drivers/usb/dwc3/drd.c - kernel/common - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * drd.c - DesignWare USB3 DRD Controller Dual-role support
  *
  * Copyright (C) 2017 Texas Instruments Incorporated - https://www.ti.com
  *
  * Authors: Roger Quadros <[email protected]>
  */

 #include <linux/extcon.h>
 #include <linux/of_graph.h>
 #include <linux/platform_device.h>
 #include <linux/property.h>

 #include "debug.h"
 #include "core.h"
 #include "gadget.h"

 static void dwc3_otg_disable_events(struct dwc3 *dwc, u32 disable_mask)
 {
 	u32 reg = dwc3_readl(dwc->regs, DWC3_OEVTEN);

 	reg &= ~(disable_mask);
 	dwc3_writel(dwc->regs, DWC3_OEVTEN, reg);
 }

 static void dwc3_otg_enable_events(struct dwc3 *dwc, u32 enable_mask)
 {
 	u32 reg = dwc3_readl(dwc->regs, DWC3_OEVTEN);

 	reg |= (enable_mask);
 	dwc3_writel(dwc->regs, DWC3_OEVTEN, reg);
 }

 static void dwc3_otg_clear_events(struct dwc3 *dwc)
 {
 	u32 reg = dwc3_readl(dwc->regs, DWC3_OEVT);

 	dwc3_writel(dwc->regs, DWC3_OEVTEN, reg);
 }

 #define DWC3_OTG_ALL_EVENTS	(DWC3_OEVTEN_XHCIRUNSTPSETEN | \
 		DWC3_OEVTEN_DEVRUNSTPSETEN | DWC3_OEVTEN_HIBENTRYEN | \
 		DWC3_OEVTEN_CONIDSTSCHNGEN | DWC3_OEVTEN_HRRCONFNOTIFEN | \
 		DWC3_OEVTEN_HRRINITNOTIFEN | DWC3_OEVTEN_ADEVIDLEEN | \
 		DWC3_OEVTEN_ADEVBHOSTENDEN | DWC3_OEVTEN_ADEVHOSTEN | \
 		DWC3_OEVTEN_ADEVHNPCHNGEN | DWC3_OEVTEN_ADEVSRPDETEN | \
 		DWC3_OEVTEN_ADEVSESSENDDETEN | DWC3_OEVTEN_BDEVBHOSTENDEN | \
 		DWC3_OEVTEN_BDEVHNPCHNGEN | DWC3_OEVTEN_BDEVSESSVLDDETEN | \
 		DWC3_OEVTEN_BDEVVBUSCHNGEN)

 static irqreturn_t dwc3_otg_thread_irq(int irq, void *_dwc)
 {
 	struct dwc3 *dwc = _dwc;

 	spin_lock(&dwc->lock);
 	if (dwc->otg_restart_host) {
 		dwc3_otg_host_init(dwc);
 		dwc->otg_restart_host = false;
 	}

 	spin_unlock(&dwc->lock);

 	dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_OTG);

 	return IRQ_HANDLED;
 }

 static irqreturn_t dwc3_otg_irq(int irq, void *_dwc)
 {
 	u32 reg;
 	struct dwc3 *dwc = _dwc;
 	irqreturn_t ret = IRQ_NONE;

 	reg = dwc3_readl(dwc->regs, DWC3_OEVT);
 	if (reg) {
 		/* ignore non OTG events, we can't disable them in OEVTEN */
 		if (!(reg & DWC3_OTG_ALL_EVENTS)) {
 			dwc3_writel(dwc->regs, DWC3_OEVT, reg);
 			return IRQ_NONE;
 		}

 		if (dwc->current_otg_role == DWC3_OTG_ROLE_HOST &&
 		    !(reg & DWC3_OEVT_DEVICEMODE))
 			dwc->otg_restart_host = true;
 		dwc3_writel(dwc->regs, DWC3_OEVT, reg);
 		ret = IRQ_WAKE_THREAD;
 	}

 	return ret;
 }

 static void dwc3_otgregs_init(struct dwc3 *dwc)
 {
 	u32 reg;

 	/*
 	 * Prevent host/device reset from resetting OTG core.
 	 * If we don't do this then xhci_reset (USBCMD.HCRST) will reset
 	 * the signal outputs sent to the PHY, the OTG FSM logic of the
 	 * core and also the resets to the VBUS filters inside the core.
 	 */
 	reg = dwc3_readl(dwc->regs, DWC3_OCFG);
 	reg |= DWC3_OCFG_SFTRSTMASK;
 	dwc3_writel(dwc->regs, DWC3_OCFG, reg);

 	/* Disable hibernation for simplicity */
 	reg = dwc3_readl(dwc->regs, DWC3_GCTL);
 	reg &= ~DWC3_GCTL_GBLHIBERNATIONEN;
 	dwc3_writel(dwc->regs, DWC3_GCTL, reg);

 	/*
 	 * Initialize OTG registers as per
 	 * Figure 11-4 OTG Driver Overall Programming Flow
 	 */
 	/* OCFG.SRPCap = 0, OCFG.HNPCap = 0 */
 	reg = dwc3_readl(dwc->regs, DWC3_OCFG);
 	reg &= ~(DWC3_OCFG_SRPCAP | DWC3_OCFG_HNPCAP);
 	dwc3_writel(dwc->regs, DWC3_OCFG, reg);
 	/* OEVT = FFFF */
 	dwc3_otg_clear_events(dwc);
 	/* OEVTEN = 0 */
 	dwc3_otg_disable_events(dwc, DWC3_OTG_ALL_EVENTS);
 	/* OEVTEN.ConIDStsChngEn = 1. Instead we enable all events */
 	dwc3_otg_enable_events(dwc, DWC3_OTG_ALL_EVENTS);
 	/*
 	 * OCTL.PeriMode = 1, OCTL.DevSetHNPEn = 0, OCTL.HstSetHNPEn = 0,
 	 * OCTL.HNPReq = 0
 	 */
 	reg = dwc3_readl(dwc->regs, DWC3_OCTL);
 	reg |= DWC3_OCTL_PERIMODE;
 	reg &= ~(DWC3_OCTL_DEVSETHNPEN | DWC3_OCTL_HSTSETHNPEN |
 		 DWC3_OCTL_HNPREQ);
 	dwc3_writel(dwc->regs, DWC3_OCTL, reg);
 }

 static int dwc3_otg_get_irq(struct dwc3 *dwc)
 {
 	struct platform_device *dwc3_pdev = to_platform_device(dwc->dev);
 	int irq;

 	irq = platform_get_irq_byname_optional(dwc3_pdev, "otg");
 	if (irq > 0)
 		goto out;

 	if (irq == -EPROBE_DEFER)
 		goto out;

 	irq = platform_get_irq_byname_optional(dwc3_pdev, "dwc_usb3");
 	if (irq > 0)
 		goto out;

 	if (irq == -EPROBE_DEFER)
 		goto out;

 	irq = platform_get_irq(dwc3_pdev, 0);
 	if (irq > 0)
 		goto out;

 	if (!irq)
 		irq = -EINVAL;

 out:
 	return irq;
 }

 void dwc3_otg_init(struct dwc3 *dwc)
 {
 	u32 reg;

