[v4,1/9] usb: dwc3: add dual-role support

Message ID 1441203864-15786-2-git-send-email-rogerq@ti.com
State New
Headers show

Commit Message

Roger Quadros Sept. 2, 2015, 2:24 p.m.
Register with the USB OTG core. Since we don't support
OTG yet we just work as a dual-role device even
if device tree says "otg".

Use extcon framework to get VBUS/ID cable events and
kick the OTG state machine.

Signed-off-by: Roger Quadros <rogerq@ti.com>
---
 drivers/usb/dwc3/core.c          | 174 ++++++++++++++++++++++++++++++++++++++-
 drivers/usb/dwc3/core.h          |   7 ++
 drivers/usb/dwc3/platform_data.h |   1 +
 3 files changed, 181 insertions(+), 1 deletion(-)

Comments

Felipe Balbi Sept. 2, 2015, 2:31 p.m. | #1
Hi,

On Wed, Sep 02, 2015 at 05:24:16PM +0300, Roger Quadros wrote:
> Register with the USB OTG core. Since we don't support
> OTG yet we just work as a dual-role device even
> if device tree says "otg".
> 
> Use extcon framework to get VBUS/ID cable events and
> kick the OTG state machine.
> 
> Signed-off-by: Roger Quadros <rogerq@ti.com>
> ---
>  drivers/usb/dwc3/core.c          | 174 ++++++++++++++++++++++++++++++++++++++-
>  drivers/usb/dwc3/core.h          |   7 ++
>  drivers/usb/dwc3/platform_data.h |   1 +
>  3 files changed, 181 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 064123e..2e36a9b 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -704,6 +704,152 @@ static int dwc3_core_get_phy(struct dwc3 *dwc)
>  	return 0;
>  }
>  
> +/* --------------------- Dual-Role management ------------------------------- */
> +
> +static void dwc3_drd_fsm_sync(struct dwc3 *dwc)
> +{
> +	int id, vbus;
> +
> +	/* get ID */
> +	id = extcon_get_cable_state(dwc->edev, "USB-HOST");
> +	/* Host means ID == 0 */
> +	id = !id;
> +
> +	/* get VBUS */
> +	vbus = extcon_get_cable_state(dwc->edev, "USB");
> +	dev_dbg(dwc->dev, "id %d vbus %d\n", id, vbus);

tracepoint please. We don't want this driver to use dev_(v)?db anymore.
Ditto to all others.

> +
> +	dwc->fsm->id = id;
> +	dwc->fsm->b_sess_vld = vbus;
> +	usb_otg_sync_inputs(dwc->fsm);
> +}
> +
> +static int dwc3_drd_start_host(struct otg_fsm *fsm, int on)
> +{
> +	struct device *dev = usb_otg_fsm_to_dev(fsm);
> +	struct dwc3 *dwc = dev_get_drvdata(dev);

how about adding a usb_otg_get_drvdata(fsm) ?

> +	dev_dbg(dwc->dev, "%s: %d\n", __func__, on);
> +	if (on) {
> +		dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_HOST);
> +		/* start the HCD */
> +		usb_otg_start_host(fsm, true);
> +	} else {
> +		/* stop the HCD */
> +		usb_otg_start_host(fsm, false);
> +	}

This can be simplified.

	if (on)
		dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_HOST);

	usb_otg_start_host(fsm, on);

> +
> +	return 0;
> +}
> +
> +static int dwc3_drd_start_gadget(struct otg_fsm *fsm, int on)
> +{
> +	struct device *dev = usb_otg_fsm_to_dev(fsm);
> +	struct dwc3 *dwc = dev_get_drvdata(dev);
> +
> +	dev_dbg(dwc->dev, "%s: %d\n", __func__, on);
> +	if (on) {
> +		dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_DEVICE);
> +		dwc3_event_buffers_setup(dwc);
> +
> +		/* start the UDC */
> +		usb_otg_start_gadget(fsm, true);
> +	} else {
> +		/* stop the UDC */
> +		usb_otg_start_gadget(fsm, false);
> +	}

likewise:

	if (on) {
		dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_DEVICE);
		dwc3_event_buffers_setup(dwc);
	}

	usb_otg_start_gadget(fsm, on);

> +	return 0;
> +}
> +
> +static struct otg_fsm_ops dwc3_drd_ops = {
> +	.start_host = dwc3_drd_start_host,
> +	.start_gadget = dwc3_drd_start_gadget,
> +};
> +
> +static int dwc3_drd_notifier(struct notifier_block *nb,
> +			     unsigned long event, void *ptr)
> +{
> +	struct dwc3 *dwc = container_of(nb, struct dwc3, otg_nb);
> +
> +	dwc3_drd_fsm_sync(dwc);
> +
> +	return NOTIFY_DONE;
> +}
> +
> +static int dwc3_drd_init(struct dwc3 *dwc)
> +{
> +	int ret, id, vbus;
> +	struct usb_otg_caps *otgcaps = &dwc->otg_config.otg_caps;
> +
> +	otgcaps->otg_rev = 0;
> +	otgcaps->hnp_support = false;
> +	otgcaps->srp_support = false;
> +	otgcaps->adp_support = false;
> +	dwc->otg_config.fsm_ops = &dwc3_drd_ops;
> +
> +	if (!dwc->edev) {
> +		dev_err(dwc->dev, "No extcon device found for OTG mode\n");
> +		return -ENODEV;
> +	}
> +
> +	dwc->otg_nb.notifier_call = dwc3_drd_notifier;
> +	ret = extcon_register_notifier(dwc->edev, EXTCON_USB, &dwc->otg_nb);
> +	if (ret < 0) {
> +		dev_err(dwc->dev, "Couldn't register USB cable notifier\n");
> +		return -ENODEV;
> +	}
> +
> +	ret = extcon_register_notifier(dwc->edev, EXTCON_USB_HOST,
> +				       &dwc->otg_nb);
> +	if (ret < 0) {
> +		dev_err(dwc->dev, "Couldn't register USB-HOST cable notifier\n");
> +		ret = -ENODEV;
> +		goto extcon_fail;
> +	}
> +
> +	/* sanity check id & vbus states */
> +	id = extcon_get_cable_state(dwc->edev, "USB-HOST");
> +	vbus = extcon_get_cable_state(dwc->edev, "USB");
> +	if (id < 0 || vbus < 0) {
> +		dev_err(dwc->dev, "Invalid USB cable state. id %d, vbus %d\n",
> +			id, vbus);
> +		ret = -ENODEV;
> +		goto fail;
> +	}
> +
> +	/* register as DRD device with OTG core */
> +	dwc->fsm = usb_otg_register(dwc->dev, &dwc->otg_config);
> +	if (IS_ERR(dwc->fsm)) {
> +		ret = PTR_ERR(dwc->fsm);
> +		if (ret == -ENOTSUPP)
> +			dev_err(dwc->dev, "CONFIG_USB_OTG needed for dual-role\n");
> +		else
> +			dev_err(dwc->dev, "Failed to register with OTG core\n");

do you need to cope with EPROBE_DEFER ?

