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Fri, 23 Oct 2026 04:52:53 -0700 (PDT) Received: from GLaDOS.station ([187.13.215.146]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4a21045df9dsm83319775e9.8.2026.10.23.04.52.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 23 Oct 2026 04:52:53 -0700 (PDT) From: Stefano Radaelli X-Google-Original-From: Stefano Radaelli To: devicetree@vger.kernel.org, imx@lists.linux.dev Cc: Stefano Radaelli , linux-arm-kernel@lists.infradead.org, Frank Li , Sascha Hauer , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Fabio Estevam , Pengutronix Kernel Team , pierluigi.p@variscite.com, Nate.D@variscite.com, Peng Fan , Shawn Guo Subject: [RFC] arm64: dts: freescale: Supporting Variscite SoM and carrier revisions Date: Fri, 23 Oct 2026 13:52:41 +0200 Message-ID: <20261023115242.11197-1-stefano.r@variscite.com> X-Mailer: git-send-email 2.47.3 X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hi all,=0D =0D At Variscite, we are starting to look at how best to maintain upstream=0D Linux support for multiple hardware revisions of our SoMs and carrier=0D boards. We would appreciate guidance before settling on an approach.=0D Our goal is to support new revisions while allowing customers to keep=0D using current kernels on older hardware.=0D =0D Our platforms are typically described by a SoM .dtsi and a carrier-board=0D .dts, for example imx8mm-var-som.dtsi and imx8mm-var-som-symphony.dts.=0D Both the SoM and the carrier can evolve independently. Some revisions=0D require changes to the hardware description, while others may work with=0D the same DT. Over time, this leaves us with several combinations to=0D support, without wanting to duplicate complete device trees for each one.=0D =0D What would be the recommended upstream approach to organizing and=0D maintaining these revisions and their supported combinations?=0D =0D One possibility we have considered is keeping the common SoM and carrier=0D descriptions in .dtsi files, with revision-specific .dtsi files extending=0D or overriding them, and small top-level .dts files selecting the required=0D combination. Would this be a suitable structure? Are there established=0D patterns or existing platforms we should follow, particularly to keep=0D changes for newer revisions from affecting older ones?=0D =0D We are also wondering how to handle revisions that can share the same=0D description. As a concrete example, we have discussed the following=0D possible grouping for DART-MX8M Mini and Sonata:=0D =0D imx8mm-var-dart-2.0-sonata-1.0.dtb=0D DART-MX8M Mini v2.0-v2.1 on Sonata v1.0-v1.3=0D =0D imx8mm-var-dart-2.2-sonata-1.4.dtb=0D DART-MX8M Mini v2.2 on Sonata v1.4=0D =0D These are proposed names, assuming that the same DT correctly describes=0D all the hardware combinations covered by each entry.=0D =0D Would it be acceptable to keep updating the first DTS to support a=0D compatible revision such as v2.1, retaining the v2.0 filename, as long as=0D it remains correct for all previously supported hardware? In this scheme,=0D we would add a separate DTS/DTB for v2.2 only if a different description=0D were needed.=0D =0D This is an initial idea rather than a settled design, so suggestions for=0D a different approach would be very welcome.=0D =0D Thanks,=0D Best Regards,=0D Stefano=0D