Re: [PATCH v2] ARM: mvebu: Fix missing binding documentation for Armada 38x

[Jason Cooper <jason@lakedaemon.net>]

On Fri, Jun 20, 2014 at 05:33:06PM -0500, Rob Herring wrote:
> On Fri, Jun 20, 2014 at 1:52 PM, Jason Cooper <jason@lakedaemon.net> wrote:
> > On Thu, Jun 19, 2014 at 06:40:43PM +0200, Gregory CLEMENT wrote:
> >> For the Armada 380 and Armada 385 SoCs, the common bindings for those
> >> 2 SoCs, was forgotten. This patch add the documentation for the
> >> marvell,aramda38x property.
> >>
> >> Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
> >> --
> >> Hi,
> >>
> >> This fix should be merged in 3.16. For 3.15 I am not sure as it is not
> >> a regression.
> >>
> >> Changelog:
> >> v1->v2
> >>
> >> - Reformulate to make clear that we will need marvell,armada38x _and_ a
> >> SoC specific string. For consistency I duplicated what we have done in
> >> armada-370-xp.txt
> >>
> >>
> >> Thanks,
> >> Gregory
> >>
> >>
> >>  Documentation/devicetree/bindings/arm/armada-38x.txt | 17 +++++++++++++++--
> >>  1 file changed, 15 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/Documentation/devicetree/bindings/arm/armada-38x.txt b/Documentation/devicetree/bindings/arm/armada-38x.txt
> >> index 11f2330a6554..fa08760046df 100644
> >> --- a/Documentation/devicetree/bindings/arm/armada-38x.txt
> >> +++ b/Documentation/devicetree/bindings/arm/armada-38x.txt
> >> @@ -6,5 +6,18 @@ following property:
> >>
> >>  Required root node property:
> >>
> >> - - compatible: must contain either "marvell,armada380" or
> >> -   "marvell,armada385" depending on the variant of the SoC being used.
> >> +compatible: must contain "marvell,armada38x"
> >
> > I agree with Sergei on this one.  We generally avoid wildcards in
> > compatible strings.  Is there a use case where specifying one of the
> > below wouldn't be sufficient?
> 
> Isn't this a case of just documenting what is already in use?

Technically, yes.  However, there are no products shipping with this SoC
yet.  So there aren't any _real_ users other than the developers
bringing in mainline support.

> I agree wildcards alone are not good, but along with a specific
> compatible is okay. But also there should be some need to have the
> common property.

I'm curious what you would consider to be a sufficient need?  This can
be easily handled by a match table, but a match table could also be
considered rather heavy for this task.

I think any implementation-based justification is prone to opening a can
of worms.  And I'm struggling to see a DT-only justification...

thx,

Jason.