Re: [PATCH] Input: adp5588-keys: Remove unused driver - Uwe Kleine-König

From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: "Hennerich, Michael" <Michael.Hennerich@analog.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	"Bogdan, Dragos" <Dragos.Bogdan@analog.com>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	"Sa, Nuno" <Nuno.Sa@analog.com>,
	"kernel@pengutronix.de" <kernel@pengutronix.de>,
	"linux-input@vger.kernel.org" <linux-input@vger.kernel.org>
Subject: Re: [PATCH] Input: adp5588-keys: Remove unused driver
Date: Fri, 27 May 2022 09:35:08 +0200	[thread overview]
Message-ID: <20220527073508.x6ryljkozvvfvro2@pengutronix.de> (raw)
In-Reply-To: <SJ0PR03MB6253FC31665D4ADA31A0A5458EC59@SJ0PR03MB6253.namprd03.prod.outlook.com>

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Hello,

On Fri, May 06, 2022 at 11:57:57AM +0000, Hennerich, Michael wrote:
> > On Thu, May 05, 2022 at 06:20:22AM +0000, Hennerich, Michael wrote:
> > > If we start removing drivers which obviously don't have a mainline
> > > in-tree user, we would upset up many users of these drivers.
> > > I agree on updating this driver to make platform data optional.
> > > We could provide a patch in a few days.
> > 
> > Just to add some background why I stumbled over this driver: On of my current
> > quests is to make i2c remove callbacks return void. As a preparation for that I
> > work on updating all i2c drivers to return 0 in
> > .remove() to make the change to void have no side effects.
> > 
> > One of the offenders is drivers/gpio/gpio-adp5588.c, which in the presence of a
> > pdata->teardown callback might return a non-zero value from .remove(). While
> > looking at the pdata of possible devices I only found
> > drivers/input/keyboard/adp5588-keys.c.
> > 
> > So the options for my quest are in increasing impact order:
> > 
> >  a) just warn if struct adp5588_gpio_platform_data::teardown fails and
> >     still return 0 from .remove()
> >  b) make struct adp5588_gpio_platform_data::teardown return void
> >  c) drop teardown support from adp5588_gpio_platform_data
> >  d) drop platform support from gpio-adp5588
> >  e) drop gpio-adp5588
> > 
> > Currently I'd go for at least d).
> > 
> > Having said that I think e) has a net benefit. If there is no user left it reduces
> > maintainance burden. If there is a user left, they hopefully will tell us, we can
> > restore the driver from git history and then at least know a tester for future
> > cleanups and changes.
> 
> Hi Uwe,
> 
> Thanks for the explanation.
> 
> I know that there are users of this driver. But I admit, we should have earlier
> made platform_data support optional and also add proper dt bindings.
> We're in progress doing so. And in the meanwhile, I would prefer a less
> disruptive intermediate change. For example c) with the promise we're working on d).

FTR: a part of c) hit the mailing list a few days ago. This is good
enough for my purpose, but to complete platform teardown (and setup)
support, it must be ripped from adp5588-keys.c, too. I won't do that as
it isn't in the way for my quest.

See
https://lore.kernel.org/linux-gpio/20220523083947.840708-1-u.kleine-koenig@pengutronix.de
for your opportunity to ack the patch.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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