Re: [PATCH v2 4/5] iio: magnetometer: ak8975: Drop deprecated enums from OF table

[Jonathan Cameron <jic23@kernel.org>]

On Fri, 18 Aug 2023 17:17:44 +0200
Geert Uytterhoeven <geert@linux-m68k.org> wrote:

> Hi Andy,
> 
> CC devicetree
> 
> On Fri, Aug 18, 2023 at 5:03 PM Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:
> > On Fri, Aug 18, 2023 at 11:40:37AM +0000, Biju Das wrote:  
> > > > Subject: Re: [PATCH v2 4/5] iio: magnetometer: ak8975: Drop deprecated
> > > > enums from OF table
> > > >
> > > > On Fri, Aug 18, 2023 at 08:55:59AM +0100, Biju Das wrote:  
> > > > > Drop deprecated enums from OF table as corresponding entries are
> > > > > removed from bindings and it also saves memory.  
> > > >
> > > > You can't do this.
> > > >
> > > > Only sorting by "prefixed first" criteria is possible.  
> > >
> > > The rule applies only for fallback compatible. I checked bindings and I don't
> > > find any fallback compatibles. All compatibles are just enums. Am I missing
> > > anything here??  
> >
> > Yes. As per above patch. The _whole_ world is not under your / our control.
> > NAK to this change, sorry.  
> 
> The single user ever in the upstream kernel was fixed in commit
> 9846210b1ec9bbaa ("ARM: tegra: seaboard: add missing DT vendor
> prefixes") in v3.8 back in 2012.
> And it had to be fixed again 9 years later in commit fa0fdb78cb5d4cde
> ("ARM: dts: am335x: Use correct vendor prefix for Asahi Kasei Corp.").
> 
> There may be other out-of-tree users, which would be broken by this
> change.  Typically we wait a few years between deprecating a compatible
> value and removing support from the driver.
> 
> As Biju is only deprecating these compatible values in PATCH 3/5 of
> his series, this may be a bit premature.
Absolutely.  I'd go a bit further.
Unless there is a maintenance reason to remove these (after a few years from
removal in the binding doc) then we never remove them as it can only hurt users.

Jonathan

> 
> Gr{oetje,eeting}s,
> 
>                         Geert
> 
> 
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
> 
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds