Re: [PATCH] ARM: dts: Add Exynos5250 Snow Rev5+ support

[Doug Anderson]

Hi,

On Wed, Sep 30, 2015 at 4:44 PM, Krzysztof Kozlowski
<k.kozlowski@xxxxxxxxxxx> wrote:
>> Switching the default meaning of "google,snow" to Rev5 is probably not
>> something we'd ever want to do, since it could confuse "rev3" boards
>> (which should be serviced by the rev4 dts).  From comments in the
>> Chrome OS tree:
>>
>> In the "rev4" DTS:
>>          * - Any real rev 0-3 boards in the field will match "google,snow",
>>          *   since older U-Boots don't look for a revision specific device tree.
>>          * - Any real rev 4 boards in the field will match "google,snow-rev4"
>>          *   first.  If that's not present they will pick the first
>>          *   "google,snow" device tree that they find (ignoring the kernel
>>          *   ordering).
>>
>> In the "rev5" DTS:
>>          * - Purposely don't add "google,snow" so old firmware (which didn't
>>          *   include a -revN suffix) won't pick this one.
>
> These are requirements written somewhere in the downstream tree... not
> in upstream. Have in mind that someone may not be using Chrome OS on
> Chromebook but custom U-Boot and different distro.
>
> You cannot expect that everyone will new some requirements of some
> downstream OS. If you need such requirements, write them in bindings
> documentation *in the upstream*.

Agreed, which is why I bring it up here.  I think Javier wasn't aware
of these when he sent up his patch.  I believe when he adds the
bindings docs he'll put this information.

Previously rev5 wasn't supported upstream and I believe rev5 didn't
even exist when the upstream stuff was submitted.

-Doug
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