> +
> +		goto fail;
> +	}
> +
> +	dwc3_drd_fsm_sync(dwc);
> +
> +	return 0;
> +fail:
> +	extcon_unregister_notifier(dwc->edev, EXTCON_USB_HOST, &dwc->otg_nb);
> +extcon_fail:
> +	extcon_unregister_notifier(dwc->edev, EXTCON_USB, &dwc->otg_nb);
> +
> +	return ret;
> +}
> +
> +static void dwc3_drd_exit(struct dwc3 *dwc)
> +{
> +	usb_otg_unregister(dwc->dev);
> +	extcon_unregister_notifier(dwc->edev, EXTCON_USB_HOST, &dwc->otg_nb);
> +	extcon_unregister_notifier(dwc->edev, EXTCON_USB, &dwc->otg_nb);
> +}
> +
> +/* -------------------------------------------------------------------------- */
> +
>  static int dwc3_core_init_mode(struct dwc3 *dwc)
>  {
>  	struct device *dev = dwc->dev;
> @@ -727,13 +873,21 @@ static int dwc3_core_init_mode(struct dwc3 *dwc)
>  		}
>  		break;
>  	case USB_DR_MODE_OTG:
> -		dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_OTG);
> +		ret = dwc3_drd_init(dwc);
> +		if (ret) {
> +			dev_err(dev, "limiting to peripheral only\n");
> +			dwc->dr_mode = USB_DR_MODE_PERIPHERAL;
> +			dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_DEVICE);
> +			goto gadget_init;
> +		}
> +
>  		ret = dwc3_host_init(dwc);
>  		if (ret) {
>  			dev_err(dev, "failed to initialize host\n");
>  			return ret;
>  		}
>  
> +gadget_init:
>  		ret = dwc3_gadget_init(dwc);
>  		if (ret) {
>  			dev_err(dev, "failed to initialize gadget\n");
> @@ -760,6 +914,7 @@ static void dwc3_core_exit_mode(struct dwc3 *dwc)
>  	case USB_DR_MODE_OTG:
>  		dwc3_host_exit(dwc);
>  		dwc3_gadget_exit(dwc);
> +		dwc3_drd_exit(dwc);
>  		break;
>  	default:
>  		/* do nothing */
> @@ -843,6 +998,16 @@ static int dwc3_probe(struct platform_device *pdev)
>  	hird_threshold = 12;
>  
>  	if (node) {
> +		if (of_property_read_bool(node, "extcon"))
> +			dwc->edev = extcon_get_edev_by_phandle(dev, 0);
> +		else if (of_property_read_bool(dev->parent->of_node, "extcon"))
> +			dwc->edev = extcon_get_edev_by_phandle(dev->parent, 0);

why do you need to check the parent ? Why isn't that done on the glue
layer ?

> +
> +		if (IS_ERR(dwc->edev)) {
> +			dev_vdbg(dev, "couldn't get extcon device\n");

dev_err() ??

> +			return -EPROBE_DEFER;

this could make us reschedule probe forever.

> +		}
> +
>  		dwc->maximum_speed = of_usb_get_maximum_speed(node);
>  		dwc->has_lpm_erratum = of_property_read_bool(node,
>  				"snps,has-lpm-erratum");
> @@ -887,6 +1052,13 @@ static int dwc3_probe(struct platform_device *pdev)
>  		of_property_read_string(node, "snps,hsphy_interface",
>  					&dwc->hsphy_interface);
>  	} else if (pdata) {
> +		if (pdata->extcon) {
> +			dwc->edev = extcon_get_extcon_dev(pdata->extcon);
> +			if (!dwc->edev) {
> +				dev_vdbg(dev, "couldn't get extcon device\n");
> +				return -EPROBE_DEFER;

ditto

> +			}
> +		}
>  		dwc->maximum_speed = pdata->maximum_speed;
>  		dwc->has_lpm_erratum = pdata->has_lpm_erratum;
>  		if (pdata->lpm_nyet_threshold)
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index 0447788..5ca2b25 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -31,8 +31,10 @@
>  #include <linux/usb/gadget.h>
>  #include <linux/usb/otg.h>
>  #include <linux/ulpi/interface.h>
> +#include <linux/usb/otg-fsm.h>
>  
>  #include <linux/phy/phy.h>
> +#include <linux/extcon.h>
>  
>  #define DWC3_MSG_MAX	500
>  
> @@ -753,6 +755,11 @@ struct dwc3 {
>  
>  	struct ulpi		*ulpi;
>  
> +	struct extcon_dev	*edev;	/* USB cable events ID & VBUS */
> +	struct notifier_block	otg_nb;	/* notifier for USB cable events */
> +	struct otg_fsm		*fsm;
> +	struct usb_otg_config	otg_config;
> +
>  	void __iomem		*regs;
>  	size_t			regs_size;
>  
> diff --git a/drivers/usb/dwc3/platform_data.h b/drivers/usb/dwc3/platform_data.h
> index d3614ec..b3b245c 100644
> --- a/drivers/usb/dwc3/platform_data.h
> +++ b/drivers/usb/dwc3/platform_data.h
> @@ -47,4 +47,5 @@ struct dwc3_platform_data {
>  	unsigned tx_de_emphasis:2;
>  
>  	const char *hsphy_interface;
> +	const char *extcon;	/* extcon name for USB cable events ID/VBUS */
>  };
> -- 
> 2.1.4
>
Roger Quadros Sept. 3, 2015, 12:21 p.m. | #2
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

