From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753064AbcERMpb (ORCPT ); Wed, 18 May 2016 08:45:31 -0400 Received: from bear.ext.ti.com ([198.47.19.11]:57179 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752741AbcERMp3 (ORCPT ); Wed, 18 May 2016 08:45:29 -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> CC: , , , , , , , , , , , , , , , , , From: Roger Quadros Message-ID: <573C63D7.9050200@ti.com> Date: Wed, 18 May 2016 15:45:11 +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: <20160518031829.GA4244@shlinux2.ap.freescale.net> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. cheers, -roger