From mboxrd@z Thu Jan 1 00:00:00 1970
From: Philipp Zabel
Subject: Re: [PATCH v2] [media] of: move graph helpers from
drivers/media/v4l2-core to drivers/media
Date: Wed, 12 Feb 2014 18:34:40 +0100
Message-ID: <1392226480.5536.61.camel@pizza.hi.pengutronix.de>
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<20140212065306.36a03e82.m.chehab@samsung.com>
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In-Reply-To: <20140212223515.71a445f4.m.chehab@samsung.com>
Sender: linux-kernel-owner@vger.kernel.org
To: Mauro Carvalho Chehab
Cc: Russell King - ARM Linux , Grant Likely , Rob Herring , Sylwester Nawrocki , Laurent Pinchart , Tomi Valkeinen , Kyungmin Park , linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, devicetree@vger.kernel.org, Guennadi Liakhovetski , Philipp Zabel
List-Id: devicetree@vger.kernel.org
Hi Mauro,
Am Mittwoch, den 12.02.2014, 22:35 +0900 schrieb Mauro Carvalho Chehab:
> Em Wed, 12 Feb 2014 10:11:54 +0100
> Philipp Zabel escreveu:
>
> > Hi Mauro,
> >
> > Am Mittwoch, den 12.02.2014, 06:53 +0900 schrieb Mauro Carvalho Chehab:
> > [...]
> > > > diff --git a/include/media/of_graph.h b/include/media/of_graph.h
> > > > new file mode 100644
> > > > index 0000000..3bbeb60
> > > > --- /dev/null
> > > > +++ b/include/media/of_graph.h
> > > > @@ -0,0 +1,46 @@
> > > > +/*
> > > > + * OF graph binding parsing helpers
> > > > + *
> > > > + * Copyright (C) 2012 - 2013 Samsung Electronics Co., Ltd.
> > > > + * Author: Sylwester Nawrocki
> > > > + *
> > > > + * Copyright (C) 2012 Renesas Electronics Corp.
> > > > + * Author: Guennadi Liakhovetski
> > > > + *
> > > > + * This program is free software; you can redistribute it and/or modify
> > > > + * it under the terms of version 2 of the GNU General Public License as
> > > > + * published by the Free Software Foundation.
> > > > + */
> > > > +#ifndef __LINUX_OF_GRAPH_H
> > > > +#define __LINUX_OF_GRAPH_H
> > > > +
> > > > +#ifdef CONFIG_OF
> > >
> > > As a matter of consistency, it would be better to test here for
> > > CONFIG_OF_GRAPH instead, to reflect the same symbol that enables such
> > > functions as used on Kconfig/Makefile.
> >
> > Maybe I'm trying to be too clever for my own good, but my reasoning was
> > as follows:
> >
> > Suppose I newly use the of_graph_ helpers in a subsystem that does not
> > yet select OF_GRAPH. In that case I'd rather get linking errors earlier
> > rather than stubbed out functions that silently fail to parse the DT
> > later.
>
> I see your point, but, imagining that someone pushed a patch using those
> symbols upstream, that would break compilation and git bisection, with
> will hurt everyone, and not only the very few of us that would actually
> need the OF_GRAPH symbol for an specific driver.
>
> Also, such push would mean that someone forgot to do his homework and
> to test if the committed functionality is actually working.
>
> So, it seems more fair that the one that did the mistake will be the one
> that will suffer the consequences for his errors instead of applying a
> penalty to everybody's else ;)
point taken.
> > Since there is
> > config VIDEO_DEV
> > select OF_GRAPH if OF
> > already and the same should be added for other users of device tree
> > graphs, I think stubbing out the functions only if OF is disabled should
> > be enough.
>
> Well, if you want to be sure that the graph will always be there if OF, then
> you could do, instead:
>
> config OF_GRAPH
> bool
> default OF
>
> (that would actually make OF_GRAPH just an alias to OF - so we could just
> use OF instead).
>
> In any case, I think that we should use the same config name at Makefile,
> Kconfig and of_graph.h (either OF_GRAPH or just OF).
If nobody states a strong preference, I'll just get rid of the
CONFIG_OF_GRAPH option altogether and use CONFIG_OF directly.
regards
Philipp