drivers/usb/phy/phy-tahvo.c - kernel/msm-4.19 - Gitiles

 /*
  * Tahvo USB transceiver driver
  *
  * Copyright (C) 2005-2006 Nokia Corporation
  *
  * Parts copied from isp1301_omap.c.
  * Copyright (C) 2004 Texas Instruments
  * Copyright (C) 2004 David Brownell
  *
  * Original driver written by Juha Yrjölä, Tony Lindgren and Timo Teräs.
  * Modified for Retu/Tahvo MFD by Aaro Koskinen.
  *
  * This file is subject to the terms and conditions of the GNU General
  * Public License. See the file "COPYING" in the main directory of this
  * archive for more details.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  * GNU General Public License for more details.
  */

 #include <linux/io.h>
 #include <linux/clk.h>
 #include <linux/usb.h>
 #include <linux/extcon.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/usb/otg.h>
 #include <linux/mfd/retu.h>
 #include <linux/usb/gadget.h>
 #include <linux/platform_device.h>

 #define DRIVER_NAME     "tahvo-usb"

 #define TAHVO_REG_IDSR	0x02
 #define TAHVO_REG_USBR	0x06

 #define USBR_SLAVE_CONTROL	(1 << 8)
 #define USBR_VPPVIO_SW		(1 << 7)
 #define USBR_SPEED		(1 << 6)
 #define USBR_REGOUT		(1 << 5)
 #define USBR_MASTER_SW2		(1 << 4)
 #define USBR_MASTER_SW1		(1 << 3)
 #define USBR_SLAVE_SW		(1 << 2)
 #define USBR_NSUSPEND		(1 << 1)
 #define USBR_SEMODE		(1 << 0)

 #define TAHVO_MODE_HOST		0
 #define TAHVO_MODE_PERIPHERAL	1

 struct tahvo_usb {
 	struct platform_device	*pt_dev;
 	struct usb_phy		phy;
 	int			vbus_state;
 	struct mutex		serialize;
 	struct clk		*ick;
 	int			irq;
 	int			tahvo_mode;
 	struct extcon_dev	*extcon;
 };

 static const unsigned int tahvo_cable[] = {
 	EXTCON_USB,
 	EXTCON_USB_HOST,

 	EXTCON_NONE,
 };

 static ssize_t vbus_state_show(struct device *device,
 			       struct device_attribute *attr, char *buf)
 {
 	struct tahvo_usb *tu = dev_get_drvdata(device);
 	return sprintf(buf, "%s\n", tu->vbus_state ? "on" : "off");
 }
 static DEVICE_ATTR(vbus, 0444, vbus_state_show, NULL);

 static void check_vbus_state(struct tahvo_usb *tu)
 {
 	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
 	int reg, prev_state;

 	reg = retu_read(rdev, TAHVO_REG_IDSR);
 	if (reg & TAHVO_STAT_VBUS) {
 		switch (tu->phy.otg->state) {
 		case OTG_STATE_B_IDLE:
 			/* Enable the gadget driver */
 			if (tu->phy.otg->gadget)
 				usb_gadget_vbus_connect(tu->phy.otg->gadget);
 			tu->phy.otg->state = OTG_STATE_B_PERIPHERAL;
 			usb_phy_set_event(&tu->phy, USB_EVENT_ENUMERATED);
 			break;
 		case OTG_STATE_A_IDLE:
 			/*
 			 * Session is now valid assuming the USB hub is driving
 			 * Vbus.
 			 */
 			tu->phy.otg->state = OTG_STATE_A_HOST;
 			break;
 		default:
 			break;
 		}
 		dev_info(&tu->pt_dev->dev, "USB cable connected\n");
 	} else {
 		switch (tu->phy.otg->state) {
 		case OTG_STATE_B_PERIPHERAL:
 			if (tu->phy.otg->gadget)
 				usb_gadget_vbus_disconnect(tu->phy.otg->gadget);
 			tu->phy.otg->state = OTG_STATE_B_IDLE;
 			usb_phy_set_event(&tu->phy, USB_EVENT_NONE);
 			break;
 		case OTG_STATE_A_HOST:
 			tu->phy.otg->state = OTG_STATE_A_IDLE;
 			break;
 		default:
 			break;
 		}
 		dev_info(&tu->pt_dev->dev, "USB cable disconnected\n");
 	}

