From: Peter Chen <peter.chen-3arQi8VN3Tc@public.gmane.org>
To: Stefan Agner <stefan-XLVq0VzYD2Y@public.gmane.org>,
Peter Chen <hzpeterchen-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Sanchayan Maity
<maitysanchayan-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
"linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
"linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
"ivan.ivanov-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org"
<ivan.ivanov-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
"linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org"
<linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>,
"devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
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<shawnguo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
"marcel-mitwqZ+T+m9Wk0Htik3J/w@public.gmane.org"
<marcel-mitwqZ+T+m9Wk0Htik3J/w@public.gmane.org>
Subject: RE: [RFC PATCH 0/4] Implement USB device/host switch for Vybrid
Date: Tue, 29 Mar 2016 00:24:46 +0000 [thread overview]
Message-ID: <HE1PR04MB1450691A838973845B7AD16F8B870@HE1PR04MB1450.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <3c2e72efc8cae93ff31be1b44f9a02b3-XLVq0VzYD2Y@public.gmane.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
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next prev parent reply other threads:[~2016-03-29 0:24 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-15 8:38 [RFC PATCH 0/4] Implement USB device/host switch for Vybrid Sanchayan Maity
[not found] ` <cover.1458030082.git.maitysanchayan-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2016-03-15 8:38 ` [RFC PATCH 1/4] usb: chipidea: Do not rely on OTG while using extcon Sanchayan Maity
[not found] ` <a3dc1c8adc4266d36267901ce6e975ddfca09abb.1458030082.git.maitysanchayan-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2016-03-17 6:15 ` Chanwoo Choi
2016-03-15 8:38 ` [RFC PATCH 4/4] ARM: dts: vf-colibri: USB device/host switch using extcon gpio Sanchayan Maity
2016-03-15 8:38 ` [RFC PATCH 2/4] usb: chipidea: ci_hdrc_imx: Introduce CI_HDRC_DUAL_ROLE_NOT_OTG for Vybrid Sanchayan Maity
2016-03-15 8:38 ` [RFC PATCH 3/4] ARM: dts: vfxxx: Make Vybrid match only on it's own compatible string Sanchayan Maity
2016-03-25 7:40 ` [RFC PATCH 0/4] Implement USB device/host switch for Vybrid Peter Chen
2016-03-28 15:28 ` Stefan Agner
[not found] ` <3c2e72efc8cae93ff31be1b44f9a02b3-XLVq0VzYD2Y@public.gmane.org>
2016-03-29 0:24 ` Peter Chen [this message]
[not found] ` <HE1PR04MB1450691A838973845B7AD16F8B870-6LN7OEpIatVC+P/YwrXEHc9NdZoXdze2vxpqHgZTriW3zl9H0oFU5g@public.gmane.org>
2016-03-30 6:32 ` maitysanchayan-Re5JQEeQqe8AvxtiuMwx3w
2016-03-30 8:07 ` Peter Chen
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