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Subject: Re: [RFC PATCH 0/5] Apple Macs machine-level ASoC driver
From:   =?utf-8?Q?Martin_Povi=C5=A1er?= <povik@cutebit.org>
In-Reply-To: <YmKjL9bOtOmsFWTs@sirena.org.uk>
Date:   Fri, 22 Apr 2022 14:53:54 +0200
Cc:     =?utf-8?Q?Martin_Povi=C5=A1er?= <povik+lin@cutebit.org>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzk+dt@kernel.org>,
        Jaroslav Kysela <perex@perex.cz>,
        Takashi Iwai <tiwai@suse.com>, alsa-devel@alsa-project.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        Mark Kettenis <kettenis@openbsd.org>,
        Hector Martin <marcan@marcan.st>,
        Sven Peter <sven@svenpeter.dev>
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Message-Id: <3CD969AD-7316-4D83-AD92-CC85ED817125@cutebit.org>
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To:     Mark Brown <broonie@kernel.org>
Precedence: bulk


> On 22. 4. 2022, at 14:44, Mark Brown <broonie@kernel.org> wrote:
>=20
> On Fri, Apr 22, 2022 at 02:36:03PM +0200, Martin Povi=C5=A1er wrote:
>=20
>>> Ah, I think the confusion here is that I'm using slot and channel
>>> interchangably whereas you're saying that previously the driver =
would
>>> allocate two channels to each speaker with duplicate data?
>=20
>> I guess you could say that. Not that there=E2=80=99s duplicate data =
on the I2S
>> bus, but the speaker amp would previously be configured to look for =
the
>> left and right channel in the same TDM slot (see e.g. set_tdm_slot of
>> tas2770 [0]).  (Each speaker amp drives a single speaker, but it =
still
>> has a notion of left and right channel.)
>=20
> Oh, I see - the speaker actually allows configuration of the slots
> independently.  Usually the left/right thing on mono devices only does
> something for I2S where the bus clocking enforces that there be both
> left and right channels.  Either configuration is fine by me TBH, if =
you
> can do that then you could just keep them mapped to the same channel
> then mark the control as disabled since it should have no effect.

Well but is there some established way to mark a control as disabled?

Another issue here is that if I disable it I can=E2=80=99t leave the =
routing
control in it=E2=80=99s default value, which is =E2=80=98I2C Offset=E2=80=99=
 and makes the speaker
amp ignore the slot mapping.