On 02/09/15 17:31, Felipe Balbi wrote:
> Hi,
> 
> On Wed, Sep 02, 2015 at 05:24:16PM +0300, Roger Quadros wrote:
>> Register with the USB OTG core. Since we don't support
>> OTG yet we just work as a dual-role device even
>> if device tree says "otg".
>>
>> Use extcon framework to get VBUS/ID cable events and
>> kick the OTG state machine.
>>
>> Signed-off-by: Roger Quadros <rogerq@ti.com>
>> ---
>>  drivers/usb/dwc3/core.c          | 174 ++++++++++++++++++++++++++++++++++++++-
>>  drivers/usb/dwc3/core.h          |   7 ++
>>  drivers/usb/dwc3/platform_data.h |   1 +
>>  3 files changed, 181 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
>> index 064123e..2e36a9b 100644
>> --- a/drivers/usb/dwc3/core.c
>> +++ b/drivers/usb/dwc3/core.c
>> @@ -704,6 +704,152 @@ static int dwc3_core_get_phy(struct dwc3 *dwc)
>>  	return 0;
>>  }
>>  
>> +/* --------------------- Dual-Role management ------------------------------- */
>> +
>> +static void dwc3_drd_fsm_sync(struct dwc3 *dwc)
>> +{
>> +	int id, vbus;
>> +
>> +	/* get ID */
>> +	id = extcon_get_cable_state(dwc->edev, "USB-HOST");
>> +	/* Host means ID == 0 */
>> +	id = !id;
>> +
>> +	/* get VBUS */
>> +	vbus = extcon_get_cable_state(dwc->edev, "USB");
>> +	dev_dbg(dwc->dev, "id %d vbus %d\n", id, vbus);
> 
> tracepoint please. We don't want this driver to use dev_(v)?db anymore.
> Ditto to all others.

OK.

> 
>> +
>> +	dwc->fsm->id = id;
>> +	dwc->fsm->b_sess_vld = vbus;
>> +	usb_otg_sync_inputs(dwc->fsm);
>> +}
>> +
>> +static int dwc3_drd_start_host(struct otg_fsm *fsm, int on)
>> +{
>> +	struct device *dev = usb_otg_fsm_to_dev(fsm);
>> +	struct dwc3 *dwc = dev_get_drvdata(dev);
> 
> how about adding a usb_otg_get_drvdata(fsm) ?

You meant for otg core? That can be done.

> 
>> +	dev_dbg(dwc->dev, "%s: %d\n", __func__, on);
>> +	if (on) {
>> +		dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_HOST);
>> +		/* start the HCD */
>> +		usb_otg_start_host(fsm, true);
>> +	} else {
>> +		/* stop the HCD */
>> +		usb_otg_start_host(fsm, false);
>> +	}
> 
> This can be simplified.
> 
> 	if (on)
> 		dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_HOST);
> 
> 	usb_otg_start_host(fsm, on);

Indeed.

> 
>> +
>> +	return 0;
>> +}
>> +
>> +static int dwc3_drd_start_gadget(struct otg_fsm *fsm, int on)
>> +{
>> +	struct device *dev = usb_otg_fsm_to_dev(fsm);
>> +	struct dwc3 *dwc = dev_get_drvdata(dev);
>> +
>> +	dev_dbg(dwc->dev, "%s: %d\n", __func__, on);
>> +	if (on) {
>> +		dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_DEVICE);
>> +		dwc3_event_buffers_setup(dwc);
>> +
>> +		/* start the UDC */
>> +		usb_otg_start_gadget(fsm, true);
>> +	} else {
>> +		/* stop the UDC */
>> +		usb_otg_start_gadget(fsm, false);
>> +	}
> 
> likewise:
> 
> 	if (on) {
> 		dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_DEVICE);
> 		dwc3_event_buffers_setup(dwc);
> 	}
> 
> 	usb_otg_start_gadget(fsm, on);

OK.
> 
>> +	return 0;
>> +}
>> +
>> +static struct otg_fsm_ops dwc3_drd_ops = {
>> +	.start_host = dwc3_drd_start_host,
>> +	.start_gadget = dwc3_drd_start_gadget,
>> +};
>> +
>> +static int dwc3_drd_notifier(struct notifier_block *nb,
>> +			     unsigned long event, void *ptr)
>> +{
>> +	struct dwc3 *dwc = container_of(nb, struct dwc3, otg_nb);
>> +
>> +	dwc3_drd_fsm_sync(dwc);
>> +
>> +	return NOTIFY_DONE;
>> +}
>> +
>> +static int dwc3_drd_init(struct dwc3 *dwc)
>> +{
>> +	int ret, id, vbus;
>> +	struct usb_otg_caps *otgcaps = &dwc->otg_config.otg_caps;
>> +
>> +	otgcaps->otg_rev = 0;
>> +	otgcaps->hnp_support = false;
>> +	otgcaps->srp_support = false;
>> +	otgcaps->adp_support = false;
>> +	dwc->otg_config.fsm_ops = &dwc3_drd_ops;
>> +
>> +	if (!dwc->edev) {
>> +		dev_err(dwc->dev, "No extcon device found for OTG mode\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	dwc->otg_nb.notifier_call = dwc3_drd_notifier;
>> +	ret = extcon_register_notifier(dwc->edev, EXTCON_USB, &dwc->otg_nb);
>> +	if (ret < 0) {
>> +		dev_err(dwc->dev, "Couldn't register USB cable notifier\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	ret = extcon_register_notifier(dwc->edev, EXTCON_USB_HOST,
>> +				       &dwc->otg_nb);
>> +	if (ret < 0) {
>> +		dev_err(dwc->dev, "Couldn't register USB-HOST cable notifier\n");
>> +		ret = -ENODEV;
>> +		goto extcon_fail;
>> +	}
>> +
>> +	/* sanity check id & vbus states */
>> +	id = extcon_get_cable_state(dwc->edev, "USB-HOST");
>> +	vbus = extcon_get_cable_state(dwc->edev, "USB");
>> +	if (id < 0 || vbus < 0) {
>> +		dev_err(dwc->dev, "Invalid USB cable state. id %d, vbus %d\n",
>> +			id, vbus);
>> +		ret = -ENODEV;
>> +		goto fail;
>> +	}
>> +
>> +	/* register as DRD device with OTG core */
>> +	dwc->fsm = usb_otg_register(dwc->dev, &dwc->otg_config);
>> +	if (IS_ERR(dwc->fsm)) {
>> +		ret = PTR_ERR(dwc->fsm);
>> +		if (ret == -ENOTSUPP)
>> +			dev_err(dwc->dev, "CONFIG_USB_OTG needed for dual-role\n");
>> +		else
>> +			dev_err(dwc->dev, "Failed to register with OTG core\n");
> 
> do you need to cope with EPROBE_DEFER ?

