To:     Janne Grunau <j@jannau.net>, Sven Peter <sven@svenpeter.dev>,
        Alyssa Rosenzweig <alyssa@rosenzweig.io>,
        Rob Herring <robh+dt@kernel.org>
Cc:     linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20211122225807.8105-1-j@jannau.net>
 <20211122225807.8105-4-j@jannau.net>
From:   Hector Martin <marcan@marcan.st>
Subject: Re: [PATCH v3 3/4] arm64: dts: apple: t8103: Add i2c nodes
Message-ID: <5f16c962-72a1-21ec-9651-744053f74365@marcan.st>
Date:   Tue, 23 Nov 2021 14:41:13 +0900
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On 23/11/2021 07.58, Janne Grunau wrote:
> Apple M1 has at least 5 i2c controllers. i2c0, i2c1 and i2c3 are used
> on all M1 Mac devices. The 2020 Mac Mini uses i2c2 and the 13-inch
> MacBook Pro uses i2c2 and i2c4.

On further testing: i2c3 is not used on the 1GbE variant of j274. iBoot 
actually kills the node entirely. The interesting thing is it doesn't 
work; it times out probe transactions. I suspect iBoot does not enable 
its clock or something like that.

I'll poke around this on IRC, but a priori we probably need m1n1 code to 
kill this node when the ADT doesn't have it. Maybe I should generalize 
the dwc3 killing code...

-- 
Hector Martin (marcan@marcan.st)
Public Key: https://mrcn.st/pub