[Gta04-owner] switching usb modes

Andreas Kemnade andreas at kemnade.info
Thu Aug 16 13:40:37 CEST 2012


Hi,

On Thu, 26 Jul 2012 17:32:12 +0930
Kevin Hremeviuc <khremeviuc at yahoo.com> wrote:

> On Thu, 2012-07-26 at 17:10 +1000, NeilBrown wrote:
> > On Wed, 25 Jul 2012 22:57:37 -0700 (PDT) Kevin Hremeviuc
> > <khremeviuc at yahoo.com> wrote:
> > 
> > > Hi all,
> > > 
> > > Thanks Neil. I thought that the switching was manual as per the gta02. Also the gta02 had a powered host mode. Is there is an equivalent on the gta04?
> > > 
> > >
> > 
> > I don't know if it is switchable via software.
> > 
> > I didn't think gta02 did have a powered now.
> > 
> > gta04 does.  When you plug in the otg cable it will supply 5V at 100mA, which
> > is just enough for a USB stick, though some claim to require 200mA, so the
> > kernel refused to talk the them.
> > 
> > lsusb -v
> > 
> > will list details of what is plugged in, including "MaxPower" which is what
> > it wants.  If you plug your device into some computer, run "lsusb" and find
> > the MaxPower is more than 100mA, the GTA04 will refuse to power it.
> 
> I have tried plugging in a powered USB hub and it just isn't detected -
> there is no output from dmesg.
> What I did with the gta02 was use a powered hub and then plug multiple
> devices into that eg. USB master midi keyboard and an Akai MPD24. I
> can't get anything to work on the gta04.
> 
what does 
/sys/bus/platform/devices/musb-hdrc/mode
show if you insert a cable with ID grounded?
It should start with a_
If not, first check if ID is really grounded.

See also 
http://lists.goldelico.com/pipermail/gta04-owner/2012-May/002361.html

That is a summary about things I found out about the usb system of the
gta04. But it is clearly a hacking guide. So first try some more normal way.

Greetings
Andreas Kemnade
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