linux-next/drivers/usb/otg/langwell_otg.c

/*
 * Intel Langwell USB OTG transceiver driver
 * Copyright (C) 2008 - 2010, 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/usb/hcd.h>
#include <linux/notifier.h>
#include <linux/delay.h>
#include <asm/intel_scu_ipc.h>

#include <linux/usb/langwell_otg.h>

#define	DRIVER_DESC		"Intel Langwell USB OTG transceiver driver"
#define	DRIVER_VERSION		"July 10, 2010"

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);
	if (timer == NULL)
		return timer;

	timer->function = function;
	timer->expires = expires;
	timer->data = data;
	return timer;
}

static struct langwell_otg_timer *a_wait_vrise_tmr, *a_aidl_bdis_tmr,
	*b_se0_srp_tmr, *b_srp_init_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(void)
{
	struct langwell_otg *lnw = the_transceiver;

	dev_dbg(lnw->dev, "transceiver is updated\n");

	if (!lnw->qwork)
		return ;

	queue_work(lnw->qwork, &lnw->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 int langwell_otg_set_vbus(struct otg_transceiver *otg, bool enabled)
{
	struct langwell_otg		*lnw = the_transceiver;
	u8 r;

	dev_dbg(lnw->dev, "%s <--- %s\n", __func__, enabled ? "on" : "off");

	/* FIXME: surely we should cache this on the first read. If not use
	   readv to avoid two transactions */
	if (intel_scu_ipc_ioread8(0x00, &r) < 0) {
		dev_dbg(lnw->dev, "Failed to read PMIC register 0xD2");
		return -EBUSY;
	}
	if ((r & 0x03) != 0x02) {
		dev_dbg(lnw->dev, "not NEC PMIC attached\n");
		return -EBUSY;
	}

	if (intel_scu_ipc_ioread8(0x20, &r) < 0) {
		dev_dbg(lnw->dev, "Failed to read PMIC register 0xD2");
		return -EBUSY;
	}

	if ((r & 0x20) == 0) {
		dev_dbg(lnw->dev, "no battery attached\n");
		return -EBUSY;
	}

	/* Workaround for battery attachment issue */
	if (r == 0x34) {
		dev_dbg(lnw->dev, "no battery attached on SH\n");
		return -EBUSY;
	}

	dev_dbg(lnw->dev, "battery attached. 2 reg = %x\n", r);

	/* workaround: FW detect writing 0x20/0xc0 to d4 event.
	 * this is only for NEC PMIC.
	 */

	if (intel_scu_ipc_iowrite8(0xD4, enabled ? 0x20 : 0xC0))
		dev_dbg(lnw->dev, "Failed to write PMIC.\n");

	dev_dbg(lnw->dev, "%s --->\n", __func__);

	return 0;
}

/* charge vbus or discharge vbus through a resistor to ground */
static void langwell_otg_chrg_vbus(int on)
{
	struct langwell_otg	*lnw = the_transceiver;
	u32	val;

	val = readl(lnw->iotg.base + CI_OTGSC);

	if (on)
		writel((val & ~OTGSC_INTSTS_MASK) | OTGSC_VC,
				lnw->iotg.base + CI_OTGSC);
	else
		writel((val & ~OTGSC_INTSTS_MASK) | OTGSC_VD,
				lnw->iotg.base + CI_OTGSC);
}

/* Start SRP */
static int langwell_otg_start_srp(struct otg_transceiver *otg)
{
	struct langwell_otg		*lnw = the_transceiver;
	struct intel_mid_otg_xceiv	*iotg = &lnw->iotg;
	u32				val;

	dev_dbg(lnw->dev, "%s --->\n", __func__);

	val = readl(iotg->base + CI_OTGSC);

	writel((val & ~OTGSC_INTSTS_MASK) | OTGSC_HADP,
				iotg->base + CI_OTGSC);

	/* Check if the data plus is finished or not */
	msleep(8);
	val = readl(iotg->base + CI_OTGSC);
	if (val & (OTGSC_HADP | OTGSC_DP))
		dev_dbg(lnw->dev, "DataLine SRP Error\n");

	/* Disable interrupt - b_sess_vld */
	val = readl(iotg->base + CI_OTGSC);
	val &= (~(OTGSC_BSVIE | OTGSC_BSEIE));
	writel(val, iotg->base + CI_OTGSC);

	/* Start VBus SRP, drive vbus to generate VBus pulse */
	iotg->otg.set_vbus(&iotg->otg, true);
	msleep(15);
	iotg->otg.set_vbus(&iotg->otg, false);

	/* Enable interrupt - b_sess_vld*/
	val = readl(iotg->base + CI_OTGSC);
	dev_dbg(lnw->dev, "after VBUS pulse otgsc = %x\n", val);

	val |= (OTGSC_BSVIE | OTGSC_BSEIE);
	writel(val, iotg->base + CI_OTGSC);

	/* If Vbus is valid, then update the hsm */
	if (val & OTGSC_BSV) {
		dev_dbg(lnw->dev, "no b_sess_vld interrupt\n");

		lnw->iotg.hsm.b_sess_vld = 1;
		langwell_update_transceiver();
	}

	dev_dbg(lnw->dev, "%s <---\n", __func__);
	return 0;
}

/* stop SOF via bus_suspend */
static void langwell_otg_loc_sof(int on)
{
	struct langwell_otg	*lnw = the_transceiver;
	struct usb_hcd		*hcd;
	int			err;

	dev_dbg(lnw->dev, "%s ---> %s\n", __func__, on ? "suspend" : "resume");

	hcd = bus_to_hcd(lnw->iotg.otg.host);
	if (on)
		err = hcd->driver->bus_resume(hcd);
	else
		err = hcd->driver->bus_suspend(hcd);

	if (err)
		dev_dbg(lnw->dev, "Fail to resume/suspend USB bus - %d\n", err);

	dev_dbg(lnw->dev, "%s <---\n", __func__);
}

static int langwell_otg_check_otgsc(void)
{
	struct langwell_otg		*lnw = the_transceiver;
	u32				otgsc, usbcfg;

	dev_dbg(lnw->dev, "check sync OTGSC and USBCFG registers\n");

	otgsc = readl(lnw->iotg.base + CI_OTGSC);
	usbcfg = readl(lnw->usbcfg);

	dev_dbg(lnw->dev, "OTGSC = %08x, USBCFG = %08x\n",
					otgsc, usbcfg);
	dev_dbg(lnw->dev, "OTGSC_AVV = %d\n", !!(otgsc & OTGSC_AVV));
	dev_dbg(lnw->dev, "USBCFG.VBUSVAL = %d\n",
					!!(usbcfg & USBCFG_VBUSVAL));
	dev_dbg(lnw->dev, "OTGSC_ASV = %d\n", !!(otgsc & OTGSC_ASV));
	dev_dbg(lnw->dev, "USBCFG.AVALID = %d\n",
					!!(usbcfg & USBCFG_AVALID));
	dev_dbg(lnw->dev, "OTGSC_BSV = %d\n", !!(otgsc & OTGSC_BSV));
	dev_dbg(lnw->dev, "USBCFG.BVALID = %d\n",
					!!(usbcfg & USBCFG_BVALID));
	dev_dbg(lnw->dev, "OTGSC_BSE = %d\n", !!(otgsc & OTGSC_BSE));
	dev_dbg(lnw->dev, "USBCFG.SESEND = %d\n",
					!!(usbcfg & USBCFG_SESEND));

	/* Check USBCFG VBusValid/AValid/BValid/SessEnd */
	if (!!(otgsc & OTGSC_AVV) ^ !!(usbcfg & USBCFG_VBUSVAL)) {
		dev_dbg(lnw->dev, "OTGSC.AVV != USBCFG.VBUSVAL\n");
		goto err;
	}
	if (!!(otgsc & OTGSC_ASV) ^ !!(usbcfg & USBCFG_AVALID)) {
		dev_dbg(lnw->dev, "OTGSC.ASV != USBCFG.AVALID\n");
		goto err;
	}
	if (!!(otgsc & OTGSC_BSV) ^ !!(usbcfg & USBCFG_BVALID)) {
		dev_dbg(lnw->dev, "OTGSC.BSV != USBCFG.BVALID\n");
		goto err;
	}
	if (!!(otgsc & OTGSC_BSE) ^ !!(usbcfg & USBCFG_SESEND)) {
		dev_dbg(lnw->dev, "OTGSC.BSE != USBCFG.SESSEN\n");
		goto err;
	}

	dev_dbg(lnw->dev, "OTGSC and USBCFG are synced\n");

	return 0;

err:
	dev_warn(lnw->dev, "OTGSC isn't equal to USBCFG\n");
	return -EPIPE;
}


static void langwell_otg_phy_low_power(int on)
{
	struct langwell_otg		*lnw = the_transceiver;
	struct intel_mid_otg_xceiv	*iotg = &lnw->iotg;
	u8				val, phcd;
	int				retval;

	dev_dbg(lnw->dev, "%s ---> %s mode\n",
			__func__, on ? "Low power" : "Normal");

