From mboxrd@z Thu Jan 1 00:00:00 1970 From: jonathanh@nvidia.com (Jon Hunter) Date: Mon, 7 Nov 2016 14:09:31 +0000 Subject: [PATCH] ARM: tegra: nyan: Mark all USB ports as host In-Reply-To: <20161107132854.GF12559@ulmo.ba.sec> References: <20160918102852.6593-1-contact@paulk.fr> <20161107132854.GF12559@ulmo.ba.sec> Message-ID: <13e7ff98-8bc2-ccf7-94bb-4e1d3c61b20d@nvidia.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 07/11/16 13:28, Thierry Reding wrote: > * PGP Signed by an unknown key > > On Sun, Sep 18, 2016 at 12:28:52PM +0200, Paul Kocialkowski wrote: >> Nyan boards only have host USB ports (2 external, 1 internal), there is >> no OTG-enabled connector. >> >> Signed-off-by: Paul Kocialkowski >> --- >> arch/arm/boot/dts/tegra124-nyan.dtsi | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) > > 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 was > derived from one of the Nyans uses one of the external host ports as > forced recovery port, for which it would need OTG. > > I suspect that the way to get U-Boot onto the Nyans is via tegrarcm? > In that case I think one of the ports must be OTG. 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 Protocol (HNP)" that allows a host and device to swap roles and so keeping it as OTG seems valid afterall. Cheers Jon -- nvpublic