Re: [PATCH] ASoC: ak4554: add DT support

[Lars-Peter Clausen <lars@metafoo.de>]

On 07/06/2013 08:58 PM, Sylwester Nawrocki wrote:
> On 07/05/2013 07:13 PM, Stephen Warren wrote:
>> On 07/05/2013 11:04 AM, Lars-Peter Clausen wrote:
>>> On 07/05/2013 06:55 PM, Stephen Warren wrote:
>>>> On 07/05/2013 03:37 AM, Lars-Peter Clausen wrote:
>>>>>> +  - compatible : "asahi-kasei,ak4554"
>>>>>
>>>>> The vendor prefix for Asahi Kasei is documented as "ak" in
>>>>> Documentation/devicetree/bindings/vendor-prefixes.txt. But it doesn;t seem
>>>>> to be used in any upstream drivers, Stephen add that prefix maybe he knows
>>>>> if it is used. If it is unused you should probably send a patch updating the
>>>>> Documentation.
>>>>
>>>> It's used at:
>>>>
>>>> arch/arm/boot/dts/tegra20-seaboard.dts:499: compatible = "ak,ak8975";
>>>>
>>>> ... although I see that somebody has incorrectly modified
>>>> ./drivers/iio/magnetometer/ak8975.c to support the "asahi-kasei," vendor
>>>> prefix:-(
>>>
>>> It looks as if the ak prefix was never in an upstream kernel and the commit
>>> date that added the dt table predates the commit date for your devicetree.
>>
>> The usage I quoted above is in the mainline kernel, along with the entry
>> in vendor-prefixes.txt.
>>
>> When I fixed vendor-prefixes.txt to define a prefix for AK, and updated
>> the Tegra DT to use them[1], I guess I didn't even look at the driver,
>> since all I2C device matching uses the i2c_device_id table rather than
>> the of_device_id, and the i2c_device_id table doesn't have a concept of
>> a vendor prefix. Hence, I didn't notice the conflict.
>>
>> So, even though the asahi-kasei prefix is in the of_device_id table in
>> the driver, I'd say the ak prefix trumps it, since it's actually in-use
>> in device trees, and is registered in vendor-prefixes.txt.
> 
> I'm going to update this [2] patch to use "ak,ak8975" compatible string
> then. Still there are some audio codec drivers that use "asahi-kasei"
> vendor prefix:
> 
> Documentation/devicetree/bindings/sound/ak4104.txt:  - compatible :
> "asahi-kasei,ak4104"
> Documentation/devicetree/bindings/sound/ak4104.txt:     compatible =
> "asahi-kasei,ak4104";
> Documentation/devicetree/bindings/sound/ak4642.txt:  - compatible :
> "asahi-kasei,ak4642" or "asahi-kasei,ak4643" or "asahi-kasei,ak4648"
> Documentation/devicetree/bindings/sound/ak4642.txt: compatible =
> "asahi-kasei,ak4642";
> Documentation/devicetree/bindings/sound/ak5386.txt:  - compatible :
> "asahi-kasei,ak5386"
> Documentation/devicetree/bindings/sound/ak5386.txt:     compatible =
> "asahi-kasei,ak5386";
> ...
> sound/soc/codecs/ak4104.c:      { .compatible = "asahi-kasei,ak4104", },
> sound/soc/codecs/ak4642.c:      { .compatible = "asahi-kasei,ak4642", .data =
> &soc_codec_dev_ak4642},
> sound/soc/codecs/ak4642.c:      { .compatible = "asahi-kasei,ak4643", .data =
> &soc_codec_dev_ak4642},
> sound/soc/codecs/ak4642.c:      { .compatible = "asahi-kasei,ak4648", .data =
> &soc_codec_dev_ak4648},
> sound/soc/codecs/ak5386.c:      { .compatible = "asahi-kasei,ak5386", },
> 
> It's not in any dts file though, I'm not sure if that makes any
> difference.
> 

Well strictly speaking this is all public ABI, so I guess the best is to add a
ak prefixed compatible string besides the asahi-kasei one and stick to ak only
fore future drivers.

- Lars