Hi,

On Wed, Sep 30, 2015 at 4:44 PM, Krzysztof Kozlowski
[off-list ref] wrote:

quoted

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