 	prev_state = tu->vbus_state;
 	tu->vbus_state = reg & TAHVO_STAT_VBUS;
 	if (prev_state != tu->vbus_state) {
 		extcon_set_state_sync(tu->extcon, EXTCON_USB, tu->vbus_state);
 		sysfs_notify(&tu->pt_dev->dev.kobj, NULL, "vbus_state");
 	}
 }

 static void tahvo_usb_become_host(struct tahvo_usb *tu)
 {
 	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);

 	extcon_set_state_sync(tu->extcon, EXTCON_USB_HOST, true);

 	/* Power up the transceiver in USB host mode */
 	retu_write(rdev, TAHVO_REG_USBR, USBR_REGOUT | USBR_NSUSPEND |
 		   USBR_MASTER_SW2 | USBR_MASTER_SW1);
 	tu->phy.otg->state = OTG_STATE_A_IDLE;

 	check_vbus_state(tu);
 }

 static void tahvo_usb_stop_host(struct tahvo_usb *tu)
 {
 	tu->phy.otg->state = OTG_STATE_A_IDLE;
 }

 static void tahvo_usb_become_peripheral(struct tahvo_usb *tu)
 {
 	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);

 	extcon_set_state_sync(tu->extcon, EXTCON_USB_HOST, false);

 	/* Power up transceiver and set it in USB peripheral mode */
 	retu_write(rdev, TAHVO_REG_USBR, USBR_SLAVE_CONTROL | USBR_REGOUT |
 		   USBR_NSUSPEND | USBR_SLAVE_SW);
 	tu->phy.otg->state = OTG_STATE_B_IDLE;

 	check_vbus_state(tu);
 }

 static void tahvo_usb_stop_peripheral(struct tahvo_usb *tu)
 {
 	if (tu->phy.otg->gadget)
 		usb_gadget_vbus_disconnect(tu->phy.otg->gadget);
 	tu->phy.otg->state = OTG_STATE_B_IDLE;
 }

 static void tahvo_usb_power_off(struct tahvo_usb *tu)
 {
 	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);

 	/* Disable gadget controller if any */
 	if (tu->phy.otg->gadget)
 		usb_gadget_vbus_disconnect(tu->phy.otg->gadget);

 	/* Power off transceiver */
 	retu_write(rdev, TAHVO_REG_USBR, 0);
 	tu->phy.otg->state = OTG_STATE_UNDEFINED;
 }

 static int tahvo_usb_set_suspend(struct usb_phy *dev, int suspend)
 {
 	struct tahvo_usb *tu = container_of(dev, struct tahvo_usb, phy);
 	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
 	u16 w;

 	dev_dbg(&tu->pt_dev->dev, "%s\n", __func__);

 	w = retu_read(rdev, TAHVO_REG_USBR);
 	if (suspend)
 		w &= ~USBR_NSUSPEND;
 	else
 		w |= USBR_NSUSPEND;
 	retu_write(rdev, TAHVO_REG_USBR, w);

 	return 0;
 }

 static int tahvo_usb_set_host(struct usb_otg *otg, struct usb_bus *host)
 {
 	struct tahvo_usb *tu = container_of(otg->usb_phy, struct tahvo_usb,
 					    phy);

 	dev_dbg(&tu->pt_dev->dev, "%s %p\n", __func__, host);

 	mutex_lock(&tu->serialize);

 	if (host == NULL) {
 		if (tu->tahvo_mode == TAHVO_MODE_HOST)
 			tahvo_usb_power_off(tu);
 		otg->host = NULL;
 		mutex_unlock(&tu->serialize);
 		return 0;
 	}

 	if (tu->tahvo_mode == TAHVO_MODE_HOST) {
 		otg->host = NULL;
 		tahvo_usb_become_host(tu);
 	}

 	otg->host = host;

 	mutex_unlock(&tu->serialize);

 	return 0;
 }

 static int tahvo_usb_set_peripheral(struct usb_otg *otg,
 				    struct usb_gadget *gadget)
 {
 	struct tahvo_usb *tu = container_of(otg->usb_phy, struct tahvo_usb,
 					    phy);

 	dev_dbg(&tu->pt_dev->dev, "%s %p\n", __func__, gadget);

 	mutex_lock(&tu->serialize);

 	if (!gadget) {
 		if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
 			tahvo_usb_power_off(tu);
 		tu->phy.otg->gadget = NULL;
 		mutex_unlock(&tu->serialize);
 		return 0;
 	}

 	tu->phy.otg->gadget = gadget;
 	if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
 		tahvo_usb_become_peripheral(tu);

 	mutex_unlock(&tu->serialize);

 	return 0;
 }

 static irqreturn_t tahvo_usb_vbus_interrupt(int irq, void *_tu)
 {
 	struct tahvo_usb *tu = _tu;

 	mutex_lock(&tu->serialize);
 	check_vbus_state(tu);
 	mutex_unlock(&tu->serialize);

 	return IRQ_HANDLED;
 }

 static ssize_t otg_mode_show(struct device *device,
 			     struct device_attribute *attr, char *buf)
 {
 	struct tahvo_usb *tu = dev_get_drvdata(device);

 	switch (tu->tahvo_mode) {
 	case TAHVO_MODE_HOST:
 		return sprintf(buf, "host\n");
 	case TAHVO_MODE_PERIPHERAL:
 		return sprintf(buf, "peripheral\n");
 	}

 	return -EINVAL;
 }

 static ssize_t otg_mode_store(struct device *device,
 			      struct device_attribute *attr,
 			      const char *buf, size_t count)
 {
 	struct tahvo_usb *tu = dev_get_drvdata(device);
 	int r;

 	mutex_lock(&tu->serialize);
 	if (count >= 4 && strncmp(buf, "host", 4) == 0) {
 		if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
 			tahvo_usb_stop_peripheral(tu);
 		tu->tahvo_mode = TAHVO_MODE_HOST;
 		if (tu->phy.otg->host) {
 			dev_info(device, "HOST mode: host controller present\n");
 			tahvo_usb_become_host(tu);
 		} else {
 			dev_info(device, "HOST mode: no host controller, powering off\n");
 			tahvo_usb_power_off(tu);
 		}
 		r = strlen(buf);
 	} else if (count >= 10 && strncmp(buf, "peripheral", 10) == 0) {
 		if (tu->tahvo_mode == TAHVO_MODE_HOST)
 			tahvo_usb_stop_host(tu);
 		tu->tahvo_mode = TAHVO_MODE_PERIPHERAL;
 		if (tu->phy.otg->gadget) {
 			dev_info(device, "PERIPHERAL mode: gadget driver present\n");
 			tahvo_usb_become_peripheral(tu);
 		} else {
 			dev_info(device, "PERIPHERAL mode: no gadget driver, powering off\n");
 			tahvo_usb_power_off(tu);
 		}
 		r = strlen(buf);
 	} else {
 		r = -EINVAL;
 	}
 	mutex_unlock(&tu->serialize);

 	return r;
 }
 static DEVICE_ATTR(otg_mode, 0644, otg_mode_show, otg_mode_store);

 static struct attribute *tahvo_attributes[] = {
 	&dev_attr_vbus.attr,
 	&dev_attr_otg_mode.attr,
 	NULL
 };

 static struct attribute_group tahvo_attr_group = {
 	.attrs = tahvo_attributes,
 };

 static int tahvo_usb_probe(struct platform_device *pdev)
 {
 	struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent);
 	struct tahvo_usb *tu;
 	int ret;

 	tu = devm_kzalloc(&pdev->dev, sizeof(*tu), GFP_KERNEL);
 	if (!tu)
 		return -ENOMEM;

 	tu->phy.otg = devm_kzalloc(&pdev->dev, sizeof(*tu->phy.otg),
 				   GFP_KERNEL);
 	if (!tu->phy.otg)
 		return -ENOMEM;

 	tu->pt_dev = pdev;

 	/* Default mode */
 #ifdef CONFIG_TAHVO_USB_HOST_BY_DEFAULT
 	tu->tahvo_mode = TAHVO_MODE_HOST;
 #else
 	tu->tahvo_mode = TAHVO_MODE_PERIPHERAL;
 #endif

 	mutex_init(&tu->serialize);

 	tu->ick = devm_clk_get(&pdev->dev, "usb_l4_ick");
 	if (!IS_ERR(tu->ick))
 		clk_enable(tu->ick);

 	/*
 	 * Set initial state, so that we generate kevents only on state changes.
 	 */
 	tu->vbus_state = retu_read(rdev, TAHVO_REG_IDSR) & TAHVO_STAT_VBUS;

 	tu->extcon = devm_extcon_dev_allocate(&pdev->dev, tahvo_cable);
 	if (IS_ERR(tu->extcon)) {
 		dev_err(&pdev->dev, "failed to allocate memory for extcon\n");
 		return -ENOMEM;
 	}

 	ret = devm_extcon_dev_register(&pdev->dev, tu->extcon);
 	if (ret) {
 		dev_err(&pdev->dev, "could not register extcon device: %d\n",
 			ret);
 		goto err_disable_clk;
 	}

 	/* Set the initial cable state. */
 	extcon_set_state_sync(tu->extcon, EXTCON_USB_HOST,
 			       tu->tahvo_mode == TAHVO_MODE_HOST);
 	extcon_set_state_sync(tu->extcon, EXTCON_USB, tu->vbus_state);

 	/* Create OTG interface */
 	tahvo_usb_power_off(tu);
 	tu->phy.dev = &pdev->dev;
 	tu->phy.otg->state = OTG_STATE_UNDEFINED;
 	tu->phy.label = DRIVER_NAME;
 	tu->phy.set_suspend = tahvo_usb_set_suspend;

 	tu->phy.otg->usb_phy = &tu->phy;
 	tu->phy.otg->set_host = tahvo_usb_set_host;
 	tu->phy.otg->set_peripheral = tahvo_usb_set_peripheral;

 	ret = usb_add_phy(&tu->phy, USB_PHY_TYPE_USB2);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "cannot register USB transceiver: %d\n",
 			ret);
 		goto err_disable_clk;
 	}

 	dev_set_drvdata(&pdev->dev, tu);

 	tu->irq = platform_get_irq(pdev, 0);
 	ret = request_threaded_irq(tu->irq, NULL, tahvo_usb_vbus_interrupt,
 				   IRQF_ONESHOT,
 				   "tahvo-vbus", tu);
 	if (ret) {
 		dev_err(&pdev->dev, "could not register tahvo-vbus irq: %d\n",
 			ret);
 		goto err_remove_phy;
 	}

 	/* Attributes */
 	ret = sysfs_create_group(&pdev->dev.kobj, &tahvo_attr_group);
 	if (ret) {
 		dev_err(&pdev->dev, "cannot create sysfs group: %d\n", ret);
 		goto err_free_irq;
 	}

 	return 0;

 err_free_irq:
 	free_irq(tu->irq, tu);
 err_remove_phy:
 	usb_remove_phy(&tu->phy);
 err_disable_clk:
 	if (!IS_ERR(tu->ick))
 		clk_disable(tu->ick);

 	return ret;
 }

 static int tahvo_usb_remove(struct platform_device *pdev)
 {
 	struct tahvo_usb *tu = platform_get_drvdata(pdev);

 	sysfs_remove_group(&pdev->dev.kobj, &tahvo_attr_group);
 	free_irq(tu->irq, tu);
 	usb_remove_phy(&tu->phy);
 	if (!IS_ERR(tu->ick))
 		clk_disable(tu->ick);

 	return 0;
 }

 static struct platform_driver tahvo_usb_driver = {
 	.probe		= tahvo_usb_probe,
 	.remove		= tahvo_usb_remove,
 	.driver		= {
 		.name	= "tahvo-usb",
 	},
 };
 module_platform_driver(tahvo_usb_driver);

