drivers/usb/dwc3/dwc3_otg.c - kernel/msm - Gitiles

 /**
  * dwc3_otg.c - DesignWare USB3 DRD Controller OTG
  *
  * Copyright (c) 2012, Code Aurora Forum. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
  * only version 2 as published by the Free Software Foundation.
  *
  * 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/usb.h>
 #include <linux/usb/hcd.h>
 #include <linux/platform_device.h>

 #include "core.h"
 #include "dwc3_otg.h"
 #include "io.h"
 #include "xhci.h"


 /**
  * dwc3_otg_set_host_regs - reset dwc3 otg registers to host operation.
  *
  * This function sets the OTG registers to work in A-Device host mode.
  * This function should be called just before entering to A-Device mode.
  *
  * @w: Pointer to the dwc3 otg workqueue.
  */
 static void dwc3_otg_set_host_regs(struct dwc3_otg *dotg)
 {
 	u32 octl;

 	/* Set OCTL[6](PeriMode) to 0 (host) */
 	octl = dwc3_readl(dotg->regs, DWC3_OCTL);
 	octl &= ~DWC3_OTG_OCTL_PERIMODE;
 	dwc3_writel(dotg->regs, DWC3_OCTL, octl);

 	/*
 	 * TODO: add more OTG registers writes for HOST mode here,
 	 * see figure 12-10 A-device flow in dwc3 Synopsis spec
 	 */
 }

 /**
  * dwc3_otg_set_peripheral_regs - reset dwc3 otg registers to peripheral operation.
  *
  * This function sets the OTG registers to work in B-Device peripheral mode.
  * This function should be called just before entering to B-Device mode.
  *
  * @w: Pointer to the dwc3 otg workqueue.
  */
 static void dwc3_otg_set_peripheral_regs(struct dwc3_otg *dotg)
 {
 	u32 octl;

 	/* Set OCTL[6](PeriMode) to 1 (peripheral) */
 	octl = dwc3_readl(dotg->regs, DWC3_OCTL);
 	octl |= DWC3_OTG_OCTL_PERIMODE;
 	dwc3_writel(dotg->regs, DWC3_OCTL, octl);

 	/*
 	 * TODO: add more OTG registers writes for PERIPHERAL mode here,
 	 * see figure 12-19 B-device flow in dwc3 Synopsis spec
 	 */
 }

 /**
  * dwc3_otg_start_host -  helper function for starting/stoping the host controller driver.
  *
  * @otg: Pointer to the otg_transceiver structure.
  * @on: start / stop the host controller driver.
  *
  * Returns 0 on success otherwise negative errno.
  */
 static int dwc3_otg_start_host(struct usb_otg *otg, int on)
 {
 	struct dwc3_otg *dotg = container_of(otg, struct dwc3_otg, otg);
 	struct usb_hcd *hcd;
 	struct xhci_hcd *xhci;
 	int ret = 0;

 	if (!otg->host)
 		return -EINVAL;

 	hcd = bus_to_hcd(otg->host);
 	xhci = hcd_to_xhci(hcd);
 	if (on) {
 		dev_dbg(otg->phy->dev, "%s: turn on host %s\n",
 					__func__, otg->host->bus_name);
 		dwc3_otg_set_host_regs(dotg);

 		/*
 		 * This should be revisited for more testing post-silicon.
 		 * In worst case we may need to disconnect the root hub
 		 * before stopping the controller so that it does not
 		 * interfere with runtime pm/system pm.
 		 * We can also consider registering and unregistering xhci
 		 * platform device. It is almost similar to add_hcd and
 		 * remove_hcd, But we may not use standard set_host method
 		 * anymore.
 		 */
 		ret = hcd->driver->start(hcd);
 		if (ret) {
 			dev_err(otg->phy->dev,
 				"%s: failed to start primary hcd, ret=%d\n",
 				__func__, ret);
 			return ret;
 		}

 		ret = xhci->shared_hcd->driver->start(xhci->shared_hcd);
 		if (ret) {
 			dev_err(otg->phy->dev,
 				"%s: failed to start secondary hcd, ret=%d\n",
 				__func__, ret);
 			return ret;
 		}
 	} else {
 		dev_dbg(otg->phy->dev, "%s: turn off host %s\n",
 					__func__, otg->host->bus_name);
 		hcd->driver->stop(hcd);
 	}

 	return 0;
 }

 /**
  * dwc3_otg_set_host -  bind/unbind the host controller driver.
  *
  * @otg: Pointer to the otg_transceiver structure.
  * @host: Pointer to the usb_bus structure.
  *
  * Returns 0 on success otherwise negative errno.
  */
 static int dwc3_otg_set_host(struct usb_otg *otg, struct usb_bus *host)
 {
 	struct dwc3_otg *dotg = container_of(otg, struct dwc3_otg, otg);

 	if (host) {
 		dev_dbg(otg->phy->dev, "%s: set host %s\n",
 					__func__, host->bus_name);
 		otg->host = host;