 	/*
 	 * As per Figure 11-4 OTG Driver Overall Programming Flow,
 	 * block "Initialize GCTL for OTG operation".
 	 */
 	/* GCTL.PrtCapDir=2'b11 */
 	dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_OTG);
 	/* GUSB2PHYCFG0.SusPHY=0 */
 	reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
 	reg &= ~DWC3_GUSB2PHYCFG_SUSPHY;
 	dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);

 	/* Initialize OTG registers */
 	dwc3_otgregs_init(dwc);
 }

 void dwc3_otg_exit(struct dwc3 *dwc)
 {
 	/* disable all OTG IRQs */
 	dwc3_otg_disable_events(dwc, DWC3_OTG_ALL_EVENTS);
 	/* clear all events */
 	dwc3_otg_clear_events(dwc);
 }

 /* should be called before Host controller driver is started */
 void dwc3_otg_host_init(struct dwc3 *dwc)
 {
 	u32 reg;

 	/* As per Figure 11-10 A-Device Flow Diagram */
 	/* OCFG.HNPCap = 0, OCFG.SRPCap = 0. Already 0 */

 	/*
 	 * OCTL.PeriMode=0, OCTL.TermSelDLPulse = 0,
 	 * OCTL.DevSetHNPEn = 0, OCTL.HstSetHNPEn = 0
 	 */
 	reg = dwc3_readl(dwc->regs, DWC3_OCTL);
 	reg &= ~(DWC3_OCTL_PERIMODE | DWC3_OCTL_TERMSELIDPULSE |
 			DWC3_OCTL_DEVSETHNPEN | DWC3_OCTL_HSTSETHNPEN);
 	dwc3_writel(dwc->regs, DWC3_OCTL, reg);

 	/*
 	 * OCFG.DisPrtPwrCutoff = 0/1
 	 */
 	reg = dwc3_readl(dwc->regs, DWC3_OCFG);
 	reg &= ~DWC3_OCFG_DISPWRCUTTOFF;
 	dwc3_writel(dwc->regs, DWC3_OCFG, reg);

 	/*
 	 * OCFG.SRPCap = 1, OCFG.HNPCap = GHWPARAMS6.HNP_CAP
 	 * We don't want SRP/HNP for simple dual-role so leave
 	 * these disabled.
 	 */

 	/*
 	 * OEVTEN.OTGADevHostEvntEn = 1
 	 * OEVTEN.OTGADevSessEndDetEvntEn = 1
 	 * We don't want HNP/role-swap so leave these disabled.
 	 */

 	/* GUSB2PHYCFG.ULPIAutoRes = 1/0, GUSB2PHYCFG.SusPHY = 1 */
 	if (!dwc->dis_u2_susphy_quirk) {
 		reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
 		reg |= DWC3_GUSB2PHYCFG_SUSPHY;
 		dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
 	}

 	/* Set Port Power to enable VBUS: OCTL.PrtPwrCtl = 1 */
 	reg = dwc3_readl(dwc->regs, DWC3_OCTL);
 	reg |= DWC3_OCTL_PRTPWRCTL;
 	dwc3_writel(dwc->regs, DWC3_OCTL, reg);
 }

 /* should be called after Host controller driver is stopped */
 static void dwc3_otg_host_exit(struct dwc3 *dwc)
 {
 	u32 reg;

 	/*
 	 * Exit from A-device flow as per
 	 * Figure 11-4 OTG Driver Overall Programming Flow
 	 */

 	/*
 	 * OEVTEN.OTGADevBHostEndEvntEn=0, OEVTEN.OTGADevHNPChngEvntEn=0
 	 * OEVTEN.OTGADevSessEndDetEvntEn=0,
 	 * OEVTEN.OTGADevHostEvntEn = 0
 	 * But we don't disable any OTG events
 	 */

 	/* OCTL.HstSetHNPEn = 0, OCTL.PrtPwrCtl=0 */
 	reg = dwc3_readl(dwc->regs, DWC3_OCTL);
 	reg &= ~(DWC3_OCTL_HSTSETHNPEN | DWC3_OCTL_PRTPWRCTL);
 	dwc3_writel(dwc->regs, DWC3_OCTL, reg);
 }

 /* should be called before the gadget controller driver is started */
 static void dwc3_otg_device_init(struct dwc3 *dwc)
 {
 	u32 reg;

 	/* As per Figure 11-20 B-Device Flow Diagram */

 	/*
 	 * OCFG.HNPCap = GHWPARAMS6.HNP_CAP, OCFG.SRPCap = 1
 	 * but we keep them 0 for simple dual-role operation.
 	 */
 	reg = dwc3_readl(dwc->regs, DWC3_OCFG);
 	/* OCFG.OTGSftRstMsk = 0/1 */
 	reg |= DWC3_OCFG_SFTRSTMASK;
 	dwc3_writel(dwc->regs, DWC3_OCFG, reg);
 	/*
 	 * OCTL.PeriMode = 1
 	 * OCTL.TermSelDLPulse = 0/1, OCTL.HNPReq = 0
 	 * OCTL.DevSetHNPEn = 0, OCTL.HstSetHNPEn = 0
 	 */
 	reg = dwc3_readl(dwc->regs, DWC3_OCTL);
 	reg |= DWC3_OCTL_PERIMODE;
 	reg &= ~(DWC3_OCTL_TERMSELIDPULSE | DWC3_OCTL_HNPREQ |
 			DWC3_OCTL_DEVSETHNPEN | DWC3_OCTL_HSTSETHNPEN);
 	dwc3_writel(dwc->regs, DWC3_OCTL, reg);
 	/* OEVTEN.OTGBDevSesVldDetEvntEn = 1 */
 	dwc3_otg_enable_events(dwc, DWC3_OEVTEN_BDEVSESSVLDDETEN);
 	/* GUSB2PHYCFG.ULPIAutoRes = 0, GUSB2PHYCFG0.SusPHY = 1 */
 	if (!dwc->dis_u2_susphy_quirk) {
 		reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
 		reg |= DWC3_GUSB2PHYCFG_SUSPHY;
 		dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
 	}
 	/* GCTL.GblHibernationEn = 0. Already 0. */
 }

 /* should be called after the gadget controller driver is stopped */
 static void dwc3_otg_device_exit(struct dwc3 *dwc)
 {
 	u32 reg;

 	/*
 	 * Exit from B-device flow as per
 	 * Figure 11-4 OTG Driver Overall Programming Flow
 	 */

 	/*
 	 * OEVTEN.OTGBDevHNPChngEvntEn = 0
 	 * OEVTEN.OTGBDevVBusChngEvntEn = 0
 	 * OEVTEN.OTGBDevBHostEndEvntEn = 0
 	 */
 	dwc3_otg_disable_events(dwc, DWC3_OEVTEN_BDEVHNPCHNGEN |
 				DWC3_OEVTEN_BDEVVBUSCHNGEN |
 				DWC3_OEVTEN_BDEVBHOSTENDEN);

 	/* OCTL.DevSetHNPEn = 0, OCTL.HNPReq = 0, OCTL.PeriMode=1 */
 	reg = dwc3_readl(dwc->regs, DWC3_OCTL);
 	reg &= ~(DWC3_OCTL_DEVSETHNPEN | DWC3_OCTL_HNPREQ);
 	reg |= DWC3_OCTL_PERIMODE;
 	dwc3_writel(dwc->regs, DWC3_OCTL, reg);
 }

 void dwc3_otg_update(struct dwc3 *dwc, bool ignore_idstatus)
 {
 	int ret;
 	u32 reg;
 	int id;
 	unsigned long flags;

 	if (dwc->dr_mode != USB_DR_MODE_OTG)
 		return;

 	/* don't do anything if debug user changed role to not OTG */
 	if (dwc->current_dr_role != DWC3_GCTL_PRTCAP_OTG)
 		return;

 	if (!ignore_idstatus) {
 		reg = dwc3_readl(dwc->regs, DWC3_OSTS);
 		id = !!(reg & DWC3_OSTS_CONIDSTS);

 		dwc->desired_otg_role = id ? DWC3_OTG_ROLE_DEVICE :
 					DWC3_OTG_ROLE_HOST;
 	}

 	if (dwc->desired_otg_role == dwc->current_otg_role)
 		return;

 	switch (dwc->current_otg_role) {
 	case DWC3_OTG_ROLE_HOST:
 		dwc3_host_exit(dwc);
 		spin_lock_irqsave(&dwc->lock, flags);
 		dwc3_otg_host_exit(dwc);
 		spin_unlock_irqrestore(&dwc->lock, flags);
 		break;
 	case DWC3_OTG_ROLE_DEVICE:
 		dwc3_gadget_exit(dwc);
 		spin_lock_irqsave(&dwc->lock, flags);
 		dwc3_event_buffers_cleanup(dwc);
 		dwc3_otg_device_exit(dwc);
 		spin_unlock_irqrestore(&dwc->lock, flags);
 		break;
 	default:
 		break;
 	}

 	spin_lock_irqsave(&dwc->lock, flags);

 	dwc->current_otg_role = dwc->desired_otg_role;

 	spin_unlock_irqrestore(&dwc->lock, flags);

 	switch (dwc->desired_otg_role) {
 	case DWC3_OTG_ROLE_HOST:
 		spin_lock_irqsave(&dwc->lock, flags);
 		dwc3_otgregs_init(dwc);
 		dwc3_otg_host_init(dwc);
 		spin_unlock_irqrestore(&dwc->lock, flags);
 		ret = dwc3_host_init(dwc);
 		if (ret) {
 			dev_err(dwc->dev, "failed to initialize host\n");
 		} else {
 			if (dwc->usb2_phy)
 				otg_set_vbus(dwc->usb2_phy->otg, true);
 			if (dwc->usb2_generic_phy)
 				phy_set_mode(dwc->usb2_generic_phy,
 					     PHY_MODE_USB_HOST);
 		}
 		break;
 	case DWC3_OTG_ROLE_DEVICE:
 		spin_lock_irqsave(&dwc->lock, flags);
 		dwc3_otgregs_init(dwc);
 		dwc3_otg_device_init(dwc);
 		dwc3_event_buffers_setup(dwc);
 		spin_unlock_irqrestore(&dwc->lock, flags);

 		if (dwc->usb2_phy)
 			otg_set_vbus(dwc->usb2_phy->otg, false);
 		if (dwc->usb2_generic_phy)
 			phy_set_mode(dwc->usb2_generic_phy,
 				     PHY_MODE_USB_DEVICE);
 		ret = dwc3_gadget_init(dwc);
 		if (ret)
 			dev_err(dwc->dev, "failed to initialize peripheral\n");
 		break;
 	default:
 		break;
 	}
 }

 static void dwc3_drd_update(struct dwc3 *dwc)
 {
 	int id;

 	if (dwc->edev) {
 		id = extcon_get_state(dwc->edev, EXTCON_USB_HOST);
 		if (id < 0)
 			id = 0;
 		dwc3_set_mode(dwc, id ?
 			      DWC3_GCTL_PRTCAP_HOST :
 			      DWC3_GCTL_PRTCAP_DEVICE);
 	}
 }

 static int dwc3_drd_notifier(struct notifier_block *nb,
 			     unsigned long event, void *ptr)
 {
 	struct dwc3 *dwc = container_of(nb, struct dwc3, edev_nb);

 	dwc3_set_mode(dwc, event ?
 		      DWC3_GCTL_PRTCAP_HOST :
 		      DWC3_GCTL_PRTCAP_DEVICE);

 	return NOTIFY_DONE;
 }

 static struct extcon_dev *dwc3_get_extcon(struct dwc3 *dwc)
 {
 	struct device *dev = dwc->dev;
 	struct device_node *np_phy, *np_conn;
 	struct extcon_dev *edev;
 	const char *name;

 	if (device_property_read_bool(dev, "extcon"))
 		return extcon_get_edev_by_phandle(dev, 0);

