Re: [PATCH v5 03/13] mmc: provide a standard MMC device-tree binding parser centrally

[Simon Horman <horms@verge.net.au>]

On Sun, Feb 17, 2013 at 04:52:16PM +0900, Simon Horman wrote:
> On Sat, Feb 16, 2013 at 05:58:25PM +0100, Sascha Hauer wrote:
> > Hi Guennadi,
> > 
> > On Sat, Feb 16, 2013 at 04:21:16PM +0100, Guennadi Liakhovetski wrote:
> > > MMC defines a number of standard DT bindings. Having each driver parse
> > > them individually adds code redundancy and is error prone. Provide a
> > > standard function to unify the parsing. After all drivers are converted
> > > to using it instead of their own parsers, this function can be integrated
> > > into mmc_alloc_host().
> > > 
> > > Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
> > > ---
> > > 
> > > v5:
> > > 
> > > 1. fix an uninitialised variable warning. Note, I don't actually know, 
> > > whether this will fix the error, reported by the kbuild test robot. None 
> > > of my compilers reports an error there, at most, I've got a warning with 
> > > one of them, and, surprisingly, it is gone after this change. 
> > > Surprisingly, because I only add the bus_width initialisation in the error 
> > > case - exactly as it actually has to be done. In the success case it is 
> > > assigned set by the function. But the compiler cannot know that!
> > 
> > Maybe the build robot builds with devicetree disabled? In this case
> > of_property_read_u32_array expands to a static inline function and the
> > compiler indeed knows that &bus_width is unitialized. It also knows that
> > this function always returns an error, so what you did below should
> > silence the compiler.
> 
> It seems so. The configuration that flagged the error was atngw100_defconfig.
> 
> ARCH=avr32 make atngw100_defconfig
> grep USE_OF .config
> [nothing]

In that vein I managed to reproduce the warning using ap4evb_defconfig
and then enabled MMC. I have also verified that v5 does not produce
the same warning.

I chose this as I don't have a avr32 cross-compile environment
but I do have one for ARM and I know that ap4evb doesn't use DT.

I will update topic/mmc with v5.