Xilinx SYSACE driver and 8-bit attachment

[John Linn]

> -----Original Message-----
> From: John Linn
> Sent: Wednesday, October 07, 2009 8:24 AM
> To: 'Grant Likely'; John Williams
> Cc: Linux Kernel list; Michal Simek; David DeBonis; Stephen Neuendorffer; devicetree-discuss
> Subject: RE: Xilinx SYSACE driver and 8-bit attachment
> 
> I'll look to see if something has changed.  It's not clear to me if it has ever been right.
> 
> It look like we normally use 16 bit mode as that's how BSB generates the system by default.
> 
> Thanks,
> John
> 
> > -----Original Message-----
> > From: glikely at secretlab.ca [mailto:glikely at secretlab.ca] On Behalf Of Grant Likely
> > Sent: Wednesday, October 07, 2009 7:35 AM
> > To: John Williams
> > Cc: Linux Kernel list; Michal Simek; John Linn; David DeBonis; Stephen Neuendorffer; devicetree-
> > discuss
> > Subject: Re: Xilinx SYSACE driver and 8-bit attachment
> >
> > [Added devicetree-discuss to cc: list]
> >
> > On Wed, Oct 7, 2009 at 1:13 AM, John Williams
> > <john.williams at petalogix.com> wrote:
> > > Hi Grant (it's your driver :) and David D ( and your DTS generator :)
> > [...]
> > > if (of_find_property(op->node, "8-bit", NULL))
> > [...]
> > > doesn't match the properties generated by Xilinx's device tree generator:
> > [...]
> > >                         xlnx,mem-width = <0x8>;

Do you know if the 8 bit mode was ever tested with the "8-bit" property in the tree?

I don't see anything in the device tree generator history to say we ever did that "8-bit", but maybe I'm missing something.

We are just generating the parameters from the h/w and the memory width is it.  We can always put something in there special, but it seems silly if it was never used anyway.

Thanks,
John

> > >
> > > So, the question is, which should change?
> >
> > Well, obviously its a device tree generator bug, the driver code is
> > perfect.  :-P
> >
> > In all seriousness though, the '8-bit' property has been present for a
> > while now and needs to be retained to not break existing users.  It
> > would be okay for the driver to be modified to *also* check for the
> > xlnx,mem-width property, but the better solution is to modify the
> > device tree generator.  Plus, the '8-bit' property is the documented
> > binding in Documentation/powerpc/dts-bindings/xilinx.txt
> >
> > Cheers,
> > g.
> >
> > --
> > Grant Likely, B.Sc., P.Eng.
> > Secret Lab Technologies Ltd.


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