 	/*
 	 * Device tree platforms should get extcon via phandle.
 	 * On ACPI platforms, we get the name from a device property.
 	 * This device property is for kernel internal use only and
 	 * is expected to be set by the glue code.
 	 */
 	if (device_property_read_string(dev, "linux,extcon-name", &name) == 0) {
 		edev = extcon_get_extcon_dev(name);
 		if (!edev)
 			return ERR_PTR(-EPROBE_DEFER);

 		return edev;
 	}

 	np_phy = of_parse_phandle(dev->of_node, "phys", 0);
 	np_conn = of_graph_get_remote_node(np_phy, -1, -1);

 	if (np_conn)
 		edev = extcon_find_edev_by_node(np_conn);
 	else
 		edev = NULL;

 	of_node_put(np_conn);
 	of_node_put(np_phy);

 	return edev;
 }

 #if IS_ENABLED(CONFIG_USB_ROLE_SWITCH)
 #define ROLE_SWITCH 1
 static int dwc3_usb_role_switch_set(struct usb_role_switch *sw,
 				    enum usb_role role)
 {
 	struct dwc3 *dwc = usb_role_switch_get_drvdata(sw);
 	u32 mode;

 	switch (role) {
 	case USB_ROLE_HOST:
 		mode = DWC3_GCTL_PRTCAP_HOST;
 		break;
 	case USB_ROLE_DEVICE:
 		mode = DWC3_GCTL_PRTCAP_DEVICE;
 		break;
 	default:
 		if (dwc->role_switch_default_mode == USB_DR_MODE_HOST)
 			mode = DWC3_GCTL_PRTCAP_HOST;
 		else
 			mode = DWC3_GCTL_PRTCAP_DEVICE;
 		break;
 	}

 	dwc3_set_mode(dwc, mode);
 	return 0;
 }

 static enum usb_role dwc3_usb_role_switch_get(struct usb_role_switch *sw)
 {
 	struct dwc3 *dwc = usb_role_switch_get_drvdata(sw);
 	unsigned long flags;
 	enum usb_role role;

 	spin_lock_irqsave(&dwc->lock, flags);
 	switch (dwc->current_dr_role) {
 	case DWC3_GCTL_PRTCAP_HOST:
 		role = USB_ROLE_HOST;
 		break;
 	case DWC3_GCTL_PRTCAP_DEVICE:
 		role = USB_ROLE_DEVICE;
 		break;
 	case DWC3_GCTL_PRTCAP_OTG:
 		role = dwc->current_otg_role;
 		break;
 	default:
 		if (dwc->role_switch_default_mode == USB_DR_MODE_HOST)
 			role = USB_ROLE_HOST;
 		else
 			role = USB_ROLE_DEVICE;
 		break;
 	}
 	spin_unlock_irqrestore(&dwc->lock, flags);
 	return role;
 }

 static int dwc3_setup_role_switch(struct dwc3 *dwc)
 {
 	struct usb_role_switch_desc dwc3_role_switch = {NULL};
 	const char *str;
 	u32 mode;
 	int ret;

 	ret = device_property_read_string(dwc->dev, "role-switch-default-mode",
 					  &str);
 	if (ret >= 0  && !strncmp(str, "host", strlen("host"))) {
 		dwc->role_switch_default_mode = USB_DR_MODE_HOST;
 		mode = DWC3_GCTL_PRTCAP_HOST;
 	} else {
 		dwc->role_switch_default_mode = USB_DR_MODE_PERIPHERAL;
 		mode = DWC3_GCTL_PRTCAP_DEVICE;
 	}

 	dwc3_role_switch.fwnode = dev_fwnode(dwc->dev);
 	dwc3_role_switch.set = dwc3_usb_role_switch_set;
 	dwc3_role_switch.get = dwc3_usb_role_switch_get;
 	dwc3_role_switch.driver_data = dwc;
 	dwc->role_sw = usb_role_switch_register(dwc->dev, &dwc3_role_switch);
 	if (IS_ERR(dwc->role_sw))
 		return PTR_ERR(dwc->role_sw);

 	dwc3_set_mode(dwc, mode);
 	return 0;
 }
 #else
 #define ROLE_SWITCH 0
 #define dwc3_setup_role_switch(x) 0
 #endif

 int dwc3_drd_init(struct dwc3 *dwc)
 {
 	int ret, irq;

 	dwc->edev = dwc3_get_extcon(dwc);
 	if (IS_ERR(dwc->edev))
 		return PTR_ERR(dwc->edev);

 	if (ROLE_SWITCH &&
 	    device_property_read_bool(dwc->dev, "usb-role-switch")) {
 		ret = dwc3_setup_role_switch(dwc);
 		if (ret < 0)
 			return ret;
 	} else if (dwc->edev) {
 		dwc->edev_nb.notifier_call = dwc3_drd_notifier;
 		ret = extcon_register_notifier(dwc->edev, EXTCON_USB_HOST,
 					       &dwc->edev_nb);
 		if (ret < 0) {
 			dev_err(dwc->dev, "couldn't register cable notifier\n");
 			return ret;
 		}

 		dwc3_drd_update(dwc);
 	} else {
 		dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_OTG);
 		dwc->current_dr_role = DWC3_GCTL_PRTCAP_OTG;

 		/* use OTG block to get ID event */
 		irq = dwc3_otg_get_irq(dwc);
 		if (irq < 0)
 			return irq;

 		dwc->otg_irq = irq;

 		/* disable all OTG IRQs */
 		dwc3_otg_disable_events(dwc, DWC3_OTG_ALL_EVENTS);
 		/* clear all events */
 		dwc3_otg_clear_events(dwc);

 		ret = request_threaded_irq(dwc->otg_irq, dwc3_otg_irq,
 					   dwc3_otg_thread_irq,
 					   IRQF_SHARED, "dwc3-otg", dwc);
 		if (ret) {
 			dev_err(dwc->dev, "failed to request irq #%d --> %d\n",
 				dwc->otg_irq, ret);
 			ret = -ENODEV;
 			return ret;
 		}

 		dwc3_otg_init(dwc);
 		dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_OTG);
 	}

 	return 0;
 }

 void dwc3_drd_exit(struct dwc3 *dwc)
 {
 	unsigned long flags;

 	if (dwc->role_sw)
 		usb_role_switch_unregister(dwc->role_sw);

 	if (dwc->edev)
 		extcon_unregister_notifier(dwc->edev, EXTCON_USB_HOST,
 					   &dwc->edev_nb);

 	cancel_work_sync(&dwc->drd_work);