 		/*
 		 * Only after both peripheral and host are set then check
 		 * OTG sm. This prevents unnecessary activation of the sm
 		 * in case the ID is high.
 		 */
 		if (otg->gadget)
 			schedule_work(&dotg->sm_work);
 	} else {
 		if (otg->phy->state == OTG_STATE_A_HOST) {
 			dwc3_otg_start_host(otg, 0);
 			otg->host = NULL;
 			otg->phy->state = OTG_STATE_UNDEFINED;
 			schedule_work(&dotg->sm_work);
 		} else {
 			otg->host = NULL;
 		}
 	}

 	return 0;
 }

 /**
  * dwc3_otg_start_peripheral -  bind/unbind the peripheral controller.
  *
  * @otg: Pointer to the otg_transceiver structure.
  * @gadget: pointer to the usb_gadget structure.
  *
  * Returns 0 on success otherwise negative errno.
  */
 static int dwc3_otg_start_peripheral(struct usb_otg *otg, int on)
 {
 	struct dwc3_otg *dotg = container_of(otg, struct dwc3_otg, otg);

 	if (!otg->gadget)
 		return -EINVAL;

 	if (on) {
 		dev_dbg(otg->phy->dev, "%s: turn on gadget %s\n",
 					__func__, otg->gadget->name);
 		dwc3_otg_set_peripheral_regs(dotg);
 		usb_gadget_vbus_connect(otg->gadget);
 	} else {
 		dev_dbg(otg->phy->dev, "%s: turn off gadget %s\n",
 					__func__, otg->gadget->name);
 		usb_gadget_vbus_disconnect(otg->gadget);
 	}

 	return 0;
 }

 /**
  * dwc3_otg_set_peripheral -  bind/unbind the peripheral controller driver.
  *
  * @otg: Pointer to the otg_transceiver structure.
  * @gadget: pointer to the usb_gadget structure.
  *
  * Returns 0 on success otherwise negative errno.
  */
 static int dwc3_otg_set_peripheral(struct usb_otg *otg,
 				struct usb_gadget *gadget)
 {
 	struct dwc3_otg *dotg = container_of(otg, struct dwc3_otg, otg);

 	if (gadget) {
 		dev_dbg(otg->phy->dev, "%s: set gadget %s\n",
 					__func__, gadget->name);
 		otg->gadget = gadget;

 		/*
 		 * Only after both peripheral and host are set then check
 		 * OTG sm. This prevents unnecessary activation of the sm
 		 * in case the ID is grounded.
 		 */
 		if (otg->host)
 			schedule_work(&dotg->sm_work);
 	} else {
 		if (otg->phy->state == OTG_STATE_B_PERIPHERAL) {
 			dwc3_otg_start_peripheral(otg, 0);
 			otg->gadget = NULL;
 			otg->phy->state = OTG_STATE_UNDEFINED;
 			schedule_work(&dotg->sm_work);
 		} else {
 			otg->gadget = NULL;
 		}
 	}

 	return 0;
 }

 /**
  * dwc3_otg_interrupt - interrupt handler for dwc3 otg events.
  * @_dotg: Pointer to out controller context structure
  *
  * Returns IRQ_HANDLED on success otherwise IRQ_NONE.
  */
 static irqreturn_t dwc3_otg_interrupt(int irq, void *_dotg)
 {
 	struct dwc3_otg *dotg = (struct dwc3_otg *)_dotg;
 	u32 oevt_reg;
 	int ret = IRQ_NONE;
 	int handled_irqs = 0;

 	oevt_reg = dwc3_readl(dotg->regs, DWC3_OEVT);

 	if (oevt_reg & DWC3_OEVTEN_OTGCONIDSTSCHNGEVNT) {
 		/*
 		 * ID sts has changed, read it and later, in the workqueue
 		 * function, switch from A to B or from B to A.
 		 */
 		dotg->osts = dwc3_readl(dotg->regs, DWC3_OSTS);
 		if ((dotg->otg.phy->state == OTG_STATE_B_IDLE) ||
 		    (dotg->otg.phy->state == OTG_STATE_A_IDLE)) {

