Re: [PATCH v2] [media] of: move graph helpers from drivers/media/v4l2-core to drivers/media

[Philipp Zabel <p.zabel@pengutronix.de>]

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 <s.nawrocki@samsung.com>
> > + *
> > + * Copyright (C) 2012 Renesas Electronics Corp.
> > + * Author: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
> > + *
> > + * 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.

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.

regards
Philipp