	phcd = 0x40;

	val = readb(iotg->base + CI_HOSTPC1 + 2);

	if (on) {
		/* Due to hardware issue, after set PHCD, sync will failed
		 * between USBCFG and OTGSC, so before set PHCD, check if
		 * sync is in process now. If the answer is "yes", then do
		 * not touch PHCD bit */
		retval = langwell_otg_check_otgsc();
		if (retval) {
			dev_dbg(lnw->dev, "Skip PHCD programming..\n");
			return ;
		}

		writeb(val | phcd, iotg->base + CI_HOSTPC1 + 2);
	} else
		writeb(val & ~phcd, iotg->base + CI_HOSTPC1 + 2);

	dev_dbg(lnw->dev, "%s <--- done\n", __func__);
}

/* After drv vbus, add 2 ms delay to set PHCD */
static void langwell_otg_phy_low_power_wait(int on)
{
	struct langwell_otg	*lnw = the_transceiver;

	dev_dbg(lnw->dev, "add 2ms delay before programing PHCD\n");

	mdelay(2);
	langwell_otg_phy_low_power(on);
}

/* Enable/Disable OTG interrupt */
static void langwell_otg_intr(int on)
{
	struct langwell_otg		*lnw = the_transceiver;
	struct intel_mid_otg_xceiv	*iotg = &lnw->iotg;
	u32				val;

	dev_dbg(lnw->dev, "%s ---> %s\n", __func__, on ? "on" : "off");

	val = readl(iotg->base + CI_OTGSC);

	/* OTGSC_INT_MASK doesn't contains 1msInt */
	if (on) {
		val = val | (OTGSC_INT_MASK);
		writel(val, iotg->base + CI_OTGSC);
	} else {
		val = val & ~(OTGSC_INT_MASK);
		writel(val, iotg->base + CI_OTGSC);
	}

	dev_dbg(lnw->dev, "%s <---\n", __func__);
}

/* set HAAR: Hardware Assist Auto-Reset */
static void langwell_otg_HAAR(int on)
{
	struct langwell_otg		*lnw = the_transceiver;
	struct intel_mid_otg_xceiv	*iotg = &lnw->iotg;
	u32				val;

	dev_dbg(lnw->dev, "%s ---> %s\n", __func__, on ? "on" : "off");

	val = readl(iotg->base + CI_OTGSC);
	if (on)
		writel((val & ~OTGSC_INTSTS_MASK) | OTGSC_HAAR,
					iotg->base + CI_OTGSC);
	else
		writel((val & ~OTGSC_INTSTS_MASK) & ~OTGSC_HAAR,
					iotg->base + CI_OTGSC);

	dev_dbg(lnw->dev, "%s <---\n", __func__);
}

/* set HABA: Hardware Assist B-Disconnect to A-Connect */
static void langwell_otg_HABA(int on)
{
	struct langwell_otg		*lnw = the_transceiver;
	struct intel_mid_otg_xceiv	*iotg = &lnw->iotg;
	u32				val;

	dev_dbg(lnw->dev, "%s ---> %s\n", __func__, on ? "on" : "off");

	val = readl(iotg->base + CI_OTGSC);
	if (on)
		writel((val & ~OTGSC_INTSTS_MASK) | OTGSC_HABA,
					iotg->base + CI_OTGSC);
	else
		writel((val & ~OTGSC_INTSTS_MASK) & ~OTGSC_HABA,
					iotg->base + CI_OTGSC);

	dev_dbg(lnw->dev, "%s <---\n", __func__);
}

static int langwell_otg_check_se0_srp(int on)
{
	struct langwell_otg	*lnw = the_transceiver;
	int			delay_time = TB_SE0_SRP * 10;
	u32			val;

	dev_dbg(lnw->dev, "%s --->\n", __func__);

	do {
		udelay(100);
		if (!delay_time--)
			break;
		val = readl(lnw->iotg.base + CI_PORTSC1);
		val &= PORTSC_LS;
	} while (!val);

	dev_dbg(lnw->dev, "%s <---\n", __func__);
	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)
{
	struct langwell_otg	*lnw = the_transceiver;

	switch (indicator) {
	case 2:
	case 4:
	case 6:
	case 7:
		dev_warn(lnw->dev,
			"OTG:NSF-%lu - deivce not responding\n", indicator);
		break;
	case 3:
		dev_warn(lnw->dev,
			"OTG:NSF-%lu - deivce not supported\n", indicator);
		break;
	default:
		dev_warn(lnw->dev, "Do not have this kind of NSF\n");
		break;
	}
}

/* Initialize timers */
static int 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);
	if (a_wait_vrise_tmr == NULL)
		return -ENOMEM;
	a_aidl_bdis_tmr = otg_timer_initializer(&set_tmout, TA_AIDL_BDIS,
				(unsigned long)&hsm->a_aidl_bdis_tmout);
	if (a_aidl_bdis_tmr == NULL)
		return -ENOMEM;
	b_se0_srp_tmr = otg_timer_initializer(&set_tmout, TB_SE0_SRP,
				(unsigned long)&hsm->b_se0_srp);
	if (b_se0_srp_tmr == NULL)
		return -ENOMEM;
	b_srp_init_tmr = otg_timer_initializer(&set_tmout, TB_SRP_INIT,
				(unsigned long)&hsm->b_srp_init_tmout);
	if (b_srp_init_tmr == NULL)
		return -ENOMEM;

	return 0;
}

/* Free timers */
static void langwell_otg_free_timers(void)
{
	kfree(a_wait_vrise_tmr);
	kfree(a_aidl_bdis_tmr);
	kfree(b_se0_srp_tmr);
	kfree(b_srp_init_tmr);
}

/* The timeout callback function to set time out bit */
static void langwell_otg_timer_fn(unsigned long indicator)
{
	struct langwell_otg *lnw = the_transceiver;

	*(int *)indicator = 1;

	dev_dbg(lnw->dev, "kernel timer - timeout\n");

	langwell_update_transceiver();
}

/* kernel timer used instead of HW based interrupt */
static void langwell_otg_add_ktimer(enum langwell_otg_timer_type timers)
{
	struct langwell_otg		*lnw = the_transceiver;
	struct intel_mid_otg_xceiv	*iotg = &lnw->iotg;
	unsigned long		j = jiffies;
	unsigned long		data, time;

	switch (timers) {
	case TA_WAIT_VRISE_TMR:
		iotg->hsm.a_wait_vrise_tmout = 0;
		data = (unsigned long)&iotg->hsm.a_wait_vrise_tmout;
		time = TA_WAIT_VRISE;
		break;
	case TA_WAIT_BCON_TMR:
		iotg->hsm.a_wait_bcon_tmout = 0;
		data = (unsigned long)&iotg->hsm.a_wait_bcon_tmout;
		time = TA_WAIT_BCON;
		break;
	case TA_AIDL_BDIS_TMR:
		iotg->hsm.a_aidl_bdis_tmout = 0;
		data = (unsigned long)&iotg->hsm.a_aidl_bdis_tmout;
		time = TA_AIDL_BDIS;
		break;
	case TB_ASE0_BRST_TMR:
		iotg->hsm.b_ase0_brst_tmout = 0;
		data = (unsigned long)&iotg->hsm.b_ase0_brst_tmout;
		time = TB_ASE0_BRST;
		break;
	case TB_SRP_INIT_TMR:
		iotg->hsm.b_srp_init_tmout = 0;
		data = (unsigned long)&iotg->hsm.b_srp_init_tmout;
		time = TB_SRP_INIT;
		break;
	case TB_SRP_FAIL_TMR:
		iotg->hsm.b_srp_fail_tmout = 0;
		data = (unsigned long)&iotg->hsm.b_srp_fail_tmout;
		time = TB_SRP_FAIL;
		break;
	case TB_BUS_SUSPEND_TMR:
		iotg->hsm.b_bus_suspend_tmout = 0;
		data = (unsigned long)&iotg->hsm.b_bus_suspend_tmout;
		time = TB_BUS_SUSPEND;
		break;
	default:
		dev_dbg(lnw->dev, "unkown timer, cannot enable it\n");
		return;
	}

	lnw->hsm_timer.data = data;
	lnw->hsm_timer.function = langwell_otg_timer_fn;
	lnw->hsm_timer.expires = j + time * HZ / 1000; /* milliseconds */

	add_timer(&lnw->hsm_timer);

	dev_dbg(lnw->dev, "add timer successfully\n");
}

/* 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;
	struct intel_mid_otg_xceiv *iotg = &the_transceiver->iotg;
	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(iotg->base + CI_OTGSC);
		writel(val32 | OTGSC_1MSE, iotg->base + 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 *lnw = the_transceiver;
	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(lnw->iotg.base + CI_OTGSC);
		writel(val32 & ~OTGSC_1MSE, lnw->iotg.base + CI_OTGSC);
	}
}

