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Message-ID: <573AD198.6030307@ti.com>
Date: Tue, 17 May 2016 11:08:56 +0300
From: Roger Quadros <rogerq@...com>
To: Jun Li <jun.li@....com>, Peter Chen <hzpeterchen@...il.com>
CC: "peter.chen@...escale.com" <peter.chen@...escale.com>,
"balbi@...nel.org" <balbi@...nel.org>,
"tony@...mide.com" <tony@...mide.com>,
"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
"dan.j.williams@...el.com" <dan.j.williams@...el.com>,
"mathias.nyman@...ux.intel.com" <mathias.nyman@...ux.intel.com>,
"Joao.Pinto@...opsys.com" <Joao.Pinto@...opsys.com>,
"sergei.shtylyov@...entembedded.com"
<sergei.shtylyov@...entembedded.com>,
"jun.li@...escale.com" <jun.li@...escale.com>,
"grygorii.strashko@...com" <grygorii.strashko@...com>,
"yoshihiro.shimoda.uh@...esas.com" <yoshihiro.shimoda.uh@...esas.com>,
"robh@...nel.org" <robh@...nel.org>,
"nsekhar@...com" <nsekhar@...com>, "b-liu@...com" <b-liu@...com>,
"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: Re: [PATCH v8 13/14] usb: gadget: udc: adapt to OTG core
On 17/05/16 10:38, Jun Li wrote:
> Hi
>
>> -----Original Message-----
>> From: Roger Quadros [mailto:rogerq@...com]
>> Sent: Monday, May 16, 2016 5:52 PM
>> To: Peter Chen <hzpeterchen@...il.com>
>> Cc: peter.chen@...escale.com; balbi@...nel.org; tony@...mide.com;
>> gregkh@...uxfoundation.org; dan.j.williams@...el.com;
>> mathias.nyman@...ux.intel.com; Joao.Pinto@...opsys.com;
>> sergei.shtylyov@...entembedded.com; jun.li@...escale.com;
>> grygorii.strashko@...com; yoshihiro.shimoda.uh@...esas.com;
>> robh@...nel.org; nsekhar@...com; b-liu@...com; linux-usb@...r.kernel.org;
>> linux-omap@...r.kernel.org; linux-kernel@...r.kernel.org;
>> devicetree@...r.kernel.org
>> Subject: Re: [PATCH v8 13/14] usb: gadget: udc: adapt to OTG core
>>
>> On 16/05/16 12:23, Peter Chen wrote:
>>> On Mon, May 16, 2016 at 11:26:57AM +0300, Roger Quadros wrote:
>>>> Hi,
>>>>
>>>> On 16/05/16 10:02, Peter Chen wrote:
>>>>> On Fri, May 13, 2016 at 01:03:27PM +0300, Roger Quadros wrote:
>>>>>> +
>>>>>> +static int usb_gadget_connect_control(struct usb_gadget *gadget,
>>>>>> +bool connect) {
>>>>>> + struct usb_udc *udc;
>>>>>> +
>>>>>> + mutex_lock(&udc_lock);
>>>>>> + udc = usb_gadget_to_udc(gadget);
>>>>>> + if (!udc) {
>>>>>> + dev_err(gadget->dev.parent, "%s: gadget not
>> registered.\n",
>>>>>> + __func__);
>>>>>> + mutex_unlock(&udc_lock);
>>>>>> + return -EINVAL;
>>>>>> + }
>>>>>> +
>>>>>> + if (connect) {
>>>>>> + if (!gadget->connected)
>>>>>> + usb_gadget_connect(udc->gadget);
>>>>>> + } else {
>>>>>> + if (gadget->connected) {
>>>>>> + usb_gadget_disconnect(udc->gadget);
>>>>>> + udc->driver->disconnect(udc->gadget);
>>>>>> + }
>>>>>> + }
>>>>>> +
>>>>>> + mutex_unlock(&udc_lock);
>>>>>> +
>>>>>> + return 0;
>>>>>> +}
>>>>>> +
>>>>>
>>>>> Since this is called for vbus interrupt, why not using
>>>>> usb_udc_vbus_handler directly, and call udc->driver->disconnect at
>>>>> usb_gadget_stop.
>>>>
>>>> We can't assume that this is always called for vbus interrupt so I
>>>> decided not to call usb_udc_vbus_handler.
>>>>
>>>> udc->vbus is really pointless for us. We keep vbus states in our
>>>> state machine and leave udc->vbus as ture always.
>>>>
>>>> Why do you want to move udc->driver->disconnect() to stop?
>>>> If USB controller disconnected from bus then the gadget driver must
>>>> be notified about the disconnect immediately. The controller may or
>>>> may not be stopped by the core.
>>>>
>>>
>>> Then, would you give some comments when this API will be used?
>>> I was assumed it is only used for drd state machine.
>>
>> drd_state machine didn't even need this API in the first place :).
>> You guys wanted me to separate out start/stop and connect/disconnect for
>> full OTG case.
>> Won't full OTG state machine want to use this API? If not what would it
>> use?
>
> Instead create those new interfaces/symbol here and there just aim to
> address build problems in diff configures, Could we only allow meaningful
> combination of those 3 drivers configures?
>
> Hcd=y, gadget=y, otg=y or
> Hcd=m, gadget=m, otg=m
This is still a limitation.
It is perfectly fine to have
hcd=m, gadget=y
or
hcd=y, gadget=m
cheers,
-roger
>
> Li Jun
>
>>
>> cheers,
>> -roger
>>
>>>
>>>>>
>>>>>> return 0;
>>>>>> @@ -660,9 +830,15 @@ static ssize_t usb_udc_softconn_store(struct
>> device *dev,
>>>>>> return -EOPNOTSUPP;
>>>>>> }
>>>>>>
>>>>>> + /* In OTG mode we don't support softconnect, but b_bus_req */
>>>>>> + if (udc->gadget->otg_dev) {
>>>>>> + dev_err(dev, "soft-connect not supported in OTG mode\n");
>>>>>> + return -EOPNOTSUPP;
>>>>>> + }
>>>>>> +
>>>>>
>>>>> The soft-connect can be supported at dual-role mode currently, we
>>>>> can use b_bus_req entry once it is implemented later.
>>>>
>>>> Soft-connect should be done via sysfs handling within the OTG core.
>>>> This can be added later. I don't want anything outside the OTG core
>>>> to handle soft-connect behaviour as it will be hard to keep things in
>>>> sync.
>>>>
>>>> I can update the comment to something like this.
>>>>
>>>> /* In OTG/dual-role mode, soft-connect should be handled by OTG core
>>>> */
>>>
>>> Ok, let's Felipe decide it.
>>>
>>>>
>>>>>
>>>>>> if (sysfs_streq(buf, "connect")) {
>>>>>> usb_gadget_udc_start(udc);
>>>>>> - usb_gadget_connect(udc->gadget);
>>>>>> + usb_udc_connect_control(udc);
>>>>>
>>>>> This line seems to be not related with this patch.
>>>>>
>>>> Right. I'll remove it.
>>>>
>>>> cheers,
>>>> -roger
>>>
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