langwell->hsm.a_conn = 0;
+
+			if (langwell->host_ops) {
+				langwell->host_ops->probe(langwell->pdev,
+					langwell->host_ops->id_table);
+				langwell->otg.state = OTG_STATE_B_WAIT_ACON;
+			} else
+				otg_dbg("host driver not loaded.\n");
+
+			langwell->hsm.a_bus_resume = 0;
+			langwell->hsm.b_ase0_brst_tmout = 0;
+			langwell_otg_add_timer(b_ase0_brst_tmr);
+		}
+		break;
+
+	case OTG_STATE_B_WAIT_ACON:
+		if (!langwell->hsm.id) {
+			langwell_otg_del_timer(b_ase0_brst_tmr);
+			langwell->otg.default_a = 1;
+			langwell->hsm.a_srp_det = 0;
+
+			langwell_otg_drv_vbus(0);
+			langwell_otg_chrg_vbus(0);
+			set_host_mode();
+
+			langwell_otg_HAAR(0);
+			if (langwell->host_ops)
+				langwell->host_ops->remove(langwell->pdev);
+			else
+				otg_dbg("host driver has been removed.\n");
+			langwell->otg.state = OTG_STATE_A_IDLE;
+			queue_work(langwell->qwork, &langwell->work);
+		} else if (!langwell->hsm.b_sess_vld) {
+			langwell_otg_del_timer(b_ase0_brst_tmr);
+			langwell->hsm.b_hnp_enable = 0;
+			langwell->hsm.b_bus_req = 0;
+			langwell_otg_chrg_vbus(0);
+			langwell_otg_HAAR(0);
+
+			if (langwell->host_ops)
+				langwell->host_ops->remove(langwell->pdev);
+			else
+				otg_dbg("host driver has been removed.\n");
+			langwell->otg.state = OTG_STATE_B_IDLE;
+		} else if (langwell->hsm.a_conn) {
+			langwell_otg_del_timer(b_ase0_brst_tmr);
+			langwell_otg_HAAR(0);
+			langwell->otg.state = OTG_STATE_B_HOST;
+			queue_work(langwell->qwork, &langwell->work);
+		} else if (langwell->hsm.a_bus_resume ||
+				langwell->hsm.b_ase0_brst_tmout) {
+			langwell_otg_del_timer(b_ase0_brst_tmr);
+			langwell_otg_HAAR(0);
+			langwell_otg_nsf_msg(7);
+
+			if (langwell->host_ops)
+				langwell->host_ops->remove(langwell->pdev);
+			else
+				otg_dbg("host driver has been removed.\n");
+
+			langwell->hsm.a_bus_suspend = 0;
+			langwell->hsm.b_bus_req = 0;
+
+			if (langwell->client_ops)
+				langwell->client_ops->resume(langwell->pdev);
+			else
+				otg_dbg("client driver not loaded.\n");
+
+			langwell->otg.state = OTG_STATE_B_PERIPHERAL;
+		}
+		break;
+
+	case OTG_STATE_B_HOST:
+		if (!langwell->hsm.id) {
+			langwell->otg.default_a = 1;
+			langwell->hsm.a_srp_det = 0;
+
+			langwell_otg_drv_vbus(0);
+			langwell_otg_chrg_vbus(0);
+			set_host_mode();
+			if (langwell->host_ops)
+				langwell->host_ops->remove(langwell->pdev);
+			else
+				otg_dbg("host driver has been removed.\n");
+			langwell->otg.state = OTG_STATE_A_IDLE;
+			queue_work(langwell->qwork, &langwell->work);
+		} else if (!langwell->hsm.b_sess_vld) {
+			langwell->hsm.b_hnp_enable = 0;
+			langwell->hsm.b_bus_req = 0;
+			langwell_otg_chrg_vbus(0);
+			if (langwell->host_ops)
+				langwell->host_ops->remove(langwell->pdev);
+			else
+				otg_dbg("host driver has been removed.\n");
+			langwell->otg.state = OTG_STATE_B_IDLE;
+		} else if ((!langwell->hsm.b_bus_req) ||
+				(!langwell->hsm.a_conn)) {
+			langwell->hsm.b_bus_req = 0;
+			langwell_otg_loc_sof(0);
+			if (langwell->host_ops)
+				langwell->host_ops->remove(langwell->pdev);
+			else
+				otg_dbg("host driver has been removed.\n");
+
+			langwell->hsm.a_bus_suspend = 0;
+
+			if (langwell->client_ops)
+				langwell->client_ops->resume(langwell->pdev);
+			else
+				otg_dbg("client driver not loaded.\n");
+
+			langwell->otg.state = OTG_STATE_B_PERIPHERAL;
+		}
+		break;
+
+	case OTG_STATE_A_IDLE:
+		langwell->otg.default_a = 1;
+		if (langwell->hsm.id) {
+			langwell->otg.default_a = 0;
+			langwell->hsm.b_bus_req = 0;
+			langwell_otg_drv_vbus(0);
+			langwell_otg_chrg_vbus(0);
+
+			langwell->otg.state = OTG_STATE_B_IDLE;
+			queue_work(langwell->qwork, &langwell->work);
+		} else if (langwell->hsm.a_sess_vld) {
+			langwell_otg_drv_vbus(1);
+			langwell->hsm.a_srp_det = 1;
+			langwell->hsm.a_wait_vrise_tmout = 0;
+			langwell_otg_add_timer(a_wait_vrise_tmr);
+			langwell->otg.state = OTG_STATE_A_WAIT_VRISE;
+			queue_work(langwell->qwork, &langwell->work);
+		} else if (!langwell->hsm.a_bus_drop &&
+			(langwell->hsm.a_srp_det || langwell->hsm.a_bus_req)) {
+			langwell_otg_drv_vbus(1);
+			langwell->hsm.a_wait_vrise_tmout = 0;
+			langwell_otg_add_timer(a_wait_vrise_tmr);
+			langwell->otg.state = OTG_STATE_A_WAIT_VRISE;
+			queue_work(langwell->qwork, &langwell->work);
+		}
+		break;
+	case OTG_STATE_A_WAIT_VRISE:
+		if (langwell->hsm.id) {
+			langwell_otg_del_timer(a_wait_vrise_tmr);
+			langwell->hsm.b_bus_req = 0;
+			langwell->otg.default_a = 0;
+			langwell_otg_drv_vbus(0);
+			langwell->otg.state = OTG_STATE_B_IDLE;
+		} else if (langwell->hsm.a_vbus_vld) {