 MODULE_DESCRIPTION("Tahvo USB transceiver driver");
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Juha Yrjölä, Tony Lindgren, and Timo Teräs");
 MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>");
	/*
	* Tahvo USB transceiver driver
	*
	* Copyright (C) 2005-2006 Nokia Corporation
	*
	* Parts copied from isp1301_omap.c.
	* Copyright (C) 2004 Texas Instruments
	* Copyright (C) 2004 David Brownell
	*
	* Original driver written by Juha Yrjölä, Tony Lindgren and Timo Teräs.
	* Modified for Retu/Tahvo MFD by Aaro Koskinen.
	*
	* This file is subject to the terms and conditions of the GNU General
	* Public License. See the file "COPYING" in the main directory of this
	* archive for more details.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*/

	#include <linux/io.h>
	#include <linux/clk.h>
	#include <linux/usb.h>
	#include <linux/extcon.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/usb/otg.h>
	#include <linux/mfd/retu.h>
	#include <linux/usb/gadget.h>
	#include <linux/platform_device.h>

	#define DRIVER_NAME "tahvo-usb"

	#define TAHVO_REG_IDSR 0x02
	#define TAHVO_REG_USBR 0x06

	#define USBR_SLAVE_CONTROL (1 << 8)
	#define USBR_VPPVIO_SW (1 << 7)
	#define USBR_SPEED (1 << 6)
	#define USBR_REGOUT (1 << 5)
	#define USBR_MASTER_SW2 (1 << 4)
	#define USBR_MASTER_SW1 (1 << 3)
	#define USBR_SLAVE_SW (1 << 2)
	#define USBR_NSUSPEND (1 << 1)
	#define USBR_SEMODE (1 << 0)

	#define TAHVO_MODE_HOST 0
	#define TAHVO_MODE_PERIPHERAL 1

	struct tahvo_usb {
	struct platform_device *pt_dev;
	struct usb_phy phy;
	int vbus_state;
	struct mutex serialize;
	struct clk *ick;
	int irq;
	int tahvo_mode;
	struct extcon_dev *extcon;
	};

	static const unsigned int tahvo_cable[] = {
	EXTCON_USB,
	EXTCON_USB_HOST,

	EXTCON_NONE,
	};

	static ssize_t vbus_state_show(struct device *device,
	struct device_attribute attr, char buf)
	{
	struct tahvo_usb *tu = dev_get_drvdata(device);
	return sprintf(buf, "%s\n", tu->vbus_state ? "on" : "off");
	}
	static DEVICE_ATTR(vbus, 0444, vbus_state_show, NULL);

	static void check_vbus_state(struct tahvo_usb *tu)
	{
	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
	int reg, prev_state;

	reg = retu_read(rdev, TAHVO_REG_IDSR);
	if (reg & TAHVO_STAT_VBUS) {
	switch (tu->phy.otg->state) {
	case OTG_STATE_B_IDLE:
	/* Enable the gadget driver */
	if (tu->phy.otg->gadget)
	usb_gadget_vbus_connect(tu->phy.otg->gadget);
	tu->phy.otg->state = OTG_STATE_B_PERIPHERAL;
	usb_phy_set_event(&tu->phy, USB_EVENT_ENUMERATED);
	break;
	case OTG_STATE_A_IDLE:
	/*
	* Session is now valid assuming the USB hub is driving
	* Vbus.
	*/
	tu->phy.otg->state = OTG_STATE_A_HOST;
	break;
	default:
	break;
	}
	dev_info(&tu->pt_dev->dev, "USB cable connected\n");
	} else {
	switch (tu->phy.otg->state) {
	case OTG_STATE_B_PERIPHERAL:
	if (tu->phy.otg->gadget)
	usb_gadget_vbus_disconnect(tu->phy.otg->gadget);
	tu->phy.otg->state = OTG_STATE_B_IDLE;
	usb_phy_set_event(&tu->phy, USB_EVENT_NONE);
	break;
	case OTG_STATE_A_HOST:
	tu->phy.otg->state = OTG_STATE_A_IDLE;
	break;
	default:
	break;
	}
	dev_info(&tu->pt_dev->dev, "USB cable disconnected\n");
	}