/* Reduce timer count by 1, and find timeout conditions.*/
static int langwell_otg_tick_timer(u32 *int_sts)
{
	struct langwell_otg	*lnw = the_transceiver;
	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)) {
		dev_dbg(lnw->dev, "tick timer: disable 1ms int\n");
		*int_sts = *int_sts & ~OTGSC_1MSE;
	}
	return expired;
}

static void reset_otg(void)
{
	struct langwell_otg	*lnw = the_transceiver;
	int			delay_time = 1000;
	u32			val;

	dev_dbg(lnw->dev, "reseting OTG controller ...\n");
	val = readl(lnw->iotg.base + CI_USBCMD);
	writel(val | USBCMD_RST, lnw->iotg.base + CI_USBCMD);
	do {
		udelay(100);
		if (!delay_time--)
			dev_dbg(lnw->dev, "reset timeout\n");
		val = readl(lnw->iotg.base + CI_USBCMD);
		val &= USBCMD_RST;
	} while (val != 0);
	dev_dbg(lnw->dev, "reset done.\n");
}

static void set_host_mode(void)
{
	struct langwell_otg	*lnw = the_transceiver;
	u32			val;

	reset_otg();
	val = readl(lnw->iotg.base + CI_USBMODE);
	val = (val & (~USBMODE_CM)) | USBMODE_HOST;
	writel(val, lnw->iotg.base + CI_USBMODE);
}

static void set_client_mode(void)
{
	struct langwell_otg	*lnw = the_transceiver;
	u32			val;

	reset_otg();
	val = readl(lnw->iotg.base + CI_USBMODE);
	val = (val & (~USBMODE_CM)) | USBMODE_DEVICE;
	writel(val, lnw->iotg.base + CI_USBMODE);
}

static void init_hsm(void)
{
	struct langwell_otg		*lnw = the_transceiver;
	struct intel_mid_otg_xceiv	*iotg = &lnw->iotg;
	u32				val32;

	/* read OTGSC after reset */
	val32 = readl(lnw->iotg.base + CI_OTGSC);
	dev_dbg(lnw->dev, "%s: OTGSC init value = 0x%x\n", __func__, val32);

	/* set init state */
	if (val32 & OTGSC_ID) {
		iotg->hsm.id = 1;
		iotg->otg.default_a = 0;
		set_client_mode();
		iotg->otg.state = OTG_STATE_B_IDLE;
	} else {
		iotg->hsm.id = 0;
		iotg->otg.default_a = 1;
		set_host_mode();
		iotg->otg.state = OTG_STATE_A_IDLE;
	}

	/* set session indicator */
	if (val32 & OTGSC_BSE)
		iotg->hsm.b_sess_end = 1;
	if (val32 & OTGSC_BSV)
		iotg->hsm.b_sess_vld = 1;
	if (val32 & OTGSC_ASV)
		iotg->hsm.a_sess_vld = 1;
	if (val32 & OTGSC_AVV)
		iotg->hsm.a_vbus_vld = 1;

	/* defautly power the bus */
	iotg->hsm.a_bus_req = 1;
	iotg->hsm.a_bus_drop = 0;
	/* defautly don't request bus as B device */
	iotg->hsm.b_bus_req = 0;
	/* no system error */
	iotg->hsm.a_clr_err = 0;

	langwell_otg_phy_low_power_wait(1);
}

static void update_hsm(void)
{
	struct langwell_otg		*lnw = the_transceiver;
	struct intel_mid_otg_xceiv	*iotg = &lnw->iotg;
	u32				val32;

	/* read OTGSC */
	val32 = readl(lnw->iotg.base + CI_OTGSC);
	dev_dbg(lnw->dev, "%s: OTGSC value = 0x%x\n", __func__, val32);

	iotg->hsm.id = !!(val32 & OTGSC_ID);
	iotg->hsm.b_sess_end = !!(val32 & OTGSC_BSE);
	iotg->hsm.b_sess_vld = !!(val32 & OTGSC_BSV);
	iotg->hsm.a_sess_vld = !!(val32 & OTGSC_ASV);
	iotg->hsm.a_vbus_vld = !!(val32 & OTGSC_AVV);
}

static irqreturn_t otg_dummy_irq(int irq, void *_dev)
{
	struct langwell_otg	*lnw = the_transceiver;
	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 (lnw->iotg.hsm.b_conn) {
		lnw->iotg.hsm.b_conn = 0;
		if (spin_trylock(&lnw->wq_lock)) {
			langwell_update_transceiver();
			spin_unlock(&lnw->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		*lnw = _dev;
	struct intel_mid_otg_xceiv	*iotg = &lnw->iotg;
	u32				int_sts, int_en;
	u32				int_mask = 0;
	int				flag = 0;

	int_sts = readl(lnw->iotg.base + 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) {
		dev_dbg(lnw->dev, "%s: id change int\n", __func__);
		iotg->hsm.id = (int_sts & OTGSC_ID) ? 1 : 0;
		dev_dbg(lnw->dev, "id = %d\n", iotg->hsm.id);
		flag = 1;
	}
	if (int_mask & OTGSC_DPIS) {
		dev_dbg(lnw->dev, "%s: data pulse int\n", __func__);
		iotg->hsm.a_srp_det = (int_sts & OTGSC_DPS) ? 1 : 0;
		dev_dbg(lnw->dev, "data pulse = %d\n", iotg->hsm.a_srp_det);
		flag = 1;
	}
	if (int_mask & OTGSC_BSEIS) {
		dev_dbg(lnw->dev, "%s: b session end int\n", __func__);
		iotg->hsm.b_sess_end = (int_sts & OTGSC_BSE) ? 1 : 0;
		dev_dbg(lnw->dev, "b_sess_end = %d\n", iotg->hsm.b_sess_end);
		flag = 1;
	}
	if (int_mask & OTGSC_BSVIS) {
		dev_dbg(lnw->dev, "%s: b session valid int\n", __func__);
		iotg->hsm.b_sess_vld = (int_sts & OTGSC_BSV) ? 1 : 0;
		dev_dbg(lnw->dev, "b_sess_vld = %d\n", iotg->hsm.b_sess_end);
		flag = 1;
	}
	if (int_mask & OTGSC_ASVIS) {
		dev_dbg(lnw->dev, "%s: a session valid int\n", __func__);
		iotg->hsm.a_sess_vld = (int_sts & OTGSC_ASV) ? 1 : 0;
		dev_dbg(lnw->dev, "a_sess_vld = %d\n", iotg->hsm.a_sess_vld);
		flag = 1;
	}
	if (int_mask & OTGSC_AVVIS) {
		dev_dbg(lnw->dev, "%s: a vbus valid int\n", __func__);
		iotg->hsm.a_vbus_vld = (int_sts & OTGSC_AVV) ? 1 : 0;
		dev_dbg(lnw->dev, "a_vbus_vld = %d\n", iotg->hsm.a_vbus_vld);
		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,
					lnw->iotg.base + CI_OTGSC);
	if (flag)
		langwell_update_transceiver();

	return IRQ_HANDLED;
}

static int langwell_otg_iotg_notify(struct notifier_block *nb,
				unsigned long action, void *data)
{
	struct langwell_otg		*lnw = the_transceiver;
	struct intel_mid_otg_xceiv	*iotg = data;
	int				flag = 0;

	if (iotg == NULL)
		return NOTIFY_BAD;

	if (lnw == NULL)
		return NOTIFY_BAD;

	switch (action) {
	case MID_OTG_NOTIFY_CONNECT:
		dev_dbg(lnw->dev, "Lnw OTG Notify Connect Event\n");
		if (iotg->otg.default_a == 1)
			iotg->hsm.b_conn = 1;
		else
			iotg->hsm.a_conn = 1;
		flag = 1;
		break;
	case MID_OTG_NOTIFY_DISCONN:
		dev_dbg(lnw->dev, "Lnw OTG Notify Disconnect Event\n");
		if (iotg->otg.default_a == 1)
			iotg->hsm.b_conn = 0;
		else
			iotg->hsm.a_conn = 0;
		flag = 1;
		break;
	case MID_OTG_NOTIFY_HSUSPEND:
		dev_dbg(lnw->dev, "Lnw OTG Notify Host Bus suspend Event\n");
		if (iotg->otg.default_a == 1)
			iotg->hsm.a_suspend_req = 1;
		else
			iotg->hsm.b_bus_req = 0;
		flag = 1;
		break;
	case MID_OTG_NOTIFY_HRESUME:
		dev_dbg(lnw->dev, "Lnw OTG Notify Host Bus resume Event\n");
		if (iotg->otg.default_a == 1)
			iotg->hsm.b_bus_resume = 1;
		flag = 1;
		break;
	case MID_OTG_NOTIFY_CSUSPEND:
		dev_dbg(lnw->dev, "Lnw OTG Notify Client Bus suspend Event\n");
		if (iotg->otg.default_a == 1) {
			if (iotg->hsm.b_bus_suspend_vld == 2) {
				iotg->hsm.b_bus_suspend = 1;
				iotg->hsm.b_bus_suspend_vld = 0;
				flag = 1;
			} else {
				iotg->hsm.b_bus_suspend_vld++;
				flag = 0;
			}
		} else {
			if (iotg->hsm.a_bus_suspend == 0) {
				iotg->hsm.a_bus_suspend = 1;
				flag = 1;
			}
		}
		break;
	case MID_OTG_NOTIFY_CRESUME:
		dev_dbg(lnw->dev, "Lnw OTG Notify Client Bus resume Event\n");
		if (iotg->otg.default_a == 0)
			iotg->hsm.a_bus_suspend = 0;
		flag = 0;
		break;
	case MID_OTG_NOTIFY_HOSTADD:
		dev_dbg(lnw->dev, "Lnw OTG Nofity Host Driver Add\n");
		flag = 1;
		break;
	case MID_OTG_NOTIFY_HOSTREMOVE:
		dev_dbg(lnw->dev, "Lnw OTG Nofity Host Driver remove\n");
		flag = 1;
		break;
	case MID_OTG_NOTIFY_CLIENTADD:
		dev_dbg(lnw->dev, "Lnw OTG Nofity Client Driver Add\n");
		flag = 1;
		break;
	case MID_OTG_NOTIFY_CLIENTREMOVE:
		dev_dbg(lnw->dev, "Lnw OTG Nofity Client Driver remove\n");
		flag = 1;
		break;
	default:
		dev_dbg(lnw->dev, "Lnw OTG Nofity unknown notify message\n");
		return NOTIFY_DONE;
	}