+			langwell_otg_del_timer(a_wait_vrise_tmr);
+			if (langwell->host_ops)
+				langwell->host_ops->probe(langwell->pdev,
+						langwell->host_ops->id_table);
+			else
+				otg_dbg("host driver not loaded.\n");
+			langwell->hsm.b_conn = 0;
+			langwell->hsm.a_set_b_hnp_en = 0;
+			langwell->hsm.a_wait_bcon_tmout = 0;
+			langwell_otg_add_timer(a_wait_bcon_tmr);
+			langwell->otg.state = OTG_STATE_A_WAIT_BCON;
+		} else if (langwell->hsm.a_wait_vrise_tmout) {
+			if (langwell->hsm.a_vbus_vld) {
+				if (langwell->host_ops)
+					langwell->host_ops->probe(
+						langwell->pdev,
+						langwell->host_ops->id_table);
+				else
+					otg_dbg("host driver not loaded.\n");
+				langwell->hsm.b_conn = 0;
+				langwell->hsm.a_set_b_hnp_en = 0;
+				langwell->hsm.a_wait_bcon_tmout = 0;
+				langwell_otg_add_timer(a_wait_bcon_tmr);
+				langwell->otg.state = OTG_STATE_A_WAIT_BCON;
+			} else {
+				langwell_otg_drv_vbus(0);
+				langwell->otg.state = OTG_STATE_A_VBUS_ERR;
+			}
+		}
+		break;
+	case OTG_STATE_A_WAIT_BCON:
+		if (langwell->hsm.id) {
+			langwell_otg_del_timer(a_wait_bcon_tmr);
+
+			langwell->otg.default_a = 0;
+			langwell->hsm.b_bus_req = 0;
+			if (langwell->host_ops)
+				langwell->host_ops->remove(langwell->pdev);
+			else
+				otg_dbg("host driver has been removed.\n");
+			langwell_otg_drv_vbus(0);
+			langwell->otg.state = OTG_STATE_B_IDLE;
+			queue_work(langwell->qwork, &langwell->work);
+		} else if (!langwell->hsm.a_vbus_vld) {
+			langwell_otg_del_timer(a_wait_bcon_tmr);
+
+			if (langwell->host_ops)
+				langwell->host_ops->remove(langwell->pdev);
+			else
+				otg_dbg("host driver has been removed.\n");
+			langwell_otg_drv_vbus(0);
+			langwell->otg.state = OTG_STATE_A_VBUS_ERR;
+		} else if (langwell->hsm.a_bus_drop ||
+				(langwell->hsm.a_wait_bcon_tmout &&
+				!langwell->hsm.a_bus_req)) {
+			langwell_otg_del_timer(a_wait_bcon_tmr);
+
+			if (langwell->host_ops)
+				langwell->host_ops->remove(langwell->pdev);
+			else
+				otg_dbg("host driver has been removed.\n");
+			langwell_otg_drv_vbus(0);
+			langwell->otg.state = OTG_STATE_A_WAIT_VFALL;
+		} else if (langwell->hsm.b_conn) {
+			langwell_otg_del_timer(a_wait_bcon_tmr);
+
+			langwell->hsm.a_suspend_req = 0;
+			langwell->otg.state = OTG_STATE_A_HOST;
+			if (!langwell->hsm.a_bus_req &&
+				langwell->hsm.a_set_b_hnp_en) {
+				/* It is not safe enough to do a fast
+				 * transistion from A_WAIT_BCON to
+				 * A_SUSPEND */
+				msleep(10000);
+				if (langwell->hsm.a_bus_req)
+					break;
+
+				if (request_irq(langwell->pdev->irq,
+					otg_dummy_irq, IRQF_SHARED,
+					driver_name, langwell->regs) != 0) {
+					otg_dbg("request interrupt %d fail\n",
+					langwell->pdev->irq);
+				}
+
+				langwell_otg_HABA(1);
+				langwell->hsm.b_bus_resume = 0;
+				langwell->hsm.a_aidl_bdis_tmout = 0;
+				langwell_otg_add_timer(a_aidl_bdis_tmr);
+
+				langwell_otg_loc_sof(0);
+				langwell->otg.state = OTG_STATE_A_SUSPEND;
+			} else if (!langwell->hsm.a_bus_req &&
+				!langwell->hsm.a_set_b_hnp_en) {
+				struct pci_dev *pdev = langwell->pdev;
+				if (langwell->host_ops)
+					langwell->host_ops->remove(pdev);
+				else
+					otg_dbg("host driver removed.\n");
+				langwell_otg_drv_vbus(0);
+				langwell->otg.state = OTG_STATE_A_WAIT_VFALL;
+			}
+		}
+		break;
+	case OTG_STATE_A_HOST:
+		if (langwell->hsm.id) {
+			langwell->otg.default_a = 0;
+			langwell->hsm.b_bus_req = 0;
+			if (langwell->host_ops)
+				langwell->host_ops->remove(langwell->pdev);
+			else
+				otg_dbg("host driver has been removed.\n");
+			langwell_otg_drv_vbus(0);
+			langwell->otg.state = OTG_STATE_B_IDLE;
+			queue_work(langwell->qwork, &langwell->work);
+		} else if (langwell->hsm.a_bus_drop ||
+		(!langwell->hsm.a_set_b_hnp_en && !langwell->hsm.a_bus_req)) {
+			if (langwell->host_ops)
+				langwell->host_ops->remove(langwell->pdev);
+			else
+				otg_dbg("host driver has been removed.\n");
+			langwell_otg_drv_vbus(0);
+			langwell->otg.state = OTG_STATE_A_WAIT_VFALL;
+		} else if (!langwell->hsm.a_vbus_vld) {
+			if (langwell->host_ops)
+				langwell->host_ops->remove(langwell->pdev);
+			else
+				otg_dbg("host driver has been removed.\n");
+			langwell_otg_drv_vbus(0);
+			langwell->otg.state = OTG_STATE_A_VBUS_ERR;
+		} else if (langwell->hsm.a_set_b_hnp_en
+				&& !langwell->hsm.a_bus_req) {
+			/* Set HABA to enable hardware assistance to signal
+			 *  A-connect after receiver B-disconnect. Hardware
+			 *  will then set client mode and enable URE, SLE and
+			 *  PCE after the assistance. otg_dummy_irq is used to
+			 *  clean these ints when client driver is not resumed.