 			/*
 			 * OTG state is ABOUT to change to A or B device, but
 			 * since ID sts was chnaged, then we return the state
 			 * machine to the start point.
 			 */
 			 dotg->otg.phy->state = OTG_STATE_UNDEFINED;
 		}
 		schedule_work(&dotg->sm_work);

 		handled_irqs |= DWC3_OEVTEN_OTGCONIDSTSCHNGEVNT;
 		ret = IRQ_HANDLED;
 	}

 	/*
 	 * Clear the interrupts we handled.
 	 */
 	if (ret == IRQ_HANDLED)
 		dwc3_writel(dotg->regs, DWC3_OEVT, handled_irqs);

 	return ret;
 }

 /**
  * dwc3_otg_sm_work - workqueue function.
  *
  * @w: Pointer to the dwc3 otg workqueue
  *
  * NOTE: After any change in phy->state,
  * we must reschdule the state machine.
  */
 static void dwc3_otg_sm_work(struct work_struct *w)
 {
 	struct dwc3_otg *dotg = container_of(w, struct dwc3_otg, sm_work);
 	struct usb_phy *phy = dotg->otg.phy;

 	dev_dbg(phy->dev, "%s state\n", otg_state_string(phy->state));

 	/* Check OTG state */
 	switch (phy->state) {
 	case OTG_STATE_UNDEFINED:
 		/* Switch to A or B-Device according to IDSTS */
 		if (dotg->osts & DWC3_OTG_OSTS_CONIDSTS)
 			phy->state = OTG_STATE_B_IDLE;
 		else
 			phy->state = OTG_STATE_A_IDLE;

 		schedule_work(&dotg->sm_work);
 		break;
 	case OTG_STATE_B_IDLE:
 		if (dwc3_otg_start_peripheral(&dotg->otg, 1)) {
 			/*
 			 * Probably set_peripheral was not called yet.
 			 * We will re-try as soon as it will be called
 			 */
 			dev_err(phy->dev,
 				"unable to start B-device\n");
 			phy->state = OTG_STATE_UNDEFINED;
 		} else
 			phy->state = OTG_STATE_B_PERIPHERAL;

 		schedule_work(&dotg->sm_work);
 		break;
 	case OTG_STATE_B_PERIPHERAL:
 		if (!(dotg->osts & DWC3_OTG_OSTS_CONIDSTS)) {
 			dwc3_otg_start_peripheral(&dotg->otg, 0);
 			phy->state = OTG_STATE_A_IDLE;
 			schedule_work(&dotg->sm_work);
 		}
 		break;
 	case OTG_STATE_A_IDLE:
 		/* Switch to A-Device*/
 		if (dwc3_otg_start_host(&dotg->otg, 1)) {
 			/*
 			 * Probably set_host was not called yet.
 			 * We will re-try as soon as it will be called
 			 */
 			dev_err(phy->dev,
 				"unable to start A-device\n");
 			phy->state = OTG_STATE_UNDEFINED;
 		} else
 			phy->state = OTG_STATE_A_HOST;

 		schedule_work(&dotg->sm_work);
 		break;
 	case OTG_STATE_A_HOST:
 		if (dotg->osts & DWC3_OTG_OSTS_CONIDSTS) {
 			dwc3_otg_start_host(&dotg->otg, 0);
 			phy->state = OTG_STATE_B_IDLE;
 			schedule_work(&dotg->sm_work);
 		}
 		break;
 	default:
 		dev_err(phy->dev, "%s: invalid otg-state\n", __func__);

 	}
 }


 /**
  * dwc3_otg_reset - reset dwc3 otg registers.
  *
  * @w: Pointer to the dwc3 otg workqueue
  */
 static void dwc3_otg_reset(struct dwc3_otg *dotg)
 {
 	/*
 	 * OCFG[2] - OTG-Version = 1
 	 * OCFG[1] - HNPCap = 0
 	 * OCFG[0] - SRPCap = 0
 	 */
 	dwc3_writel(dotg->regs, DWC3_OCFG, 0x4);