 	/* debug user might have changed role, clean based on current role */
 	switch (dwc->current_dr_role) {
 	case DWC3_GCTL_PRTCAP_HOST:
 		dwc3_host_exit(dwc);
 		break;
 	case DWC3_GCTL_PRTCAP_DEVICE:
 		dwc3_gadget_exit(dwc);
 		dwc3_event_buffers_cleanup(dwc);
 		break;
 	case DWC3_GCTL_PRTCAP_OTG:
 		dwc3_otg_exit(dwc);
 		spin_lock_irqsave(&dwc->lock, flags);
 		dwc->desired_otg_role = DWC3_OTG_ROLE_IDLE;
 		spin_unlock_irqrestore(&dwc->lock, flags);
 		dwc3_otg_update(dwc, 1);
 		break;
 	default:
 		break;
 	}

 	if (dwc->otg_irq)
 		free_irq(dwc->otg_irq, dwc);
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* drd.c - DesignWare USB3 DRD Controller Dual-role support
	*
	* Copyright (C) 2017 Texas Instruments Incorporated - https://www.ti.com
	*
	* Authors: Roger Quadros <[email protected]>
	*/

	#include <linux/extcon.h>
	#include <linux/of_graph.h>
	#include <linux/platform_device.h>
	#include <linux/property.h>

	#include "debug.h"
	#include "core.h"
	#include "gadget.h"

	static void dwc3_otg_disable_events(struct dwc3 *dwc, u32 disable_mask)
	{
	u32 reg = dwc3_readl(dwc->regs, DWC3_OEVTEN);

	reg &= ~(disable_mask);
	dwc3_writel(dwc->regs, DWC3_OEVTEN, reg);
	}

	static void dwc3_otg_enable_events(struct dwc3 *dwc, u32 enable_mask)
	{
	u32 reg = dwc3_readl(dwc->regs, DWC3_OEVTEN);

	reg \|= (enable_mask);
	dwc3_writel(dwc->regs, DWC3_OEVTEN, reg);
	}

	static void dwc3_otg_clear_events(struct dwc3 *dwc)
	{
	u32 reg = dwc3_readl(dwc->regs, DWC3_OEVT);

	dwc3_writel(dwc->regs, DWC3_OEVTEN, reg);
	}

	#define DWC3_OTG_ALL_EVENTS (DWC3_OEVTEN_XHCIRUNSTPSETEN \| \
	DWC3_OEVTEN_DEVRUNSTPSETEN \| DWC3_OEVTEN_HIBENTRYEN \| \
	DWC3_OEVTEN_CONIDSTSCHNGEN \| DWC3_OEVTEN_HRRCONFNOTIFEN \| \
	DWC3_OEVTEN_HRRINITNOTIFEN \| DWC3_OEVTEN_ADEVIDLEEN \| \
	DWC3_OEVTEN_ADEVBHOSTENDEN \| DWC3_OEVTEN_ADEVHOSTEN \| \
	DWC3_OEVTEN_ADEVHNPCHNGEN \| DWC3_OEVTEN_ADEVSRPDETEN \| \
	DWC3_OEVTEN_ADEVSESSENDDETEN \| DWC3_OEVTEN_BDEVBHOSTENDEN \| \
	DWC3_OEVTEN_BDEVHNPCHNGEN \| DWC3_OEVTEN_BDEVSESSVLDDETEN \| \
	DWC3_OEVTEN_BDEVVBUSCHNGEN)

	static irqreturn_t dwc3_otg_thread_irq(int irq, void *_dwc)
	{
	struct dwc3 *dwc = _dwc;

	spin_lock(&dwc->lock);
	if (dwc->otg_restart_host) {
	dwc3_otg_host_init(dwc);
	dwc->otg_restart_host = false;
	}

	spin_unlock(&dwc->lock);

	dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_OTG);

	return IRQ_HANDLED;
	}

	static irqreturn_t dwc3_otg_irq(int irq, void *_dwc)
	{
	u32 reg;
	struct dwc3 *dwc = _dwc;
	irqreturn_t ret = IRQ_NONE;

	reg = dwc3_readl(dwc->regs, DWC3_OEVT);
	if (reg) {
	/* ignore non OTG events, we can't disable them in OEVTEN */
	if (!(reg & DWC3_OTG_ALL_EVENTS)) {
	dwc3_writel(dwc->regs, DWC3_OEVT, reg);
	return IRQ_NONE;
	}

	if (dwc->current_otg_role == DWC3_OTG_ROLE_HOST &&
	!(reg & DWC3_OEVT_DEVICEMODE))
	dwc->otg_restart_host = true;
	dwc3_writel(dwc->regs, DWC3_OEVT, reg);
	ret = IRQ_WAKE_THREAD;
	}

	return ret;
	}

	static void dwc3_otgregs_init(struct dwc3 *dwc)
	{
	u32 reg;

	/*
	* Prevent host/device reset from resetting OTG core.
	* If we don't do this then xhci_reset (USBCMD.HCRST) will reset
	* the signal outputs sent to the PHY, the OTG FSM logic of the
	* core and also the resets to the VBUS filters inside the core.
	*/
	reg = dwc3_readl(dwc->regs, DWC3_OCFG);
	reg \|= DWC3_OCFG_SFTRSTMASK;
	dwc3_writel(dwc->regs, DWC3_OCFG, reg);

	/* Disable hibernation for simplicity */
	reg = dwc3_readl(dwc->regs, DWC3_GCTL);
	reg &= ~DWC3_GCTL_GBLHIBERNATIONEN;
	dwc3_writel(dwc->regs, DWC3_GCTL, reg);

	/*
	* Initialize OTG registers as per
	* Figure 11-4 OTG Driver Overall Programming Flow
	*/
	/* OCFG.SRPCap = 0, OCFG.HNPCap = 0 */
	reg = dwc3_readl(dwc->regs, DWC3_OCFG);
	reg &= ~(DWC3_OCFG_SRPCAP \| DWC3_OCFG_HNPCAP);
	dwc3_writel(dwc->regs, DWC3_OCFG, reg);
	/* OEVT = FFFF */
	dwc3_otg_clear_events(dwc);
	/* OEVTEN = 0 */
	dwc3_otg_disable_events(dwc, DWC3_OTG_ALL_EVENTS);
	/* OEVTEN.ConIDStsChngEn = 1. Instead we enable all events */
	dwc3_otg_enable_events(dwc, DWC3_OTG_ALL_EVENTS);
	/*
	* OCTL.PeriMode = 1, OCTL.DevSetHNPEn = 0, OCTL.HstSetHNPEn = 0,
	* OCTL.HNPReq = 0
	*/
	reg = dwc3_readl(dwc->regs, DWC3_OCTL);
	reg \|= DWC3_OCTL_PERIMODE;
	reg &= ~(DWC3_OCTL_DEVSETHNPEN \| DWC3_OCTL_HSTSETHNPEN \|
	DWC3_OCTL_HNPREQ);
	dwc3_writel(dwc->regs, DWC3_OCTL, reg);
	}

