Re: [PATCH v2] altera_ps2: Add devicetree support

[Mitch Bradley]

On 2/3/2011 12:27 PM, Walter Goossens wrote:
> On 2/2/11 4:39 PM, Grant Likely wrote:
> > On Wed, Feb 02, 2011 at 07:48:58PM +0800, Thomas Chou wrote:
> > > On 02/02/2011 12:31 PM, Grant Likely wrote:
> > > > > +static const struct of_device_id altera_ps2_match[] = {
> > > > > + { .compatible = "altr,ps2-1.0", },
> > > > I thought I had seen 'altera' instead of an abbreviation being used in
> > > > a previous patch. I don't care much whether 'altr' or 'altera' is
> > > > used, but I'd like to know that there is consensus from the Altera
> > > > users so that all the drivers use the same prefix.
> > > We had discussed on nios2-dev mailing list, and decided to use
> > > 'altr' as Walter suggested that it saves space.
> > Is altr the stock ticker symbol? The convention is to either use the
> > stock ticker in all uppercase (although the uppercase bit hasn't been
> > consistently applied), or to use the full name in lowercase.
> >
> > g.
> Risking my limbs here by breaking in this late in the discussion... (I
> wasn't able to reply earlier) but where does it state it needs to be
> uppercase? I found a bunch of microblaze code which seems to use the
> lowercase xlnx and freescale seems happy with fsl. Unless I'm missing
> something obvious here I guess ALTR would actually be the first to use
> uppercase.
> The only reference to uppercase I found in the ePAPR docs was chapter
> 1.6 that talks about uppercase hex-characters as an OUI.
> Not that I terribly mind either way, but I want to double-check before
> we go ahead and change all altera-related devicetree stuff to uppercase.


The relevant text in IEEE 1275-1994 is in the description of the "name" 
property in Annex A.  If a node name begins with a sequence of from one 
to five uppercase letters followed by a comma, that means a stock symbol 
on some exchange whose names do not conflict with NYSE or NASDAQ.

A lower-case prefix is okay, but it does not necessarily mean that it is 
a ticker symbol.  So in some sense, a lower case prefix provides less 
protection against collisions than an upper case prefix, which comes 
from an externally-arbitrated name space.  Case is explicitly 
significant in node names.

In practice, the important thing is that names must not conflict.  Name 
collisions haven't been much of a problem so far.

> Greetz
> Walter
>
>
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