 	/*
 	 * OCTL[6] - PeriMode = 1
 	 * OCTL[5] - PrtPwrCtl = 0
 	 * OCTL[4] - HNPReq = 0
 	 * OCTL[3] - SesReq = 0
 	 * OCTL[2] - TermSelDLPulse = 0
 	 * OCTL[1] - DevSetHNPEn = 0
 	 * OCTL[0] - HstSetHNPEn = 0
 	 */
 	dwc3_writel(dotg->regs, DWC3_OCTL, 0x40);

 	/* Clear all otg events (interrupts) indications  */
 	dwc3_writel(dotg->regs, DWC3_OEVT, 0xFFFF);

 	/* Enable only the ConIDStsChngEn event*/
 	dwc3_writel(dotg->regs, DWC3_OEVTEN,
 				DWC3_OEVTEN_OTGCONIDSTSCHNGEVNT);

 	/* Read OSTS  */
 	dotg->osts = dwc3_readl(dotg->regs, DWC3_OSTS);

 }

 /**
  * dwc3_otg_init - Initializes otg related registers
  * @dwc: Pointer to out controller context structure
  *
  * Returns 0 on success otherwise negative errno.
  */
 int dwc3_otg_init(struct dwc3 *dwc)
 {
 	u32	reg;
 	int ret = 0;
 	struct dwc3_otg *dotg;

 	dev_dbg(dwc->dev, "dwc3_otg_init\n");

 	/*
 	 * GHWPARAMS6[10] bit is SRPSupport.
 	 * This bit also reflects DWC_USB3_EN_OTG
 	 */
 	reg = dwc3_readl(dwc->regs, DWC3_GHWPARAMS6);
 	if (!(reg & DWC3_GHWPARAMS6_SRP_SUPPORT)) {
 		/*
 		 * No OTG support in the HW core.
 		 * We return 0 to indicate no error, since this is acceptable
 		 * situation, just continue probe the dwc3 driver without otg.
 		 */
 		dev_dbg(dwc->dev, "dwc3_otg address space is not supported\n");
 		return 0;
 	}

 	/* Allocate and init otg instance */
 	dotg = kzalloc(sizeof(struct dwc3_otg), GFP_KERNEL);
 	if (!dotg) {
 		dev_err(dwc->dev, "unable to allocate dwc3_otg\n");
 		return -ENOMEM;
 	}

 	dotg->irq = platform_get_irq(to_platform_device(dwc->dev), 0);
 	if (dotg->irq < 0) {
 		dev_err(dwc->dev, "%s: missing IRQ\n", __func__);
 		ret = -ENODEV;
 		goto err1;
 	}

 	dotg->regs = dwc->regs;

 	dotg->otg.set_peripheral = dwc3_otg_set_peripheral;
 	dotg->otg.set_host = dwc3_otg_set_host;

 	/* This reference is used by dwc3 modules for checking otg existance */
 	dwc->dotg = dotg;

 	dotg->otg.phy = kzalloc(sizeof(struct usb_phy), GFP_KERNEL);
 	if (!dotg->otg.phy) {
 		dev_err(dwc->dev, "unable to allocate dwc3_otg.phy\n");
 		ret = -ENOMEM;
 		goto err1;
 	}

 	dotg->otg.phy->otg = &dotg->otg;
 	dotg->otg.phy->dev = dwc->dev;

 	ret = usb_set_transceiver(dotg->otg.phy);
 	if (ret) {
 		dev_err(dotg->otg.phy->dev,
 			"%s: failed to set transceiver, already exists\n",
 			__func__);
 		goto err2;
 	}

 	dwc3_otg_reset(dotg);

 	dotg->otg.phy->state = OTG_STATE_UNDEFINED;

 	INIT_WORK(&dotg->sm_work, dwc3_otg_sm_work);

 	ret = request_irq(dotg->irq, dwc3_otg_interrupt, IRQF_SHARED,
 				"dwc3_otg", dotg);
 	if (ret) {
 		dev_err(dotg->otg.phy->dev, "failed to request irq #%d --> %d\n",
 				dotg->irq, ret);
 		goto err3;
 	}

 	return 0;

 err3:
 	cancel_work_sync(&dotg->sm_work);
 	usb_set_transceiver(NULL);
 err2:
 	kfree(dotg->otg.phy);
 err1:
 	dwc->dotg = NULL;
 	kfree(dotg);

 	return ret;
 }

 /**
  * dwc3_otg_exit
  * @dwc: Pointer to out controller context structure
  *
  * Returns 0 on success otherwise negative errno.
  */
 void dwc3_otg_exit(struct dwc3 *dwc)
 {
 	struct dwc3_otg *dotg = dwc->dotg;

