Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Mon, 24 Feb 2020 19:46:25 +0100
From:   Andreas Kemnade <andreas@kemnade.info>
To:     Mark Brown <broonie@kernel.org>
Cc:     hns@goldelico.com, j.neuschaefer@gmx.net, contact@paulk.fr,
        GNUtoo@cyberdimension.org, josua.mayer@jm0.eu, lgirdwood@gmail.com,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC] regulator: core: fix handling negative voltages
 e.g. in EPD PMICs
Message-ID: <20200224194625.20078cf2@kemnade.info>
In-Reply-To: <20200224120512.GG6215@sirena.org.uk>
References: <20200223153502.15306-1-andreas@kemnade.info>
        <20200224120512.GG6215@sirena.org.uk>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha256;
 boundary="Sig_/yAS+qN3RrSi7FCLSBI+4oPT"; protocol="application/pgp-signature"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

--Sig_/yAS+qN3RrSi7FCLSBI+4oPT
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: quoted-printable

Hi,

On Mon, 24 Feb 2020 12:05:12 +0000
Mark Brown <broonie@kernel.org> wrote:

> On Sun, Feb 23, 2020 at 04:35:01PM +0100, Andreas Kemnade wrote:
>=20
> > An alternative would be to handle voltages as absolute values.
> > There are probably no regulators with support both negative
> > and positive output. =20
>=20
> This is what'd be needed, your approach here is a bit of a hack and
> leaves some values unrepresentable if they overlap with errnos which
> obviously has issues if someone has a need for those values.  Ground is
> to a large extent somewhat arbatrary anyway and some systems do just
> redefine it as part of their normal operation (eg, VMID based audio
> systems) so this wouldn't be a huge departure.

Thanks for clarification, outputs from 0mV to -4mV would not be be
representable. I am now converting stuff to think positive ;-) That
is good to decide early before pushing my huge pile of things needed
for EPD support on top of mainline somewhere.
Parallel I am evaluating upstreaming of the tps65181 driver which
probably ends up in a rewrite...

Regards,
Andreas

--Sig_/yAS+qN3RrSi7FCLSBI+4oPT
Content-Type: application/pgp-signature
Content-Description: OpenPGP digital signature

-----BEGIN PGP SIGNATURE-----
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=BW7X
-----END PGP SIGNATURE-----

--Sig_/yAS+qN3RrSi7FCLSBI+4oPT--