From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9B3D1C77B73 for ; Mon, 22 May 2023 21:35:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: In-Reply-To:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Reply-To:Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date :Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=6hlnGDR+tMkmymnJ2w4yE8ZEx7SAsJqlEOreOQRKC0k=; b=hz3Q9FnEtZfkNEOKPePfQtCukf TDssodkoYckwOY374FQp5qywzUqhoRCArC6EqNdBH4SUgo0TSoHYY+f6GXwgL0JUtOn6gKE6Ohy7k BprOl8p8C/vz7Nz6T4mcA/xxFW0fCmUZwUhdQRN7UYvMOaBx+0Tg+X1sJivaaZe1Y82Gb4/mzwXOV PWtEmMWg13kXcLuOnkulqKQ8y0F5mStPCQ0V8+fWEZGzuTif3sYTKyxbYiB9y9T8dbWgo9A+/fGqO QcgOumZEpRZQJp9DxvaorIopBse5NwDVsOkCrdvoMTJ0IZ7C86jn/Di+RP1R5r7yAhPQ58MMY13xy Fqvg8gTQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1q1DAo-0086oC-22; Mon, 22 May 2023 21:34:34 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1q1DAm-0086n7-0g; Mon, 22 May 2023 21:34:33 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B9B61625BA; Mon, 22 May 2023 21:34:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2F292C433D2; Mon, 22 May 2023 21:34:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1684791271; bh=9IvHbwxWotRDGLurTj9kBGUNDEMevIUG0y7FUrF3eGo=; h=Date:From:To:List-Id:Cc:Subject:References:In-Reply-To:From; b=rLgjnFw894v6/OxfNpvLixauDGVx9TiVYw2+j2jHtrwSFQQVTeC5MN1BdyQKuwOYj x1r4GT9VdN34Fki1AkrDzQNfTUJtZwlBut1d0b8AtbZe7sntfwYH43qtowDeQllFhV SsrBdhxbdF9T7xnmO2LwwE2OXr6Tq3qk5LnWVXf5d8mZpzFuQ1FquXXuc/wvVo6Wu0 C6JTMz4uFg0dgjOCg9vbBfVGMquAt51X1y82DNKiRuL2FOMNyIsH91kqZ2Ni0OoSDU Qnzrwv4g4uWka5frZ9rdrdkVk6DVKrHu2KBtTiZjwWrMv7FncqwxtAkLOndCKQNYq8 W28l5oxFt0X4w== Date: Mon, 22 May 2023 22:34:25 +0100 From: Conor Dooley To: Krzysztof Kozlowski Cc: soc@kernel.org, Conor Dooley , Arnd Bergmann , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Jonathan Corbet , Olof Johansson , Palmer Dabbelt , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH v1] Documentation/process: add soc maintainer handbook Message-ID: <20230522-concrete-unpeeled-7e4718e61b46@spud> References: <20230515-geometry-olympics-b0556ff8a5f7@spud> MIME-Version: 1.0 In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230522_143432_325260_9F138FDF X-CRM114-Status: GOOD ( 23.60 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============8878306625223784461==" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org --===============8878306625223784461== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="d2KZAKHL08ilPcp3" Content-Disposition: inline --d2KZAKHL08ilPcp3 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, May 16, 2023 at 10:31:19AM +0200, Krzysztof Kozlowski wrote: > On 15/05/2023 21:20, Conor Dooley wrote: > > +devicetree ABI stability > > +~~~~~~~~~~~~~~~~~~~~~~~~ > > + > > +Perhaps one of the most important things to highlight is that dt-bindi= ngs > > +document the ABI between the devicetree and the kernel. Once dt-bindi= ngs have > > +been merged (and appear in a release of the kernel) they are set in st= one, and > > +any changes made must be compatible with existing devicetrees. This m= eans that, > > +when changing properties, a "new" kernel must still be able to handle = an old > > +devicetree. For many systems the devicetree is provided by firmware, = and > > +upgrading to a newer kernel cannot cause regressions. Ideally, the in= verse is > > +also true, and a new devicetree will also be compatible with an old ke= rnel, > > +although this is often not possible. >=20 > I would prefer to skip it and instead: enhance > Documentation/devicetree/bindings/ABI.rst and then reference it here. >=20 > > + > > +If changes are being made to a devicetree that are incompatible with o= ld > > +kernels, the devicetree patch should not be applied until the driver i= s, or an > > +appropriate time later. Most importantly, any incompatible changes sh= ould be > > +clearly pointed out in the patch description and pull request, along w= ith the > > +expected impact on existing users. I'm not really sure that I like this truncated section so much, but here it is... I kept the last paragraph intact as it does not talk about the ABI, but rather exceptions of submaintainers. devicetree ABI stability ~~~~~~~~~~~~~~~~~~~~~~~~ Perhaps one of the most important things to highlight is that dt-bindings document the ABI between the devicetree and the kernel. Please see :ref:`devicetree-abi` for devicetree ABI rules. If changes are being made to a devicetree that are incompatible with old kernels, the devicetree patch should not be applied until the driver is, or= an appropriate time later. Most importantly, any incompatible changes should = be clearly pointed out in the patch description and pull request, along with t= he expected impact on existing users. --d2KZAKHL08ilPcp3 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCZGvf4QAKCRB4tDGHoIJi 0tlRAP0Xv64GpLbhEZCmHfeE6R0ZjOht40u/pXgdh7zKn+HlQQD/cR99qreVnVJr ISgfexcq8exhTueLUoA4bLLbeWj+GwM= =DvjU -----END PGP SIGNATURE----- --d2KZAKHL08ilPcp3-- --===============8878306625223784461== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel --===============8878306625223784461==--