[PATCH v2 2/8] ARM: PXA: Z2: Enable OHCI on Zipit Z2

Marek Vasut marek.vasut at gmail.com
Fri Mar 11 19:07:58 EST 2011


On Friday 11 March 2011 23:34:18 Vasily Khoruzhick wrote:
> On Saturday 12 March 2011 00:13:51 Marek Vasut wrote:
> > On Friday 11 March 2011 22:55:28 Vasily Khoruzhick wrote:
> > > On Friday 11 March 2011 23:50:56 Marek Vasut wrote:
> > > > On Friday 11 March 2011 22:49:13 Vasily Khoruzhick wrote:
> > > > > On Friday 11 March 2011 23:42:30 Marek Vasut wrote:
> > > > > > On Friday 11 March 2011 15:56:46 Vasily Khoruzhick wrote:
> > > > > > > This patch is a part of similar mozzwald's patch which was
> > > > > > > based on GPSFan and rkdavis work.
> > > > > > 
> > > > > > Noone knows what/who is "mozzwald" or "rkdavis" or "GPSFan", the
> > > > > > comment for this patch is irelevant and has zero information
> > > > > > value.
> > > > > 
> > > > > Heh, I can add 'from Zipit Z2 community', I don't know their actual
> > > > > names nor mail addresses.
> > > > 
> > > > That's not the point. The point is the comment has zero value, it
> > > > doesn't describe the change.
> > > > 
> > > > > > I also suspect, the pins on the back connector are USB UDC, not
> > > > > > UHC ... aka. the hardware has no UHC.
> > > > > 
> > > > > They are UHC, check http://www.mozzwald.com/node/60
> > > > 
> > > > So it is compliant or is it a hack ?
> > > 
> > > PXA27x has OHCI (check datasheet), and it's wired to expansion
> > > connector, so you can use it with self-powered USB devices (Zipit Z2
> > > provides only 3.3V on expansion connector). It's definitely not a
> > > hack.
> > 
> > This doesn't make me believe it's compliant. Besides, iirc the zipit
> > hardware wiki says it's only meant for UDC. The fact you can reconfigure
> > it for UHC and use it with a limited amount of devices if you're lucky
> > makes me feel it's so much of a hack.
> 
> AFAIK UDC pins are separate from UHC, so you can't use it as UDC. If I'm
> wrong, please correct me. Because UDC on Zipit is much more usefull for me
> than UHC :)

Check datasheet, they're likely the same pins.
> 
> And, btw, you can connect powered hub to UHC and use ANY usb device with
> Zipit.
> I can't understand why you think that it's a hack.
> 
> Regards
> Vasily



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