 	/* dotg is null when GHWPARAMS6[10]=SRPSupport=0, see dwc3_otg_init */
 	if (dotg) {
 		cancel_work_sync(&dotg->sm_work);
 		usb_set_transceiver(NULL);
 		free_irq(dotg->irq, dotg);
 		kfree(dotg->otg.phy);
 		kfree(dotg);
 		dwc->dotg = NULL;
 	}
 }
	/**
	* dwc3_otg.c - DesignWare USB3 DRD Controller OTG
	*
	* Copyright (c) 2012, Code Aurora Forum. All rights reserved.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 and
	* only version 2 as published by the Free Software Foundation.
	*
	* 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/usb.h>
	#include <linux/usb/hcd.h>
	#include <linux/platform_device.h>

	#include "core.h"
	#include "dwc3_otg.h"
	#include "io.h"
	#include "xhci.h"


	/**
	* dwc3_otg_set_host_regs - reset dwc3 otg registers to host operation.
	*
	* This function sets the OTG registers to work in A-Device host mode.
	* This function should be called just before entering to A-Device mode.
	*
	* @w: Pointer to the dwc3 otg workqueue.
	*/
	static void dwc3_otg_set_host_regs(struct dwc3_otg *dotg)
	{
	u32 octl;

	/* Set OCTL[6](PeriMode) to 0 (host) */
	octl = dwc3_readl(dotg->regs, DWC3_OCTL);
	octl &= ~DWC3_OTG_OCTL_PERIMODE;
	dwc3_writel(dotg->regs, DWC3_OCTL, octl);

	/*
	* TODO: add more OTG registers writes for HOST mode here,
	* see figure 12-10 A-device flow in dwc3 Synopsis spec
	*/
	}

	/**
	* dwc3_otg_set_peripheral_regs - reset dwc3 otg registers to peripheral operation.
	*
	* This function sets the OTG registers to work in B-Device peripheral mode.
	* This function should be called just before entering to B-Device mode.
	*
	* @w: Pointer to the dwc3 otg workqueue.
	*/
	static void dwc3_otg_set_peripheral_regs(struct dwc3_otg *dotg)
	{
	u32 octl;

	/* Set OCTL[6](PeriMode) to 1 (peripheral) */
	octl = dwc3_readl(dotg->regs, DWC3_OCTL);
	octl \|= DWC3_OTG_OCTL_PERIMODE;
	dwc3_writel(dotg->regs, DWC3_OCTL, octl);

	/*
	* TODO: add more OTG registers writes for PERIPHERAL mode here,
	* see figure 12-19 B-device flow in dwc3 Synopsis spec
	*/
	}

	/**
	* dwc3_otg_start_host - helper function for starting/stoping the host controller driver.
	*
	* @otg: Pointer to the otg_transceiver structure.
	* @on: start / stop the host controller driver.
	*
	* Returns 0 on success otherwise negative errno.
	*/
	static int dwc3_otg_start_host(struct usb_otg *otg, int on)
	{
	struct dwc3_otg *dotg = container_of(otg, struct dwc3_otg, otg);
	struct usb_hcd *hcd;
	struct xhci_hcd *xhci;
	int ret = 0;

	if (!otg->host)
	return -EINVAL;

	hcd = bus_to_hcd(otg->host);
	xhci = hcd_to_xhci(hcd);
	if (on) {
	dev_dbg(otg->phy->dev, "%s: turn on host %s\n",
	__func__, otg->host->bus_name);
	dwc3_otg_set_host_regs(dotg);

	/*
	* This should be revisited for more testing post-silicon.
	* In worst case we may need to disconnect the root hub
	* before stopping the controller so that it does not
	* interfere with runtime pm/system pm.
	* We can also consider registering and unregistering xhci
	* platform device. It is almost similar to add_hcd and
	* remove_hcd, But we may not use standard set_host method
	* anymore.
	*/
	ret = hcd->driver->start(hcd);
	if (ret) {
	dev_err(otg->phy->dev,
	"%s: failed to start primary hcd, ret=%d\n",
	__func__, ret);
	return ret;
	}

	ret = xhci->shared_hcd->driver->start(xhci->shared_hcd);
	if (ret) {
	dev_err(otg->phy->dev,
	"%s: failed to start secondary hcd, ret=%d\n",
	__func__, ret);
	return ret;
	}
	} else {
	dev_dbg(otg->phy->dev, "%s: turn off host %s\n",
	__func__, otg->host->bus_name);
	hcd->driver->stop(hcd);
	}