	if (flag)
		langwell_update_transceiver();

	return NOTIFY_OK;
}

static void langwell_otg_work(struct work_struct *work)
{
	struct langwell_otg		*lnw;
	struct intel_mid_otg_xceiv	*iotg;
	int				retval;
	struct pci_dev			*pdev;

	lnw = container_of(work, struct langwell_otg, work);
	iotg = &lnw->iotg;
	pdev = to_pci_dev(lnw->dev);

	dev_dbg(lnw->dev, "%s: old state = %s\n", __func__,
			state_string(iotg->otg.state));

	switch (iotg->otg.state) {
	case OTG_STATE_UNDEFINED:
	case OTG_STATE_B_IDLE:
		if (!iotg->hsm.id) {
			langwell_otg_del_timer(b_srp_init_tmr);
			del_timer_sync(&lnw->hsm_timer);

			iotg->otg.default_a = 1;
			iotg->hsm.a_srp_det = 0;

			langwell_otg_chrg_vbus(0);
			set_host_mode();
			langwell_otg_phy_low_power(1);

			iotg->otg.state = OTG_STATE_A_IDLE;
			langwell_update_transceiver();
		} else if (iotg->hsm.b_sess_vld) {
			langwell_otg_del_timer(b_srp_init_tmr);
			del_timer_sync(&lnw->hsm_timer);
			iotg->hsm.b_sess_end = 0;
			iotg->hsm.a_bus_suspend = 0;
			langwell_otg_chrg_vbus(0);

			if (lnw->iotg.start_peripheral) {
				lnw->iotg.start_peripheral(&lnw->iotg);
				iotg->otg.state = OTG_STATE_B_PERIPHERAL;
			} else
				dev_dbg(lnw->dev, "client driver not loaded\n");

		} else if (iotg->hsm.b_srp_init_tmout) {
			iotg->hsm.b_srp_init_tmout = 0;
			dev_warn(lnw->dev, "SRP init timeout\n");
		} else if (iotg->hsm.b_srp_fail_tmout) {
			iotg->hsm.b_srp_fail_tmout = 0;
			iotg->hsm.b_bus_req = 0;

			/* No silence failure */
			langwell_otg_nsf_msg(6);
		} else if (iotg->hsm.b_bus_req && iotg->hsm.b_sess_end) {
			del_timer_sync(&lnw->hsm_timer);
			/* workaround for b_se0_srp detection */
			retval = langwell_otg_check_se0_srp(0);
			if (retval) {
				iotg->hsm.b_bus_req = 0;
				dev_dbg(lnw->dev, "LS isn't SE0, try later\n");
			} else {
				/* clear the PHCD before start srp */
				langwell_otg_phy_low_power(0);

				/* Start SRP */
				langwell_otg_add_timer(b_srp_init_tmr);
				iotg->otg.start_srp(&iotg->otg);
				langwell_otg_del_timer(b_srp_init_tmr);
				langwell_otg_add_ktimer(TB_SRP_FAIL_TMR);

				/* reset PHY low power mode here */
				langwell_otg_phy_low_power_wait(1);
			}
		}
		break;
	case OTG_STATE_B_SRP_INIT:
		if (!iotg->hsm.id) {
			iotg->otg.default_a = 1;
			iotg->hsm.a_srp_det = 0;

			/* Turn off VBus */
			iotg->otg.set_vbus(&iotg->otg, false);
			langwell_otg_chrg_vbus(0);
			set_host_mode();
			langwell_otg_phy_low_power(1);
			iotg->otg.state = OTG_STATE_A_IDLE;
			langwell_update_transceiver();
		} else if (iotg->hsm.b_sess_vld) {
			langwell_otg_chrg_vbus(0);
			if (lnw->iotg.start_peripheral) {
				lnw->iotg.start_peripheral(&lnw->iotg);
				iotg->otg.state = OTG_STATE_B_PERIPHERAL;
			} else
				dev_dbg(lnw->dev, "client driver not loaded\n");
		}
		break;
	case OTG_STATE_B_PERIPHERAL:
		if (!iotg->hsm.id) {
			iotg->otg.default_a = 1;
			iotg->hsm.a_srp_det = 0;

			langwell_otg_chrg_vbus(0);

			if (lnw->iotg.stop_peripheral)
				lnw->iotg.stop_peripheral(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"client driver has been removed.\n");

			set_host_mode();
			langwell_otg_phy_low_power(1);
			iotg->otg.state = OTG_STATE_A_IDLE;
			langwell_update_transceiver();
		} else if (!iotg->hsm.b_sess_vld) {
			iotg->hsm.b_hnp_enable = 0;

			if (lnw->iotg.stop_peripheral)
				lnw->iotg.stop_peripheral(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"client driver has been removed.\n");

			iotg->otg.state = OTG_STATE_B_IDLE;
		} else if (iotg->hsm.b_bus_req && iotg->otg.gadget &&
					iotg->otg.gadget->b_hnp_enable &&
					iotg->hsm.a_bus_suspend) {

			if (lnw->iotg.stop_peripheral)
				lnw->iotg.stop_peripheral(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"client driver has been removed.\n");

			langwell_otg_HAAR(1);
			iotg->hsm.a_conn = 0;

			if (lnw->iotg.start_host) {
				lnw->iotg.start_host(&lnw->iotg);
				iotg->otg.state = OTG_STATE_B_WAIT_ACON;
			} else
				dev_dbg(lnw->dev,
						"host driver not loaded.\n");

			iotg->hsm.a_bus_resume = 0;
			langwell_otg_add_ktimer(TB_ASE0_BRST_TMR);
		}
		break;

	case OTG_STATE_B_WAIT_ACON:
		if (!iotg->hsm.id) {
			/* delete hsm timer for b_ase0_brst_tmr */
			del_timer_sync(&lnw->hsm_timer);

			iotg->otg.default_a = 1;
			iotg->hsm.a_srp_det = 0;

			langwell_otg_chrg_vbus(0);

			langwell_otg_HAAR(0);
			if (lnw->iotg.stop_host)
				lnw->iotg.stop_host(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"host driver has been removed.\n");

			set_host_mode();
			langwell_otg_phy_low_power(1);
			iotg->otg.state = OTG_STATE_A_IDLE;
			langwell_update_transceiver();
		} else if (!iotg->hsm.b_sess_vld) {
			/* delete hsm timer for b_ase0_brst_tmr */
			del_timer_sync(&lnw->hsm_timer);

			iotg->hsm.b_hnp_enable = 0;
			iotg->hsm.b_bus_req = 0;

			langwell_otg_chrg_vbus(0);
			langwell_otg_HAAR(0);

			if (lnw->iotg.stop_host)
				lnw->iotg.stop_host(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"host driver has been removed.\n");

			set_client_mode();
			langwell_otg_phy_low_power(1);
			iotg->otg.state = OTG_STATE_B_IDLE;
		} else if (iotg->hsm.a_conn) {
			/* delete hsm timer for b_ase0_brst_tmr */
			del_timer_sync(&lnw->hsm_timer);

			langwell_otg_HAAR(0);
			iotg->otg.state = OTG_STATE_B_HOST;
			langwell_update_transceiver();
		} else if (iotg->hsm.a_bus_resume ||
				iotg->hsm.b_ase0_brst_tmout) {
			/* delete hsm timer for b_ase0_brst_tmr */
			del_timer_sync(&lnw->hsm_timer);

			langwell_otg_HAAR(0);
			langwell_otg_nsf_msg(7);

			if (lnw->iotg.stop_host)
				lnw->iotg.stop_host(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"host driver has been removed.\n");

			iotg->hsm.a_bus_suspend = 0;
			iotg->hsm.b_bus_req = 0;

			if (lnw->iotg.start_peripheral)
				lnw->iotg.start_peripheral(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"client driver not loaded.\n");

