From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964818AbbDIJHd (ORCPT ); Thu, 9 Apr 2015 05:07:33 -0400 Received: from mailout4.samsung.com ([203.254.224.34]:12612 "EHLO mailout4.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933881AbbDIJHX (ORCPT ); Thu, 9 Apr 2015 05:07:23 -0400 X-AuditID: cbfee68f-f793b6d000005f66-c3-55264148a4c9 Message-id: <55264148.8070903@samsung.com> Date: Thu, 09 Apr 2015 18:07:20 +0900 From: Chanwoo Choi User-Agent: Mozilla/5.0 (X11; Linux i686; rv:17.0) Gecko/20130106 Thunderbird/17.0.2 MIME-version: 1.0 To: Robert Baldyga Cc: myungjoo.ham@samsung.com, rogerq@ti.com, linux-usb@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, m.szyprowski@samsung.com Subject: Re: [PATCH v3 2/4] extcon: usb-gpio: add support for VBUS detection References: <1427980385-21285-1-git-send-email-r.baldyga@samsung.com> <1427980385-21285-3-git-send-email-r.baldyga@samsung.com> <5525E012.5050207@samsung.com> <552630E4.9030309@samsung.com> In-reply-to: <552630E4.9030309@samsung.com> Content-type: text/plain; charset=windows-1252 Content-transfer-encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprBIsWRmVeSWpSXmKPExsWyRsSkWNfDUS3U4MJZJYv5R86xWlzeNYfN YtGyVmaLtUfuslvcblzBZvHg8E52i55HWg7sHn1bVjF6HL+xncnj8ya5AOYoLpuU1JzMstQi fbsEroyGb+sYC75wVuyaMYWtgfEJexcjJ4eEgInEtVeb2CBsMYkL99YD2VwcQgJLGSUa5vUz wRQtf76HESKxiFHibNNZVgjnAaPEwq1HwEbxCmhJTLoAkuDkYBFQldh4eDEjiM0GFN//4gbY ClGBMImV06+wQNQLSvyYfA/MFgGqufNxPjvIUGaBeYwSi+e+B3I4OIQFfCQW3oBadpBRYvrM G2BDOQW0JWYsussIUsMsoCdx/6IWSJhZQF5i85q3zCD1EgL72CV+v77NDnGQgMS3yYdYQOol BGQlNh1ghvhMUuLgihssExjFZiE5aRbC1FlIpi5gZF7FKJpakFxQnJReZKxXnJhbXJqXrpec n7uJERhhp/8969/BePeA9SFGAQ5GJR7eF99UQ4VYE8uKK3MPMZoCHTGRWUo0OR8Yx3kl8YbG ZkYWpiamxkbmlmZK4rwLpX4GCwmkJ5akZqemFqQWxReV5qQWH2Jk4uCUamBse7Jvu3RCgfDT +usn7Qyqd5Rz+xTXJET/lfmePsHo47EKgdUCJSdreBbOvpmrsbG/Z2Fo240pTzIPnlt0xrjo zh+OmPB5GsbCO2+v+Xzyde2yRn1zjYWCG0yX+h7t4vu4+HROw3r9HX2FTaePLGfdvHPGi097 PvVz8rP5vpia72bcM+FHBU+kEktxRqKhFnNRcSIA0OiMoKsCAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrEIsWRmVeSWpSXmKPExsVy+t9jAV0PR7VQgz+bpS3mHznHanF51xw2 i0XLWpkt1h65y25xu3EFm8WDwzvZLXoeaTmwe/RtWcXocfzGdiaPz5vkApijGhhtMlITU1KL FFLzkvNTMvPSbZW8g+Od403NDAx1DS0tzJUU8hJzU22VXHwCdN0yc4CWKymUJeaUAoUCEouL lfTtME0IDXHTtYBpjND1DQmC6zEyQAMJaxgzGr6tYyz4wlmxa8YUtgbGJ+xdjJwcEgImEsuf 72GEsMUkLtxbz9bFyMUhJLCIUeJs01lWCOcBo8TCrUfAOngFtCQmXQBJcHKwCKhKbDy8GKyb DSi+/8UNNhBbVCBMYuX0KywQ9YISPybfA7NFgGrufJzPDjKUWWAeo8Tiue+BHA4OYQEfiYU3 oJYdZJSYPvMG2FBOAW2JGYvuMoLUMAvoSdy/qAUSZhaQl9i85i3zBEaBWUhWzEKomoWkagEj 8ypG0dSC5ILipPRcQ73ixNzi0rx0veT83E2M4Ph9JrWDcWWDxSFGAQ5GJR7eF99UQ4VYE8uK K3MPMUpwMCuJ8Eabq4UK8aYkVlalFuXHF5XmpBYfYjQFBsBEZinR5HxgaskriTc0NjEzsjQy N7QwMjZXEuedoysXKiSQnliSmp2aWpBaBNPHxMEp1cBYfI1p5oGWGt9Gd6at319sVfRSetvr kRLj9qQq79pkllN5emxb3x/XOfbIN3Wz78u43GMXGP1FviYVarxMmeuwZf7lb09tMqtfWQjx y1554Tpd8Eas++TA3D9rArNPPCvvkep49DAsrepk/OyPRt+XCC97uvRdR4N34oWJDIrn7vba zWdh2yqtxFKckWioxVxUnAgAOMZQ1fUCAAA= DLP-Filter: Pass X-MTR: 20000000000000000@CPGS X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Robert, On 04/09/2015 04:57 PM, Robert Baldyga wrote: > Hi Chanwoo, > > On 04/09/2015 04:12 AM, Chanwoo Choi wrote: >> Hi Robert, >> [snip] >> But, I have one question about case[3] >> >> If id is low and vbus is high, this patch will update the state of both USB and USB-HOST cable as attached state. >> Is it possible that two different cables (both USB and USB-HOST) are connected to one port simultaneously? >> > > It's because state of single USB cable connection cannot be completely > described using single extcon cable. USB cable state has two bits (VBUS > and ID), so we need to use two cables for single cable connection. We > use following convention: > cable "USB" = VBUS > cable "USB-HOST" = !ID. I think that extcon provider driver have to update the only one cable state of either USB or USB-HOST because USB and USB-HOST feature can not be used at the same time through one h/w port. If extcon-usb-gpio.c update two connected event of both USB and USB-HOST cable at the same time, the extcon consumer driver can not decide what handle either USB or USB-HOST. > In fact it would be better to have cables named "USB-VBUS" and "USB-ID" > - in this convention it would be more clear. Thanks, Chanwoo Choi