+			 */
+			if (request_irq(langwell->pdev->irq,
+				otg_dummy_irq, IRQF_SHARED, driver_name,
+				langwell->regs) != 0) {
+				otg_dbg("request interrupt %d failed\n",
+						langwell->pdev->irq);
+			}
+
+			/* set HABA */
+			langwell_otg_HABA(1);
+			langwell->hsm.b_bus_resume = 0;
+			langwell->hsm.a_aidl_bdis_tmout = 0;
+			langwell_otg_add_timer(a_aidl_bdis_tmr);
+			langwell_otg_loc_sof(0);
+			langwell->otg.state = OTG_STATE_A_SUSPEND;
+		} else if (!langwell->hsm.b_conn || !langwell->hsm.a_bus_req) {
+			langwell->hsm.a_wait_bcon_tmout = 0;
+			langwell->hsm.a_set_b_hnp_en = 0;
+			langwell_otg_add_timer(a_wait_bcon_tmr);
+			langwell->otg.state = OTG_STATE_A_WAIT_BCON;
+		}
+		break;
+	case OTG_STATE_A_SUSPEND:
+		if (langwell->hsm.id) {
+			langwell_otg_del_timer(a_aidl_bdis_tmr);
+			langwell_otg_HABA(0);
+			free_irq(langwell->pdev->irq, langwell->regs);
+			langwell->otg.default_a = 0;
+			langwell->hsm.b_bus_req = 0;
+			if (langwell->host_ops)
+				langwell->host_ops->remove(langwell->pdev);
+			else
+				otg_dbg("host driver has been removed.\n");
+			langwell_otg_drv_vbus(0);
+			langwell->otg.state = OTG_STATE_B_IDLE;
+			queue_work(langwell->qwork, &langwell->work);
+		} else if (langwell->hsm.a_bus_req ||
+				langwell->hsm.b_bus_resume) {
+			langwell_otg_del_timer(a_aidl_bdis_tmr);
+			langwell_otg_HABA(0);
+			free_irq(langwell->pdev->irq, langwell->regs);
+			langwell->hsm.a_suspend_req = 0;
+			langwell_otg_loc_sof(1);
+			langwell->otg.state = OTG_STATE_A_HOST;
+		} else if (langwell->hsm.a_aidl_bdis_tmout ||
+				langwell->hsm.a_bus_drop) {
+			langwell_otg_del_timer(a_aidl_bdis_tmr);
+			langwell_otg_HABA(0);
+			free_irq(langwell->pdev->irq, langwell->regs);
+			if (langwell->host_ops)
+				langwell->host_ops->remove(langwell->pdev);
+			else
+				otg_dbg("host driver has been removed.\n");
+			langwell_otg_drv_vbus(0);
+			langwell->otg.state = OTG_STATE_A_WAIT_VFALL;
+		} else if (!langwell->hsm.b_conn &&
+				langwell->hsm.a_set_b_hnp_en) {
+			langwell_otg_del_timer(a_aidl_bdis_tmr);
+			langwell_otg_HABA(0);
+			free_irq(langwell->pdev->irq, langwell->regs);
+
+			if (langwell->host_ops)
+				langwell->host_ops->remove(langwell->pdev);
+			else
+				otg_dbg("host driver has been removed.\n");
+
+			langwell->hsm.b_bus_suspend = 0;
+			langwell->hsm.b_bus_suspend_vld = 0;
+			langwell->hsm.b_bus_suspend_tmout = 0;
+
+			/* msleep(200); */
+			if (langwell->client_ops)
+				langwell->client_ops->resume(langwell->pdev);
+			else
+				otg_dbg("client driver not loaded.\n");
+
+			langwell_otg_add_timer(b_bus_suspend_tmr);
+			langwell->otg.state = OTG_STATE_A_PERIPHERAL;
+			break;
+		} else if (!langwell->hsm.a_vbus_vld) {
+			langwell_otg_del_timer(a_aidl_bdis_tmr);
+			langwell_otg_HABA(0);
+			free_irq(langwell->pdev->irq, langwell->regs);
+			if (langwell->host_ops)
+				langwell->host_ops->remove(langwell->pdev);
+			else
+				otg_dbg("host driver has been removed.\n");
+			langwell_otg_drv_vbus(0);
+			langwell->otg.state = OTG_STATE_A_VBUS_ERR;
+		}
+		break;
+	case OTG_STATE_A_PERIPHERAL:
+		if (langwell->hsm.id) {
+			langwell_otg_del_timer(b_bus_suspend_tmr);
+			langwell->otg.default_a = 0;
+			langwell->hsm.b_bus_req = 0;
+			if (langwell->client_ops)
+				langwell->client_ops->suspend(langwell->pdev,
+					PMSG_FREEZE);
+			else
+				otg_dbg("client driver has been removed.\n");
+			langwell_otg_drv_vbus(0);
+			langwell->otg.state = OTG_STATE_B_IDLE;
+			queue_work(langwell->qwork, &langwell->work);
+		} else if (!langwell->hsm.a_vbus_vld) {
+			langwell_otg_del_timer(b_bus_suspend_tmr);
+			if (langwell->client_ops)
+				langwell->client_ops->suspend(langwell->pdev,
+					PMSG_FREEZE);
+			else
+				otg_dbg("client driver has been removed.\n");
+			langwell_otg_drv_vbus(0);
+			langwell->otg.state = OTG_STATE_A_VBUS_ERR;
+		} else if (langwell->hsm.a_bus_drop) {
+			langwell_otg_del_timer(b_bus_suspend_tmr);
+			if (langwell->client_ops)
+				langwell->client_ops->suspend(langwell->pdev,
+					PMSG_FREEZE);
+			else
+				otg_dbg("client driver has been removed.\n");
+			langwell_otg_drv_vbus(0);
+			langwell->otg.state = OTG_STATE_A_WAIT_VFALL;
+		} else if (langwell->hsm.b_bus_suspend) {
+			langwell_otg_del_timer(b_bus_suspend_tmr);
+			if (langwell->client_ops)
+				langwell->client_ops->suspend(langwell->pdev,
+					PMSG_FREEZE);
+			else
+				otg_dbg("client driver has been removed.\n");
+
+			if (langwell->host_ops)
+				langwell->host_ops->probe(langwell->pdev,
+						langwell->host_ops->id_table);
+			else
+				otg_dbg("host driver not loaded.\n");
+			langwell->hsm.a_set_b_hnp_en = 0;
+			langwell->hsm.a_wait_bcon_tmout = 0;
