From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752008AbbJFMWv (ORCPT ); Tue, 6 Oct 2015 08:22:51 -0400 Received: from arroyo.ext.ti.com ([192.94.94.40]:60144 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751204AbbJFMWu (ORCPT ); Tue, 6 Oct 2015 08:22:50 -0400 Subject: Re: [PATCH 2/2] extcon: Add the support of EXTCON_CHG_USB when SDP port is attached or detached To: Chanwoo Choi , References: <1444130485-23325-1-git-send-email-cw00.choi@samsung.com> <1444130485-23325-3-git-send-email-cw00.choi@samsung.com> <5613B553.9080005@ti.com> <5613BAB9.7070105@samsung.com> CC: , , , , , From: Roger Quadros Message-ID: <5613BD10.3070300@ti.com> Date: Tue, 6 Oct 2015 15:22:40 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <5613BAB9.7070105@samsung.com> 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 Chanwoo, On 06/10/15 15:12, Chanwoo Choi wrote: > Roger, > > On 2015년 10월 06일 20:49, Roger Quadros wrote: >> Hi, >> >> On 06/10/15 14:21, Chanwoo Choi wrote: >>> The SDP (Standard Downstream Port) is one of various USB Charging ports. The SDP >>> supports both the data transmission and the charging through USB connector at >>> the same time. So, the EXTCON framework defines two connector type for USB SDP >>> connector as following: >>> - EXTCON_USB means the USB cable for data transmission. >>> - EXTCON_CHG_USB means the USB charger cable for battery charging. >>> >>> This patch add the support of EXTCON_CHG_USB when USB SDP is attached or >>> detached. >> >> I didn't understand why this change is needed. SDP, EXTCON_USB and EXTCON_CHG_USB >> are the same thing. no? > > As you knew, SDP support both data transmission and charging > through one port at the same time. Also, On patch1 of this patch-set, > I add the prefix to clarify both attribute and meaning of external connector as following: > - EXTCON_CHG_* mean the charger connector. > > So, there are three possible naming approach for USB SDP. > > Approach 1. > - EXTCON_USB /* SDP for both data transmission and charging */ > > Approach 2. > - EXTCON_USB /* SDP for data transmission */ > - EXTCON_CHG_USB /* SDP for charging */ This only adds confusion. There is only one cable that will always do both jobs so no point in using 2 names for it. > > Approach 3. > - EXTCON_CHG_USB /* SDP for both data transmission and charging */ > > It is not fixed about name. I want to discuss what is proper name for USB SDP. I do not have any preference over 1 or 3. cheers, -roger