Yes, we should.

> 
>> +
>> +		goto fail;
>> +	}
>> +
>> +	dwc3_drd_fsm_sync(dwc);
>> +
>> +	return 0;
>> +fail:
>> +	extcon_unregister_notifier(dwc->edev, EXTCON_USB_HOST, &dwc->otg_nb);
>> +extcon_fail:
>> +	extcon_unregister_notifier(dwc->edev, EXTCON_USB, &dwc->otg_nb);
>> +
>> +	return ret;
>> +}
>> +
>> +static void dwc3_drd_exit(struct dwc3 *dwc)
>> +{
>> +	usb_otg_unregister(dwc->dev);
>> +	extcon_unregister_notifier(dwc->edev, EXTCON_USB_HOST, &dwc->otg_nb);
>> +	extcon_unregister_notifier(dwc->edev, EXTCON_USB, &dwc->otg_nb);
>> +}
>> +
>> +/* -------------------------------------------------------------------------- */
>> +
>>  static int dwc3_core_init_mode(struct dwc3 *dwc)
>>  {
>>  	struct device *dev = dwc->dev;
>> @@ -727,13 +873,21 @@ static int dwc3_core_init_mode(struct dwc3 *dwc)
>>  		}
>>  		break;
>>  	case USB_DR_MODE_OTG:
>> -		dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_OTG);
>> +		ret = dwc3_drd_init(dwc);
>> +		if (ret) {

So here if ret is -EPROBE_DEFER, we return.

>> +			dev_err(dev, "limiting to peripheral only\n");
>> +			dwc->dr_mode = USB_DR_MODE_PERIPHERAL;
>> +			dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_DEVICE);
>> +			goto gadget_init;
>> +		}
>> +
>>  		ret = dwc3_host_init(dwc);
>>  		if (ret) {
>>  			dev_err(dev, "failed to initialize host\n");
>>  			return ret;
>>  		}
>>  
>> +gadget_init:
>>  		ret = dwc3_gadget_init(dwc);
>>  		if (ret) {
>>  			dev_err(dev, "failed to initialize gadget\n");
>> @@ -760,6 +914,7 @@ static void dwc3_core_exit_mode(struct dwc3 *dwc)
>>  	case USB_DR_MODE_OTG:
>>  		dwc3_host_exit(dwc);
>>  		dwc3_gadget_exit(dwc);
>> +		dwc3_drd_exit(dwc);
>>  		break;
>>  	default:
>>  		/* do nothing */
>> @@ -843,6 +998,16 @@ static int dwc3_probe(struct platform_device *pdev)
>>  	hird_threshold = 12;
>>  
>>  	if (node) {
>> +		if (of_property_read_bool(node, "extcon"))
>> +			dwc->edev = extcon_get_edev_by_phandle(dev, 0);
>> +		else if (of_property_read_bool(dev->parent->of_node, "extcon"))
>> +			dwc->edev = extcon_get_edev_by_phandle(dev->parent, 0);
> 
> why do you need to check the parent ? Why isn't that done on the glue
> layer ?

On DRA7-evm, the extcon device is defined in the glue layer node. But
we need the device both at the glue layer and at the core layer.
We do get the extcon device in dwc3-omap.c

Any suggestion how to pass the extcon device from glue layer to core.c?
Or should I add the extcon property to dwc3 USB node as well in the DT?

> 
>> +
>> +		if (IS_ERR(dwc->edev)) {
>> +			dev_vdbg(dev, "couldn't get extcon device\n");
> 
> dev_err() ??

Is it ok to print it even in EPROBE_DEFER case?

> 
>> +			return -EPROBE_DEFER;
> 
> this could make us reschedule probe forever.

Good catch, we must return PTR_ERR(dwc->edev).

> 
>> +		}
>> +
>>  		dwc->maximum_speed = of_usb_get_maximum_speed(node);
>>  		dwc->has_lpm_erratum = of_property_read_bool(node,
>>  				"snps,has-lpm-erratum");
>> @@ -887,6 +1052,13 @@ static int dwc3_probe(struct platform_device *pdev)
>>  		of_property_read_string(node, "snps,hsphy_interface",
>>  					&dwc->hsphy_interface);
>>  	} else if (pdata) {
>> +		if (pdata->extcon) {
>> +			dwc->edev = extcon_get_extcon_dev(pdata->extcon);
>> +			if (!dwc->edev) {
>> +				dev_vdbg(dev, "couldn't get extcon device\n");
>> +				return -EPROBE_DEFER;
> 
> ditto

OK.

> 
>> +			}
>> +		}
>>  		dwc->maximum_speed = pdata->maximum_speed;
>>  		dwc->has_lpm_erratum = pdata->has_lpm_erratum;
>>  		if (pdata->lpm_nyet_threshold)
>> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
>> index 0447788..5ca2b25 100644
>> --- a/drivers/usb/dwc3/core.h
>> +++ b/drivers/usb/dwc3/core.h
>> @@ -31,8 +31,10 @@
>>  #include <linux/usb/gadget.h>
>>  #include <linux/usb/otg.h>
>>  #include <linux/ulpi/interface.h>
>> +#include <linux/usb/otg-fsm.h>
>>  
>>  #include <linux/phy/phy.h>
>> +#include <linux/extcon.h>
>>  
>>  #define DWC3_MSG_MAX	500
>>  
>> @@ -753,6 +755,11 @@ struct dwc3 {
>>  
>>  	struct ulpi		*ulpi;
>>  
>> +	struct extcon_dev	*edev;	/* USB cable events ID & VBUS */
>> +	struct notifier_block	otg_nb;	/* notifier for USB cable events */
>> +	struct otg_fsm		*fsm;
>> +	struct usb_otg_config	otg_config;
>> +
>>  	void __iomem		*regs;
>>  	size_t			regs_size;
>>  
>> diff --git a/drivers/usb/dwc3/platform_data.h b/drivers/usb/dwc3/platform_data.h
>> index d3614ec..b3b245c 100644
>> --- a/drivers/usb/dwc3/platform_data.h
>> +++ b/drivers/usb/dwc3/platform_data.h
>> @@ -47,4 +47,5 @@ struct dwc3_platform_data {
>>  	unsigned tx_de_emphasis:2;
>>  
>>  	const char *hsphy_interface;
>> +	const char *extcon;	/* extcon name for USB cable events ID/VBUS */
>>  };
>> -- 
>> 2.1.4
>>
> 

