Re: [PATCH v1 0/9] Support UDC on Tegra 20/30/114/124

[Marcel Ziswiler <marcel.ziswiler-2KBjVHiyJgBBDgjK7y7TUQ@public.gmane.org>]

On Thu, 2017-07-06 at 14:03 +0200, Thierry Reding wrote:
> On Thu, Jul 06, 2017 at 02:20:04AM +0300, Dmitry Osipenko wrote:
> > On 06.07.2017 01:54, Stephen Warren wrote:
> > > On 07/05/2017 04:13 PM, Dmitry Osipenko wrote:
> > > > On 05.07.2017 23:31, Stephen Warren wrote:
> > > > > On 07/05/2017 11:19 AM, Dmitry Osipenko wrote:
> > > > > > Some time ago Thierry Reding sent out patches that enabled
> > > > > > UDC on NVIDIA
> > > > > > Tegra, unfortunately they haven't got enough traction to
> > > > > > get into the
> > > > > > kernel. I've rebased those patches and added a fix for the
> > > > > > Ethernet USB
> > > > > > Gadget on Tegra20, Marc Dietrich tested UDC driver on AC100
> > > > > > and Nicolas
> > > > > > Chauvet on TK1. Like an original patchset, this series adds
> > > > > > support for
> > > > > > the peripheral mode only.
> > > > > 
> > > > > Does this mean that the relevant ports no longer support host
> > > > > mode? That's going
> > > > > to be a user-visible regression, which doesn't sound like a
> > > > > good idea. Isn't OTG
> > > > > possible instead?
> > > > 
> > > > We are going to switch only AC100 and TrimSlice to use the UDC
> > > > driver.
> > > 
> > > Really? I saw patches in the series for Beaver, Dalmore, and
> > > Jetson TK1 too.
> > > 
> > 
> > Yes, the "PHY" and "EHCI" nodes are disabled on those boards in DT.
> > 
> > > > Do you
> > > > know whether that port is working in a host mode with the
> > > > tegra-ehci driver on
> > > > these devices?
> > > 
> > > If any USB port is enabled in the DT, it was certainly validated
> > > at some point.
> > > IIRC, we only have host mode enabled at present. So, yes, I'd
> > > expect this port
> > > to work in host mode currently without any issue.
> > > 
> > 
> > Okay, so we have to decide whether it's reasonable to switch AC100
> > and TrimSlice
> > to the peripheral mode. I think realistically chances that someone
> > uses that
> > port in a host mode are quite low, while it works fine and probably
> > more useful
> > in a device mode.
> 
> Judging by this:
> 
> 	http://trimslice.com/download/documentation/trim-slice-man.pdf
> 
> at least TrimSlice doesn't seem to implement OTG, so we'd have to
> make a
> choice to support either host or peripheral mode. I guess technically
> it
> would need to be peripheral mode because pin 4 is not connected.
> 
> Does a similar document exist for AC100?

Judging by the Compal PAZ00 schematics it does indeed have an ID pin
which is connected to the mini USB socket.

USB1_ID1: From Connector

USB1_ID2: From EC

So an alternative possibility to switch device/host mode would be from
the EC (;-p).

> Thierry

Cheers

Marcel