	static int dwc3_otg_get_irq(struct dwc3 *dwc)
	{
	struct platform_device *dwc3_pdev = to_platform_device(dwc->dev);
	int irq;

	irq = platform_get_irq_byname_optional(dwc3_pdev, "otg");
	if (irq > 0)
	goto out;

	if (irq == -EPROBE_DEFER)
	goto out;

	irq = platform_get_irq_byname_optional(dwc3_pdev, "dwc_usb3");
	if (irq > 0)
	goto out;

	if (irq == -EPROBE_DEFER)
	goto out;

	irq = platform_get_irq(dwc3_pdev, 0);
	if (irq > 0)
	goto out;

	if (!irq)
	irq = -EINVAL;

	out:
	return irq;
	}

	void dwc3_otg_init(struct dwc3 *dwc)
	{
	u32 reg;

	/*
	* As per Figure 11-4 OTG Driver Overall Programming Flow,
	* block "Initialize GCTL for OTG operation".
	*/
	/* GCTL.PrtCapDir=2'b11 */
	dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_OTG);
	/* GUSB2PHYCFG0.SusPHY=0 */
	reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
	reg &= ~DWC3_GUSB2PHYCFG_SUSPHY;
	dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);

	/* Initialize OTG registers */
	dwc3_otgregs_init(dwc);
	}

	void dwc3_otg_exit(struct dwc3 *dwc)
	{
	/* disable all OTG IRQs */
	dwc3_otg_disable_events(dwc, DWC3_OTG_ALL_EVENTS);
	/* clear all events */
	dwc3_otg_clear_events(dwc);
	}

	/* should be called before Host controller driver is started */
	void dwc3_otg_host_init(struct dwc3 *dwc)
	{
	u32 reg;

	/* As per Figure 11-10 A-Device Flow Diagram */
	/* OCFG.HNPCap = 0, OCFG.SRPCap = 0. Already 0 */

	/*
	* OCTL.PeriMode=0, OCTL.TermSelDLPulse = 0,
	* OCTL.DevSetHNPEn = 0, OCTL.HstSetHNPEn = 0
	*/
	reg = dwc3_readl(dwc->regs, DWC3_OCTL);
	reg &= ~(DWC3_OCTL_PERIMODE \| DWC3_OCTL_TERMSELIDPULSE \|
	DWC3_OCTL_DEVSETHNPEN \| DWC3_OCTL_HSTSETHNPEN);
	dwc3_writel(dwc->regs, DWC3_OCTL, reg);

	/*
	* OCFG.DisPrtPwrCutoff = 0/1
	*/
	reg = dwc3_readl(dwc->regs, DWC3_OCFG);
	reg &= ~DWC3_OCFG_DISPWRCUTTOFF;
	dwc3_writel(dwc->regs, DWC3_OCFG, reg);

	/*
	* OCFG.SRPCap = 1, OCFG.HNPCap = GHWPARAMS6.HNP_CAP
	* We don't want SRP/HNP for simple dual-role so leave
	* these disabled.
	*/

	/*
	* OEVTEN.OTGADevHostEvntEn = 1
	* OEVTEN.OTGADevSessEndDetEvntEn = 1
	* We don't want HNP/role-swap so leave these disabled.
	*/

	/* GUSB2PHYCFG.ULPIAutoRes = 1/0, GUSB2PHYCFG.SusPHY = 1 */
	if (!dwc->dis_u2_susphy_quirk) {
	reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
	reg \|= DWC3_GUSB2PHYCFG_SUSPHY;
	dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
	}

	/* Set Port Power to enable VBUS: OCTL.PrtPwrCtl = 1 */
	reg = dwc3_readl(dwc->regs, DWC3_OCTL);
	reg \|= DWC3_OCTL_PRTPWRCTL;
	dwc3_writel(dwc->regs, DWC3_OCTL, reg);
	}

	/* should be called after Host controller driver is stopped */
	static void dwc3_otg_host_exit(struct dwc3 *dwc)
	{
	u32 reg;

	/*
	* Exit from A-device flow as per
	* Figure 11-4 OTG Driver Overall Programming Flow
	*/

	/*
	* OEVTEN.OTGADevBHostEndEvntEn=0, OEVTEN.OTGADevHNPChngEvntEn=0
	* OEVTEN.OTGADevSessEndDetEvntEn=0,
	* OEVTEN.OTGADevHostEvntEn = 0
	* But we don't disable any OTG events
	*/

	/* OCTL.HstSetHNPEn = 0, OCTL.PrtPwrCtl=0 */
	reg = dwc3_readl(dwc->regs, DWC3_OCTL);
	reg &= ~(DWC3_OCTL_HSTSETHNPEN \| DWC3_OCTL_PRTPWRCTL);
	dwc3_writel(dwc->regs, DWC3_OCTL, reg);
	}

	/* should be called before the gadget controller driver is started */
	static void dwc3_otg_device_init(struct dwc3 *dwc)
	{
	u32 reg;

	/* As per Figure 11-20 B-Device Flow Diagram */

	/*
	* OCFG.HNPCap = GHWPARAMS6.HNP_CAP, OCFG.SRPCap = 1
	* but we keep them 0 for simple dual-role operation.
	*/
	reg = dwc3_readl(dwc->regs, DWC3_OCFG);
	/* OCFG.OTGSftRstMsk = 0/1 */
	reg \|= DWC3_OCFG_SFTRSTMASK;
	dwc3_writel(dwc->regs, DWC3_OCFG, reg);
	/*
	* OCTL.PeriMode = 1
	* OCTL.TermSelDLPulse = 0/1, OCTL.HNPReq = 0
	* OCTL.DevSetHNPEn = 0, OCTL.HstSetHNPEn = 0
	*/
	reg = dwc3_readl(dwc->regs, DWC3_OCTL);
	reg \|= DWC3_OCTL_PERIMODE;
	reg &= ~(DWC3_OCTL_TERMSELIDPULSE \| DWC3_OCTL_HNPREQ \|
	DWC3_OCTL_DEVSETHNPEN \| DWC3_OCTL_HSTSETHNPEN);
	dwc3_writel(dwc->regs, DWC3_OCTL, reg);
	/* OEVTEN.OTGBDevSesVldDetEvntEn = 1 */
	dwc3_otg_enable_events(dwc, DWC3_OEVTEN_BDEVSESSVLDDETEN);
	/* GUSB2PHYCFG.ULPIAutoRes = 0, GUSB2PHYCFG0.SusPHY = 1 */
	if (!dwc->dis_u2_susphy_quirk) {
	reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
	reg \|= DWC3_GUSB2PHYCFG_SUSPHY;
	dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
	}
	/* GCTL.GblHibernationEn = 0. Already 0. */
	}

