From: Roger Quadros <rogerq@ti.com>
To: Peter Chen <hzpeterchen@gmail.com>
Cc: <peter.chen@freescale.com>, <balbi@kernel.org>,
<tony@atomide.com>, <gregkh@linuxfoundation.org>,
<dan.j.williams@intel.com>, <mathias.nyman@linux.intel.com>,
<Joao.Pinto@synopsys.com>, <sergei.shtylyov@cogentembedded.com>,
<jun.li@freescale.com>, <grygorii.strashko@ti.com>,
<yoshihiro.shimoda.uh@renesas.com>, <robh@kernel.org>,
<nsekhar@ti.com>, <b-liu@ti.com>, <linux-usb@vger.kernel.org>,
<linux-omap@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<devicetree@vger.kernel.org>
Subject: Re: [PATCH v8 13/14] usb: gadget: udc: adapt to OTG core
Date: Fri, 20 May 2016 10:26:03 +0300 [thread overview]
Message-ID: <573EBC0B.7030204@ti.com> (raw)
In-Reply-To: <20160520013931.GA10896@shlinux2>
Peter,
On 20/05/16 04:39, Peter Chen wrote:
> On Wed, May 18, 2016 at 03:45:11PM +0300, Roger Quadros wrote:
>> On 18/05/16 06:18, Peter Chen wrote:
>>> On Mon, May 16, 2016 at 12:51:53PM +0300, Roger Quadros wrote:
>>>> 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?
>>>>
>>>
>>> Oh, I meant only drd and fully otg state machine needs it. I am
>>> wondering if we need have a new API to do it. Two questions:
>>
>> OK.
>>>
>>> - Except for vbus interrupt, any chances this API will be used at
>>> current logic?
>>
>> I don't think so. But we can't assume caller behaviour for any API.
>>
>>> - When this API is called but without a coming gadget->stop?
>>>
>> Never for DRD case. But we want to catch wrong users.
>>
>
> In future, otg_start_gadget will be used for both DRD and fully OTG FSM.
> There is no otg_loc_conn at current DRD FSM, but there is
> otg_loc_conn at current OTG FSM, see below.
>
> DRD FSM:
> case OTG_STATE_B_IDLE:
> drd_set_protocol(fsm, PROTO_UNDEF);
> otg_drv_vbus(otg, 0);
> break;
> case OTG_STATE_B_PERIPHERAL:
> drd_set_protocol(fsm, PROTO_GADGET);
> otg_drv_vbus(otg, 0);
> break;
>
> OTG FSM:
> case OTG_STATE_B_IDLE:
> otg_drv_vbus(otg, 0);
> otg_chrg_vbus(otg, 0);
> otg_loc_conn(otg, 0);
> otg_loc_sof(otg, 0);
> /*
> * Driver is responsible for starting ADP probing
> * if ADP sensing times out.
> */
> otg_start_adp_sns(otg);
> otg_set_protocol(fsm, PROTO_UNDEF);
> otg_add_timer(otg, B_SE0_SRP);
> break;
> case OTG_STATE_B_PERIPHERAL:
> otg_chrg_vbus(otg, 0);
> otg_loc_sof(otg, 0);
> otg_set_protocol(fsm, PROTO_GADGET);
> otg_loc_conn(otg, 1);
> break;
>
> My original suggestion is to have an API to do pull dp and this API
> will be used at both DRD and OTG FSM, and called at otg_loc_conn.
The API is usb_gadget_connect_control();
> The (de)initialize is the same for both two FSMs, it both includes
> init peripheral mode and pull up dp, and can be done by drd_set_protocol(fsm, PROTO_GADGET)
> otg_loc_conn(otg, 1);
>
> What do you think?
>
I think loc_conn is a bit confusing to drd users. Another issue I see is that
DRD controller drivers will need to explicitly pass .loc_conn ops via the otg_fsm_ops.
