From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754152AbcETBo0 (ORCPT ); Thu, 19 May 2016 21:44:26 -0400 Received: from mail-pf0-f195.google.com ([209.85.192.195]:34055 "EHLO mail-pf0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753349AbcETBoY (ORCPT ); Thu, 19 May 2016 21:44:24 -0400 Date: Fri, 20 May 2016 09:39:31 +0800 From: Peter Chen To: Roger Quadros 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 Message-ID: <20160520013931.GA10896@shlinux2> References: <1463133808-10630-1-git-send-email-rogerq@ti.com> <1463133808-10630-14-git-send-email-rogerq@ti.com> <20160516070249.GB24609@shlinux2.ap.freescale.net> <57398451.2060103@ti.com> <20160516092323.GD24609@shlinux2.ap.freescale.net> <57399839.90706@ti.com> <20160518031829.GA4244@shlinux2.ap.freescale.net> <573C63D7.9050200@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <573C63D7.9050200@ti.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 (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? -- Best Regards, Peter Chen