	prev_state = tu->vbus_state;
	tu->vbus_state = reg & TAHVO_STAT_VBUS;
	if (prev_state != tu->vbus_state) {
	extcon_set_state_sync(tu->extcon, EXTCON_USB, tu->vbus_state);
	sysfs_notify(&tu->pt_dev->dev.kobj, NULL, "vbus_state");
	}
	}

	static void tahvo_usb_become_host(struct tahvo_usb *tu)
	{
	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);

	extcon_set_state_sync(tu->extcon, EXTCON_USB_HOST, true);

	/* Power up the transceiver in USB host mode */
	retu_write(rdev, TAHVO_REG_USBR, USBR_REGOUT \| USBR_NSUSPEND \|
	USBR_MASTER_SW2 \| USBR_MASTER_SW1);
	tu->phy.otg->state = OTG_STATE_A_IDLE;

	check_vbus_state(tu);
	}

	static void tahvo_usb_stop_host(struct tahvo_usb *tu)
	{
	tu->phy.otg->state = OTG_STATE_A_IDLE;
	}

	static void tahvo_usb_become_peripheral(struct tahvo_usb *tu)
	{
	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);

	extcon_set_state_sync(tu->extcon, EXTCON_USB_HOST, false);

	/* Power up transceiver and set it in USB peripheral mode */
	retu_write(rdev, TAHVO_REG_USBR, USBR_SLAVE_CONTROL \| USBR_REGOUT \|
	USBR_NSUSPEND \| USBR_SLAVE_SW);
	tu->phy.otg->state = OTG_STATE_B_IDLE;

	check_vbus_state(tu);
	}

	static void tahvo_usb_stop_peripheral(struct tahvo_usb *tu)
	{
	if (tu->phy.otg->gadget)
	usb_gadget_vbus_disconnect(tu->phy.otg->gadget);
	tu->phy.otg->state = OTG_STATE_B_IDLE;
	}

	static void tahvo_usb_power_off(struct tahvo_usb *tu)
	{
	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);

	/* Disable gadget controller if any */
	if (tu->phy.otg->gadget)
	usb_gadget_vbus_disconnect(tu->phy.otg->gadget);

	/* Power off transceiver */
	retu_write(rdev, TAHVO_REG_USBR, 0);
	tu->phy.otg->state = OTG_STATE_UNDEFINED;
	}

	static int tahvo_usb_set_suspend(struct usb_phy *dev, int suspend)
	{
	struct tahvo_usb *tu = container_of(dev, struct tahvo_usb, phy);
	struct retu_dev *rdev = dev_get_drvdata(tu->pt_dev->dev.parent);
	u16 w;

	dev_dbg(&tu->pt_dev->dev, "%s\n", __func__);

	w = retu_read(rdev, TAHVO_REG_USBR);
	if (suspend)
	w &= ~USBR_NSUSPEND;
	else
	w \|= USBR_NSUSPEND;
	retu_write(rdev, TAHVO_REG_USBR, w);

	return 0;
	}

	static int tahvo_usb_set_host(struct usb_otg otg, struct usb_bus host)
	{
	struct tahvo_usb *tu = container_of(otg->usb_phy, struct tahvo_usb,
	phy);

	dev_dbg(&tu->pt_dev->dev, "%s %p\n", __func__, host);

	mutex_lock(&tu->serialize);

	if (host == NULL) {
	if (tu->tahvo_mode == TAHVO_MODE_HOST)
	tahvo_usb_power_off(tu);
	otg->host = NULL;
	mutex_unlock(&tu->serialize);
	return 0;
	}

	if (tu->tahvo_mode == TAHVO_MODE_HOST) {
	otg->host = NULL;
	tahvo_usb_become_host(tu);
	}

	otg->host = host;

	mutex_unlock(&tu->serialize);