+			langwell_otg_add_timer(a_wait_bcon_tmr);
+			langwell->otg.state = OTG_STATE_A_WAIT_BCON;
+		} else if (langwell->hsm.b_bus_suspend_tmout) {
+			u32	val;
+			val = readl(langwell->regs + CI_PORTSC1);
+			if (!(val & PORTSC_SUSP))
+				break;
+			if (langwell->client_ops)
+				langwell->client_ops->suspend(langwell->pdev,
+						PMSG_FREEZE);
+			else
+				otg_dbg("client driver has been removed.\n");
+			if (langwell->host_ops)
+				langwell->host_ops->probe(langwell->pdev,
+						langwell->host_ops->id_table);
+			else
+				otg_dbg("host driver not loaded.\n");
+			langwell->hsm.a_set_b_hnp_en = 0;
+			langwell->hsm.a_wait_bcon_tmout = 0;
+			langwell_otg_add_timer(a_wait_bcon_tmr);
+			langwell->otg.state = OTG_STATE_A_WAIT_BCON;
+		}
+		break;
+	case OTG_STATE_A_VBUS_ERR:
+		if (langwell->hsm.id) {
+			langwell->otg.default_a = 0;
+			langwell->hsm.a_clr_err = 0;
+			langwell->hsm.a_srp_det = 0;
+			langwell->otg.state = OTG_STATE_B_IDLE;
+			queue_work(langwell->qwork, &langwell->work);
+		} else if (langwell->hsm.a_clr_err) {
+			langwell->hsm.a_clr_err = 0;
+			langwell->hsm.a_srp_det = 0;
+			reset_otg();
+			init_hsm();
+			if (langwell->otg.state == OTG_STATE_A_IDLE)
+				queue_work(langwell->qwork, &langwell->work);
+		}
+		break;
+	case OTG_STATE_A_WAIT_VFALL:
+		if (langwell->hsm.id) {
+			langwell->otg.default_a = 0;
+			langwell->otg.state = OTG_STATE_B_IDLE;
+			queue_work(langwell->qwork, &langwell->work);
+		} else if (langwell->hsm.a_bus_req) {
+			langwell_otg_drv_vbus(1);
+			langwell->hsm.a_wait_vrise_tmout = 0;
+			langwell_otg_add_timer(a_wait_vrise_tmr);
+			langwell->otg.state = OTG_STATE_A_WAIT_VRISE;
+		} else if (!langwell->hsm.a_sess_vld) {
+			langwell->hsm.a_srp_det = 0;
+			langwell_otg_drv_vbus(0);
+			set_host_mode();
+			langwell->otg.state = OTG_STATE_A_IDLE;
+		}
+		break;
+	default:
+		;
+	}
+
+	otg_dbg("%s: new state = %s\n", __func__,
+			state_string(langwell->otg.state));
+}
+
+	static ssize_t
+show_registers(struct device *_dev, struct device_attribute *attr, char *buf)
+{
+	struct langwell_otg *langwell;
+	char *next;
+	unsigned size;
+	unsigned t;
+
+	langwell = the_transceiver;
+	next = buf;
+	size = PAGE_SIZE;
+
+	t = scnprintf(next, size,
+		"\n"
+		"USBCMD = 0x%08x \n"
+		"USBSTS = 0x%08x \n"
+		"USBINTR = 0x%08x \n"
+		"ASYNCLISTADDR = 0x%08x \n"
+		"PORTSC1 = 0x%08x \n"
+		"HOSTPC1 = 0x%08x \n"
+		"OTGSC = 0x%08x \n"
+		"USBMODE = 0x%08x \n",
+		readl(langwell->regs + 0x30),
+		readl(langwell->regs + 0x34),
+		readl(langwell->regs + 0x38),
+		readl(langwell->regs + 0x48),
+		readl(langwell->regs + 0x74),
+		readl(langwell->regs + 0xb4),
+		readl(langwell->regs + 0xf4),
+		readl(langwell->regs + 0xf8)
+		);
+	size -= t;
+	next += t;
+
+	return PAGE_SIZE - size;
+}
+static DEVICE_ATTR(registers, S_IRUGO, show_registers, NULL);
+
+static ssize_t
+show_hsm(struct device *_dev, struct device_attribute *attr, char *buf)
+{
+	struct langwell_otg *langwell;
+	char *next;
+	unsigned size;
+	unsigned t;
+
+	langwell = the_transceiver;
+	next = buf;
+	size = PAGE_SIZE;
+
+	t = scnprintf(next, size,
+		"\n"
+		"current state = %s\n"
+		"a_bus_resume = \t%d\n"
+		"a_bus_suspend = \t%d\n"
+		"a_conn = \t%d\n"
+		"a_sess_vld = \t%d\n"
+		"a_srp_det = \t%d\n"
+		"a_vbus_vld = \t%d\n"
+		"b_bus_resume = \t%d\n"
+		"b_bus_suspend = \t%d\n"
+		"b_conn = \t%d\n"
+		"b_se0_srp = \t%d\n"
+		"b_sess_end = \t%d\n"
+		"b_sess_vld = \t%d\n"
+		"id = \t%d\n"
+		"a_set_b_hnp_en = \t%d\n"
+		"b_srp_done = \t%d\n"
+		"b_hnp_enable = \t%d\n"
+		"a_wait_vrise_tmout = \t%d\n"
+		"a_wait_bcon_tmout = \t%d\n"
+		"a_aidl_bdis_tmout = \t%d\n"
+		"b_ase0_brst_tmout = \t%d\n"
+		"a_bus_drop = \t%d\n"
+		"a_bus_req = \t%d\n"
+		"a_clr_err = \t%d\n"
+		"a_suspend_req = \t%d\n"
+		"b_bus_req = \t%d\n"
+		"b_bus_suspend_tmout = \t%d\n"
+		"b_bus_suspend_vld = \t%d\n",
+		state_string(langwell->otg.state),
+		langwell->hsm.a_bus_resume,
+		langwell->hsm.a_bus_suspend,
+		langwell->hsm.a_conn,
+		langwell->hsm.a_sess_vld,
+		langwell->hsm.a_srp_det,
+		langwell->hsm.a_vbus_vld,
+		langwell->hsm.b_bus_resume,
+		langwell->hsm.b_bus_suspend,
+		langwell->hsm.b_conn,
+		langwell->hsm.b_se0_srp,
+		langwell->hsm.b_sess_end,
+		langwell->hsm.b_sess_vld,
+		langwell->hsm.id,
+		langwell->hsm.a_set_b_hnp_en,
+		langwell->hsm.b_srp_done,
+		langwell->hsm.b_hnp_enable,
+		langwell->hsm.a_wait_vrise_tmout,
+		langwell->hsm.a_wait_bcon_tmout,
+		langwell->hsm.a_aidl_bdis_tmout,
+		langwell->hsm.b_ase0_brst_tmout,
+		langwell->hsm.a_bus_drop,
+		langwell->hsm.a_bus_req,
+		langwell->hsm.a_clr_err,
+		langwell->hsm.a_suspend_req,
+		langwell->hsm.b_bus_req,
+		langwell->hsm.b_bus_suspend_tmout,
