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From: Wolfram Sang <wsa+renesas@sang-engineering.com>
To: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc: Peter Rosin <peda@axentia.se>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	Wojciech Siudy <wojciech.siudy@nokia.com>,
	linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] i2c: muxes: pca954x: Fix broken reset-gpio usage
Date: Mon, 3 Nov 2025 16:48:16 +0100	[thread overview]
Message-ID: <aQjOwInKQWIVdjQJ@shikoro> (raw)
In-Reply-To: <69ef304b-491a-4434-97c1-97eccd99ea66@linaro.org>

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> Maybe I should also add to emphasize:
> 
> That offending commit 690de2902dca breaks the ABI which was:
> 1. documented at
> Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.yaml (line 57)
> 2. implemented in Linux kernel around v3.14.
> 
> This ABI breakage was not justified at all, not explained not even
> mentioned in the commit msg, which is a requirement (see writing
> bindings document).

We were under the assumption that the reset-core will provide exactly
the same functionality at a centralized place. It made sense to me, too,
to avoid all the open-coded reset-gpio handlings in various drivers. I
only learnt from Morimoto-san's regression report that things were not
as I thought.

So, I sent out an RFC to discuss how to handle this issue. And if even
Philipp as the maintainer did not point me directly to revert the
offending i2c-mux commit, despite it is "obviously" sooo wrong, then
probably that optional fallback part in the reset-core needs way more
explanations and documentation.


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  reply	other threads:[~2025-11-03 15:48 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-03 15:19 [PATCH] i2c: muxes: pca954x: Fix broken reset-gpio usage Krzysztof Kozlowski
2025-11-03 15:36 ` Krzysztof Kozlowski
2025-11-03 15:48   ` Wolfram Sang [this message]
2025-11-03 17:05 ` Wolfram Sang

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