	return 0;
	}

	/**
	* dwc3_otg_set_host - bind/unbind the host controller driver.
	*
	* @otg: Pointer to the otg_transceiver structure.
	* @host: Pointer to the usb_bus structure.
	*
	* Returns 0 on success otherwise negative errno.
	*/
	static int dwc3_otg_set_host(struct usb_otg otg, struct usb_bus host)
	{
	struct dwc3_otg *dotg = container_of(otg, struct dwc3_otg, otg);

	if (host) {
	dev_dbg(otg->phy->dev, "%s: set host %s\n",
	__func__, host->bus_name);
	otg->host = host;

	/*
	* Only after both peripheral and host are set then check
	* OTG sm. This prevents unnecessary activation of the sm
	* in case the ID is high.
	*/
	if (otg->gadget)
	schedule_work(&dotg->sm_work);
	} else {
	if (otg->phy->state == OTG_STATE_A_HOST) {
	dwc3_otg_start_host(otg, 0);
	otg->host = NULL;
	otg->phy->state = OTG_STATE_UNDEFINED;
	schedule_work(&dotg->sm_work);
	} else {
	otg->host = NULL;
	}
	}

	return 0;
	}

	/**
	* dwc3_otg_start_peripheral - bind/unbind the peripheral controller.
	*
	* @otg: Pointer to the otg_transceiver structure.
	* @gadget: pointer to the usb_gadget structure.
	*
	* Returns 0 on success otherwise negative errno.
	*/
	static int dwc3_otg_start_peripheral(struct usb_otg *otg, int on)
	{
	struct dwc3_otg *dotg = container_of(otg, struct dwc3_otg, otg);

	if (!otg->gadget)
	return -EINVAL;

	if (on) {
	dev_dbg(otg->phy->dev, "%s: turn on gadget %s\n",
	__func__, otg->gadget->name);
	dwc3_otg_set_peripheral_regs(dotg);
	usb_gadget_vbus_connect(otg->gadget);
	} else {
	dev_dbg(otg->phy->dev, "%s: turn off gadget %s\n",
	__func__, otg->gadget->name);
	usb_gadget_vbus_disconnect(otg->gadget);
	}

	return 0;
	}

	/**
	* dwc3_otg_set_peripheral - bind/unbind the peripheral controller driver.
	*
	* @otg: Pointer to the otg_transceiver structure.
	* @gadget: pointer to the usb_gadget structure.
	*
	* Returns 0 on success otherwise negative errno.
	*/
	static int dwc3_otg_set_peripheral(struct usb_otg *otg,
	struct usb_gadget *gadget)
	{
	struct dwc3_otg *dotg = container_of(otg, struct dwc3_otg, otg);

	if (gadget) {
	dev_dbg(otg->phy->dev, "%s: set gadget %s\n",
	__func__, gadget->name);
	otg->gadget = gadget;

	/*
	* Only after both peripheral and host are set then check
	* OTG sm. This prevents unnecessary activation of the sm
	* in case the ID is grounded.
	*/
	if (otg->host)
	schedule_work(&dotg->sm_work);
	} else {
	if (otg->phy->state == OTG_STATE_B_PERIPHERAL) {
	dwc3_otg_start_peripheral(otg, 0);
	otg->gadget = NULL;
	otg->phy->state = OTG_STATE_UNDEFINED;
	schedule_work(&dotg->sm_work);
	} else {
	otg->gadget = NULL;
	}
	}

	return 0;
	}

	/**
	* dwc3_otg_interrupt - interrupt handler for dwc3 otg events.
	* @_dotg: Pointer to out controller context structure
	*
	* Returns IRQ_HANDLED on success otherwise IRQ_NONE.
	*/
	static irqreturn_t dwc3_otg_interrupt(int irq, void *_dotg)
	{
	struct dwc3_otg dotg = (struct dwc3_otg )_dotg;
	u32 oevt_reg;
	int ret = IRQ_NONE;
	int handled_irqs = 0;

	oevt_reg = dwc3_readl(dotg->regs, DWC3_OEVT);

	if (oevt_reg & DWC3_OEVTEN_OTGCONIDSTSCHNGEVNT) {
	/*
	* ID sts has changed, read it and later, in the workqueue
	* function, switch from A to B or from B to A.
	*/
	dotg->osts = dwc3_readl(dotg->regs, DWC3_OSTS);
	if ((dotg->otg.phy->state == OTG_STATE_B_IDLE) \|\|
	(dotg->otg.phy->state == OTG_STATE_A_IDLE)) {

