USB: Add Intel Langwell USB OTG Transceiver Drive

Description:
This driver is used for Intel Langwell* USB OTG controller in Intel
Moorestown* platform. It tries to implement host/device role switch
according to OTG spec.  The actual hsot and device functions are
accomplished in modified EHCI driver and Intel Langwell USB OTG client
controller driver.

* Langwell and Moorestown are names used in development. They are not
  approved official name.

Note:
This patch is the first version Intel Langwell USB OTG Transceiver
driver. The development is not finished, and the bug fixing is on going
for some hardware and software issues. The main purpose of this
submission is for code view.

Supported features:
- Data-line Pulsing SRP
- Support HNP to switch roles
- PCI D0/D3 power management support

Known issues:
- HNP is only tested with another Moorestown platform.
- PCI D0/D3 power management support is not fully tested.
- VBus Pulsing SRP is not support in current version.
Signed-off-by: Hao Wu <hao.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

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

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

drivers/usb/otg/langwell_otg.c

+/*
+ * 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);

include/linux/usb/langwell_otg.h

+/*
+ * 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__ */