From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751842AbcEUCto (ORCPT ); Fri, 20 May 2016 22:49:44 -0400 Received: from mail-pa0-f67.google.com ([209.85.220.67]:34871 "EHLO mail-pa0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751582AbcEUCtl (ORCPT ); Fri, 20 May 2016 22:49:41 -0400 Date: Sat, 21 May 2016 10:44:47 +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: <20160521024447.GB15088@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> <20160520013931.GA10896@shlinux2> <573EBC0B.7030204@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <573EBC0B.7030204@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 Fri, May 20, 2016 at 10:26:03AM +0300, Roger Quadros wrote: > 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. > If you are stick to that, let's follow your way if Felipe agree with it too, although it lets the DRD state machine look different with OTG's. -- Best Regards, Peter Chen