From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755310AbcETH0Z (ORCPT ); Fri, 20 May 2016 03:26:25 -0400 Received: from bear.ext.ti.com ([198.47.19.11]:59630 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753719AbcETH0X (ORCPT ); Fri, 20 May 2016 03:26:23 -0400 Subject: Re: [PATCH v8 13/14] usb: gadget: udc: adapt to OTG core To: Peter Chen 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> CC: , , , , , , , , , , , , , , , , , From: Roger Quadros Message-ID: <573EBC0B.7030204@ti.com> Date: Fri, 20 May 2016 10:26:03 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.2 MIME-Version: 1.0 In-Reply-To: <20160520013931.GA10896@shlinux2> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roger Quadros Subject: Re: [PATCH v8 13/14] usb: gadget: udc: adapt to OTG core Date: Fri, 20 May 2016 10:26:03 +0300 Message-ID: <573EBC0B.7030204@ti.com> 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> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20160520013931.GA10896@shlinux2> Sender: linux-kernel-owner@vger.kernel.org To: Peter Chen 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 List-Id: devicetree@vger.kernel.org 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