Re: [PATCHv5 7/9] ASoC: dt-bindings: imx-audio-spdif: remove binding

[Elinor Montmasson <elinor.montmasson@savoirfairelinux.com>]

From: "Krzysztof Kozlowski" <krzk@kernel.org>
Sent: Monday, 24 June, 2024 10:55:31
> On 24/06/2024 10:51, Elinor Montmasson wrote:
>> From: "Krzysztof Kozlowski" <krzk@kernel.org>
>> Sent: Sunday, 23 June, 2024 13:09:33
>>> On 20/06/2024 15:25, Elinor Montmasson wrote:
>>>> imx-audio-spdif was merged into the fsl-asoc-card driver, and therefore
>>>> removed.
>>>
>>> So what happens with all existing users (e.g. DTS)? They become
>>> invalid/not supported?
>> 
>> 
>> Next commits, 8/9 and 9/9, update all DTS files that currently use
>> the "fsl,imx-audio-spdif" compatible.
> 
> You mean in-tree. I mean all users, in- and out-of-tree. Other projects.

Oh you're right

>> From the users point of view, currently configured spdif audio cards
>> will behave just the same.
>> 
>> 
>>> After quick look, I do not see backwards compatibility in the driver and
>>> above commit msg tells me nothing about ABI break.
>> 
>> 
>> For the next version I will state in this commit message the upcoming
>> modifications to DTS
>> and compatibility, why it will be done, and that support for existing DTS is not
>> dropped.
>> 
>> Previous `imx-spdif` driver used the dummy codec instead of
>> using declared spdif codecs. It was discussed in previous version of this
>> contribution
>> that using the dummy codec isn't good practice. So one to one backward
>> compatibility
>> isn't really possible.
> 
> Heh, that's not good. This is improvement, cleanup. While it is
> important and useful, it should also not break existing users.


Should I introduce then the use of the dummy codec in `fsl-asoc-card` to
assure backward compatibility at least for a time ?
With maybe warning messages in code to indicate that spdif codecs drivers
should be declared and used in the future ?


Best regards,
Elinor Montmasson