Re: [PATCH] SATA: OCTEON: support SATA on OCTEON platform

[Mark Rutland]

On Thu, Jan 22, 2015 at 02:19:55PM +0000, Rob Herring wrote:
> On Wed, Jan 21, 2015 at 11:17 AM, David Daney <ddaney@xxxxxxxxxxxxxxxxxx> wrote:
> > On 01/21/2015 08:54 AM, Mark Rutland wrote:
> >>
> >> On Mon, Jan 19, 2015 at 07:16:28PM +0000, David Daney wrote:
> >
> > [...]
> >>>>>
> >>>>> @@ -67,6 +76,7 @@ static const struct of_device_id ahci_of_match[] = {
> >>>>>         { .compatible = "ibm,476gtr-ahci", },
> >>>>>         { .compatible = "snps,dwc-ahci", },
> >>>>>         { .compatible = "hisilicon,hisi-ahci", },
> >>>>> +       { .compatible = "cavium,octeon-7130-ahci", },
> >>>>>         {},
> >>>>
> >>>>
> >>>> I was under the impression that the strings other than "generic-ahci"
> >>>> were only for compatibility with existing DTBs. Why do we need to add
> >>>> new platform-specific strings here?
> >>>
> >>>
> >>> Because it is an "existing DTB", The device tree doesn't contain the
> >>> compatible property of "generic-ahci", only "cavium,octeon-7130-ahci".
> >>
> >>
> >> While the DTB may already exist, the string "cavium,octeon-7130-ahci"
> >> isn't in mainline, and as far as I can see has never been supported.
> >
> >
> > There seems to be a disconnect here.  The DTB comes from the hardware boot
> > environment.  The hardware is in some cases already deployed.  It is for all
> > practical purposes, impossible to change the DTB.
> >
> > The idea that the kernel source code controls the content of the device tree
> > doesn't apply here.
> 
> I have to agree that adding the compatible string here is okay.
> Allowing/using generic names is the exception, not the rule. We're
> usually pushing the other way. People often complain about having to
> add a compatible string when they don't need it (yet).

If people are happy adding the string, then I have no problem with that.

My concern was with the "existing DTB" argument, which you've covered
below.

Thanks,
Mark.

> However, the argument that the privately developed DTB has to be
> accepted as is is complete crap. Maybe you have done a good job and
> have all straightforward bindings, so having them accepted won't be a
> big deal. We should be reasonable and not bikeshed things which are
> already in use and only affect a single device. Many of the bindings
> in vendor trees I have seen are a complete mess, but I expect better
> from you.
> 
> Rob
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