	/* should be called after the gadget controller driver is stopped */
	static void dwc3_otg_device_exit(struct dwc3 *dwc)
	{
	u32 reg;

	/*
	* Exit from B-device flow as per
	* Figure 11-4 OTG Driver Overall Programming Flow
	*/

	/*
	* OEVTEN.OTGBDevHNPChngEvntEn = 0
	* OEVTEN.OTGBDevVBusChngEvntEn = 0
	* OEVTEN.OTGBDevBHostEndEvntEn = 0
	*/
	dwc3_otg_disable_events(dwc, DWC3_OEVTEN_BDEVHNPCHNGEN \|
	DWC3_OEVTEN_BDEVVBUSCHNGEN \|
	DWC3_OEVTEN_BDEVBHOSTENDEN);

	/* OCTL.DevSetHNPEn = 0, OCTL.HNPReq = 0, OCTL.PeriMode=1 */
	reg = dwc3_readl(dwc->regs, DWC3_OCTL);
	reg &= ~(DWC3_OCTL_DEVSETHNPEN \| DWC3_OCTL_HNPREQ);
	reg \|= DWC3_OCTL_PERIMODE;
	dwc3_writel(dwc->regs, DWC3_OCTL, reg);
	}

	void dwc3_otg_update(struct dwc3 *dwc, bool ignore_idstatus)
	{
	int ret;
	u32 reg;
	int id;
	unsigned long flags;

	if (dwc->dr_mode != USB_DR_MODE_OTG)
	return;

	/* don't do anything if debug user changed role to not OTG */
	if (dwc->current_dr_role != DWC3_GCTL_PRTCAP_OTG)
	return;

	if (!ignore_idstatus) {
	reg = dwc3_readl(dwc->regs, DWC3_OSTS);
	id = !!(reg & DWC3_OSTS_CONIDSTS);

	dwc->desired_otg_role = id ? DWC3_OTG_ROLE_DEVICE :
	DWC3_OTG_ROLE_HOST;
	}

	if (dwc->desired_otg_role == dwc->current_otg_role)
	return;

	switch (dwc->current_otg_role) {
	case DWC3_OTG_ROLE_HOST:
	dwc3_host_exit(dwc);
	spin_lock_irqsave(&dwc->lock, flags);
	dwc3_otg_host_exit(dwc);
	spin_unlock_irqrestore(&dwc->lock, flags);
	break;
	case DWC3_OTG_ROLE_DEVICE:
	dwc3_gadget_exit(dwc);
	spin_lock_irqsave(&dwc->lock, flags);
	dwc3_event_buffers_cleanup(dwc);
	dwc3_otg_device_exit(dwc);
	spin_unlock_irqrestore(&dwc->lock, flags);
	break;
	default:
	break;
	}

	spin_lock_irqsave(&dwc->lock, flags);

	dwc->current_otg_role = dwc->desired_otg_role;

	spin_unlock_irqrestore(&dwc->lock, flags);

	switch (dwc->desired_otg_role) {
	case DWC3_OTG_ROLE_HOST:
	spin_lock_irqsave(&dwc->lock, flags);
	dwc3_otgregs_init(dwc);
	dwc3_otg_host_init(dwc);
	spin_unlock_irqrestore(&dwc->lock, flags);
	ret = dwc3_host_init(dwc);
	if (ret) {
	dev_err(dwc->dev, "failed to initialize host\n");
	} else {
	if (dwc->usb2_phy)
	otg_set_vbus(dwc->usb2_phy->otg, true);
	if (dwc->usb2_generic_phy)
	phy_set_mode(dwc->usb2_generic_phy,
	PHY_MODE_USB_HOST);
	}
	break;
	case DWC3_OTG_ROLE_DEVICE:
	spin_lock_irqsave(&dwc->lock, flags);
	dwc3_otgregs_init(dwc);
	dwc3_otg_device_init(dwc);
	dwc3_event_buffers_setup(dwc);
	spin_unlock_irqrestore(&dwc->lock, flags);

	if (dwc->usb2_phy)
	otg_set_vbus(dwc->usb2_phy->otg, false);
	if (dwc->usb2_generic_phy)
	phy_set_mode(dwc->usb2_generic_phy,
	PHY_MODE_USB_DEVICE);
	ret = dwc3_gadget_init(dwc);
	if (ret)
	dev_err(dwc->dev, "failed to initialize peripheral\n");
	break;
	default:
	break;
	}
	}

	static void dwc3_drd_update(struct dwc3 *dwc)
	{
	int id;

	if (dwc->edev) {
	id = extcon_get_state(dwc->edev, EXTCON_USB_HOST);
	if (id < 0)
	id = 0;
	dwc3_set_mode(dwc, id ?
	DWC3_GCTL_PRTCAP_HOST :
	DWC3_GCTL_PRTCAP_DEVICE);
	}
	}

	static int dwc3_drd_notifier(struct notifier_block *nb,
	unsigned long event, void *ptr)
	{
	struct dwc3 *dwc = container_of(nb, struct dwc3, edev_nb);

	dwc3_set_mode(dwc, event ?
	DWC3_GCTL_PRTCAP_HOST :
	DWC3_GCTL_PRTCAP_DEVICE);

	return NOTIFY_DONE;
	}

	static struct extcon_dev dwc3_get_extcon(struct dwc3 dwc)
	{
	struct device *dev = dwc->dev;
	struct device_node np_phy, np_conn;
	struct extcon_dev *edev;
	const char *name;

	if (device_property_read_bool(dev, "extcon"))
	return extcon_get_edev_by_phandle(dev, 0);

