Re: [PATCH 1/3] watchdog: make Siemens Simatic watchdog driver default on platform

[Guenter Roeck]

On 7/19/23 00:18, Henning Schild wrote:
> Am Tue, 18 Jul 2023 08:10:09 -0700
> schrieb Guenter Roeck <linux@xxxxxxxxxxxx>:
>
> > On 7/18/23 07:42, Henning Schild wrote:
> > > Am Tue, 18 Jul 2023 17:20:48 +0300
> > > schrieb Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>:
> > >    
> > > > On Tue, Jul 18, 2023 at 12:52:11PM +0200, Henning Schild wrote:
> > > > > If a user did choose to enable Siemens Simatic platform support
> > > > > they likely want that driver to be enabled without having to flip
> > > > > more config switches. So we make the watchdog driver config switch
> > > > > default to the platform driver switches value.
> > > >
> > > > A nit-pick below.
> > > >
> > > > ...
> > > >   
> > > > >    config SIEMENS_SIMATIC_IPC_WDT
> > > > >    	tristate "Siemens Simatic IPC Watchdog"
> > > > >    	depends on SIEMENS_SIMATIC_IPC
> > > >   
> > > > > +	default SIEMENS_SIMATIC_IPC
> > > >
> > > > It's more natural to group tristate and default, vs. depends and
> > > > select.
> > >
> > > Will be ignored unless maintainer insists.
> > >    
> >
> > Maintainer wants to know why "default SIEMENS_SIMATIC_IPC" is needed
> > or warranted instead of the much simpler and easier to understand
> > "default y".
>
> I thought a "default y" or "default m" was maybe not the best idea for
> a platform that is not super common. That is why i did not dare to even
> think about defaulting any of the Simatic stuff to not-no.
>
> But it seems that this would be ok after all. And i would be very happy
> to do so because it means less work on distro configs.
>
> SIEMENS_SIMATIC_IPC_WDT will drive a platform device which gets
> registered by SIEMENS_SIMATIC_IPC and nothing else. That is why
> "default SIEMENS_SIMATIC_IPC" was chosen.

It depends on SIEMENS_SIMATIC_IPC. "default y" would make it y if
SIEMENS_SIMATIC_IPC=y, and m if SIEMENS_SIMATIC_IPC=m. If
SIEMENS_SIMATIC_IPC=n, it won't even be offered as option, and
default={m,y} will be ignored.

> But if i may i would change that to "default m", not "y" because there
> is an out of tree driver package which if installed on top, should be
> able to override the in-tree drivers.
>
> So i will go ahead and make that one "default m"

Why make it m as default even if SIEMENS_SIMATIC_IPC=y for whatever
reason ? Presumably anyone selecting SIEMENS_SIMATIC_IPC=y would
also want SIEMENS_SIMATIC_IPC_WDT=y, which is what you had before.
Sorry, I don't understand your logic.

Guenter