Message-ID: <e8f50fe8-bad3-e59e-4d80-e2f7db9c9933@gmail.com>
Date:   Sun, 19 Mar 2023 08:36:20 +0200
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Subject: Re: [PATCH v4 2/8] kunit: drm/tests: move generic helpers
To:     Maxime Ripard <maxime@cerno.tech>
Cc:     Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>, Emma Anholt <emma@anholt.net>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        =?UTF-8?Q?Ma=c3=adra_Canal?= <mcanal@igalia.com>,
        Javier Martinez Canillas <javierm@redhat.com>,
        =?UTF-8?Q?Noralf_Tr=c3=b8nnes?= <noralf@tronnes.org>,
        linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
        Stephen Boyd <sboyd@kernel.org>
References: <cover.1679062529.git.mazziesaccount@gmail.com>
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 <20230317150916.a3xrh25ywe5k77yp@houat>
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From:   Matti Vaittinen <mazziesaccount@gmail.com>
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Hi Maxime & All

First of all - I am sorry. During the last minute rebase I accidentally 
dropped the header file from this series. Will fix that for v5. (Also 
the build bot pointed this mistake).

On 3/17/23 17:09, Maxime Ripard wrote:
> Hi Matti,
> 
> On Fri, Mar 17, 2023 at 04:42:25PM +0200, Matti Vaittinen wrote:
>> The creation of a dummy device in order to test managed interfaces is a
>> generally useful test feature. The drm test helpers
>> test_kunit_helper_alloc_device() and test_kunit_helper_free_device()
>> are doing exactly this. It makes no sense that each and every component
>> which intends to be testing managed interfaces will create similar
>> helpers.
>>
>> Move these functions to place where it is more obvious they can be used
>> also by other subsystems but drm.
>>
>> Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
>>
>> ---
>>
>> Please note that there's something similat ongoing in the CCF:
>> https://lore.kernel.org/all/20230302013822.1808711-1-sboyd@kernel.org/
>>
>> I do like the simplicity of these DRM-originated helpers so I think
>> they're worth. I do equally like the Stephen's idea of having the
>> "dummy platform device" related helpers under drivers/base and the
>> header being in include/kunit/platform_device.h which is similar to real
>> platform device under include/linux/platform_device.h - so, in the end
>> of the day I hope Stephen's changes as well as the changes this patch
>> introduces to end up in those files. This, however, will require some
>> co-operation to avoid conflicts.
> 
> I think you would have an easier time if you just copied and renamed
> them into the kunit folder as an preparation series.

Yes. That would simplify the syncing between the trees. It slightly bugs 
me to add dublicate code in kernel-but the clean-up series for DRM users 
could be prepared at the same time. It would be even possible to just 
change the drm-helper to be a wrapper for the generic one - and leave 
the callers intact - although it leaves some seemingly unnecessary 
"onion code" there.

> That way, you wouldn't have to coordinate DRM, CCF and IIO, you'd just
> create new helpers that can be reused/converted to by everyone eventually

Yes. Thanks - I think I may go with this approach for the v5 :)

Yours,
	-- Matti

-- 
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

~~ When things go utterly wrong vim users can always type :help! ~~