Re: [PATCH v3 7/9] dt-bindings: arm: stm32: Switch st,stm32mp23/25-syscfg into simple-mfd

From: Krzysztof Kozlowski <krzk@kernel.org>
To: Marek Vasut <marex@nabladev.com>
Cc: linux-usb@vger.kernel.org, fabrice.gasnier@foss.st.com,
	 Alexandre Torgue <alexandre.torgue@foss.st.com>,
	Christian Bruel <christian.bruel@foss.st.com>,
	 Conor Dooley <conor+dt@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	 Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	 Neil Armstrong <neil.armstrong@linaro.org>,
	Pankaj Dev <pankaj.dev@st.com>,
	 Rahul Kumar <rahul.kumar05@st.com>,
	Rob Herring <robh@kernel.org>, Rosen Penev <rosenp@gmail.com>,
	 Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
	Vinod Koul <vkoul@kernel.org>,
	devicetree@vger.kernel.org,  kernel@dh-electronics.com,
	linux-arm-kernel@lists.infradead.org,
	 linux-kernel@vger.kernel.org, linux-phy@lists.infradead.org,
	 linux-stm32@st-md-mailman.stormreply.com
Subject: Re: [PATCH v3 7/9] dt-bindings: arm: stm32: Switch st,stm32mp23/25-syscfg into simple-mfd
Date: Thu, 27 Aug 2026 15:07:11 +0200	[thread overview]
Message-ID: <20260827-skilled-optimal-shellfish-c548e5@quoll> (raw)
In-Reply-To: <20260822074816.548662-8-marex@nabladev.com>

On Sat, Aug 22, 2026 at 09:46:40AM +0200, Marek Vasut wrote:
> The st,stm32mp23-syscfg and st,stm32mp25-syscfg can have subnodes, which
> represent the USB 2.0 FEMTO-PHY. Turn the syscfg into "simple-mfd" so the
> PHYs would get populated by the OS.

Sashiko comment is partially valid - you change the ABI in incompatible
way, by requiring a new compatible. Commit msg should briefly explain
the impact, e.g. that there is no impact because phy was not
implemented by Linux and was not described in the binding.

OTOH, adding simple-mfd means children have no dependency on the parent,
so this should be considered or even explicitly mentioned in commit msg
(parent clock is irrelevant to child, right?)

OTOH2, you have now patchset dependency which is nowwhere explained.
Merging constraints are the most important part of cover letter so must
be clearly stated. IMO, should be stated also here, because many
maintainers do not read cover letters. Or just decouple dependencies
with using 'compatibles' pattern (see Qualcomm msm/mdss display
bindings).

Best regards,
Krzysztof

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