	/*
	* OTG state is ABOUT to change to A or B device, but
	* since ID sts was chnaged, then we return the state
	* machine to the start point.
	*/
	dotg->otg.phy->state = OTG_STATE_UNDEFINED;
	}
	schedule_work(&dotg->sm_work);

	handled_irqs \|= DWC3_OEVTEN_OTGCONIDSTSCHNGEVNT;
	ret = IRQ_HANDLED;
	}

	/*
	* Clear the interrupts we handled.
	*/
	if (ret == IRQ_HANDLED)
	dwc3_writel(dotg->regs, DWC3_OEVT, handled_irqs);

	return ret;
	}

	/**
	* dwc3_otg_sm_work - workqueue function.
	*
	* @w: Pointer to the dwc3 otg workqueue
	*
	* NOTE: After any change in phy->state,
	* we must reschdule the state machine.
	*/
	static void dwc3_otg_sm_work(struct work_struct *w)
	{
	struct dwc3_otg *dotg = container_of(w, struct dwc3_otg, sm_work);
	struct usb_phy *phy = dotg->otg.phy;

	dev_dbg(phy->dev, "%s state\n", otg_state_string(phy->state));

	/* Check OTG state */
	switch (phy->state) {
	case OTG_STATE_UNDEFINED:
	/* Switch to A or B-Device according to IDSTS */
	if (dotg->osts & DWC3_OTG_OSTS_CONIDSTS)
	phy->state = OTG_STATE_B_IDLE;
	else
	phy->state = OTG_STATE_A_IDLE;

	schedule_work(&dotg->sm_work);
	break;
	case OTG_STATE_B_IDLE:
	if (dwc3_otg_start_peripheral(&dotg->otg, 1)) {
	/*
	* Probably set_peripheral was not called yet.
	* We will re-try as soon as it will be called
	*/
	dev_err(phy->dev,
	"unable to start B-device\n");
	phy->state = OTG_STATE_UNDEFINED;
	} else
	phy->state = OTG_STATE_B_PERIPHERAL;

	schedule_work(&dotg->sm_work);
	break;
	case OTG_STATE_B_PERIPHERAL:
	if (!(dotg->osts & DWC3_OTG_OSTS_CONIDSTS)) {
	dwc3_otg_start_peripheral(&dotg->otg, 0);
	phy->state = OTG_STATE_A_IDLE;
	schedule_work(&dotg->sm_work);
	}
	break;
	case OTG_STATE_A_IDLE:
	/* Switch to A-Device*/
	if (dwc3_otg_start_host(&dotg->otg, 1)) {
	/*
	* Probably set_host was not called yet.
	* We will re-try as soon as it will be called
	*/
	dev_err(phy->dev,
	"unable to start A-device\n");
	phy->state = OTG_STATE_UNDEFINED;
	} else
	phy->state = OTG_STATE_A_HOST;

	schedule_work(&dotg->sm_work);
	break;
	case OTG_STATE_A_HOST:
	if (dotg->osts & DWC3_OTG_OSTS_CONIDSTS) {
	dwc3_otg_start_host(&dotg->otg, 0);
	phy->state = OTG_STATE_B_IDLE;
	schedule_work(&dotg->sm_work);
	}
	break;
	default:
	dev_err(phy->dev, "%s: invalid otg-state\n", __func__);

	}
	}


	/**
	* dwc3_otg_reset - reset dwc3 otg registers.
	*
	* @w: Pointer to the dwc3 otg workqueue
	*/
	static void dwc3_otg_reset(struct dwc3_otg *dotg)
	{
	/*
	* OCFG[2] - OTG-Version = 1
	* OCFG[1] - HNPCap = 0
	* OCFG[0] - SRPCap = 0
	*/
	dwc3_writel(dotg->regs, DWC3_OCFG, 0x4);

	/*
	* OCTL[6] - PeriMode = 1
	* OCTL[5] - PrtPwrCtl = 0
	* OCTL[4] - HNPReq = 0
	* OCTL[3] - SesReq = 0
	* OCTL[2] - TermSelDLPulse = 0
	* OCTL[1] - DevSetHNPEn = 0
	* OCTL[0] - HstSetHNPEn = 0
	*/
	dwc3_writel(dotg->regs, DWC3_OCTL, 0x40);

