From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Chen Subject: RE: [RFC PATCH 0/4] Implement USB device/host switch for Vybrid Date: Tue, 29 Mar 2016 00:24:46 +0000 Message-ID: References: <20160325074051.GB22398@peterchendt> <3c2e72efc8cae93ff31be1b44f9a02b3@agner.ch> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Return-path: In-Reply-To: <3c2e72efc8cae93ff31be1b44f9a02b3-XLVq0VzYD2Y@public.gmane.org> Content-Language: en-US Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Stefan Agner , Peter Chen Cc: Sanchayan Maity , "linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "ivan.ivanov-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "shawnguo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org" , "marcel-mitwqZ+T+m9Wk0Htik3J/w@public.gmane.org" List-Id: devicetree@vger.kernel.org > > 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. Peter -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html