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

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Date:   Wed, 19 Jul 2023 16:40:34 +0200
From:   Henning Schild <henning.schild@...mens.com>
To:     Guenter Roeck <linux@...ck-us.net>
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Lee Jones <lee@...nel.org>,
        Hans de Goede <hdegoede@...hat.com>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        linux-kernel@...r.kernel.org, linux-leds@...r.kernel.org,
        platform-driver-x86@...r.kernel.org,
        linux-watchdog@...r.kernel.org, Pavel Machek <pavel@....cz>,
        Mark Gross <markgross@...nel.org>,
        Tobias Schaffner <tobias.schaffner@...mens.com>
Subject: Re: [PATCH 1/3] watchdog: make Siemens Simatic watchdog driver
 default on platform

Am Wed, 19 Jul 2023 06:27:19 -0700
schrieb Guenter Roeck <linux@...ck-us.net>:

> On 7/19/23 00:18, Henning Schild wrote:
> > Am Tue, 18 Jul 2023 08:10:09 -0700
> > schrieb Guenter Roeck <linux@...ck-us.net>:
> >   
> >> On 7/18/23 07:42, Henning Schild wrote:  
> >>> Am Tue, 18 Jul 2023 17:20:48 +0300
> >>> schrieb Andy Shevchenko <andriy.shevchenko@...ux.intel.com>:
> >>>      
> >>>> 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.

At the time of writing i did not know what you described above. That y
with depends does not result in y.

Next round will have a "default y", Thanks.

Henning

> Guenter
>