			iotg->otg.state = OTG_STATE_B_PERIPHERAL;
		}
		break;

	case OTG_STATE_B_HOST:
		if (!iotg->hsm.id) {
			iotg->otg.default_a = 1;
			iotg->hsm.a_srp_det = 0;

			langwell_otg_chrg_vbus(0);

			if (lnw->iotg.stop_host)
				lnw->iotg.stop_host(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"host driver has been removed.\n");

			set_host_mode();
			langwell_otg_phy_low_power(1);
			iotg->otg.state = OTG_STATE_A_IDLE;
			langwell_update_transceiver();
		} else if (!iotg->hsm.b_sess_vld) {
			iotg->hsm.b_hnp_enable = 0;
			iotg->hsm.b_bus_req = 0;

			langwell_otg_chrg_vbus(0);
			if (lnw->iotg.stop_host)
				lnw->iotg.stop_host(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"host driver has been removed.\n");

			set_client_mode();
			langwell_otg_phy_low_power(1);
			iotg->otg.state = OTG_STATE_B_IDLE;
		} else if ((!iotg->hsm.b_bus_req) ||
				(!iotg->hsm.a_conn)) {
			iotg->hsm.b_bus_req = 0;
			langwell_otg_loc_sof(0);

			if (lnw->iotg.stop_host)
				lnw->iotg.stop_host(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"host driver has been removed.\n");

			iotg->hsm.a_bus_suspend = 0;

			if (lnw->iotg.start_peripheral)
				lnw->iotg.start_peripheral(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
						"client driver not loaded.\n");

			iotg->otg.state = OTG_STATE_B_PERIPHERAL;
		}
		break;

	case OTG_STATE_A_IDLE:
		iotg->otg.default_a = 1;
		if (iotg->hsm.id) {
			iotg->otg.default_a = 0;
			iotg->hsm.b_bus_req = 0;
			iotg->hsm.vbus_srp_up = 0;

			langwell_otg_chrg_vbus(0);
			set_client_mode();
			langwell_otg_phy_low_power(1);
			iotg->otg.state = OTG_STATE_B_IDLE;
			langwell_update_transceiver();
		} else if (!iotg->hsm.a_bus_drop &&
			(iotg->hsm.a_srp_det || iotg->hsm.a_bus_req)) {
			langwell_otg_phy_low_power(0);

			/* Turn on VBus */
			iotg->otg.set_vbus(&iotg->otg, true);

			iotg->hsm.vbus_srp_up = 0;
			iotg->hsm.a_wait_vrise_tmout = 0;
			langwell_otg_add_timer(a_wait_vrise_tmr);
			iotg->otg.state = OTG_STATE_A_WAIT_VRISE;
			langwell_update_transceiver();
		} else if (!iotg->hsm.a_bus_drop && iotg->hsm.a_sess_vld) {
			iotg->hsm.vbus_srp_up = 1;
		} else if (!iotg->hsm.a_sess_vld && iotg->hsm.vbus_srp_up) {
			msleep(10);
			langwell_otg_phy_low_power(0);

			/* Turn on VBus */
			iotg->otg.set_vbus(&iotg->otg, true);
			iotg->hsm.a_srp_det = 1;
			iotg->hsm.vbus_srp_up = 0;
			iotg->hsm.a_wait_vrise_tmout = 0;
			langwell_otg_add_timer(a_wait_vrise_tmr);
			iotg->otg.state = OTG_STATE_A_WAIT_VRISE;
			langwell_update_transceiver();
		} else if (!iotg->hsm.a_sess_vld &&
				!iotg->hsm.vbus_srp_up) {
			langwell_otg_phy_low_power(1);
		}
		break;
	case OTG_STATE_A_WAIT_VRISE:
		if (iotg->hsm.id) {
			langwell_otg_del_timer(a_wait_vrise_tmr);
			iotg->hsm.b_bus_req = 0;
			iotg->otg.default_a = 0;

			/* Turn off VBus */
			iotg->otg.set_vbus(&iotg->otg, false);
			set_client_mode();
			langwell_otg_phy_low_power_wait(1);
			iotg->otg.state = OTG_STATE_B_IDLE;
		} else if (iotg->hsm.a_vbus_vld) {
			langwell_otg_del_timer(a_wait_vrise_tmr);
			iotg->hsm.b_conn = 0;
			if (lnw->iotg.start_host)
				lnw->iotg.start_host(&lnw->iotg);
			else {
				dev_dbg(lnw->dev, "host driver not loaded.\n");
				break;
			}

			langwell_otg_add_ktimer(TA_WAIT_BCON_TMR);
			iotg->otg.state = OTG_STATE_A_WAIT_BCON;
		} else if (iotg->hsm.a_wait_vrise_tmout) {
			iotg->hsm.b_conn = 0;
			if (iotg->hsm.a_vbus_vld) {
				if (lnw->iotg.start_host)
					lnw->iotg.start_host(&lnw->iotg);
				else {
					dev_dbg(lnw->dev,
						"host driver not loaded.\n");
					break;
				}
				langwell_otg_add_ktimer(TA_WAIT_BCON_TMR);
				iotg->otg.state = OTG_STATE_A_WAIT_BCON;
			} else {

				/* Turn off VBus */
				iotg->otg.set_vbus(&iotg->otg, false);
				langwell_otg_phy_low_power_wait(1);
				iotg->otg.state = OTG_STATE_A_VBUS_ERR;
			}
		}
		break;
	case OTG_STATE_A_WAIT_BCON:
		if (iotg->hsm.id) {
			/* delete hsm timer for a_wait_bcon_tmr */
			del_timer_sync(&lnw->hsm_timer);

			iotg->otg.default_a = 0;
			iotg->hsm.b_bus_req = 0;

			if (lnw->iotg.stop_host)
				lnw->iotg.stop_host(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"host driver has been removed.\n");

			/* Turn off VBus */
			iotg->otg.set_vbus(&iotg->otg, false);
			set_client_mode();
			langwell_otg_phy_low_power_wait(1);
			iotg->otg.state = OTG_STATE_B_IDLE;
			langwell_update_transceiver();
		} else if (!iotg->hsm.a_vbus_vld) {
			/* delete hsm timer for a_wait_bcon_tmr */
			del_timer_sync(&lnw->hsm_timer);

			if (lnw->iotg.stop_host)
				lnw->iotg.stop_host(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"host driver has been removed.\n");

			/* Turn off VBus */
			iotg->otg.set_vbus(&iotg->otg, false);
			langwell_otg_phy_low_power_wait(1);
			iotg->otg.state = OTG_STATE_A_VBUS_ERR;
		} else if (iotg->hsm.a_bus_drop ||
				(iotg->hsm.a_wait_bcon_tmout &&
				!iotg->hsm.a_bus_req)) {
			/* delete hsm timer for a_wait_bcon_tmr */
			del_timer_sync(&lnw->hsm_timer);

			if (lnw->iotg.stop_host)
				lnw->iotg.stop_host(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"host driver has been removed.\n");

			/* Turn off VBus */
			iotg->otg.set_vbus(&iotg->otg, false);
			iotg->otg.state = OTG_STATE_A_WAIT_VFALL;
		} else if (iotg->hsm.b_conn) {
			/* delete hsm timer for a_wait_bcon_tmr */
			del_timer_sync(&lnw->hsm_timer);

			iotg->hsm.a_suspend_req = 0;
			iotg->otg.state = OTG_STATE_A_HOST;
			if (iotg->hsm.a_srp_det && iotg->otg.host &&
					!iotg->otg.host->b_hnp_enable) {
				/* SRP capable peripheral-only device */
				iotg->hsm.a_bus_req = 1;
				iotg->hsm.a_srp_det = 0;
			} else if (!iotg->hsm.a_bus_req && iotg->otg.host &&
					iotg->otg.host->b_hnp_enable) {
				/* It is not safe enough to do a fast
				 * transistion from A_WAIT_BCON to
				 * A_SUSPEND */
				msleep(10000);
				if (iotg->hsm.a_bus_req)
					break;

				if (request_irq(pdev->irq,
					otg_dummy_irq, IRQF_SHARED,
					driver_name, iotg->base) != 0) {
					dev_dbg(lnw->dev,
						"request interrupt %d fail\n",
						pdev->irq);
				}

				langwell_otg_HABA(1);
				iotg->hsm.b_bus_resume = 0;
				iotg->hsm.a_aidl_bdis_tmout = 0;

				langwell_otg_loc_sof(0);
				/* clear PHCD to enable HW timer */
				langwell_otg_phy_low_power(0);
				langwell_otg_add_timer(a_aidl_bdis_tmr);
				iotg->otg.state = OTG_STATE_A_SUSPEND;
			} else if (!iotg->hsm.a_bus_req && iotg->otg.host &&
				!iotg->otg.host->b_hnp_enable) {
				if (lnw->iotg.stop_host)
					lnw->iotg.stop_host(&lnw->iotg);
				else
					dev_dbg(lnw->dev,
						"host driver removed.\n");

