Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753227AbcC3Gik (ORCPT ); Wed, 30 Mar 2016 02:38:40 -0400 Received: from mail-pa0-f53.google.com ([209.85.220.53]:32841 "EHLO mail-pa0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751926AbcC3Gii (ORCPT ); Wed, 30 Mar 2016 02:38:38 -0400 Date: Wed, 30 Mar 2016 12:02:46 +0530 From: maitysanchayan@gmail.com To: Peter Chen Cc: Stefan Agner , Peter Chen , "linux-usb@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "ivan.ivanov@linaro.org" , "linux-arm-kernel@lists.infradead.org" , "devicetree@vger.kernel.org" , "shawnguo@kernel.org" , "marcel@ziswiler.com" Subject: Re: [RFC PATCH 0/4] Implement USB device/host switch for Vybrid Message-ID: <20160330063246.GA16028@Sanchayan-Arch.toradex.int> References: <20160325074051.GB22398@peterchendt> <3c2e72efc8cae93ff31be1b44f9a02b3@agner.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1942 Lines: 49 Hello Peter, On 16-03-29 00:24:46, Peter Chen wrote: > > > > > On 2016-03-25 00:40, Peter Chen wrote: > > > On Tue, Mar 15, 2016 at 02:08:26PM +0530, Sanchayan Maity wrote: > > >> Hello Peter, > > >> > > >> The existing usage of extcon in Chipidea driver relies on OTG > > >> registers. In case of SoC with dual role device but not a true OTG > > >> controller, this does not work. Such SoC's should specify the > > >> existing CI_HDRC_DUAL_ROLE_NOT_OTG flag and do the role switch > > >> without checking any of the OTG registers in my opinion. > > >> This is the case for Vybrid which uses a Chipidea IP but does not > > >> have a true 5 pin OTG implemented. > > > > > > Sorry to reply you late due to my new born baby. > > > > > > Are you sure Vybrid is NOT OTG core? Afaik, it is uses the same IP > > > base with other Freescale SoCs, just the IP core is 2.40a. > > > When working at device mode, can you read vbus status through OTGSC? > > > And if there is an ID pin (input pin) for Vybrid? I mean SoC, not the > > > board. > > > > I think the IP is actually OTG capable, the registers are there, but the signals > > seem not to be available on the SoC package. That is also what the RM says... > > > > Quotes from the RM: > > > > "OTG controller should be treated as > > Dual role controller that allows the > > controller to act as either a Host or a > > device with no support for HNP/SRP." > > > > And later, in Chapter 11.1: > > > > "The USB is not a true OTG. It can be configured by software to function either > > as peripheral or as host. The ID pin, which is unique for OTG operation, is not > > present in this implementation. There are no five pin interface. The user will > > get four pin host/ device interface." > > > > Get it, thanks. I am doing a patch for covering this case and vbus always-on case. If I may ask at this point, how would your implementation be covering this case for Vybrid? - Sanchayan.