From mboxrd@z Thu Jan  1 00:00:00 1970
From: dbaryshkov@gmail.com (Dmitry Eremin-Solenikov)
Date: Wed, 06 Jul 2011 11:30:52 +0400
Subject: [PATCH 15/15] pxa2[57]x_udc: drop gpio_pullup handling
In-Reply-To: <20110706072042.GC10729@legolas.emea.dhcp.ti.com>
References: <1309871321-11305-1-git-send-email-dbaryshkov@gmail.com>
	<1309871321-11305-16-git-send-email-dbaryshkov@gmail.com>
	<4E13772B.2090406@free.fr>
	<CALT56yP5yNPZoJ_+6a4t2t6rY_hmej5fc-NG02Jef-QiXHrc=Q@mail.gmail.com>
	<20110706072042.GC10729@legolas.emea.dhcp.ti.com>
Message-ID: <4E140F2C.2010900@gmail.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On 06.07.2011 11:20, Felipe Balbi wrote:
> hi,
>
> On Wed, Jul 06, 2011 at 12:58:48AM +0400, Dmitry Eremin-Solenikov wrote:
>> On 7/6/11, Robert Jarzmik<robert.jarzmik@free.fr>  wrote:
>>> On 07/05/2011 03:08 PM, Dmitry Eremin-Solenikov wrote:
>>>> Now as all drivers were converted to using gpio-vbus, drop gpio-pullup
>>>> handling from pxa UDC drivers, thus simplifying them a bit.
>>>
>>> Is this patch compliant with USB 2 specification regarding maximum time
>>> between pullup triggering and UDC ready to answer the "RESET" packet and
>>> be assigned an address ?
>>>
>>> This is the sequence I'm worried about :
>>>    (1) The gpio-vbus is loaded
>>>    (2) The pxa27x_udc is loaded
>>>    (3) USB cable is plugged
>>>        =>  VBUS is sensed
>>>    (4) gpio-vbus pulls up the D+ (Dmitry, is that right ?)
>>>    (5) the host waits for UDC to settle (100 ms ?)
>>>    (5) set address packet(s) are sent from host to UDC
>>>    (6) UDC is not enabled, as no gadget is registered
>>>        =>  UDC doesn't answer
>>>        =>  usb host cannot assign it an address
>>>    (7) a gadget is loaded (g_ether for example)
>>>        =>  UDC is enabled, but too late
>>>
>>> Alan, Gregh, could you confirm point (5) about a maximum time between D+
>>> line activation and UDC duty to repond to "set address" packets, as well
>>> as the consequence of point (6) where the usb device is rejected because
>>> no address could be assigned ?
>>>
>>> Dmitry, could you confirm the the D+ pullup is done at point (4) ?
>>
>> No, I can't confirm this. IIUC, evrything happens in abit different way:
>> (4) trancseiver notifies udc about VBUS sense
>> (5) a gadget is loaded (g_ether for example)
>> (6) gadget asks udc to enale  pullup
>> (7) udc tells gpio_vbus to enable pullup.
>
> yeah, with udc-core.c we only enable pullup after gadget driver is
> loaded.
>
> 290                 ret = bind(udc->gadget);
> 291                 if (ret)
> 292                         goto err1;
> 293                 ret = usb_gadget_udc_start(udc->gadget, driver);
> 294                 if (ret) {
> 295                         driver->unbind(udc->gadget);
> 296                         goto err1;
> 297                 }
> 298                 usb_gadget_connect(udc->gadget);
>
> but this is the new style bind() and many UDCs still need to be
> converted.

This was working before the udc-core. If it doesn't work now for 
unconverted drivers (PXA e.g.) that's really a huge regression!

-- 
With best wishes
Dmitry