	return 0;
	}

	static int tahvo_usb_set_peripheral(struct usb_otg *otg,
	struct usb_gadget *gadget)
	{
	struct tahvo_usb *tu = container_of(otg->usb_phy, struct tahvo_usb,
	phy);

	dev_dbg(&tu->pt_dev->dev, "%s %p\n", __func__, gadget);

	mutex_lock(&tu->serialize);

	if (!gadget) {
	if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
	tahvo_usb_power_off(tu);
	tu->phy.otg->gadget = NULL;
	mutex_unlock(&tu->serialize);
	return 0;
	}

	tu->phy.otg->gadget = gadget;
	if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
	tahvo_usb_become_peripheral(tu);

	mutex_unlock(&tu->serialize);

	return 0;
	}

	static irqreturn_t tahvo_usb_vbus_interrupt(int irq, void *_tu)
	{
	struct tahvo_usb *tu = _tu;

	mutex_lock(&tu->serialize);
	check_vbus_state(tu);
	mutex_unlock(&tu->serialize);

	return IRQ_HANDLED;
	}

	static ssize_t otg_mode_show(struct device *device,
	struct device_attribute attr, char buf)
	{
	struct tahvo_usb *tu = dev_get_drvdata(device);

	switch (tu->tahvo_mode) {
	case TAHVO_MODE_HOST:
	return sprintf(buf, "host\n");
	case TAHVO_MODE_PERIPHERAL:
	return sprintf(buf, "peripheral\n");
	}

	return -EINVAL;
	}

	static ssize_t otg_mode_store(struct device *device,
	struct device_attribute *attr,
	const char *buf, size_t count)
	{
	struct tahvo_usb *tu = dev_get_drvdata(device);
	int r;

	mutex_lock(&tu->serialize);
	if (count >= 4 && strncmp(buf, "host", 4) == 0) {
	if (tu->tahvo_mode == TAHVO_MODE_PERIPHERAL)
	tahvo_usb_stop_peripheral(tu);
	tu->tahvo_mode = TAHVO_MODE_HOST;
	if (tu->phy.otg->host) {
	dev_info(device, "HOST mode: host controller present\n");
	tahvo_usb_become_host(tu);
	} else {
	dev_info(device, "HOST mode: no host controller, powering off\n");
	tahvo_usb_power_off(tu);
	}
	r = strlen(buf);
	} else if (count >= 10 && strncmp(buf, "peripheral", 10) == 0) {
	if (tu->tahvo_mode == TAHVO_MODE_HOST)
	tahvo_usb_stop_host(tu);
	tu->tahvo_mode = TAHVO_MODE_PERIPHERAL;
	if (tu->phy.otg->gadget) {
	dev_info(device, "PERIPHERAL mode: gadget driver present\n");
	tahvo_usb_become_peripheral(tu);
	} else {
	dev_info(device, "PERIPHERAL mode: no gadget driver, powering off\n");
	tahvo_usb_power_off(tu);
	}
	r = strlen(buf);
	} else {
	r = -EINVAL;
	}
	mutex_unlock(&tu->serialize);

	return r;
	}
	static DEVICE_ATTR(otg_mode, 0644, otg_mode_show, otg_mode_store);

	static struct attribute *tahvo_attributes[] = {
	&dev_attr_vbus.attr,
	&dev_attr_otg_mode.attr,
	NULL
	};

	static struct attribute_group tahvo_attr_group = {
	.attrs = tahvo_attributes,
	};

	static int tahvo_usb_probe(struct platform_device *pdev)
	{
	struct retu_dev *rdev = dev_get_drvdata(pdev->dev.parent);
	struct tahvo_usb *tu;
	int ret;

	tu = devm_kzalloc(&pdev->dev, sizeof(*tu), GFP_KERNEL);
	if (!tu)
	return -ENOMEM;

	tu->phy.otg = devm_kzalloc(&pdev->dev, sizeof(*tu->phy.otg),
	GFP_KERNEL);
	if (!tu->phy.otg)
	return -ENOMEM;

	tu->pt_dev = pdev;