This is an additional step and totally unnecessary as it can be automatically done
via direct DRD -> UDC-core call.
cheers,
-roger
next prev parent reply other threads:[~2016-05-20 7:26 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-13 10:03 [PATCH v8 00/14] USB OTG/dual-role framework Roger Quadros
2016-05-13 10:03 ` [PATCH v8 01/14] usb: hcd: Initialize hcd->flags to 0 Roger Quadros
2016-05-13 10:03 ` [PATCH v8 02/14] usb: otg-fsm: Prevent build warning "VDBG" redefined Roger Quadros
2016-05-13 10:03 ` [PATCH v8 03/14] usb: hcd.h: Add OTG to HCD interface Roger Quadros
2016-05-13 10:03 ` [PATCH v8 04/14] usb: otg-fsm: use usb_otg wherever possible Roger Quadros
2016-05-13 10:03 ` [PATCH v8 05/14] usb: otg-fsm: move host controller operations into usb_otg->hcd_ops Roger Quadros
2016-05-13 10:03 ` [PATCH v8 06/14] usb: gadget.h: Add OTG to gadget interface Roger Quadros
2016-05-13 10:03 ` [PATCH v8 07/14] usb: otg: get rid of CONFIG_USB_OTG_FSM in favour of CONFIG_USB_OTG Roger Quadros
2016-05-13 10:03 ` [PATCH v8 08/14] usb: otg: add OTG/dual-role core Roger Quadros
2016-05-16 9:00 ` Roger Quadros
[not found] ` <CAL411-qb0dHQrn+AarSApCq6L=toKPRerLKDcx_H+5WDWu_VDg@mail.gmail.com>
2016-05-18 12:59 ` Roger Quadros
2016-05-20 8:31 ` Roger Quadros
2016-05-20 9:19 ` Roger Quadros
2016-05-20 9:53 ` Peter Chen
2016-05-23 10:06 ` Roger Quadros
2016-05-24 9:45 ` Roger Quadros
2016-05-25 2:44 ` Peter Chen
2016-05-25 3:19 ` Jun Li
2016-05-25 12:26 ` Roger Quadros
2016-05-25 12:21 ` Roger Quadros
2016-05-25 14:44 ` Jun Li
2016-05-13 10:03 ` [PATCH v8 09/14] usb: of: add an API to get OTG device from USB controller node Roger Quadros
2016-05-20 9:29 ` [PATCH v9 " Roger Quadros
2016-05-23 21:06 ` Rob Herring
2016-05-13 10:03 ` [PATCH v8 10/14] usb: otg: add hcd companion support Roger Quadros
2016-05-13 18:13 ` Rob Herring
2016-05-16 8:12 ` Roger Quadros
2016-05-20 9:32 ` [PATCH v9 " Roger Quadros
2016-05-23 21:07 ` Rob Herring
2016-05-13 10:03 ` [PATCH v8 11/14] usb: otg: use dev_dbg() instead of VDBG() Roger Quadros
2016-05-13 10:03 ` [PATCH v8 12/14] usb: hcd: Adapt to OTG core Roger Quadros
2016-05-13 10:03 ` [PATCH v8 13/14] usb: gadget: udc: adapt " Roger Quadros
2016-05-16 7:02 ` Peter Chen
2016-05-16 8:26 ` Roger Quadros
2016-05-16 9:23 ` Peter Chen
2016-05-16 9:51 ` Roger Quadros
2016-05-17 7:38 ` Jun Li
2016-05-17 8:08 ` Roger Quadros
2016-05-17 8:28 ` Jun Li
2016-05-18 12:42 ` Roger Quadros
2016-05-18 13:12 ` Jun Li
2016-05-18 13:43 ` Roger Quadros
2016-05-18 14:46 ` Jun Li
2016-05-19 7:32 ` Roger Quadros
2016-05-21 2:29 ` Peter Chen
2016-05-23 3:21 ` Peter Chen
2016-05-23 10:11 ` Roger Quadros
2016-05-23 10:34 ` Jun Li
2016-05-23 10:36 ` Roger Quadros
2016-05-24 2:53 ` Peter Chen
2016-06-08 7:32 ` Roger Quadros
2016-06-08 9:05 ` Peter Chen
2016-05-18 3:18 ` Peter Chen
2016-05-18 12:45 ` Roger Quadros
2016-05-20 1:39 ` Peter Chen
2016-05-20 7:26 ` Roger Quadros [this message]
2016-05-21 2:44 ` Peter Chen
2016-06-01 7:38 ` Peter Chen
2016-06-02 11:07 ` Roger Quadros
2016-05-13 10:03 ` [PATCH v8 14/14] usb: host: xhci-plat: Add otg device to platform data Roger Quadros
2016-05-30 9:29 ` [PATCH v8 00/14] USB OTG/dual-role framework Peter Chen
2016-05-30 14:04 ` Roger Quadros
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