Re: [PATCH v2 13/13] ARM: s3c24xx: camif: include header with prototypes and unify declaration

[Sylwester Nawrocki <s.nawrocki@samsung.com>]

On 12.08.2020 15:31, Krzysztof Kozlowski wrote:
> On Wed, Aug 12, 2020 at 03:11:41PM +0200, Sylwester Nawrocki wrote:
>> On 12.08.2020 13:28, Arnd Bergmann wrote:
>>> On Wed, Aug 12, 2020 at 12:46 PM Sylwester Nawrocki
>>> <s.nawrocki@samsung.com> wrote:
>>>> On 12.08.2020 11:14, Arnd Bergmann wrote:

>>> I see two board files (and no DT) instantiate the camif device:
>>> NexVision Nexcoder 2440 and the FriendlyARM mini2440.
>>>
>>> Can you say whether the camif on those would actually work
>>> at all without your patch? If not, we know that there are no
>>> users of that driver and could either drop it completely or move
>>> it to staging for a release or two.
>>
>> Without additional patches the camif will not work, the driver 
>> needs an instance of struct s3c_camif_plat_data which specifies
>> what image sensor is attached.
>>
>> I think we can drop the driver, together with the s3c_camif_device
>> platform device definitions. It can always be added again if anyone
>> ever needs it or converts the platform to DT.
> 
> Since the header was in /include/media I assumed there might be some
> user-space tools using it. But if it is not the case, I'll drop the code
> then.

That's a kernel internal header, only for board files, it should really 
have been added to include/linux/platform_data.
  
>> IMO all non-DT code in arch/arm/mach-s3c24xx is a candidate for
>> removal, it just adds to the maintenance effort and I seriously
>> doubt there are now any users of it.
> 
> That is quite tricky... I really do not know whether there are any real
> world users of S3C24xx and S3C64xx platforms. Evalkits are mostly not
> available for buying so I do not expect new designs. However still
> existing ones might be somewhere... Few years ago, back in Samsung, I
> mentioned removing them. That time I think Marek or you Sylwester, said
> that there are industrial applications using S3C24xx. I believe, why
> not. The trouble is - how to find such users? How to get in touch for
> testing or at least for bug reports if something is broken?

I believe if there any such applications of the S3C24XX SoCs still existing 
somewhere their long term support doesn't include updating to new kernels. 
I used to keep a running S3C2440 SoC based board just for the purpose of
testing patches touching the common code, but I stopped it, I think it is
not worth to waste time and health on it any more. For example support for 
the OSELAS.BSP-Pengutronix-Mini2440 BSP I used for tests ended 5 years ago
[1].

> Or even more important - is it worth to spend effort and time on this?
> If there is no single production system using recent Linux kernel, the
> answer should be negative...

I suspect nobody cares about that code (non-DT s3c24xx) any more for other
than sentimental reasons.

[1] https://git.pengutronix.de/cgit/OSELAS.BSP-Pengutronix-Mini2440

-- 
Regards,
Sylwester