+		langwell->hsm.b_bus_suspend_vld
+		);
+	size -= t;
+	next += t;
+
+	return PAGE_SIZE - size;
+}
+static DEVICE_ATTR(hsm, S_IRUGO, show_hsm, NULL);
+
+static ssize_t
+get_a_bus_req(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct langwell_otg *langwell;
+	char *next;
+	unsigned size;
+	unsigned t;
+
+	langwell =  the_transceiver;
+	next = buf;
+	size = PAGE_SIZE;
+
+	t = scnprintf(next, size, "%d", langwell->hsm.a_bus_req);
+	size -= t;
+	next += t;
+
+	return PAGE_SIZE - size;
+}
+
+static ssize_t
+set_a_bus_req(struct device *dev, struct device_attribute *attr,
+		const char *buf, size_t count)
+{
+	struct langwell_otg *langwell;
+	langwell = the_transceiver;
+	if (!langwell->otg.default_a)
+		return -1;
+	if (count > 2)
+		return -1;
+
+	if (buf[0] == '0') {
+		langwell->hsm.a_bus_req = 0;
+		otg_dbg("a_bus_req = 0\n");
+	} else if (buf[0] == '1') {
+		/* If a_bus_drop is TRUE, a_bus_req can't be set */
+		if (langwell->hsm.a_bus_drop)
+			return -1;
+		langwell->hsm.a_bus_req = 1;
+		otg_dbg("a_bus_req = 1\n");
+	}
+	if (spin_trylock(&langwell->wq_lock)) {
+		queue_work(langwell->qwork, &langwell->work);
+		spin_unlock(&langwell->wq_lock);
+	}
+	return count;
+}
+static DEVICE_ATTR(a_bus_req, S_IRUGO | S_IWUGO, get_a_bus_req, set_a_bus_req);
+
+static ssize_t
+get_a_bus_drop(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct langwell_otg *langwell;
+	char *next;
+	unsigned size;
+	unsigned t;
+
+	langwell =  the_transceiver;
+	next = buf;
+	size = PAGE_SIZE;
+
+	t = scnprintf(next, size, "%d", langwell->hsm.a_bus_drop);
+	size -= t;
+	next += t;
+
+	return PAGE_SIZE - size;
+}
+
+static ssize_t
+set_a_bus_drop(struct device *dev, struct device_attribute *attr,
+		const char *buf, size_t count)
+{
+	struct langwell_otg *langwell;
+	langwell = the_transceiver;
+	if (!langwell->otg.default_a)
+		return -1;
+	if (count > 2)
+		return -1;
+
+	if (buf[0] == '0') {
+		langwell->hsm.a_bus_drop = 0;
+		otg_dbg("a_bus_drop = 0\n");
+	} else if (buf[0] == '1') {
+		langwell->hsm.a_bus_drop = 1;
+		langwell->hsm.a_bus_req = 0;
+		otg_dbg("a_bus_drop = 1, then a_bus_req = 0\n");
+	}
+	if (spin_trylock(&langwell->wq_lock)) {
+		queue_work(langwell->qwork, &langwell->work);
+		spin_unlock(&langwell->wq_lock);
+	}
+	return count;
+}
+static DEVICE_ATTR(a_bus_drop, S_IRUGO | S_IWUGO,
+	get_a_bus_drop, set_a_bus_drop);
+
+static ssize_t
+get_b_bus_req(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct langwell_otg *langwell;
+	char *next;
+	unsigned size;
+	unsigned t;
+
+	langwell =  the_transceiver;
+	next = buf;
+	size = PAGE_SIZE;
+
+	t = scnprintf(next, size, "%d", langwell->hsm.b_bus_req);
+	size -= t;
+	next += t;
+
+	return PAGE_SIZE - size;
+}
+
+static ssize_t
+set_b_bus_req(struct device *dev, struct device_attribute *attr,
+		const char *buf, size_t count)
+{
+	struct langwell_otg *langwell;
+	langwell = the_transceiver;
+
+	if (langwell->otg.default_a)
+		return -1;
+
+	if (count > 2)
+		return -1;
+
+	if (buf[0] == '0') {
+		langwell->hsm.b_bus_req = 0;
+		otg_dbg("b_bus_req = 0\n");
+	} else if (buf[0] == '1') {
+		langwell->hsm.b_bus_req = 1;
+		otg_dbg("b_bus_req = 1\n");
+	}
+	if (spin_trylock(&langwell->wq_lock)) {
+		queue_work(langwell->qwork, &langwell->work);
+		spin_unlock(&langwell->wq_lock);
+	}
+	return count;
+}
+static DEVICE_ATTR(b_bus_req, S_IRUGO | S_IWUGO, get_b_bus_req, set_b_bus_req);
+
+static ssize_t
+set_a_clr_err(struct device *dev, struct device_attribute *attr,
+		const char *buf, size_t count)
+{
+	struct langwell_otg *langwell;
+	langwell = the_transceiver;
+
+	if (!langwell->otg.default_a)
+		return -1;
+	if (count > 2)
+		return -1;
+
+	if (buf[0] == '1') {
+		langwell->hsm.a_clr_err = 1;
+		otg_dbg("a_clr_err = 1\n");
+	}
+	if (spin_trylock(&langwell->wq_lock)) {
+		queue_work(langwell->qwork, &langwell->work);
+		spin_unlock(&langwell->wq_lock);
+	}
+	return count;
+}
+static DEVICE_ATTR(a_clr_err, S_IWUGO, NULL, set_a_clr_err);
+
+static struct attribute *inputs_attrs[] = {
+	&dev_attr_a_bus_req.attr,
+	&dev_attr_a_bus_drop.attr,
+	&dev_attr_b_bus_req.attr,
+	&dev_attr_a_clr_err.attr,
+	NULL,
+};
+
+static struct attribute_group debug_dev_attr_group = {
+	.name = "inputs",
+	.attrs = inputs_attrs,
+};
+
+int langwell_register_host(struct pci_driver *host_driver)
+{
+	int	ret = 0;
+
+	the_transceiver->host_ops = host_driver;
+	queue_work(the_transceiver->qwork, &the_transceiver->work);
+	otg_dbg("host controller driver is registered\n");
+
+	return ret;
+}
+EXPORT_SYMBOL(langwell_register_host);
+
+void langwell_unregister_host(struct pci_driver *host_driver)
+{
+	if (the_transceiver->host_ops)
