Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933505AbcKHNDA (ORCPT ); Tue, 8 Nov 2016 08:03:00 -0500 Received: from gagarine.paulk.fr ([109.190.93.129]:55323 "EHLO gagarine.paulk.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933193AbcKHNC7 (ORCPT ); Tue, 8 Nov 2016 08:02:59 -0500 Message-ID: <1478610158.853.1.camel@paulk.fr> Subject: Re: [PATCH] ARM: tegra: nyan: Mark all USB ports as host From: Paul Kocialkowski To: Jon Hunter , Thierry Reding Cc: Peter De Schrijver , devicetree@vger.kernel.org, Stephen Warren , linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org, Alexandre Courbot , linux-arm-kernel@lists.infradead.org Date: Tue, 08 Nov 2016 14:02:38 +0100 In-Reply-To: <3fbd3fb9-1dc5-a46d-355b-f7c94b3c43ef@nvidia.com> References: <20160918102852.6593-1-contact@paulk.fr> <20161107132854.GF12559@ulmo.ba.sec> <13e7ff98-8bc2-ccf7-94bb-4e1d3c61b20d@nvidia.com> <20161108085420.GG2478@tbergstrom-lnx.Nvidia.com> <58046fbb-8e19-e629-770a-940a40ca6ef9@nvidia.com> <20161108110735.GA13098@ulmo.ba.sec> <3fbd3fb9-1dc5-a46d-355b-f7c94b3c43ef@nvidia.com> Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-DWgfa25UGIKfFbl3odNQ" X-Mailer: Evolution 3.20.5 Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4166 Lines: 119 --=-DWgfa25UGIKfFbl3odNQ Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Le mardi 08 novembre 2016 =C3=A0 11:09 +0000, Jon Hunter a =C3=A9crit=C2=A0= : > On 08/11/16 11:07, Thierry Reding wrote: > >=20 > > * PGP Signed by an unknown key > >=20 > > On Tue, Nov 08, 2016 at 09:47:42AM +0000, Jon Hunter wrote: > > >=20 > > >=20 > > > On 08/11/16 08:54, Peter De Schrijver wrote: > > > >=20 > > > > On Mon, Nov 07, 2016 at 02:09:31PM +0000, Jon Hunter wrote: > > > > >=20 > > > > >=20 > > > > > On 07/11/16 13:28, Thierry Reding wrote: > > > > > >=20 > > > > > > >=20 > > > > > > > Old Signed by an unknown key > > > > > >=20 > > > > > > On Sun, Sep 18, 2016 at 12:28:52PM +0200, Paul Kocialkowski wro= te: > > > > > > >=20 > > > > > > > Nyan boards only have host USB ports (2 external, 1 internal)= , > > > > > > > there is > > > > > > > no OTG-enabled connector. > > > > > > >=20 > > > > > > > Signed-off-by: Paul Kocialkowski > > > > > > > --- > > > > > > > =C2=A0arch/arm/boot/dts/tegra124-nyan.dtsi | 2 +- > > > > > > > =C2=A01 file changed, 1 insertion(+), 1 deletion(-) > > > > > >=20 > > > > > > Where is this information coming from? I don't have one of the = Nyans > > > > > > myself, but one of the Tegra132 devices I have, which I think w= as > > > > > > derived from one of the Nyans uses one of the external host por= ts as > > > > > > forced recovery port, for which it would need OTG. > > > > > >=20 > > > > > > I suspect that the way to get U-Boot onto the Nyans is via tegr= arcm? > > > > > > In that case I think one of the ports must be OTG. > > > > >=20 > > > > > It is true that the port on the back on the nyan-big can be used = with > > > > > recovery mode. I was thinking that this is not a true OTG port as= it > > > > > is > > > > > just a 4-pin type A socket and does not have an ID pin. Thinking = some > > > > > more about this the USB spec does include a "Host Negotiation Pro= tocol > > > > > (HNP)" that allows a host and device to swap roles and so keeping= it > > > > > as > > > > > OTG seems valid afterall. > > > >=20 > > > > I don't think the bootrom implements that though. I expect recovery= mode > > > > to just program the controller in device mode, without performing a= ny > > > > negotiation. > > >=20 > > > I am not talking about the bootrom and I would not expect the bootrom= to > > > do that. However, the kernel could. > >=20 > > Either way, configuring the controller in device mode is enough to make > > the host detect it, otherwise tegrarcm wouldn't work. > >=20 > > From the point of view of the binding I think "otg" is the most accurat= e > > option because we know that the controller can operate in both modes. I= f > > it currently doesn't or how exactly switching modes is done is outside > > the scope of this property. > >=20 > > Is everyone okay with just dropping this patch? >=20 > Fine with me. Same here. --=20 Paul Kocialkowski, developer of low-level free software for embedded device= s Website: https://www.paulk.fr/ Coding blog: https://code.paulk.fr/ Git repositories: https://git.paulk.fr/ https://git.code.paulk.fr/ --=-DWgfa25UGIKfFbl3odNQ Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQIcBAABCAAGBQJYIczvAAoJEIT9weqP7pUMb6QP/RDLvBpkvSPK4+aHkxKspJMU vZO/tcTn7gvEQdLP/BDxopydNOx36up+WAynJsnj3m7IzGvooc6isPIsyDf1a0Sd nhPLL/8sBty3XAlWqx2hwb86yoeizjdxmqV9bp2IsHppDPHeRzmqKjo57fGKMcOQ MmgJXtYwyLB8CEXgXMmMNag3TNH43sJmZlVv2LVki9C11+ZPniiun4nYtQYXiMJ8 outBBe2KAsxLOsUdFixuZBW878rCNqaBx6vALZ4mYMmLgu7ggBSO3ULIXUPNa5F7 dymLBYJ17LFfTxmcBf+1jzy5BOqyTuZsvRuxgs8wpMOlpSuNGK0VvDS884q88LE+ Na/QJWCZa2BHQWZZ+gWU4Jvobg4IhQueIIAP9eInWyJw2SG7UWNnGI6XwK5K0nVc fmXKN33jZsDXCwir7AOs7DcygQqyHKlFdtIsmxS/kF8Zvcz6qwmuxqyl843mCnwA 11dIRqiqXYj5QKOMY3KJWC1lMbcW89sQRk/LKlBd80o34cTf8QYYMSAC1rxYwJOf E88oJAo4KM9JuJAgCi7GtOXouYSDQTl3v9dJbjoHr7sXOAr7KJDozb/9thHqVq5d 1TGqXyxjOj5qL/cdbBM71sTTxTKEOfJKO6hwaKnfblGx4RGQqd9huEvVcRsoHMc2 19eWM2EY3FxSalYUs3ld =rWpd -----END PGP SIGNATURE----- --=-DWgfa25UGIKfFbl3odNQ--