Re: [RFC PATCH 2/2] dt: spi: s3c64xx: add compatible to controller-data

[Michal Suchanek]

On 29 July 2015 at 16:00, Mark Brown <broonie@xxxxxxxxxx> wrote:
> On Wed, Jul 29, 2015 at 12:19:57PM +0200, Michal Suchanek wrote:
>
> Please use subject lines matching the style for the subsytsem so people
> can spot that the patch is in some way relevant.
>
>> The controller-data subnode has no compatible. This can lead to other
>> drivers getting confused by it. Add a compatible to make devicetreee
>> unambiguous.
>
> I can't tell from this commit message what the issue you're trying to
> fix is, sorry.  Nodes without compatible strings are entirely normal and
> don't need compatible strings.  It sounds like a bug in whatever other
> driver is becoming confused.

The driver that gets confused is ofpart.

The two-line patch to allow it to just ignore controller-data has been
rejected on the basis that s3c64xx should use a compatible string
because ofpart monopolizes all nodes without compatible which are
children of a mtd device. Devicetrees containing such nodes that are
not partitions are presumably invalid and should be rejected when
ofpart is compiled into the kernel.

>
>> +     if (!of_get_property(data_np, "compatible", NULL) ||
>> +         strcmp(of_get_property(data_np, "compatible", NULL),
>> +                "samsung,s3c-controller-data"))
>> +             dev_err(&spi->dev, "child node 'controller-data' does not have correct compatible\n");
>
> This will break all existing users which is not acceptable for
> mainline, we need to preserve compatibility with existing device trees.

It will not break anything. It will just spam dmesg.

Thanks

Michal
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