				/* Turn off VBus */
				iotg->otg.set_vbus(&iotg->otg, false);
				iotg->otg.state = OTG_STATE_A_WAIT_VFALL;
			}
		}
		break;
	case OTG_STATE_A_HOST:
		if (iotg->hsm.id) {
			iotg->otg.default_a = 0;
			iotg->hsm.b_bus_req = 0;

			if (lnw->iotg.stop_host)
				lnw->iotg.stop_host(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"host driver has been removed.\n");

			/* Turn off VBus */
			iotg->otg.set_vbus(&iotg->otg, false);
			set_client_mode();
			langwell_otg_phy_low_power_wait(1);
			iotg->otg.state = OTG_STATE_B_IDLE;
			langwell_update_transceiver();
		} else if (iotg->hsm.a_bus_drop ||
				(iotg->otg.host &&
				!iotg->otg.host->b_hnp_enable &&
					!iotg->hsm.a_bus_req)) {
			if (lnw->iotg.stop_host)
				lnw->iotg.stop_host(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"host driver has been removed.\n");

			/* Turn off VBus */
			iotg->otg.set_vbus(&iotg->otg, false);
			iotg->otg.state = OTG_STATE_A_WAIT_VFALL;
		} else if (!iotg->hsm.a_vbus_vld) {
			if (lnw->iotg.stop_host)
				lnw->iotg.stop_host(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"host driver has been removed.\n");

			/* Turn off VBus */
			iotg->otg.set_vbus(&iotg->otg, false);
			langwell_otg_phy_low_power_wait(1);
			iotg->otg.state = OTG_STATE_A_VBUS_ERR;
		} else if (iotg->otg.host &&
				iotg->otg.host->b_hnp_enable &&
				!iotg->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(pdev->irq, otg_dummy_irq, IRQF_SHARED,
					driver_name, iotg->base) != 0) {
				dev_dbg(lnw->dev,
					"request interrupt %d failed\n",
						pdev->irq);
			}

			/* set HABA */
			langwell_otg_HABA(1);
			iotg->hsm.b_bus_resume = 0;
			iotg->hsm.a_aidl_bdis_tmout = 0;
			langwell_otg_loc_sof(0);
			/* clear PHCD to enable HW timer */
			langwell_otg_phy_low_power(0);
			langwell_otg_add_timer(a_aidl_bdis_tmr);
			iotg->otg.state = OTG_STATE_A_SUSPEND;
		} else if (!iotg->hsm.b_conn || !iotg->hsm.a_bus_req) {
			langwell_otg_add_ktimer(TA_WAIT_BCON_TMR);
			iotg->otg.state = OTG_STATE_A_WAIT_BCON;
		}
		break;
	case OTG_STATE_A_SUSPEND:
		if (iotg->hsm.id) {
			langwell_otg_del_timer(a_aidl_bdis_tmr);
			langwell_otg_HABA(0);
			free_irq(pdev->irq, iotg->base);
			iotg->otg.default_a = 0;
			iotg->hsm.b_bus_req = 0;

			if (lnw->iotg.stop_host)
				lnw->iotg.stop_host(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"host driver has been removed.\n");

			/* Turn off VBus */
			iotg->otg.set_vbus(&iotg->otg, false);
			set_client_mode();
			langwell_otg_phy_low_power(1);
			iotg->otg.state = OTG_STATE_B_IDLE;
			langwell_update_transceiver();
		} else if (iotg->hsm.a_bus_req ||
				iotg->hsm.b_bus_resume) {
			langwell_otg_del_timer(a_aidl_bdis_tmr);
			langwell_otg_HABA(0);
			free_irq(pdev->irq, iotg->base);
			iotg->hsm.a_suspend_req = 0;
			langwell_otg_loc_sof(1);
			iotg->otg.state = OTG_STATE_A_HOST;
		} else if (iotg->hsm.a_aidl_bdis_tmout ||
				iotg->hsm.a_bus_drop) {
			langwell_otg_del_timer(a_aidl_bdis_tmr);
			langwell_otg_HABA(0);
			free_irq(pdev->irq, iotg->base);
			if (lnw->iotg.stop_host)
				lnw->iotg.stop_host(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"host driver has been removed.\n");

			/* Turn off VBus */
			iotg->otg.set_vbus(&iotg->otg, false);
			iotg->otg.state = OTG_STATE_A_WAIT_VFALL;
		} else if (!iotg->hsm.b_conn && iotg->otg.host &&
				iotg->otg.host->b_hnp_enable) {
			langwell_otg_del_timer(a_aidl_bdis_tmr);
			langwell_otg_HABA(0);
			free_irq(pdev->irq, iotg->base);

			if (lnw->iotg.stop_host)
				lnw->iotg.stop_host(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"host driver has been removed.\n");

			iotg->hsm.b_bus_suspend = 0;
			iotg->hsm.b_bus_suspend_vld = 0;

			/* msleep(200); */
			if (lnw->iotg.start_peripheral)
				lnw->iotg.start_peripheral(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"client driver not loaded.\n");

			langwell_otg_add_ktimer(TB_BUS_SUSPEND_TMR);
			iotg->otg.state = OTG_STATE_A_PERIPHERAL;
			break;
		} else if (!iotg->hsm.a_vbus_vld) {
			langwell_otg_del_timer(a_aidl_bdis_tmr);
			langwell_otg_HABA(0);
			free_irq(pdev->irq, iotg->base);
			if (lnw->iotg.stop_host)
				lnw->iotg.stop_host(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"host driver has been removed.\n");

			/* Turn off VBus */
			iotg->otg.set_vbus(&iotg->otg, false);
			langwell_otg_phy_low_power_wait(1);
			iotg->otg.state = OTG_STATE_A_VBUS_ERR;
		}
		break;
	case OTG_STATE_A_PERIPHERAL:
		if (iotg->hsm.id) {
			/* delete hsm timer for b_bus_suspend_tmr */
			del_timer_sync(&lnw->hsm_timer);
			iotg->otg.default_a = 0;
			iotg->hsm.b_bus_req = 0;
			if (lnw->iotg.stop_peripheral)
				lnw->iotg.stop_peripheral(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"client driver has been removed.\n");

			/* Turn off VBus */
			iotg->otg.set_vbus(&iotg->otg, false);
			set_client_mode();
			langwell_otg_phy_low_power_wait(1);
			iotg->otg.state = OTG_STATE_B_IDLE;
			langwell_update_transceiver();
		} else if (!iotg->hsm.a_vbus_vld) {
			/* delete hsm timer for b_bus_suspend_tmr */
			del_timer_sync(&lnw->hsm_timer);

			if (lnw->iotg.stop_peripheral)
				lnw->iotg.stop_peripheral(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"client driver has been removed.\n");

			/* Turn off VBus */
			iotg->otg.set_vbus(&iotg->otg, false);
			langwell_otg_phy_low_power_wait(1);
			iotg->otg.state = OTG_STATE_A_VBUS_ERR;
		} else if (iotg->hsm.a_bus_drop) {
			/* delete hsm timer for b_bus_suspend_tmr */
			del_timer_sync(&lnw->hsm_timer);

			if (lnw->iotg.stop_peripheral)
				lnw->iotg.stop_peripheral(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"client driver has been removed.\n");

			/* Turn off VBus */
			iotg->otg.set_vbus(&iotg->otg, false);
			iotg->otg.state = OTG_STATE_A_WAIT_VFALL;
		} else if (iotg->hsm.b_bus_suspend) {
			/* delete hsm timer for b_bus_suspend_tmr */
			del_timer_sync(&lnw->hsm_timer);

			if (lnw->iotg.stop_peripheral)
				lnw->iotg.stop_peripheral(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"client driver has been removed.\n");

			if (lnw->iotg.start_host)
				lnw->iotg.start_host(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
						"host driver not loaded.\n");
			langwell_otg_add_ktimer(TA_WAIT_BCON_TMR);
			iotg->otg.state = OTG_STATE_A_WAIT_BCON;
		} else if (iotg->hsm.b_bus_suspend_tmout) {
			u32	val;
			val = readl(lnw->iotg.base + CI_PORTSC1);
			if (!(val & PORTSC_SUSP))
				break;

			if (lnw->iotg.stop_peripheral)
				lnw->iotg.stop_peripheral(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
					"client driver has been removed.\n");

			if (lnw->iotg.start_host)
				lnw->iotg.start_host(&lnw->iotg);
			else
				dev_dbg(lnw->dev,
						"host driver not loaded.\n");
			langwell_otg_add_ktimer(TA_WAIT_BCON_TMR);
			iotg->otg.state = OTG_STATE_A_WAIT_BCON;
		}
		break;
	case OTG_STATE_A_VBUS_ERR:
		if (iotg->hsm.id) {
			iotg->otg.default_a = 0;
			iotg->hsm.a_clr_err = 0;
			iotg->hsm.a_srp_det = 0;
			set_client_mode();
			langwell_otg_phy_low_power(1);
			iotg->otg.state = OTG_STATE_B_IDLE;
			langwell_update_transceiver();
		} else if (iotg->hsm.a_clr_err) {
			iotg->hsm.a_clr_err = 0;
			iotg->hsm.a_srp_det = 0;
			reset_otg();
			init_hsm();
			if (iotg->otg.state == OTG_STATE_A_IDLE)
				langwell_update_transceiver();
		} else {
			/* FW will clear PHCD bit when any VBus
			 * event detected. Reset PHCD to 1 again */
			langwell_otg_phy_low_power(1);
		}
		break;
	case OTG_STATE_A_WAIT_VFALL:
		if (iotg->hsm.id) {
			iotg->otg.default_a = 0;
			set_client_mode();
			langwell_otg_phy_low_power(1);
			iotg->otg.state = OTG_STATE_B_IDLE;
			langwell_update_transceiver();
		} else if (iotg->hsm.a_bus_req) {

