Re: [PATCH 0/2] usb: exynos: Fix compatible strings used for device

[Sylwester Nawrocki <s.nawrocki-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>]

On 01/22/2013 06:35 AM, Kukjin Kim wrote:
>>>>> -     { .compatible = "samsung,exynos-dwc3" },
>>>>> +     { .compatible = "samsung,synopsis-dwc3" },
>>>>>
>>>>> Or if any version or something, how about following?
>>>>>
>>>>> +     { .compatible = "samsung,dwc-v3" },
>>>>>
>>> Well, yes the newer SoCs with same IP using the chip name can cause some
>>> confusion, but won't it be fine that -
>>> "Newer parts using the same core can claim compatibility by
>>> including the older string in the compatible list" - as quoted by Grant
> Likely
>>>
>>> Or, can we try another option, using multiple compatible strings for
>>> SoC specific
>>> in of_match_table, so that we don't create any confusion by using same
>>> compatible for newer SoCs also. Like,
>>>
>>> -     { .compatible = "samsung,exynos-dwc3" },
>>> +     { .compatible = "samsung,exynos5250-dwc3" },
>>> +     { .compatible =<new SoC using same IP>  },
>>
>> Yes, why not just use an SoC name where given IP first appeared ? I
> believe
>> IP revision numbers are not always well documented. Also when an IP is
>> instantiated multiple times in specific SoC, its revision number might not
>> be sufficient to determine the system integration details for each
> instance.
>> I think having version for some devices and SoC name for others just adds
>> to the confusion. Thus using specific chip name in the compatible property
>> seems more clear to me.
>>
> Well, I don't think so. Let's see the DMAC PL330. Its compatible is
> "arm,pl330" and "arm,primecell" not SoC/Chip name. I think DWC is a same
> case or at least similar.
> 
> You know, the DWC is a IP from Synopsis and I _Believe_ it has a kind of
> version and it can be used for identify.

That's a good point, but isn't DesignWare just a name of a family of IP
cores from Synopsys [1] ? And what would DWC be supposed to signify ?
DesignWare Controller ? Wouldn't that be too generic ? Synopsys seems
to offer multiple different controllers and any of them could eventually
end up in a specific SoC [2].

Maybe the compatible property should be something like:

compatible = "samsung,exynos5250-dwc-3", "synopsys,dw-usb-3";
or
compatible = "samsung,exynos5250-usb3", "synopsys,dw-ss-usb3";

? Or anything more specific in the synopsys part to indicate which
exactly USB controller IP is used ?

[1] http://www.synopsys.com/IP/InterfaceIP/USB/Pages/default.aspx
[2] http://www.synopsys.com/IP/InterfaceIP/Pages/default.aspx

--

Regards,
Sylwester
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