+		the_transceiver->host_ops->remove(the_transceiver->pdev);
+	the_transceiver->host_ops = NULL;
+	the_transceiver->hsm.a_bus_drop = 1;
+	queue_work(the_transceiver->qwork, &the_transceiver->work);
+	otg_dbg("host controller driver is unregistered\n");
+}
+EXPORT_SYMBOL(langwell_unregister_host);
+
+int langwell_register_peripheral(struct pci_driver *client_driver)
+{
+	int	ret = 0;
+
+	if (client_driver)
+		ret = client_driver->probe(the_transceiver->pdev,
+				client_driver->id_table);
+	if (!ret) {
+		the_transceiver->client_ops = client_driver;
+		queue_work(the_transceiver->qwork, &the_transceiver->work);
+		otg_dbg("client controller driver is registered\n");
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(langwell_register_peripheral);
+
+void langwell_unregister_peripheral(struct pci_driver *client_driver)
+{
+	if (the_transceiver->client_ops)
+		the_transceiver->client_ops->remove(the_transceiver->pdev);
+	the_transceiver->client_ops = NULL;
+	the_transceiver->hsm.b_bus_req = 0;
+	queue_work(the_transceiver->qwork, &the_transceiver->work);
+	otg_dbg("client controller driver is unregistered\n");
+}
+EXPORT_SYMBOL(langwell_unregister_peripheral);
+
+static int langwell_otg_probe(struct pci_dev *pdev,
+		const struct pci_device_id *id)
+{
+	unsigned long		resource, len;
+	void __iomem 		*base = NULL;
+	int			retval;
+	u32			val32;
+	struct langwell_otg	*langwell;
+	char			qname[] = "langwell_otg_queue";
+
+	retval = 0;
+	otg_dbg("\notg controller is detected.\n");
+	if (pci_enable_device(pdev) < 0) {
+		retval = -ENODEV;
+		goto done;
+	}
+
+	langwell = kzalloc(sizeof *langwell, GFP_KERNEL);
+	if (langwell == NULL) {
+		retval = -ENOMEM;
+		goto done;
+	}
+	the_transceiver = langwell;
+
+	/* control register: BAR 0 */
+	resource = pci_resource_start(pdev, 0);
+	len = pci_resource_len(pdev, 0);
+	if (!request_mem_region(resource, len, driver_name)) {
+		retval = -EBUSY;
+		goto err;
+	}
+	langwell->region = 1;
+
+	base = ioremap_nocache(resource, len);
+	if (base == NULL) {
+		retval = -EFAULT;
+		goto err;
+	}
+	langwell->regs = base;
+
+	if (!pdev->irq) {
+		otg_dbg("No IRQ.\n");
+		retval = -ENODEV;
+		goto err;
+	}
+
+	langwell->qwork = create_workqueue(qname);
+	if (!langwell->qwork) {
+		otg_dbg("cannot create workqueue %s\n", qname);
+		retval = -ENOMEM;
+		goto err;
+	}
+	INIT_WORK(&langwell->work, langwell_otg_work);
+
+	/* OTG common part */
+	langwell->pdev = pdev;
+	langwell->otg.dev = &pdev->dev;
+	langwell->otg.label = driver_name;
+	langwell->otg.set_host = langwell_otg_set_host;
+	langwell->otg.set_peripheral = langwell_otg_set_peripheral;
+	langwell->otg.set_power = langwell_otg_set_power;
+	langwell->otg.start_srp = langwell_otg_start_srp;
+	langwell->otg.state = OTG_STATE_UNDEFINED;
+	if (otg_set_transceiver(&langwell->otg)) {
+		otg_dbg("can't set transceiver\n");
+		retval = -EBUSY;
+		goto err;
+	}
+
+	reset_otg();
+	init_hsm();
+
+	spin_lock_init(&langwell->lock);
+	spin_lock_init(&langwell->wq_lock);
+	INIT_LIST_HEAD(&active_timers);
+	langwell_otg_init_timers(&langwell->hsm);
+
+	if (request_irq(pdev->irq, otg_irq, IRQF_SHARED,
+				driver_name, langwell) != 0) {
+		otg_dbg("request interrupt %d failed\n", pdev->irq);
+		retval = -EBUSY;
+		goto err;
+	}
+
+	/* enable OTGSC int */
+	val32 = OTGSC_DPIE | OTGSC_BSEIE | OTGSC_BSVIE |
+		OTGSC_ASVIE | OTGSC_AVVIE | OTGSC_IDIE | OTGSC_IDPU;
+	writel(val32, langwell->regs + CI_OTGSC);
+
+	retval = device_create_file(&pdev->dev, &dev_attr_registers);
+	if (retval < 0) {
+		otg_dbg("Can't register sysfs attribute: %d\n", retval);
+		goto err;
+	}
+
+	retval = device_create_file(&pdev->dev, &dev_attr_hsm);
+	if (retval < 0) {
+		otg_dbg("Can't hsm sysfs attribute: %d\n", retval);
+		goto err;
+	}
+
+	retval = sysfs_create_group(&pdev->dev.kobj, &debug_dev_attr_group);
+	if (retval < 0) {
+		otg_dbg("Can't register sysfs attr group: %d\n", retval);
+		goto err;
+	}
+
+	if (langwell->otg.state == OTG_STATE_A_IDLE)
+		queue_work(langwell->qwork, &langwell->work);
+
+	return 0;
+
+err:
+	if (the_transceiver)
+		langwell_otg_remove(pdev);
+done:
+	return retval;
+}
+
+static void langwell_otg_remove(struct pci_dev *pdev)
+{
+	struct langwell_otg *langwell;
+
+	langwell = the_transceiver;
+
+	if (langwell->qwork) {
+		flush_workqueue(langwell->qwork);
+		destroy_workqueue(langwell->qwork);
+	}
+	langwell_otg_free_timers();
+
+	/* disable OTGSC interrupt as OTGSC doesn't change in reset */
+	writel(0, langwell->regs + CI_OTGSC);
+
+	if (pdev->irq)
+		free_irq(pdev->irq, langwell);
+	if (langwell->regs)
+		iounmap(langwell->regs);
+	if (langwell->region)
+		release_mem_region(pci_resource_start(pdev, 0),
+				pci_resource_len(pdev, 0));
+