			/* Turn on VBus */
			iotg->otg.set_vbus(&iotg->otg, true);
			iotg->hsm.a_wait_vrise_tmout = 0;
			langwell_otg_add_timer(a_wait_vrise_tmr);
			iotg->otg.state = OTG_STATE_A_WAIT_VRISE;
		} else if (!iotg->hsm.a_sess_vld) {
			iotg->hsm.a_srp_det = 0;
			set_host_mode();
			langwell_otg_phy_low_power(1);
			iotg->otg.state = OTG_STATE_A_IDLE;
		}
		break;
	default:
		;
	}

	dev_dbg(lnw->dev, "%s: new state = %s\n", __func__,
			state_string(iotg->otg.state));
}

static ssize_t
show_registers(struct device *_dev, struct device_attribute *attr, char *buf)
{
	struct langwell_otg	*lnw = the_transceiver;
	char			*next;
	unsigned		size, t;

	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(lnw->iotg.base + 0x30),
		readl(lnw->iotg.base + 0x34),
		readl(lnw->iotg.base + 0x38),
		readl(lnw->iotg.base + 0x48),
		readl(lnw->iotg.base + 0x74),
		readl(lnw->iotg.base + 0xb4),
		readl(lnw->iotg.base + 0xf4),
		readl(lnw->iotg.base + 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		*lnw = the_transceiver;
	struct intel_mid_otg_xceiv	*iotg = &lnw->iotg;
	char				*next;
	unsigned			size, t;

	next = buf;
	size = PAGE_SIZE;

	if (iotg->otg.host)
		iotg->hsm.a_set_b_hnp_en = iotg->otg.host->b_hnp_enable;

	if (iotg->otg.gadget)
		iotg->hsm.b_hnp_enable = iotg->otg.gadget->b_hnp_enable;

	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(iotg->otg.state),
		iotg->hsm.a_bus_resume,
		iotg->hsm.a_bus_suspend,
		iotg->hsm.a_conn,
		iotg->hsm.a_sess_vld,
		iotg->hsm.a_srp_det,
		iotg->hsm.a_vbus_vld,
		iotg->hsm.b_bus_resume,
		iotg->hsm.b_bus_suspend,
		iotg->hsm.b_conn,
		iotg->hsm.b_se0_srp,
		iotg->hsm.b_sess_end,
		iotg->hsm.b_sess_vld,
		iotg->hsm.id,
		iotg->hsm.a_set_b_hnp_en,
		iotg->hsm.b_srp_done,
		iotg->hsm.b_hnp_enable,
		iotg->hsm.a_wait_vrise_tmout,
		iotg->hsm.a_wait_bcon_tmout,
		iotg->hsm.a_aidl_bdis_tmout,
		iotg->hsm.b_ase0_brst_tmout,
		iotg->hsm.a_bus_drop,
		iotg->hsm.a_bus_req,
		iotg->hsm.a_clr_err,
		iotg->hsm.a_suspend_req,
		iotg->hsm.b_bus_req,
		iotg->hsm.b_bus_suspend_tmout,
		iotg->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	*lnw = the_transceiver;
	char			*next;
	unsigned		size, t;

	next = buf;
	size = PAGE_SIZE;

	t = scnprintf(next, size, "%d", lnw->iotg.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		*lnw = the_transceiver;
	struct intel_mid_otg_xceiv	*iotg = &lnw->iotg;

	if (!iotg->otg.default_a)
		return -1;
	if (count > 2)
		return -1;

	if (buf[0] == '0') {
		iotg->hsm.a_bus_req = 0;
		dev_dbg(lnw->dev, "User request: a_bus_req = 0\n");
	} else if (buf[0] == '1') {
		/* If a_bus_drop is TRUE, a_bus_req can't be set */
		if (iotg->hsm.a_bus_drop)
			return -1;
		iotg->hsm.a_bus_req = 1;
		dev_dbg(lnw->dev, "User request: a_bus_req = 1\n");
	}
	if (spin_trylock(&lnw->wq_lock)) {
		langwell_update_transceiver();
		spin_unlock(&lnw->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	*lnw = the_transceiver;
	char			*next;
	unsigned		size, t;

	next = buf;
	size = PAGE_SIZE;

	t = scnprintf(next, size, "%d", lnw->iotg.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		*lnw = the_transceiver;
	struct intel_mid_otg_xceiv	*iotg = &lnw->iotg;

	if (!iotg->otg.default_a)
		return -1;
	if (count > 2)
		return -1;

	if (buf[0] == '0') {
		iotg->hsm.a_bus_drop = 0;
		dev_dbg(lnw->dev, "User request: a_bus_drop = 0\n");
	} else if (buf[0] == '1') {
		iotg->hsm.a_bus_drop = 1;
		iotg->hsm.a_bus_req = 0;
		dev_dbg(lnw->dev, "User request: a_bus_drop = 1\n");
		dev_dbg(lnw->dev, "User request: and a_bus_req = 0\n");
	}
	if (spin_trylock(&lnw->wq_lock)) {
		langwell_update_transceiver();
		spin_unlock(&lnw->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	*lnw = the_transceiver;
	char			*next;
	unsigned		size, t;

	next = buf;
	size = PAGE_SIZE;

	t = scnprintf(next, size, "%d", lnw->iotg.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		*lnw = the_transceiver;
	struct intel_mid_otg_xceiv	*iotg = &lnw->iotg;

	if (iotg->otg.default_a)
		return -1;

	if (count > 2)
		return -1;

	if (buf[0] == '0') {
		iotg->hsm.b_bus_req = 0;
		dev_dbg(lnw->dev, "User request: b_bus_req = 0\n");
	} else if (buf[0] == '1') {
		iotg->hsm.b_bus_req = 1;
		dev_dbg(lnw->dev, "User request: b_bus_req = 1\n");
	}
	if (spin_trylock(&lnw->wq_lock)) {
		langwell_update_transceiver();
		spin_unlock(&lnw->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		*lnw = the_transceiver;
	struct intel_mid_otg_xceiv	*iotg = &lnw->iotg;

	if (!iotg->otg.default_a)
		return -1;
	if (count > 2)
		return -1;

	if (buf[0] == '1') {
		iotg->hsm.a_clr_err = 1;
		dev_dbg(lnw->dev, "User request: a_clr_err = 1\n");
	}
	if (spin_trylock(&lnw->wq_lock)) {
		langwell_update_transceiver();
		spin_unlock(&lnw->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,
};

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	*lnw;
	char			qname[] = "langwell_otg_queue";

	retval = 0;
	dev_dbg(&pdev->dev, "\notg controller is detected.\n");
	if (pci_enable_device(pdev) < 0) {
		retval = -ENODEV;
		goto done;
	}

	lnw = kzalloc(sizeof *lnw, GFP_KERNEL);
	if (lnw == NULL) {
		retval = -ENOMEM;
		goto done;
	}
	the_transceiver = lnw;

	/* 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;
	}
	lnw->region = 1;

	base = ioremap_nocache(resource, len);
	if (base == NULL) {
		retval = -EFAULT;
		goto err;
	}
	lnw->iotg.base = base;

	if (!request_mem_region(USBCFG_ADDR, USBCFG_LEN, driver_name)) {
		retval = -EBUSY;
		goto err;
	}
	lnw->cfg_region = 1;

	/* For the SCCB.USBCFG register */
	base = ioremap_nocache(USBCFG_ADDR, USBCFG_LEN);
	if (base == NULL) {
		retval = -EFAULT;
		goto err;
	}
	lnw->usbcfg = base;

	if (!pdev->irq) {
		dev_dbg(&pdev->dev, "No IRQ.\n");
		retval = -ENODEV;
		goto err;
	}

	lnw->qwork = create_singlethread_workqueue(qname);
	if (!lnw->qwork) {
		dev_dbg(&pdev->dev, "cannot create workqueue %s\n", qname);
		retval = -ENOMEM;
		goto err;
	}
	INIT_WORK(&lnw->work, langwell_otg_work);

