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

[Rob Herring]

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).

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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