+	otg_set_transceiver(NULL);
+	pci_disable_device(pdev);
+	sysfs_remove_group(&pdev->dev.kobj, &debug_dev_attr_group);
+	device_remove_file(&pdev->dev, &dev_attr_hsm);
+	device_remove_file(&pdev->dev, &dev_attr_registers);
+	kfree(langwell);
+	langwell = NULL;
+}
+
+static void transceiver_suspend(struct pci_dev *pdev)
+{
+	pci_save_state(pdev);
+	pci_set_power_state(pdev, PCI_D3hot);
+	langwell_otg_phy_low_power(1);
+}
+
+static int langwell_otg_suspend(struct pci_dev *pdev, pm_message_t message)
+{
+	int 	ret = 0;
+	struct langwell_otg *langwell;
+
+	langwell = the_transceiver;
+
+	/* Disbale OTG interrupts */
+	langwell_otg_intr(0);
+
+	if (pdev->irq)
+		free_irq(pdev->irq, langwell);
+
+	/* Prevent more otg_work */
+	flush_workqueue(langwell->qwork);
+	spin_lock(&langwell->wq_lock);
+
+	/* start actions */
+	switch (langwell->otg.state) {
+	case OTG_STATE_A_IDLE:
+	case OTG_STATE_B_IDLE:
+	case OTG_STATE_A_WAIT_VFALL:
+	case OTG_STATE_A_VBUS_ERR:
+		transceiver_suspend(pdev);
+		break;
+	case OTG_STATE_A_WAIT_VRISE:
+		langwell_otg_del_timer(a_wait_vrise_tmr);
+		langwell->hsm.a_srp_det = 0;
+		langwell_otg_drv_vbus(0);
+		langwell->otg.state = OTG_STATE_A_IDLE;
+		transceiver_suspend(pdev);
+		break;
+	case OTG_STATE_A_WAIT_BCON:
+		langwell_otg_del_timer(a_wait_bcon_tmr);
+		if (langwell->host_ops)
+			ret = langwell->host_ops->suspend(pdev, message);
+		langwell_otg_drv_vbus(0);
+		break;
+	case OTG_STATE_A_HOST:
+		if (langwell->host_ops)
+			ret = langwell->host_ops->suspend(pdev, message);
+		langwell_otg_drv_vbus(0);
+		langwell_otg_phy_low_power(1);
+		break;
+	case OTG_STATE_A_SUSPEND:
+		langwell_otg_del_timer(a_aidl_bdis_tmr);
+		langwell_otg_HABA(0);
+		if (langwell->host_ops)
+			langwell->host_ops->remove(pdev);
+		else
+			otg_dbg("host driver has been removed.\n");
+		langwell_otg_drv_vbus(0);
+		transceiver_suspend(pdev);
+		langwell->otg.state = OTG_STATE_A_WAIT_VFALL;
+		break;
+	case OTG_STATE_A_PERIPHERAL:
+		if (langwell->client_ops)
+			ret = langwell->client_ops->suspend(pdev, message);
+		else
+			otg_dbg("client driver has been removed.\n");
+		langwell_otg_drv_vbus(0);
+		transceiver_suspend(pdev);
+		langwell->otg.state = OTG_STATE_A_WAIT_VFALL;
+		break;
+	case OTG_STATE_B_HOST:
+		if (langwell->host_ops)
+			langwell->host_ops->remove(pdev);
+		else
+			otg_dbg("host driver has been removed.\n");
+		langwell->hsm.b_bus_req = 0;
+		transceiver_suspend(pdev);
+		langwell->otg.state = OTG_STATE_B_IDLE;
+		break;
+	case OTG_STATE_B_PERIPHERAL:
+		if (langwell->client_ops)
+			ret = langwell->client_ops->suspend(pdev, message);
+		else
+			otg_dbg("client driver has been removed.\n");
+		break;
+	case OTG_STATE_B_WAIT_ACON:
+		langwell_otg_del_timer(b_ase0_brst_tmr);
+		langwell_otg_HAAR(0);
+		if (langwell->host_ops)
+			langwell->host_ops->remove(pdev);
+		else
+			otg_dbg("host driver has been removed.\n");
+		langwell->hsm.b_bus_req = 0;
+		langwell->otg.state = OTG_STATE_B_IDLE;
+		transceiver_suspend(pdev);
+		break;
+	default:
+		otg_dbg("error state before suspend\n ");
+		break;
+	}
+	spin_unlock(&langwell->wq_lock);
+
+	return ret;
+}
+
+static void transceiver_resume(struct pci_dev *pdev)
+{
+	pci_restore_state(pdev);
+	pci_set_power_state(pdev, PCI_D0);
+	langwell_otg_phy_low_power(0);
+}
+
+static int langwell_otg_resume(struct pci_dev *pdev)
+{
+	int 	ret = 0;
+	struct langwell_otg *langwell;
+
+	langwell = the_transceiver;
+
+	spin_lock(&langwell->wq_lock);
+
+	switch (langwell->otg.state) {
+	case OTG_STATE_A_IDLE:
+	case OTG_STATE_B_IDLE:
+	case OTG_STATE_A_WAIT_VFALL:
+	case OTG_STATE_A_VBUS_ERR:
+		transceiver_resume(pdev);
+		break;
+	case OTG_STATE_A_WAIT_BCON:
+		langwell_otg_add_timer(a_wait_bcon_tmr);
+		langwell_otg_drv_vbus(1);
+		if (langwell->host_ops)
+			ret = langwell->host_ops->resume(pdev);
+		break;
+	case OTG_STATE_A_HOST:
+		langwell_otg_drv_vbus(1);
+		langwell_otg_phy_low_power(0);
+		if (langwell->host_ops)
+			ret = langwell->host_ops->resume(pdev);
+		break;
+	case OTG_STATE_B_PERIPHERAL:
+		if (langwell->client_ops)
+			ret = langwell->client_ops->resume(pdev);
+		else
+			otg_dbg("client driver not loaded.\n");
+		break;
+	default:
+		otg_dbg("error state before suspend\n ");
+		break;
+	}
+
+	if (request_irq(pdev->irq, otg_irq, IRQF_SHARED,
+				driver_name, the_transceiver) != 0) {
+		otg_dbg("request interrupt %d failed\n", pdev->irq);
+		ret = -EBUSY;
+	}
+
+	/* enable OTG interrupts */
+	langwell_otg_intr(1);
+
+	spin_unlock(&langwell->wq_lock);
+
+	queue_work(langwell->qwork, &langwell->work);
+
+
+	return ret;
+}
+
+static int __init langwell_otg_init(void)
+{
+	return pci_register_driver(&otg_pci_driver);
+}
