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Sender: Guenter Roeck <groeck7@gmail.com>
Message-ID: <160cb639-5081-ec50-2c41-fc31502107a2@roeck-us.net>
Date:   Wed, 19 Jul 2023 06:27:19 -0700
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Subject: Re: [PATCH 1/3] watchdog: make Siemens Simatic watchdog driver
 default on platform
Content-Language: en-US
To:     Henning Schild <henning.schild@siemens.com>
Cc:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Lee Jones <lee@kernel.org>,
        Hans de Goede <hdegoede@redhat.com>,
        Wim Van Sebroeck <wim@linux-watchdog.org>,
        linux-kernel@vger.kernel.org, linux-leds@vger.kernel.org,
        platform-driver-x86@vger.kernel.org,
        linux-watchdog@vger.kernel.org, Pavel Machek <pavel@ucw.cz>,
        Mark Gross <markgross@kernel.org>,
        Tobias Schaffner <tobias.schaffner@siemens.com>
References: <20230718105213.1275-1-henning.schild@siemens.com>
 <20230718105213.1275-2-henning.schild@siemens.com>
 <ZLafwOPrw+puH+rF@smile.fi.intel.com>
 <20230718164251.13855c47@md1za8fc.ad001.siemens.net>
 <b1528e3d-15f7-7ab2-b803-917f79efe999@roeck-us.net>
 <20230719091816.6661d535@md1za8fc.ad001.siemens.net>
From:   Guenter Roeck <linux@roeck-us.net>
In-Reply-To: <20230719091816.6661d535@md1za8fc.ad001.siemens.net>
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On 7/19/23 00:18, Henning Schild wrote:
> Am Tue, 18 Jul 2023 08:10:09 -0700
> schrieb Guenter Roeck <linux@roeck-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@linux.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.

Guenter