[RFC PATCH V2 1/2] dtc: add 'compat' output option, prints board string

[Jason Cooper]

On Mon, Nov 18, 2013 at 12:01:02PM -0700, Stephen Warren wrote:
> On 11/18/2013 11:38 AM, Jason Cooper wrote:
> > Consumers of the Linux kernel's build products are beginning to hardcode
> > the filenames of the dtbs generated.  Since the dtb filenames are
> > currently the dts filename s/dts/dtb/, this prevents the kernel
> > community from renaming dts files as needed.
> > 
> > Let's provide a consistent naming structure for consumers to script
> > against.  Or at least, as consistent as the dts properties themselves.
> > 
> > With this patch, adding the '-O compat' option to the dtc commandline
> > will cause dtc to parse the provided file, and print out the board
> > compatible string to stdout.
> > 
> > This will facilitate an 'installdtbs.sh' script in the kernel for naming
> > dtb files by their compatible string, eg:
> > 
> > $ dtc -I dtb -O compat arch/arm/boot/dts/armada-370-mirabox.dtb
> > globalscale,mirabox
> > 
> > This change will also simplify distribution install scripts that need to
> > search through many dtbs to find the right one for a target board.
> > 
> > Signed-off-by: Jason Cooper <jason at lakedaemon.net>
> > ---
> > changes since v1:
> >  - made patch against in-tree dtc code to facilitate testing
> 
> I assume this patch would first get applied to the upstream dtc, then
> back-ported into the kernel though?
> 
> I wonder if dtc is the correct place to put this feature at all though.
> It seems like a tiny standalone utility using libfdt would be better.
> Actually, perhaps the existing fdtget utility (which seems to be
> scripts/dtc/fdtget.c in the kernel although I don't know if it's built
> by the kernel yet) can be used rather than creating a new one? Using
> fdtget seems like it'd allow more flexibility later, if the naming rules
> change, via scripting rather than having to edit the dtc source code.

yep, just tested it.  It was easier to build fdtget in the dtc source
tree, but the result was suitable:

$ ./fdtget ../linux/arch/arm/boot/dts/armada-370-mirabox.dtb / compatible
globalscale,mirabox marvell,armada370 marvell,armada-370-xp

Thanks for the pointer.

thx,

Jason.