+module_init(langwell_otg_init);
+
+static void __exit langwell_otg_cleanup(void)
+{
+	pci_unregister_driver(&otg_pci_driver);
+}
+module_exit(langwell_otg_cleanup);
diff --git a/include/linux/usb/langwell_otg.h b/include/linux/usb/langwell_otg.h
new file mode 100644
index 000000000000..e115ae6df1da
--- /dev/null
+++ b/include/linux/usb/langwell_otg.h
@@ -0,0 +1,177 @@
+/*
+ * Intel Langwell USB OTG transceiver driver
+ * Copyright (C) 2008, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#ifndef __LANGWELL_OTG_H__
+#define __LANGWELL_OTG_H__
+
+/* notify transceiver driver about OTG events */
+extern void langwell_update_transceiver(void);
+/* HCD register bus driver */
+extern int langwell_register_host(struct pci_driver *host_driver);
+/* HCD unregister bus driver */
+extern void langwell_unregister_host(struct pci_driver *host_driver);
+/* DCD register bus driver */
+extern int langwell_register_peripheral(struct pci_driver *client_driver);
+/* DCD unregister bus driver */
+extern void langwell_unregister_peripheral(struct pci_driver *client_driver);
+/* No silent failure, output warning message */
+extern void langwell_otg_nsf_msg(unsigned long message);
+
+#define CI_USBCMD		0x30
+#	define USBCMD_RST		BIT(1)
+#	define USBCMD_RS		BIT(0)
+#define CI_USBSTS		0x34
+#	define USBSTS_SLI		BIT(8)
+#	define USBSTS_URI		BIT(6)
+#	define USBSTS_PCI		BIT(2)
+#define CI_PORTSC1		0x74
+#	define PORTSC_PP		BIT(12)
+#	define PORTSC_LS		(BIT(11) | BIT(10))
+#	define PORTSC_SUSP		BIT(7)
+#	define PORTSC_CCS		BIT(0)
+#define CI_HOSTPC1		0xb4
+#	define HOSTPC1_PHCD		BIT(22)
+#define CI_OTGSC		0xf4
+#	define OTGSC_DPIE		BIT(30)
+#	define OTGSC_1MSE		BIT(29)
+#	define OTGSC_BSEIE		BIT(28)
+#	define OTGSC_BSVIE		BIT(27)
+#	define OTGSC_ASVIE		BIT(26)
+#	define OTGSC_AVVIE		BIT(25)
+#	define OTGSC_IDIE		BIT(24)
+#	define OTGSC_DPIS		BIT(22)
+#	define OTGSC_1MSS		BIT(21)
+#	define OTGSC_BSEIS		BIT(20)
+#	define OTGSC_BSVIS		BIT(19)
+#	define OTGSC_ASVIS		BIT(18)
+#	define OTGSC_AVVIS		BIT(17)
+#	define OTGSC_IDIS		BIT(16)
+#	define OTGSC_DPS		BIT(14)
+#	define OTGSC_1MST		BIT(13)
+#	define OTGSC_BSE		BIT(12)
+#	define OTGSC_BSV		BIT(11)
+#	define OTGSC_ASV		BIT(10)
+#	define OTGSC_AVV		BIT(9)
+#	define OTGSC_ID			BIT(8)
+#	define OTGSC_HABA		BIT(7)
+#	define OTGSC_HADP		BIT(6)
+#	define OTGSC_IDPU		BIT(5)
+#	define OTGSC_DP			BIT(4)
+#	define OTGSC_OT			BIT(3)
+#	define OTGSC_HAAR		BIT(2)
+#	define OTGSC_VC			BIT(1)
+#	define OTGSC_VD			BIT(0)
+#	define OTGSC_INTEN_MASK		(0x7f << 24)
+#	define OTGSC_INTSTS_MASK	(0x7f << 16)
+#define CI_USBMODE		0xf8
+#	define USBMODE_CM		(BIT(1) | BIT(0))
+#	define USBMODE_IDLE		0
+#	define USBMODE_DEVICE		0x2
+#	define USBMODE_HOST		0x3
+
+#define INTR_DUMMY_MASK (USBSTS_SLI | USBSTS_URI | USBSTS_PCI)
+
+struct otg_hsm {
+	/* Input */
+	int a_bus_resume;
+	int a_bus_suspend;
+	int a_conn;
+	int a_sess_vld;
+	int a_srp_det;
+	int a_vbus_vld;
+	int b_bus_resume;
+	int b_bus_suspend;
+	int b_conn;
+	int b_se0_srp;
+	int b_sess_end;
+	int b_sess_vld;
+	int id;
+
+	/* Internal variables */
+	int a_set_b_hnp_en;
+	int b_srp_done;
+	int b_hnp_enable;
+
+	/* Timeout indicator for timers */
+	int a_wait_vrise_tmout;
+	int a_wait_bcon_tmout;
+	int a_aidl_bdis_tmout;
+	int b_ase0_brst_tmout;
+	int b_bus_suspend_tmout;
+	int b_srp_res_tmout;
+
+	/* Informative variables */
+	int a_bus_drop;
+	int a_bus_req;
+	int a_clr_err;
+	int a_suspend_req;
+	int b_bus_req;
+
+	/* Output */
+	int drv_vbus;
+	int loc_conn;
+	int loc_sof;
+
+	/* Others */
+	int b_bus_suspend_vld;
+};
+
+#define TA_WAIT_VRISE	100
+#define TA_WAIT_BCON	30000
+#define TA_AIDL_BDIS	15000
+#define TB_ASE0_BRST	5000
+#define TB_SE0_SRP	2
+#define TB_SRP_RES	100
+#define TB_BUS_SUSPEND	500
+
+struct langwell_otg_timer {
+	unsigned long expires;	/* Number of count increase to timeout */
+	unsigned long count;	/* Tick counter */
+	void (*function)(unsigned long);	/* Timeout function */
+	unsigned long data;	/* Data passed to function */
+	struct list_head list;
+};
+
+struct langwell_otg {
+	struct otg_transceiver 	otg;
+	struct otg_hsm 		hsm;
+	void __iomem 		*regs;
+	unsigned 		region;
+	struct pci_driver	*host_ops;
+	struct pci_driver	*client_ops;
+	struct pci_dev		*pdev;
+	struct work_struct 	work;
+	struct workqueue_struct	*qwork;
+	spinlock_t 		lock;
+	spinlock_t 		wq_lock;
+};
+
+static inline struct langwell_otg *otg_to_langwell(struct otg_transceiver *otg)
+{
+	return container_of(otg, struct langwell_otg, otg);
+}
+
+#ifdef DEBUG
+#define otg_dbg(fmt, args...) \
+	printk(KERN_DEBUG fmt , ## args)
+#else
+#define otg_dbg(fmt, args...) \
+	do { } while (0)
+#endif /* DEBUG */
+#endif /* __LANGWELL_OTG_H__ */