	/* OTG common part */
	lnw->dev = &pdev->dev;
	lnw->iotg.otg.dev = lnw->dev;
	lnw->iotg.otg.label = driver_name;
	lnw->iotg.otg.set_host = langwell_otg_set_host;
	lnw->iotg.otg.set_peripheral = langwell_otg_set_peripheral;
	lnw->iotg.otg.set_power = langwell_otg_set_power;
	lnw->iotg.otg.set_vbus = langwell_otg_set_vbus;
	lnw->iotg.otg.start_srp = langwell_otg_start_srp;
	lnw->iotg.otg.state = OTG_STATE_UNDEFINED;

	if (otg_set_transceiver(&lnw->iotg.otg)) {
		dev_dbg(lnw->dev, "can't set transceiver\n");
		retval = -EBUSY;
		goto err;
	}

	reset_otg();
	init_hsm();

	spin_lock_init(&lnw->lock);
	spin_lock_init(&lnw->wq_lock);
	INIT_LIST_HEAD(&active_timers);
	retval = langwell_otg_init_timers(&lnw->iotg.hsm);
	if (retval) {
		dev_dbg(&pdev->dev, "Failed to init timers\n");
		goto err;
	}

	init_timer(&lnw->hsm_timer);
	ATOMIC_INIT_NOTIFIER_HEAD(&lnw->iotg.iotg_notifier);

	lnw->iotg_notifier.notifier_call = langwell_otg_iotg_notify;

	retval = intel_mid_otg_register_notifier(&lnw->iotg,
						&lnw->iotg_notifier);
	if (retval) {
		dev_dbg(lnw->dev, "Failed to register notifier\n");
		goto err;
	}

	if (request_irq(pdev->irq, otg_irq, IRQF_SHARED,
				driver_name, lnw) != 0) {
		dev_dbg(lnw->dev, "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, lnw->iotg.base + CI_OTGSC);

	retval = device_create_file(&pdev->dev, &dev_attr_registers);
	if (retval < 0) {
		dev_dbg(lnw->dev,
			"Can't register sysfs attribute: %d\n", retval);
		goto err;
	}

	retval = device_create_file(&pdev->dev, &dev_attr_hsm);
	if (retval < 0) {
		dev_dbg(lnw->dev, "Can't hsm sysfs attribute: %d\n", retval);
		goto err;
	}

	retval = sysfs_create_group(&pdev->dev.kobj, &debug_dev_attr_group);
	if (retval < 0) {
		dev_dbg(lnw->dev,
			"Can't register sysfs attr group: %d\n", retval);
		goto err;
	}

	if (lnw->iotg.otg.state == OTG_STATE_A_IDLE)
		langwell_update_transceiver();

	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 *lnw = the_transceiver;

	if (lnw->qwork) {
		flush_workqueue(lnw->qwork);
		destroy_workqueue(lnw->qwork);
	}
	intel_mid_otg_unregister_notifier(&lnw->iotg, &lnw->iotg_notifier);
	langwell_otg_free_timers();

	/* disable OTGSC interrupt as OTGSC doesn't change in reset */
	writel(0, lnw->iotg.base + CI_OTGSC);

	if (pdev->irq)
		free_irq(pdev->irq, lnw);
	if (lnw->usbcfg)
		iounmap(lnw->usbcfg);
	if (lnw->cfg_region)
		release_mem_region(USBCFG_ADDR, USBCFG_LEN);
	if (lnw->iotg.base)
		iounmap(lnw->iotg.base);
	if (lnw->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(lnw);
	lnw = 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)
{
	struct langwell_otg		*lnw = the_transceiver;
	struct intel_mid_otg_xceiv	*iotg = &lnw->iotg;
	int				ret = 0;

	/* Disbale OTG interrupts */
	langwell_otg_intr(0);

	if (pdev->irq)
		free_irq(pdev->irq, lnw);

	/* Prevent more otg_work */
	flush_workqueue(lnw->qwork);
	destroy_workqueue(lnw->qwork);
	lnw->qwork = NULL;

	/* start actions */
	switch (iotg->otg.state) {
	case OTG_STATE_A_WAIT_VFALL:
		iotg->otg.state = OTG_STATE_A_IDLE;
	case OTG_STATE_A_IDLE:
	case OTG_STATE_B_IDLE:
	case OTG_STATE_A_VBUS_ERR:
		transceiver_suspend(pdev);
		break;
	case OTG_STATE_A_WAIT_VRISE:
		langwell_otg_del_timer(a_wait_vrise_tmr);
		iotg->hsm.a_srp_det = 0;

		/* Turn off VBus */
		iotg->otg.set_vbus(&iotg->otg, false);
		iotg->otg.state = OTG_STATE_A_IDLE;
		transceiver_suspend(pdev);
		break;
	case OTG_STATE_A_WAIT_BCON:
		del_timer_sync(&lnw->hsm_timer);
		if (lnw->iotg.stop_host)
			lnw->iotg.stop_host(&lnw->iotg);
		else
			dev_dbg(&pdev->dev, "host driver has been removed.\n");

		iotg->hsm.a_srp_det = 0;

		/* Turn off VBus */
		iotg->otg.set_vbus(&iotg->otg, false);
		iotg->otg.state = OTG_STATE_A_IDLE;
		transceiver_suspend(pdev);
		break;
	case OTG_STATE_A_HOST:
		if (lnw->iotg.stop_host)
			lnw->iotg.stop_host(&lnw->iotg);
		else
			dev_dbg(&pdev->dev, "host driver has been removed.\n");

		iotg->hsm.a_srp_det = 0;

		/* Turn off VBus */
		iotg->otg.set_vbus(&iotg->otg, false);

		iotg->otg.state = OTG_STATE_A_IDLE;
		transceiver_suspend(pdev);
		break;
	case OTG_STATE_A_SUSPEND:
		langwell_otg_del_timer(a_aidl_bdis_tmr);
		langwell_otg_HABA(0);
		if (lnw->iotg.stop_host)
			lnw->iotg.stop_host(&lnw->iotg);
		else
			dev_dbg(lnw->dev, "host driver has been removed.\n");
		iotg->hsm.a_srp_det = 0;

		/* Turn off VBus */
		iotg->otg.set_vbus(&iotg->otg, false);
		iotg->otg.state = OTG_STATE_A_IDLE;
		transceiver_suspend(pdev);
		break;
	case OTG_STATE_A_PERIPHERAL:
		del_timer_sync(&lnw->hsm_timer);

		if (lnw->iotg.stop_peripheral)
			lnw->iotg.stop_peripheral(&lnw->iotg);
		else
			dev_dbg(&pdev->dev,
				"client driver has been removed.\n");
		iotg->hsm.a_srp_det = 0;

		/* Turn off VBus */
		iotg->otg.set_vbus(&iotg->otg, false);
		iotg->otg.state = OTG_STATE_A_IDLE;
		transceiver_suspend(pdev);
		break;
	case OTG_STATE_B_HOST:
		if (lnw->iotg.stop_host)
			lnw->iotg.stop_host(&lnw->iotg);
		else
			dev_dbg(&pdev->dev, "host driver has been removed.\n");
		iotg->hsm.b_bus_req = 0;
		iotg->otg.state = OTG_STATE_B_IDLE;
		transceiver_suspend(pdev);
		break;
	case OTG_STATE_B_PERIPHERAL:
		if (lnw->iotg.stop_peripheral)
			lnw->iotg.stop_peripheral(&lnw->iotg);
		else
			dev_dbg(&pdev->dev,
				"client driver has been removed.\n");
		iotg->otg.state = OTG_STATE_B_IDLE;
		transceiver_suspend(pdev);
		break;
	case OTG_STATE_B_WAIT_ACON:
		/* delete hsm timer for b_ase0_brst_tmr */
		del_timer_sync(&lnw->hsm_timer);

		langwell_otg_HAAR(0);

		if (lnw->iotg.stop_host)
			lnw->iotg.stop_host(&lnw->iotg);
		else
			dev_dbg(&pdev->dev, "host driver has been removed.\n");
		iotg->hsm.b_bus_req = 0;
		iotg->otg.state = OTG_STATE_B_IDLE;
		transceiver_suspend(pdev);
		break;
	default:
		dev_dbg(lnw->dev, "error state before suspend\n");
		break;
	}

	return ret;
}

static void transceiver_resume(struct pci_dev *pdev)
{
	pci_restore_state(pdev);
	pci_set_power_state(pdev, PCI_D0);
}

static int langwell_otg_resume(struct pci_dev *pdev)
{
	struct langwell_otg	*lnw = the_transceiver;
	int			ret = 0;

	transceiver_resume(pdev);

	lnw->qwork = create_singlethread_workqueue("langwell_otg_queue");
	if (!lnw->qwork) {
		dev_dbg(&pdev->dev, "cannot create langwell otg workqueuen");
		ret = -ENOMEM;
		goto error;
	}

	if (request_irq(pdev->irq, otg_irq, IRQF_SHARED,
				driver_name, lnw) != 0) {
		dev_dbg(&pdev->dev, "request interrupt %d failed\n", pdev->irq);
		ret = -EBUSY;
		goto error;
	}

	/* enable OTG interrupts */
	langwell_otg_intr(1);

	update_hsm();

	langwell_update_transceiver();

	return ret;
error:
	langwell_otg_intr(0);
	transceiver_suspend(pdev);
	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);