- --
cheers,
- -roger
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Felipe Balbi Sept. 3, 2015, 3:44 p.m. | #3
Hi,

On Thu, Sep 03, 2015 at 03:21:48PM +0300, Roger Quadros wrote:
> >> +	dwc->fsm->id = id;
> >> +	dwc->fsm->b_sess_vld = vbus;
> >> +	usb_otg_sync_inputs(dwc->fsm);
> >> +}
> >> +
> >> +static int dwc3_drd_start_host(struct otg_fsm *fsm, int on)
> >> +{
> >> +	struct device *dev = usb_otg_fsm_to_dev(fsm);
> >> +	struct dwc3 *dwc = dev_get_drvdata(dev);
> > 
> > how about adding a usb_otg_get_drvdata(fsm) ?
> 
> You meant for otg core? That can be done.

yeah. BTW, I think otg core needs quite a few changes to become actually
useful. Currently it's just too much pointer ping-pong going back and
forth between phy, otg core, udc and hcd.

Also, I caught a ton of issues with it and suspend/resume. You might
want to fix them before adding more users to it.

It's also rather racy and that needs fixing too. On top of all that, I
think there's too much being added to UDC just to get Dual-Role, let's
see if we can improve that too.

> >> @@ -843,6 +998,16 @@ static int dwc3_probe(struct platform_device *pdev)
> >>  	hird_threshold = 12;
> >>  
> >>  	if (node) {
> >> +		if (of_property_read_bool(node, "extcon"))
> >> +			dwc->edev = extcon_get_edev_by_phandle(dev, 0);
> >> +		else if (of_property_read_bool(dev->parent->of_node, "extcon"))
> >> +			dwc->edev = extcon_get_edev_by_phandle(dev->parent, 0);
> > 
> > why do you need to check the parent ? Why isn't that done on the glue
> > layer ?
> 
> On DRA7-evm, the extcon device is defined in the glue layer node. But
> we need the device both at the glue layer and at the core layer.

why do you need extcon here ? Glue updates core via UTMI about the
states, right ? So you should get proper VBUS and ID status via OTG IRQ.
Is that not working ?

> We do get the extcon device in dwc3-omap.c
> 
> Any suggestion how to pass the extcon device from glue layer to core.c?
> Or should I add the extcon property to dwc3 USB node as well in the DT?

GPIO toggles
  dwc3-omap extcon event
    update status via UTMI STATUS register
      OTG IRQ on core
        Horray!

:-)

> >> +
> >> +		if (IS_ERR(dwc->edev)) {
> >> +			dev_vdbg(dev, "couldn't get extcon device\n");
> > 
> > dev_err() ??
> 
> Is it ok to print it even in EPROBE_DEFER case?

hmm, probably pointless, indeed.
Roger Quadros Sept. 4, 2015, 9:06 a.m. | #4
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

Felipe,

On 03/09/15 18:44, Felipe Balbi wrote:
> Hi,
> 
> On Thu, Sep 03, 2015 at 03:21:48PM +0300, Roger Quadros wrote:
>>>> +	dwc->fsm->id = id;
>>>> +	dwc->fsm->b_sess_vld = vbus;
>>>> +	usb_otg_sync_inputs(dwc->fsm);
>>>> +}
>>>> +
>>>> +static int dwc3_drd_start_host(struct otg_fsm *fsm, int on)
>>>> +{
>>>> +	struct device *dev = usb_otg_fsm_to_dev(fsm);
>>>> +	struct dwc3 *dwc = dev_get_drvdata(dev);
>>>
>>> how about adding a usb_otg_get_drvdata(fsm) ?
>>
>> You meant for otg core? That can be done.
> 
> yeah. BTW, I think otg core needs quite a few changes to become actually
> useful. Currently it's just too much pointer ping-pong going back and
> forth between phy, otg core, udc and hcd.

Sure, any inputs for improvement appreciated.

> 
> Also, I caught a ton of issues with it and suspend/resume. You might
> want to fix them before adding more users to it.

OK.

> 
> It's also rather racy and that needs fixing too. On top of all that, I
> think there's too much being added to UDC just to get Dual-Role, let's
> see if we can improve that too.

Would appreciate if you could give all your inputs on the otg core thread
as early as you can :)

> 
>>>> @@ -843,6 +998,16 @@ static int dwc3_probe(struct platform_device *pdev)
>>>>  	hird_threshold = 12;
>>>>  
>>>>  	if (node) {
>>>> +		if (of_property_read_bool(node, "extcon"))
>>>> +			dwc->edev = extcon_get_edev_by_phandle(dev, 0);
>>>> +		else if (of_property_read_bool(dev->parent->of_node, "extcon"))
>>>> +			dwc->edev = extcon_get_edev_by_phandle(dev->parent, 0);
>>>
>>> why do you need to check the parent ? Why isn't that done on the glue
>>> layer ?
>>
>> On DRA7-evm, the extcon device is defined in the glue layer node. But
>> we need the device both at the glue layer and at the core layer.
> 
> why do you need extcon here ? Glue updates core via UTMI about the
> states, right ? So you should get proper VBUS and ID status via OTG IRQ.
> Is that not working ?

I didn't even expect that would work. Let me give that a try.