	/*
	* Device tree platforms should get extcon via phandle.
	* On ACPI platforms, we get the name from a device property.
	* This device property is for kernel internal use only and
	* is expected to be set by the glue code.
	*/
	if (device_property_read_string(dev, "linux,extcon-name", &name) == 0) {
	edev = extcon_get_extcon_dev(name);
	if (!edev)
	return ERR_PTR(-EPROBE_DEFER);

	return edev;
	}

	np_phy = of_parse_phandle(dev->of_node, "phys", 0);
	np_conn = of_graph_get_remote_node(np_phy, -1, -1);

	if (np_conn)
	edev = extcon_find_edev_by_node(np_conn);
	else
	edev = NULL;

	of_node_put(np_conn);
	of_node_put(np_phy);

	return edev;
	}

	#if IS_ENABLED(CONFIG_USB_ROLE_SWITCH)
	#define ROLE_SWITCH 1
	static int dwc3_usb_role_switch_set(struct usb_role_switch *sw,
	enum usb_role role)
	{
	struct dwc3 *dwc = usb_role_switch_get_drvdata(sw);
	u32 mode;

	switch (role) {
	case USB_ROLE_HOST:
	mode = DWC3_GCTL_PRTCAP_HOST;
	break;
	case USB_ROLE_DEVICE:
	mode = DWC3_GCTL_PRTCAP_DEVICE;
	break;
	default:
	if (dwc->role_switch_default_mode == USB_DR_MODE_HOST)
	mode = DWC3_GCTL_PRTCAP_HOST;
	else
	mode = DWC3_GCTL_PRTCAP_DEVICE;
	break;
	}

	dwc3_set_mode(dwc, mode);
	return 0;
	}

	static enum usb_role dwc3_usb_role_switch_get(struct usb_role_switch *sw)
	{
	struct dwc3 *dwc = usb_role_switch_get_drvdata(sw);
	unsigned long flags;
	enum usb_role role;

	spin_lock_irqsave(&dwc->lock, flags);
	switch (dwc->current_dr_role) {
	case DWC3_GCTL_PRTCAP_HOST:
	role = USB_ROLE_HOST;
	break;
	case DWC3_GCTL_PRTCAP_DEVICE:
	role = USB_ROLE_DEVICE;
	break;
	case DWC3_GCTL_PRTCAP_OTG:
	role = dwc->current_otg_role;
	break;
	default:
	if (dwc->role_switch_default_mode == USB_DR_MODE_HOST)
	role = USB_ROLE_HOST;
	else
	role = USB_ROLE_DEVICE;
	break;
	}
	spin_unlock_irqrestore(&dwc->lock, flags);
	return role;
	}

	static int dwc3_setup_role_switch(struct dwc3 *dwc)
	{
	struct usb_role_switch_desc dwc3_role_switch = {NULL};
	const char *str;
	u32 mode;
	int ret;

	ret = device_property_read_string(dwc->dev, "role-switch-default-mode",
	&str);
	if (ret >= 0 && !strncmp(str, "host", strlen("host"))) {
	dwc->role_switch_default_mode = USB_DR_MODE_HOST;
	mode = DWC3_GCTL_PRTCAP_HOST;
	} else {
	dwc->role_switch_default_mode = USB_DR_MODE_PERIPHERAL;
	mode = DWC3_GCTL_PRTCAP_DEVICE;
	}

	dwc3_role_switch.fwnode = dev_fwnode(dwc->dev);
	dwc3_role_switch.set = dwc3_usb_role_switch_set;
	dwc3_role_switch.get = dwc3_usb_role_switch_get;
	dwc3_role_switch.driver_data = dwc;
	dwc->role_sw = usb_role_switch_register(dwc->dev, &dwc3_role_switch);
	if (IS_ERR(dwc->role_sw))
	return PTR_ERR(dwc->role_sw);

	dwc3_set_mode(dwc, mode);
	return 0;
	}
	#else
	#define ROLE_SWITCH 0
	#define dwc3_setup_role_switch(x) 0
	#endif

	int dwc3_drd_init(struct dwc3 *dwc)
	{
	int ret, irq;

	dwc->edev = dwc3_get_extcon(dwc);
	if (IS_ERR(dwc->edev))
	return PTR_ERR(dwc->edev);

	if (ROLE_SWITCH &&
	device_property_read_bool(dwc->dev, "usb-role-switch")) {
	ret = dwc3_setup_role_switch(dwc);
	if (ret < 0)
	return ret;
	} else if (dwc->edev) {
	dwc->edev_nb.notifier_call = dwc3_drd_notifier;
	ret = extcon_register_notifier(dwc->edev, EXTCON_USB_HOST,
	&dwc->edev_nb);
	if (ret < 0) {
	dev_err(dwc->dev, "couldn't register cable notifier\n");
	return ret;
	}

	dwc3_drd_update(dwc);
	} else {
	dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_OTG);
	dwc->current_dr_role = DWC3_GCTL_PRTCAP_OTG;

	/* use OTG block to get ID event */
	irq = dwc3_otg_get_irq(dwc);
	if (irq < 0)
	return irq;

	dwc->otg_irq = irq;

	/* disable all OTG IRQs */
	dwc3_otg_disable_events(dwc, DWC3_OTG_ALL_EVENTS);
	/* clear all events */
	dwc3_otg_clear_events(dwc);

	ret = request_threaded_irq(dwc->otg_irq, dwc3_otg_irq,
	dwc3_otg_thread_irq,
	IRQF_SHARED, "dwc3-otg", dwc);
	if (ret) {
	dev_err(dwc->dev, "failed to request irq #%d --> %d\n",
	dwc->otg_irq, ret);
	ret = -ENODEV;
	return ret;
	}

	dwc3_otg_init(dwc);
	dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_OTG);
	}

	return 0;
	}

	void dwc3_drd_exit(struct dwc3 *dwc)
	{
	unsigned long flags;

	if (dwc->role_sw)
	usb_role_switch_unregister(dwc->role_sw);

	if (dwc->edev)
	extcon_unregister_notifier(dwc->edev, EXTCON_USB_HOST,
	&dwc->edev_nb);

	cancel_work_sync(&dwc->drd_work);

	/* debug user might have changed role, clean based on current role */
	switch (dwc->current_dr_role) {
	case DWC3_GCTL_PRTCAP_HOST:
	dwc3_host_exit(dwc);
	break;
	case DWC3_GCTL_PRTCAP_DEVICE:
	dwc3_gadget_exit(dwc);
	dwc3_event_buffers_cleanup(dwc);
	break;
	case DWC3_GCTL_PRTCAP_OTG:
	dwc3_otg_exit(dwc);
	spin_lock_irqsave(&dwc->lock, flags);
	dwc->desired_otg_role = DWC3_OTG_ROLE_IDLE;
	spin_unlock_irqrestore(&dwc->lock, flags);
	dwc3_otg_update(dwc, 1);
	break;
	default:
	break;
	}

	if (dwc->otg_irq)
	free_irq(dwc->otg_irq, dwc);
	}