	/* Default mode */
	#ifdef CONFIG_TAHVO_USB_HOST_BY_DEFAULT
	tu->tahvo_mode = TAHVO_MODE_HOST;
	#else
	tu->tahvo_mode = TAHVO_MODE_PERIPHERAL;
	#endif

	mutex_init(&tu->serialize);

	tu->ick = devm_clk_get(&pdev->dev, "usb_l4_ick");
	if (!IS_ERR(tu->ick))
	clk_enable(tu->ick);

	/*
	* Set initial state, so that we generate kevents only on state changes.
	*/
	tu->vbus_state = retu_read(rdev, TAHVO_REG_IDSR) & TAHVO_STAT_VBUS;

	tu->extcon = devm_extcon_dev_allocate(&pdev->dev, tahvo_cable);
	if (IS_ERR(tu->extcon)) {
	dev_err(&pdev->dev, "failed to allocate memory for extcon\n");
	return -ENOMEM;
	}

	ret = devm_extcon_dev_register(&pdev->dev, tu->extcon);
	if (ret) {
	dev_err(&pdev->dev, "could not register extcon device: %d\n",
	ret);
	goto err_disable_clk;
	}

	/* Set the initial cable state. */
	extcon_set_state_sync(tu->extcon, EXTCON_USB_HOST,
	tu->tahvo_mode == TAHVO_MODE_HOST);
	extcon_set_state_sync(tu->extcon, EXTCON_USB, tu->vbus_state);

	/* Create OTG interface */
	tahvo_usb_power_off(tu);
	tu->phy.dev = &pdev->dev;
	tu->phy.otg->state = OTG_STATE_UNDEFINED;
	tu->phy.label = DRIVER_NAME;
	tu->phy.set_suspend = tahvo_usb_set_suspend;

	tu->phy.otg->usb_phy = &tu->phy;
	tu->phy.otg->set_host = tahvo_usb_set_host;
	tu->phy.otg->set_peripheral = tahvo_usb_set_peripheral;

	ret = usb_add_phy(&tu->phy, USB_PHY_TYPE_USB2);
	if (ret < 0) {
	dev_err(&pdev->dev, "cannot register USB transceiver: %d\n",
	ret);
	goto err_disable_clk;
	}

	dev_set_drvdata(&pdev->dev, tu);

	tu->irq = platform_get_irq(pdev, 0);
	ret = request_threaded_irq(tu->irq, NULL, tahvo_usb_vbus_interrupt,
	IRQF_ONESHOT,
	"tahvo-vbus", tu);
	if (ret) {
	dev_err(&pdev->dev, "could not register tahvo-vbus irq: %d\n",
	ret);
	goto err_remove_phy;
	}

	/* Attributes */
	ret = sysfs_create_group(&pdev->dev.kobj, &tahvo_attr_group);
	if (ret) {
	dev_err(&pdev->dev, "cannot create sysfs group: %d\n", ret);
	goto err_free_irq;
	}

	return 0;

	err_free_irq:
	free_irq(tu->irq, tu);
	err_remove_phy:
	usb_remove_phy(&tu->phy);
	err_disable_clk:
	if (!IS_ERR(tu->ick))
	clk_disable(tu->ick);

	return ret;
	}

	static int tahvo_usb_remove(struct platform_device *pdev)
	{
	struct tahvo_usb *tu = platform_get_drvdata(pdev);

	sysfs_remove_group(&pdev->dev.kobj, &tahvo_attr_group);
	free_irq(tu->irq, tu);
	usb_remove_phy(&tu->phy);
	if (!IS_ERR(tu->ick))
	clk_disable(tu->ick);

	return 0;
	}

	static struct platform_driver tahvo_usb_driver = {
	.probe = tahvo_usb_probe,
	.remove = tahvo_usb_remove,
	.driver = {
	.name = "tahvo-usb",
	},
	};
	module_platform_driver(tahvo_usb_driver);

	MODULE_DESCRIPTION("Tahvo USB transceiver driver");
	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Juha Yrjölä, Tony Lindgren, and Timo Teräs");
	MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>");