> 
>> We do get the extcon device in dwc3-omap.c
>>
>> Any suggestion how to pass the extcon device from glue layer to core.c?
>> Or should I add the extcon property to dwc3 USB node as well in the DT?
> 
> GPIO toggles
>   dwc3-omap extcon event
>     update status via UTMI STATUS register
>       OTG IRQ on core
>         Horray!
> 
> :-)

That's great. Thanks :)

> 
>>>> +
>>>> +		if (IS_ERR(dwc->edev)) {
>>>> +			dev_vdbg(dev, "couldn't get extcon device\n");
>>>
>>> dev_err() ??
>>
>> Is it ok to print it even in EPROBE_DEFER case?
> 
> hmm, probably pointless, indeed.
> 

cheers,
- -roger
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Peter Chen Sept. 6, 2015, 2:02 a.m. | #5
On Wed, Sep 02, 2015 at 05:24:16PM +0300, Roger Quadros wrote:
> Register with the USB OTG core. Since we don't support
> OTG yet we just work as a dual-role device even
> if device tree says "otg".
> 
> +
> +static int dwc3_drd_init(struct dwc3 *dwc)
> +{
> +	int ret, id, vbus;
> +	struct usb_otg_caps *otgcaps = &dwc->otg_config.otg_caps;
> +
> +	otgcaps->otg_rev = 0;
> +	otgcaps->hnp_support = false;
> +	otgcaps->srp_support = false;
> +	otgcaps->adp_support = false;
> +	dwc->otg_config.fsm_ops = &dwc3_drd_ops;
> +
> +	if (!dwc->edev) {
> +		dev_err(dwc->dev, "No extcon device found for OTG mode\n");
> +		return -ENODEV;
> +	}
> +

Do All dwc3 platforms id/vbus need to get through extcon? Do the
SoCs have id/vbus pin?
Roger Quadros Sept. 7, 2015, 9:39 a.m. | #6
Peter,

On 06/09/15 05:02, Peter Chen wrote:
> On Wed, Sep 02, 2015 at 05:24:16PM +0300, Roger Quadros wrote:
>> Register with the USB OTG core. Since we don't support
>> OTG yet we just work as a dual-role device even
>> if device tree says "otg".
>>
>> +
>> +static int dwc3_drd_init(struct dwc3 *dwc)
>> +{
>> +	int ret, id, vbus;
>> +	struct usb_otg_caps *otgcaps = &dwc->otg_config.otg_caps;
>> +
>> +	otgcaps->otg_rev = 0;
>> +	otgcaps->hnp_support = false;
>> +	otgcaps->srp_support = false;
>> +	otgcaps->adp_support = false;
>> +	dwc->otg_config.fsm_ops = &dwc3_drd_ops;
>> +
>> +	if (!dwc->edev) {
>> +		dev_err(dwc->dev, "No extcon device found for OTG mode\n");
>> +		return -ENODEV;
>> +	}
>> +
> 
> Do All dwc3 platforms id/vbus need to get through extcon? Do the
> SoCs have id/vbus pin?
> 
> 

Extcon access is in fact not needed from dwc3 driver and I will be getting
rid of this patch. We will support dual-role only via the OTG irq as in patch 5.

The way it works is that the OMAP glue layer dwc3-omap.c requests extcon device
and sets some mailbox register and this causes the VBUS/ID events to come over
OTG irq/status. So this patch is redundant.

The extcon device is not needed for all TI platforms. e.g. we need it for
DRA7 but not for AM437x.

cheers,
-roger
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Roger Quadros Sept. 7, 2015, 9:42 a.m. | #7
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

On 04/09/15 12:06, Roger Quadros wrote:
> Felipe,
> 
> On 03/09/15 18:44, Felipe Balbi wrote:
>> Hi,
> 
>> On Thu, Sep 03, 2015 at 03:21:48PM +0300, Roger Quadros wrote:
>>>>> +	dwc->fsm->id = id;
>>>>> +	dwc->fsm->b_sess_vld = vbus;
>>>>> +	usb_otg_sync_inputs(dwc->fsm);
>>>>> +}
>>>>> +
>>>>> +static int dwc3_drd_start_host(struct otg_fsm *fsm, int on)
>>>>> +{
>>>>> +	struct device *dev = usb_otg_fsm_to_dev(fsm);
>>>>> +	struct dwc3 *dwc = dev_get_drvdata(dev);
>>>>
>>>> how about adding a usb_otg_get_drvdata(fsm) ?
>>>
>>> You meant for otg core? That can be done.
> 
>> yeah. BTW, I think otg core needs quite a few changes to become actually
>> useful. Currently it's just too much pointer ping-pong going back and
>> forth between phy, otg core, udc and hcd.
> 
> Sure, any inputs for improvement appreciated.
> 
> 
>> Also, I caught a ton of issues with it and suspend/resume. You might
>> want to fix them before adding more users to it.
> 
> OK.
> 
> 
>> It's also rather racy and that needs fixing too. On top of all that, I
>> think there's too much being added to UDC just to get Dual-Role, let's
>> see if we can improve that too.
> 
> Would appreciate if you could give all your inputs on the otg core thread
> as early as you can :)
> 
> 
>>>>> @@ -843,6 +998,16 @@ static int dwc3_probe(struct platform_device *pdev)
>>>>>  	hird_threshold = 12;
>>>>>  
>>>>>  	if (node) {
>>>>> +		if (of_property_read_bool(node, "extcon"))
>>>>> +			dwc->edev = extcon_get_edev_by_phandle(dev, 0);
>>>>> +		else if (of_property_read_bool(dev->parent->of_node, "extcon"))
>>>>> +			dwc->edev = extcon_get_edev_by_phandle(dev->parent, 0);
>>>>
>>>> why do you need to check the parent ? Why isn't that done on the glue
>>>> layer ?
>>>
>>> On DRA7-evm, the extcon device is defined in the glue layer node. But
>>> we need the device both at the glue layer and at the core layer.
> 
>> why do you need extcon here ? Glue updates core via UTMI about the
>> states, right ? So you should get proper VBUS and ID status via OTG IRQ.
>> Is that not working ?
> 
> I didn't even expect that would work. Let me give that a try.
> 
> 
>>> We do get the extcon device in dwc3-omap.c
>>>
>>> Any suggestion how to pass the extcon device from glue layer to core.c?
>>> Or should I add the extcon property to dwc3 USB node as well in the DT?
> 
>> GPIO toggles
>>   dwc3-omap extcon event
>>     update status via UTMI STATUS register
>>       OTG IRQ on core
>>         Horray!
> 
>> :-)
> 
> That's great. Thanks :)

This approach worked. Had to do the following change to the dwc3-omap glue
to make it work.

From: Roger Quadros <rogerq@ti.com>
Date: Fri, 4 Sep 2015 15:13:59 +0300
Subject: [PATCH] usb: dwc3: omap: Pass VBUS and ID events transparently

Don't make any decisions regarding VBUS session based on ID
status. That is best left to the OTG core.

Pass ID and VBUS events independent of each other so that OTG
core knows exactly what to do.

This makes dual-role with extcon work with OTG irq on OMAP platforms.

