Date: Tue, 9 Oct 2012 19:04:26 -0500
From: Scott Wood <scottwood@freescale.com>
Subject: Re: dtc: import latest upstream dtc
To: Mitch Bradley <wmb@firmworks.com>
CC: Stephen Warren <swarren@wwwdotorg.org>, Michal Marek <mmarek@suse.cz>,
        Stephen Warren <swarren@nvidia.com>,
        <devicetree-discuss@lists.ozlabs.org>, <linux-kernel@vger.kernel.org>
In-Reply-To: <5074B155.4090703@firmworks.com> (from wmb@firmworks.com on Tue
	Oct  9 18:20:53 2012)
Message-ID: <1349827466.26044.16@snotra>
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On 10/09/2012 06:20:53 PM, Mitch Bradley wrote:
> On 10/9/2012 11:16 AM, Stephen Warren wrote:
> > On 10/01/2012 12:39 PM, Jon Loeliger wrote:
> >>>
> >>> What more do you think needs discussion re: dtc+cpp?
> >>
> >> How not to abuse the ever-loving shit out of it? :-)
> >
> > Perhaps we can just handle this through the regular patch review
> > process; I think it may be difficult to define and agree upon  
> exactly
> > what "abuse" means ahead of time, but it's probably going to be easy
> > enough to recognize it when one sees it?
> 
> 
> One of the ways it could get out of hand would be via "include
> dependency hell".  People will be tempted to reuse existing .h files
> containing pin definitions, which, if history is a guide, will end up
> depending on all sorts of other .h files.
> 
> Another problem I often face with symbolic names is the difficulty of
> figuring out what the numerical values really are (for debugging),
> especially when .h files are in different subtrees from the files that
> use the definitions, and when they use multiple macro levels and fancy
> features like concatenation.  Sometimes I think it's clearer just to
> write the number and use a comment to say what it is.

Both comments apply just as well to ordinary C code, and I don't think  
anyone would seriously suggest just using comments instead for C code.

Is there a way to ask CPP to evaluate a macro in the context of the  
input file, rather than produce normal output?  If not, I guess you  
could make a tool that creates a wrapper file that includes the main  
file and then evaluates the symbol you want.

-Scott
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