Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758273AbcDHLvQ (ORCPT ); Fri, 8 Apr 2016 07:51:16 -0400 Received: from mail-yw0-f174.google.com ([209.85.161.174]:33214 "EHLO mail-yw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758107AbcDHLvN convert rfc822-to-8bit (ORCPT ); Fri, 8 Apr 2016 07:51:13 -0400 MIME-Version: 1.0 In-Reply-To: References: <6b323d5168c10ccb47882687b1251c31b6cad587.1460029375.git.baolin.wang@linaro.org> Date: Fri, 8 Apr 2016 19:51:12 +0800 Message-ID: Subject: Re: [PATCH v10 1/4] gadget: Introduce the usb charger framework From: Baolin Wang To: Jun Li Cc: "balbi@kernel.org" , "gregkh@linuxfoundation.org" , "sre@kernel.org" , "dbaryshkov@gmail.com" , "dwmw2@infradead.org" , "peter.chen@freescale.com" , "stern@rowland.harvard.edu" , "r.baldyga@samsung.com" , "yoshihiro.shimoda.uh@renesas.com" , "lee.jones@linaro.org" , "broonie@kernel.org" , "ckeepax@opensource.wolfsonmicro.com" , "patches@opensource.wolfsonmicro.com" , "linux-pm@vger.kernel.org" , "linux-usb@vger.kernel.org" , "device-mainlining@lists.linuxfoundation.org" , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3791 Lines: 97 On 8 April 2016 at 19:27, Jun Li wrote: > > >> -----Original Message----- >> From: Baolin Wang [mailto:baolin.wang@linaro.org] >> Sent: Friday, April 08, 2016 7:00 PM >> To: Jun Li >> Cc: balbi@kernel.org; gregkh@linuxfoundation.org; sre@kernel.org; >> dbaryshkov@gmail.com; dwmw2@infradead.org; peter.chen@freescale.com; >> stern@rowland.harvard.edu; r.baldyga@samsung.com; >> yoshihiro.shimoda.uh@renesas.com; lee.jones@linaro.org; broonie@kernel.org; >> ckeepax@opensource.wolfsonmicro.com; patches@opensource.wolfsonmicro.com; >> linux-pm@vger.kernel.org; linux-usb@vger.kernel.org; device- >> mainlining@lists.linuxfoundation.org; linux-kernel@vger.kernel.org >> Subject: Re: [PATCH v10 1/4] gadget: Introduce the usb charger framework >> >> Hi Jun, >> >> >> >> +/* >> >> >> + * usb_charger_detect_type() - detect the charger type manually. >> >> >> + * @uchger - usb charger device >> >> >> + * >> >> >> + * Note: You should ensure you need to detect the charger type >> >> >> +manually on your >> >> >> + * platform. >> >> >> + * You should call it at the right gadget state to avoid >> >> >> +affecting gadget >> >> >> + * enumeration. >> >> >> + */ >> >> >> +int usb_charger_detect_type(struct usb_charger *uchger) { >> >> >> + enum usb_charger_type type; >> >> >> + >> >> >> + if (WARN(!uchger->charger_detect, >> >> >> + "charger detection method should not be NULL")) >> >> >> + return -EINVAL; >> >> >> + >> >> >> + type = uchger->charger_detect(uchger); >> >> >> + >> >> >> + mutex_lock(&uchger->lock); >> >> >> + uchger->type = type; >> >> >> + mutex_unlock(&uchger->lock); >> >> >> + >> >> >> + return 0; >> >> >> +} >> >> >> +EXPORT_SYMBOL_GPL(usb_charger_detect_type); >> >> > >> >> > I still recommend have a central place to call >> >> > usb_charger_detect_type() to cover real charger detection instead >> >> > of leaving this question open to diff users. This can be done after >> >> > vbus-on is detected and before do gadget connect. I don't think >> >> > this >> >> will make your framework complicated. >> >> >> >> This API is used for detecting the charger type manually (software >> >> charger detection), so if user's udc driver is needed to do this, >> >> then they can issue it at their right place to make it more flexible. >> >> But let us see other people's suggestion. Thanks. >> > >> > Ok, actually this API can be used for what ever charger detection >> > type, user can implement any method(manual detection, directly read >> > result from some HW...what ever) in uchger->charger_detect(), target >> > is >> >> But reading result from some HW dose not means *detect*, actually is *get*. >> We can not mix them together with the different semantics. > > It doesn’t matter here, you already define the _get_ API for just read > the charger type from the saved value(uchger->type), so we can think > the API to make uchger->type from UNKNOW to ONE KNOWN type is *detect*, > because we don't need 2 separate API one for *get* type from HW and another > one for *detect* from HW, only one API involve HW access is enough. But another issue is some users may need to get the charger type from power supply by "power_supply_get_property()" function, we need to integrate with the power supply things in the usb charger framework, not user to implement that. > > - Detect: (write to and) read from HW to get the charger type, > save to uchger->type; > - Get: read the charger type from uchger->type. > >> >> > to have the charger type and set uchger->type, then you no need to add >> > the comments/description to limit it usage. Also I do see there is >> possible central place to do this. >> > >> >> -- >> Baolin.wang >> Best Regards -- Baolin.wang Best Regards