Signed-off-by: Roger Quadros <rogerq@ti.com>
- ---
 drivers/usb/dwc3/dwc3-omap.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/drivers/usb/dwc3/dwc3-omap.c b/drivers/usb/dwc3/dwc3-omap.c
index b18f2a3..751feee 100644
- --- a/drivers/usb/dwc3/dwc3-omap.c
+++ b/drivers/usb/dwc3/dwc3-omap.c
@@ -233,19 +233,14 @@ static void dwc3_omap_set_mailbox(struct dwc3_omap *omap,
 		}
 
 		val = dwc3_omap_read_utmi_ctrl(omap);
- -		val &= ~(USBOTGSS_UTMI_OTG_CTRL_IDDIG
- -				| USBOTGSS_UTMI_OTG_CTRL_VBUSVALID
- -				| USBOTGSS_UTMI_OTG_CTRL_SESSEND);
- -		val |= USBOTGSS_UTMI_OTG_CTRL_SESSVALID
- -				| USBOTGSS_UTMI_OTG_CTRL_POWERPRESENT;
+		val &= ~USBOTGSS_UTMI_OTG_CTRL_IDDIG;
 		dwc3_omap_write_utmi_ctrl(omap, val);
 		break;
 
 	case OMAP_DWC3_VBUS_VALID:
 		val = dwc3_omap_read_utmi_ctrl(omap);
 		val &= ~USBOTGSS_UTMI_OTG_CTRL_SESSEND;
- -		val |= USBOTGSS_UTMI_OTG_CTRL_IDDIG
- -				| USBOTGSS_UTMI_OTG_CTRL_VBUSVALID
+		val |= USBOTGSS_UTMI_OTG_CTRL_VBUSVALID
 				| USBOTGSS_UTMI_OTG_CTRL_SESSVALID
 				| USBOTGSS_UTMI_OTG_CTRL_POWERPRESENT;
 		dwc3_omap_write_utmi_ctrl(omap, val);
@@ -254,14 +249,16 @@ static void dwc3_omap_set_mailbox(struct dwc3_omap *omap,
 	case OMAP_DWC3_ID_FLOAT:
 		if (omap->vbus_reg)
 			regulator_disable(omap->vbus_reg);
+		val = dwc3_omap_read_utmi_ctrl(omap);
+		val |= USBOTGSS_UTMI_OTG_CTRL_IDDIG;
+		dwc3_omap_write_utmi_ctrl(omap, val);
 
 	case OMAP_DWC3_VBUS_OFF:
 		val = dwc3_omap_read_utmi_ctrl(omap);
 		val &= ~(USBOTGSS_UTMI_OTG_CTRL_SESSVALID
 				| USBOTGSS_UTMI_OTG_CTRL_VBUSVALID
 				| USBOTGSS_UTMI_OTG_CTRL_POWERPRESENT);
- -		val |= USBOTGSS_UTMI_OTG_CTRL_SESSEND
- -				| USBOTGSS_UTMI_OTG_CTRL_IDDIG;
+		val |= USBOTGSS_UTMI_OTG_CTRL_SESSEND;
 		dwc3_omap_write_utmi_ctrl(omap, val);
 		break;
 
- -- 
2.1.4
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Patch

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 064123e..2e36a9b 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -704,6 +704,152 @@  static int dwc3_core_get_phy(struct dwc3 *dwc)
 	return 0;
 }
 
+/* --------------------- Dual-Role management ------------------------------- */
+
+static void dwc3_drd_fsm_sync(struct dwc3 *dwc)
+{
+	int id, vbus;
+
+	/* get ID */
+	id = extcon_get_cable_state(dwc->edev, "USB-HOST");
+	/* Host means ID == 0 */
+	id = !id;
+
+	/* get VBUS */
+	vbus = extcon_get_cable_state(dwc->edev, "USB");
+	dev_dbg(dwc->dev, "id %d vbus %d\n", id, vbus);
+
+	dwc->fsm->id = id;
+	dwc->fsm->b_sess_vld = vbus;
+	usb_otg_sync_inputs(dwc->fsm);
+}
+
+static int dwc3_drd_start_host(struct otg_fsm *fsm, int on)
+{
+	struct device *dev = usb_otg_fsm_to_dev(fsm);
+	struct dwc3 *dwc = dev_get_drvdata(dev);
+
+	dev_dbg(dwc->dev, "%s: %d\n", __func__, on);
+	if (on) {
+		dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_HOST);
+		/* start the HCD */
+		usb_otg_start_host(fsm, true);
+	} else {
+		/* stop the HCD */
+		usb_otg_start_host(fsm, false);
+	}
+
+	return 0;
+}
+
+static int dwc3_drd_start_gadget(struct otg_fsm *fsm, int on)
+{
+	struct device *dev = usb_otg_fsm_to_dev(fsm);
+	struct dwc3 *dwc = dev_get_drvdata(dev);
+
+	dev_dbg(dwc->dev, "%s: %d\n", __func__, on);
+	if (on) {
+		dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_DEVICE);
+		dwc3_event_buffers_setup(dwc);
+
+		/* start the UDC */
+		usb_otg_start_gadget(fsm, true);
+	} else {
+		/* stop the UDC */
+		usb_otg_start_gadget(fsm, false);
+	}
+
+	return 0;
+}
+
+static struct otg_fsm_ops dwc3_drd_ops = {
+	.start_host = dwc3_drd_start_host,
+	.start_gadget = dwc3_drd_start_gadget,
+};
+
+static int dwc3_drd_notifier(struct notifier_block *nb,
+			     unsigned long event, void *ptr)
+{
+	struct dwc3 *dwc = container_of(nb, struct dwc3, otg_nb);
+
+	dwc3_drd_fsm_sync(dwc);
+
+	return NOTIFY_DONE;
+}
+
+static int dwc3_drd_init(struct dwc3 *dwc)
+{
+	int ret, id, vbus;
+	struct usb_otg_caps *otgcaps = &dwc->otg_config.otg_caps;
+
+	otgcaps->otg_rev = 0;
+	otgcaps->hnp_support = false;
+	otgcaps->srp_support = false;
+	otgcaps->adp_support = false;
+	dwc->otg_config.fsm_ops = &dwc3_drd_ops;
+
+	if (!dwc->edev) {
+		dev_err(dwc->dev, "No extcon device found for OTG mode\n");
+		return -ENODEV;
+	}
+
+	dwc->otg_nb.notifier_call = dwc3_drd_notifier;
+	ret = extcon_register_notifier(dwc->edev, EXTCON_USB, &dwc->otg_nb);
+	if (ret < 0) {
+		dev_err(dwc->dev, "Couldn't register USB cable notifier\n");
+		return -ENODEV;
+	}
+
+	ret = extcon_register_notifier(dwc->edev, EXTCON_USB_HOST,
+				       &dwc->otg_nb);
+	if (ret < 0) {
+		dev_err(dwc->dev, "Couldn't register USB-HOST cable notifier\n");
+		ret = -ENODEV;
+		goto extcon_fail;
+	}
+
+	/* sanity check id & vbus states */
+	id = extcon_get_cable_state(dwc->edev, "USB-HOST");
+	vbus = extcon_get_cable_state(dwc->edev, "USB");
+	if (id < 0 || vbus < 0) {
+		dev_err(dwc->dev, "Invalid USB cable state. id %d, vbus %d\n",
+			id, vbus);
+		ret = -ENODEV;
+		goto fail;
+	}
+
+	/* register as DRD device with OTG core */
+	dwc->fsm = usb_otg_register(dwc->dev, &dwc->otg_config);
+	if (IS_ERR(dwc->fsm)) {
+		ret = PTR_ERR(dwc->fsm);
+		if (ret == -ENOTSUPP)
+			dev_err(dwc->dev, "CONFIG_USB_OTG needed for dual-role\n");
+		else
+			dev_err(dwc->dev, "Failed to register with OTG core\n");
+
+		goto fail;
+	}
+
+	dwc3_drd_fsm_sync(dwc);
+
+	return 0;
+fail:
+	extcon_unregister_notifier(dwc->edev, EXTCON_USB_HOST, &dwc->otg_nb);
+extcon_fail:
+	extcon_unregister_notifier(dwc->edev, EXTCON_USB, &dwc->otg_nb);
+
+	return ret;
+}
+
+static void dwc3_drd_exit(struct dwc3 *dwc)
+{
+	usb_otg_unregister(dwc->dev);
+	extcon_unregister_notifier(dwc->edev, EXTCON_USB_HOST, &dwc->otg_nb);
+	extcon_unregister_notifier(dwc->edev, EXTCON_USB, &dwc->otg_nb);
+}
+
+/* -------------------------------------------------------------------------- */
+
 static int dwc3_core_init_mode(struct dwc3 *dwc)
 {
 	struct device *dev = dwc->dev;
@@ -727,13 +873,21 @@  static int dwc3_core_init_mode(struct dwc3 *dwc)
 		}
 		break;
 	case USB_DR_MODE_OTG:
-		dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_OTG);
+		ret = dwc3_drd_init(dwc);
+		if (ret) {
+			dev_err(dev, "limiting to peripheral only\n");
+			dwc->dr_mode = USB_DR_MODE_PERIPHERAL;
+			dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_DEVICE);
+			goto gadget_init;
+		}
+
 		ret = dwc3_host_init(dwc);
 		if (ret) {
 			dev_err(dev, "failed to initialize host\n");
 			return ret;
 		}
 
