questions about current RM9200 state

[M. Warner Losh]

In message: <20061209114124.GB54209 at cicely12.cicely.de>
            Bernd Walter <ticso at cicely12.cicely.de> writes:
: On Fri, Dec 08, 2006 at 10:32:00PM -0700, M. Warner Losh wrote:
: > In message: <20061208114906.GJ54209 at cicely12.cicely.de>
: >             Bernd Walter <ticso at cicely12.cicely.de> writes:
: > : On Fri, Dec 08, 2006 at 11:42:28AM +0100, Bernd Walter wrote:
: > : > On Thu, Dec 07, 2006 at 08:50:08PM -0700, M. Warner Losh wrote:
: > : > > In message: <20061208015032.GF54209 at cicely12.cicely.de>
: > : > >             Bernd Walter <ticso at cicely12.cicely.de> writes:
: > : > > : But I can't probe the bus from userland:
: > : > > : [56]arm9# ./iic_probe /dev/iic0 
: > : > > : - and nothing listed.
: > : > > 
: > : > > twi doesn't support START/STOP ioctls that you use.  Hmmm, that's in
: > : > > p4 that I've removed them because I never got that working.  I also
: > : > > think the version in -head isn't the latest, working one.  I think you
: > : > > do the same thing with a 0 byte transfer.  Except we don't detect
: > : > > NOACK quite right yet, I'm afraid.  I'd expect an error each time you
: > : > > tried.
: > : > 
: > : > Ah - Ok, will switch to 0 Byte transfers and retest.
: > : 
: > : iic.c:
: > :         case I2CWRITE:
: > :                 if (s->count <= 0) {
: > :                         error = EINVAL;
: > :                         break;
: > :                 }
: > : 
: > : Well - it wouldn't work without NOACK detection anyway.
: > 
: > I think a zero-byte transfer would do it.
: 
: Unfortunately the TWI controller can't do zero transfers at all :(
: I thought the RM9200 has different one, but it is the same ^$%@ as in
: the AT91SAM7 series, which I already had some hard time with.
: The TWI controller in the AVR series is much better IMHO.
: I'll send you a diff later today to fix some small bugs that I've found
: in the driver - those points aren't documented very well in the
: handbook.

OK.  We can put back in the old interface.  The TWI bugs are very
underdocumented.

Warner