	/* Clear all otg events (interrupts) indications */
	dwc3_writel(dotg->regs, DWC3_OEVT, 0xFFFF);

	/* Enable only the ConIDStsChngEn event*/
	dwc3_writel(dotg->regs, DWC3_OEVTEN,
	DWC3_OEVTEN_OTGCONIDSTSCHNGEVNT);

	/* Read OSTS */
	dotg->osts = dwc3_readl(dotg->regs, DWC3_OSTS);

	}

	/**
	* dwc3_otg_init - Initializes otg related registers
	* @dwc: Pointer to out controller context structure
	*
	* Returns 0 on success otherwise negative errno.
	*/
	int dwc3_otg_init(struct dwc3 *dwc)
	{
	u32 reg;
	int ret = 0;
	struct dwc3_otg *dotg;

	dev_dbg(dwc->dev, "dwc3_otg_init\n");

	/*
	* GHWPARAMS6[10] bit is SRPSupport.
	* This bit also reflects DWC_USB3_EN_OTG
	*/
	reg = dwc3_readl(dwc->regs, DWC3_GHWPARAMS6);
	if (!(reg & DWC3_GHWPARAMS6_SRP_SUPPORT)) {
	/*
	* No OTG support in the HW core.
	* We return 0 to indicate no error, since this is acceptable
	* situation, just continue probe the dwc3 driver without otg.
	*/
	dev_dbg(dwc->dev, "dwc3_otg address space is not supported\n");
	return 0;
	}

	/* Allocate and init otg instance */
	dotg = kzalloc(sizeof(struct dwc3_otg), GFP_KERNEL);
	if (!dotg) {
	dev_err(dwc->dev, "unable to allocate dwc3_otg\n");
	return -ENOMEM;
	}

	dotg->irq = platform_get_irq(to_platform_device(dwc->dev), 0);
	if (dotg->irq < 0) {
	dev_err(dwc->dev, "%s: missing IRQ\n", __func__);
	ret = -ENODEV;
	goto err1;
	}

	dotg->regs = dwc->regs;

	dotg->otg.set_peripheral = dwc3_otg_set_peripheral;
	dotg->otg.set_host = dwc3_otg_set_host;

	/* This reference is used by dwc3 modules for checking otg existance */
	dwc->dotg = dotg;

	dotg->otg.phy = kzalloc(sizeof(struct usb_phy), GFP_KERNEL);
	if (!dotg->otg.phy) {
	dev_err(dwc->dev, "unable to allocate dwc3_otg.phy\n");
	ret = -ENOMEM;
	goto err1;
	}

	dotg->otg.phy->otg = &dotg->otg;
	dotg->otg.phy->dev = dwc->dev;

	ret = usb_set_transceiver(dotg->otg.phy);
	if (ret) {
	dev_err(dotg->otg.phy->dev,
	"%s: failed to set transceiver, already exists\n",
	__func__);
	goto err2;
	}

	dwc3_otg_reset(dotg);

	dotg->otg.phy->state = OTG_STATE_UNDEFINED;

	INIT_WORK(&dotg->sm_work, dwc3_otg_sm_work);

	ret = request_irq(dotg->irq, dwc3_otg_interrupt, IRQF_SHARED,
	"dwc3_otg", dotg);
	if (ret) {
	dev_err(dotg->otg.phy->dev, "failed to request irq #%d --> %d\n",
	dotg->irq, ret);
	goto err3;
	}

	return 0;

	err3:
	cancel_work_sync(&dotg->sm_work);
	usb_set_transceiver(NULL);
	err2:
	kfree(dotg->otg.phy);
	err1:
	dwc->dotg = NULL;
	kfree(dotg);

	return ret;
	}

	/**
	* dwc3_otg_exit
	* @dwc: Pointer to out controller context structure
	*
	* Returns 0 on success otherwise negative errno.
	*/
	void dwc3_otg_exit(struct dwc3 *dwc)
	{
	struct dwc3_otg *dotg = dwc->dotg;

	/* dotg is null when GHWPARAMS6[10]=SRPSupport=0, see dwc3_otg_init */
	if (dotg) {
	cancel_work_sync(&dotg->sm_work);
	usb_set_transceiver(NULL);
	free_irq(dotg->irq, dotg);
	kfree(dotg->otg.phy);
	kfree(dotg);
	dwc->dotg = NULL;
	}
	}