+gadget_init:
 		ret = dwc3_gadget_init(dwc);
 		if (ret) {
 			dev_err(dev, "failed to initialize gadget\n");
@@ -760,6 +914,7 @@  static void dwc3_core_exit_mode(struct dwc3 *dwc)
 	case USB_DR_MODE_OTG:
 		dwc3_host_exit(dwc);
 		dwc3_gadget_exit(dwc);
+		dwc3_drd_exit(dwc);
 		break;
 	default:
 		/* do nothing */
@@ -843,6 +998,16 @@  static int dwc3_probe(struct platform_device *pdev)
 	hird_threshold = 12;
 
 	if (node) {
+		if (of_property_read_bool(node, "extcon"))
+			dwc->edev = extcon_get_edev_by_phandle(dev, 0);
+		else if (of_property_read_bool(dev->parent->of_node, "extcon"))
+			dwc->edev = extcon_get_edev_by_phandle(dev->parent, 0);
+
+		if (IS_ERR(dwc->edev)) {
+			dev_vdbg(dev, "couldn't get extcon device\n");
+			return -EPROBE_DEFER;
+		}
+
 		dwc->maximum_speed = of_usb_get_maximum_speed(node);
 		dwc->has_lpm_erratum = of_property_read_bool(node,
 				"snps,has-lpm-erratum");
@@ -887,6 +1052,13 @@  static int dwc3_probe(struct platform_device *pdev)
 		of_property_read_string(node, "snps,hsphy_interface",
 					&dwc->hsphy_interface);
 	} else if (pdata) {
+		if (pdata->extcon) {
+			dwc->edev = extcon_get_extcon_dev(pdata->extcon);
+			if (!dwc->edev) {
+				dev_vdbg(dev, "couldn't get extcon device\n");
+				return -EPROBE_DEFER;
+			}
+		}
 		dwc->maximum_speed = pdata->maximum_speed;
 		dwc->has_lpm_erratum = pdata->has_lpm_erratum;
 		if (pdata->lpm_nyet_threshold)
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 0447788..5ca2b25 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -31,8 +31,10 @@ 
 #include <linux/usb/gadget.h>
 #include <linux/usb/otg.h>
 #include <linux/ulpi/interface.h>
+#include <linux/usb/otg-fsm.h>
 
 #include <linux/phy/phy.h>
+#include <linux/extcon.h>
 
 #define DWC3_MSG_MAX	500
 
@@ -753,6 +755,11 @@  struct dwc3 {
 
 	struct ulpi		*ulpi;
 
+	struct extcon_dev	*edev;	/* USB cable events ID & VBUS */
+	struct notifier_block	otg_nb;	/* notifier for USB cable events */
+	struct otg_fsm		*fsm;
+	struct usb_otg_config	otg_config;
+
 	void __iomem		*regs;
 	size_t			regs_size;
 
diff --git a/drivers/usb/dwc3/platform_data.h b/drivers/usb/dwc3/platform_data.h
index d3614ec..b3b245c 100644
--- a/drivers/usb/dwc3/platform_data.h
+++ b/drivers/usb/dwc3/platform_data.h
@@ -47,4 +47,5 @@  struct dwc3_platform_data {
 	unsigned tx_de_emphasis:2;
 
 	const char *hsphy_interface;
+	const char *extcon;	/* extcon name for USB cable events ID/VBUS */
 };