Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754686AbcDYOEu (ORCPT ); Mon, 25 Apr 2016 10:04:50 -0400 Received: from bear.ext.ti.com ([192.94.94.41]:47856 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751708AbcDYOEs (ORCPT ); Mon, 25 Apr 2016 10:04:48 -0400 Subject: Re: [PATCH v6 09/12] usb: gadget: udc: adapt to OTG core To: Jun Li , "stern@rowland.harvard.edu" , "balbi@kernel.org" , "gregkh@linuxfoundation.org" , "peter.chen@freescale.com" References: <1459865117-7032-1-git-send-email-rogerq@ti.com> <1459865117-7032-10-git-send-email-rogerq@ti.com> CC: "dan.j.williams@intel.com" , "jun.li@freescale.com" , "mathias.nyman@linux.intel.com" , "tony@atomide.com" , "Joao.Pinto@synopsys.com" , "abrestic@chromium.org" , "r.baldyga@samsung.com" , "linux-usb@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-omap@vger.kernel.org" From: Roger Quadros Message-ID: <571E23D7.5070501@ti.com> Date: Mon, 25 Apr 2016 17:04:07 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: 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 Content-Length: 2343 Lines: 97 Hi, On 21/04/16 09:38, Jun Li wrote: > Hi, > > ... >> >> /** >> + * usb_gadget_start - start the usb gadget controller and connect to >> +bus >> + * @gadget: the gadget device to start >> + * >> + * This is external API for use by OTG core. >> + * >> + * Start the usb device controller and connect to bus (enable pull). >> + */ >> +static int usb_gadget_start(struct usb_gadget *gadget) { >> + int ret; >> + struct usb_udc *udc = NULL; >> + >> + dev_dbg(&gadget->dev, "%s\n", __func__); >> + mutex_lock(&udc_lock); >> + list_for_each_entry(udc, &udc_list, list) >> + if (udc->gadget == gadget) >> + goto found; >> + >> + dev_err(gadget->dev.parent, "%s: gadget not registered.\n", >> + __func__); >> + mutex_unlock(&udc_lock); >> + return -EINVAL; >> + >> +found: >> + ret = usb_gadget_udc_start(udc); >> + if (ret) >> + dev_err(&udc->dev, "USB Device Controller didn't start: %d\n", >> + ret); >> + else >> + usb_udc_connect_control(udc); > > For drd, it's fine, but for real otg, gadget connect should be done > by loc_conn() instead of gadget start. It is upto the OTG state machine to call gadget_start() when it needs to connect to the bus (i.e. loc_conn()). I see no point in calling gadget start before. Do you see any issue in doing so? cheers, -roger > >> + >> + mutex_unlock(&udc_lock); >> + >> + return ret; >> +} >> + >> +/** >> + * usb_gadget_stop - disconnect from bus and stop the usb gadget >> + * @gadget: The gadget device we want to stop >> + * >> + * This is external API for use by OTG core. >> + * >> + * Disconnect from the bus (disable pull) and stop the >> + * gadget controller. >> + */ >> +static int usb_gadget_stop(struct usb_gadget *gadget) { >> + struct usb_udc *udc = NULL; >> + >> + dev_dbg(&gadget->dev, "%s\n", __func__); >> + mutex_lock(&udc_lock); >> + list_for_each_entry(udc, &udc_list, list) >> + if (udc->gadget == gadget) >> + goto found; >> + >> + dev_err(gadget->dev.parent, "%s: gadget not registered.\n", >> + __func__); >> + mutex_unlock(&udc_lock); >> + return -EINVAL; >> + >> +found: >> + usb_gadget_disconnect(udc->gadget); > > Likewise, gadget disconnect also should be done by loc_conn() > instead of gadget stop. > >> + udc->driver->disconnect(udc->gadget); >> + usb_gadget_udc_stop(udc); >> + mutex_unlock(&udc_lock); >> + >> + return 0; >> +} >> + > > Li Jun >