linux-kernel - Re: [RFC][PATCH v2 04/13] usb: gadget: add usb_gadget

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Message-ID: <20150416114839.GD3181@shlinux2>
Date:	Thu, 16 Apr 2015 19:48:40 +0800
From:	Peter Chen <peter.chen@...escale.com>
To:	Roger Quadros <rogerq@...com>
CC:	<gregkh@...uxfoundation.org>, <balbi@...com>,
	<stern@...land.harvard.edu>, <dan.j.williams@...el.com>,
	<jun.li@...escale.com>, <mathias.nyman@...ux.intel.com>,
	<tony@...mide.com>, <linux-usb@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <linux-omap@...r.kernel.org>
Subject: Re: [RFC][PATCH v2 04/13] usb: gadget: add usb_gadget_start/stop()

On Tue, Apr 14, 2015 at 01:41:51PM +0300, Roger Quadros wrote:
> The OTG state machine needs a mechanism to start and
> stop the gadget controller. Add usb_gadget_start()
> and usb_gadget_stop().
> 
> Signed-off-by: Roger Quadros <rogerq@...com>
> ---
>  drivers/usb/gadget/udc/udc-core.c | 74 +++++++++++++++++++++++++++++++++++++++
>  include/linux/usb/gadget.h        |  3 ++
>  2 files changed, 77 insertions(+)
> 
> diff --git a/drivers/usb/gadget/udc/udc-core.c b/drivers/usb/gadget/udc/udc-core.c
> index 5a81cb0..3aa5dd5 100644
> --- a/drivers/usb/gadget/udc/udc-core.c
> +++ b/drivers/usb/gadget/udc/udc-core.c
> @@ -187,6 +187,7 @@ EXPORT_SYMBOL_GPL(usb_gadget_udc_reset);
>   */
>  static inline int usb_gadget_udc_start(struct usb_udc *udc)
>  {
> +	dev_dbg(&udc->dev, "%s\n", __func__);
>  	return udc->gadget->ops->udc_start(udc->gadget, udc->driver);
>  }
>  
> @@ -204,10 +205,83 @@ static inline int usb_gadget_udc_start(struct usb_udc *udc)
>   */
>  static inline void usb_gadget_udc_stop(struct usb_udc *udc)
>  {
> +	dev_dbg(&udc->dev, "%s\n", __func__);
>  	udc->gadget->ops->udc_stop(udc->gadget);
>  }
>  
>  /**
> + * usb_gadget_start - start the usb gadget controller and connect to bus
> + * @gadget: the gadget device to start
> + *
> + * This is external API for use by OTG core.
> + *
> + * Start the usb device controller and connect to bus (enable pull).
> + */
> +int usb_gadget_start(struct usb_gadget *gadget)
> +{
> +	int ret;
> +	struct usb_udc *udc = NULL;
> +
> +	dev_dbg(&gadget->dev, "%s\n", __func__);
> +	mutex_lock(&udc_lock);
> +	list_for_each_entry(udc, &udc_list, list)
> +		if (udc->gadget == gadget)
> +			goto found;
> +
> +	dev_err(gadget->dev.parent, "%s: gadget not registered.\n",
> +		__func__);
> +	mutex_unlock(&udc_lock);
> +	return -EINVAL;
> +
> +found:
> +	ret = usb_gadget_udc_start(udc);
> +	if (ret)
> +		dev_err(&udc->dev, "USB Device Controller didn't start: %d\n",
> +			ret);
> +	else
> +		usb_gadget_connect(udc->gadget);

OTG FSM manages its pullup/pulldown itself through its fsm->ops->loc_conn

> +
> +	mutex_unlock(&udc_lock);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(usb_gadget_start);
> +
> +/**
> + * usb_gadget_stop - disconnect from bus and stop the usb gadget
> + * @gadget: The gadget device we want to stop
> + *
> + * This is external API for use by OTG core.
> + *
> + * Disconnect from the bus (disable pull) and stop the
> + * gadget controller.
> + */
> +int usb_gadget_stop(struct usb_gadget *gadget)
> +{
> +	struct usb_udc *udc = NULL;
> +
> +	dev_dbg(&gadget->dev, "%s\n", __func__);
> +	mutex_lock(&udc_lock);
> +	list_for_each_entry(udc, &udc_list, list)
> +		if (udc->gadget == gadget)
> +			goto found;
> +
> +	dev_err(gadget->dev.parent, "%s: gadget not registered.\n",
> +		__func__);
> +	mutex_unlock(&udc_lock);
> +	return -EINVAL;
> +
> +found:
> +	usb_gadget_disconnect(udc->gadget);
> +	udc->driver->disconnect(udc->gadget);
> +	usb_gadget_udc_stop(udc);
> +	mutex_unlock(&udc_lock);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_gadget_stop);
> +
> +/**
>   * usb_udc_release - release the usb_udc struct
>   * @dev: the dev member within usb_udc
>   *
> diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
> index e2f00fd..7ada7e6 100644
> --- a/include/linux/usb/gadget.h
> +++ b/include/linux/usb/gadget.h
> @@ -922,6 +922,9 @@ int usb_gadget_probe_driver(struct usb_gadget_driver *driver);
>   */
>  int usb_gadget_unregister_driver(struct usb_gadget_driver *driver);
>  
> +int usb_gadget_start(struct usb_gadget *gadget);
> +int usb_gadget_stop(struct usb_gadget *gadget);
> +
>  extern int usb_add_gadget_udc_release(struct device *parent,
>  		struct usb_gadget *gadget, void (*release)(struct device *dev));
>  extern int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget);
> -- 
> 2.1.0
> 

-- 

Best Regards,
Peter Chen
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