Re: [RFC 2/5] USB: core: OTG Supplement Revision 2.0 updates

[Pavan Kondeti <pkondeti@codeaurora.org>]

On 12/15/2010 5:46 PM, Felipe Balbi wrote:
> Hi,
> 
> On Wed, Dec 15, 2010 at 04:44:11PM +0530, Pavankumar Kondeti wrote:
>> OTG supplement revision 2.0 spec introduces Attach Detection Protocol
>> (ADP) for detecting peripheral connection without applying power on
>> VBUS.  ADP is optional and is included in the OTG descriptor along with
>> SRP and HNP.
>>
>> HNP polling is introduced for peripheral to notify its wish to become
>> host.  Host polls (GET_STATUS on DEVICE) peripheral for host_request
>> and suspend the bus when peripheral returns host_request TRUE.  The spec
>> insists the polling frequency to be in 1-2 sec range and bus should be
>> suspended with in 2 sec from host_request is set.
> 
> within ?
> 
yeah. will fix it in V2.

>> diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
>> index b9278a1..38885b6 100644
>> --- a/drivers/usb/core/driver.c
>> +++ b/drivers/usb/core/driver.c
>> @@ -1207,6 +1207,19 @@ static int usb_suspend_both(struct usb_device *udev, pm_message_t msg)
>> 	 * and flush any outstanding URBs.
>> 	 */
>> 	} else {
>> +#ifdef CONFIG_USB_OTG
>> +		/* According to OTG supplement Rev 2.0 section 6.3
>> +		 * Unless an A-device enables b_hnp_enable before entering
>> +		 * suspend it shall also continue polling while the bus is
>> +		 * suspended.
>> +		 *
>> +		 * We don't have to perform HNP polling, as we are going to
>> +		 * enable b_hnp_enable before suspending.
>> +		 */
>> +		if (udev->bus->hnp_support &&
>> +			udev->portnum == udev->bus->otg_port)
>> +			cancel_delayed_work(&udev->bus->hnp_polling);
>> +#endif
>> 		udev->can_submit = 0;
>> 		for (i = 0; i < 16; ++i) {
>> 			usb_hcd_flush_endpoint(udev, udev->ep_out[i]);
>> @@ -1270,6 +1283,43 @@ static int usb_resume_both(struct usb_device *udev, pm_message_t msg)
>> 	return status;
>> }
>>
>> +#ifdef CONFIG_USB_OTG
>> +void usb_hnp_polling_work(struct work_struct *work)
> 
> do you really need this to be exported ??
> 

The work struct is per USB bus. The bus is initialized in core/hcd.c. I
kept the work function here as it it belongs to usb core (I mean not HCD
specific) like other USB auto suspend functions.

Thanks,
Pavan

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