From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Subject: Re: [PATCH 1/2] ARM: Dove: Add the audio devices in DT
Date: Wed, 28 Aug 2013 13:58:27 +0200
Message-ID: <20130828135827.2307c89e@skate>
References: <20130828113459.48ecbb34@armhf>
	<521DCD33.2070008@gmail.com>
	<20130828121943.1c8327ca@skate>
	<521DD057.4040208@gmail.com>
	<20130828131548.0009d613@skate>
	<521DE2B3.9050508@gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: QUOTED-PRINTABLE
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <521DE2B3.9050508@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
To: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Cc: Jean-Francois Moine <moinejf@free.fr>, Mark Rutland <mark.rutland@arm.com>, devicetree@vger.kernel.org, Russell King <linux@arm.linux.org.uk>, Jason Cooper <jason@lakedaemon.net>, Pawel Moll <pawel.moll@arm.com>, Stephen Warren <swarren@wwwdotorg.org>, linux-kernel@vger.kernel.org, Rob Herring <rob.herring@calxeda.com>, Gregory CLEMENT <gregory.clement@free-electrons.com>, linux-arm-kernel@lists.infradead.org, Ian Campbell <ian.campbell@citrix.com>
List-Id: devicetree@vger.kernel.org

Dear Sebastian Hesselbarth,

On Wed, 28 Aug 2013 13:44:51 +0200, Sebastian Hesselbarth wrote:

> > For 3.12, right? So 3.12 hasn't been released yet, so it's still ti=
me
> > to fix this.
>=20
> I guess, yes.

Jean-Fran=C3=A7ois, could you cook and submit a patch to change the
compatible string?

> >> Also, we'll need to distinguish between the different audio contro=
llers
> >> on a single SoC, i.e. i2s0 and i2s1. I suggest checking the (phys)=
 reg
> >> base passed.
> >
> > For what reason does the driver needs to know whether it's the inst=
ance
> > 0 or instance 1 ? If it's needed for some specific reason, then the=
re
> > should probably be something like marvell,i2s-channel-id =3D <0> an=
d
> > marvell,i2s-channel-id =3D <1>.
>=20
> On Dove, audio1 has SPDIF out, audio0 hasn't. Russell also mentioned =
to
> get rid of "i2s" and use "audio" instead. Most SoC's controllers are
> i2s only but as soon as SPDIF comes into play, it is a different
> interface protocol.
>=20
> I am fine with having a "marvell,channel-id" (no "i2s") to discrimina=
te
> the instances, although reg offset should be sufficient.

Well, the reg offset is a possibility, but it's not really nice, and
would have to be adapted to each and every SoC even if the reset of the
audio IP is the same.

Though, if the difference between the two units is the availability of
SPDIF support, then we shouldn't encode the channel number, but instead
the availability of SPDIF, i.e:

	audio0 {
		reg =3D <... ...>;
		compatible =3D "marvell,kirkwood-audio";
		marvell,has-spdif;
	};

	audio1 {
		reg =3D <... ...>;
		compatible =3D "marvell,kirkwood-audio";
	};

Thomas
--=20
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com