Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Fri, 11 Dec 2020 09:33:55 +0100
From:   Thierry Reding <thierry.reding@gmail.com>
To:     Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= <u.kleine-koenig@pengutronix.de>
Cc:     Sven Van Asbroeck <thesven73@gmail.com>,
        Clemens Gruber <clemens.gruber@pqgruber.com>,
        linux-pwm@vger.kernel.org, Lee Jones <lee.jones@linaro.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        David Jander <david@protonic.nl>
Subject: Re: [PATCH v4 1/4] pwm: pca9685: Switch to atomic API
Message-ID: <X9Mu8zrJjFTe6fJq@ulmo>
References: <20201208091033.bxzrlad7mjbe3dsp@pengutronix.de>
 <X89RgpTb3sBBI++w@workstation.tuxnet>
 <X8+DI7ZN7mXtsxv9@ulmo>
 <CAGngYiXgVbEXj-yR=DTeA4pO-N3=WhiHjQhknFsbfXBeD_yRbw@mail.gmail.com>
 <X8+waLH58pOaMI06@ulmo>
 <20201208182637.hm5uzuw5ueelo26k@pengutronix.de>
 <X9EDGHySNYb7CxcW@ulmo>
 <20201210090124.rfswkrcttsg5gszp@pengutronix.de>
 <X9JWlVPb9ZGdB4q9@ulmo>
 <20201210203926.ouzrq3ff5k6zhlvt@pengutronix.de>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha256;
        protocol="application/pgp-signature"; boundary="hmzyeSm2KOFrlm0S"
Content-Disposition: inline
In-Reply-To: <20201210203926.ouzrq3ff5k6zhlvt@pengutronix.de>
User-Agent: Mutt/2.0.3 (a51f058f) (2020-12-04)
Precedence: bulk


--hmzyeSm2KOFrlm0S
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

On Thu, Dec 10, 2020 at 09:39:26PM +0100, Uwe Kleine-K=C3=B6nig wrote:
> Hello Thierry,
>=20
> On Thu, Dec 10, 2020 at 06:10:45PM +0100, Thierry Reding wrote:
> > Like I said, that's not what I was saying. I was merely saying that if
> > there aren't any use-cases that current users rely on that would be
> > broken by using this simpler implementation, then I'm okay with it, even
> > if it's less flexible than a more complicated implementation. It should
> > be possible to determine what the current users are by inspecting device
> > trees present in the kernel. Anything outside the kernel isn't something
> > we need to consider, as usual.
>=20
> If "users in mainline" is the criteria that's a word.

I didn't say "users in mainline", I said "use-cases". What I don't want
to happen is for this change under discussion to break any existing use-
cases of any existing users in the kernel. I said that we can determine
what the existing users are by looking at which device trees use the
compatible strings that the driver matches on.

> So you agree we remove the following drivers?:
>=20
>  - pwm-hibvt.c
>    Last driver specific change in Feb 2019, no mainline user
>  - pwm-sprd.c
>    Last driver specific change in Aug 2019, no mainline user

No, that's an extrapolation of what I was saying above. Drivers with no
apparent users are a separate topic, so don't conflate it with the issue
at hand.

While it's certainly unfortunate that these don't seem to be used, I see
no reason why we should remove them. They don't create much of a
maintenance burden, so I'm fine with keeping them in the hopes that
users may still show up at some point.

> Most PWMs are added to cpu.dtsi files with status =3D "disabled", I wonder
> if it makes sense to check the machine.dts files if some of the PMWs are
> completely unused. Do you consider status =3D "okay" a use that we have to
> retain even if the node has no phandle?

A PWM controller may be in use via sysfs even if it has no phandle.

Thierry

--hmzyeSm2KOFrlm0S
Content-Type: application/pgp-signature; name="signature.asc"

-----BEGIN PGP SIGNATURE-----
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=W/qR
-----END PGP SIGNATURE-----

--hmzyeSm2KOFrlm0S--