From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 10D80328B77; Mon, 27 Oct 2025 19:24:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761593088; cv=none; b=nchqTMsFJTqa3W8YKhe9p3YBqZw/U/XOGf0pnNJiKysTQTxAhT6JC/8ZxwFGtBRoPlFhez8DigdV2GQpc7kmwVgR57FmmkiVKxpErs18N2Oln8ZVPm+WKzcl7+y1wLKdzkQKIpMG4rSZln4EUAeQvrdeze7iw5YJGisoieOIXQA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761593088; c=relaxed/simple; bh=blBWTCT+SIFaa8+odPy1K2NT/1/JwxUEuNBKMUHBGBU=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=PbOWGdJPC4hOoE/jzOmtQ+6vsQD5qHMQcQkR0gOP+ZQ4uAbC0z6dyJ2zeKxGXlrOMIAqnEeCRNFNsXC6VJYlPZAxpPdWw5sDGBXrWdHxXAm9RbC2dzD6/54F9q16eMUY/ARf1Uyf15tZ77wv26o/RTLIMJY0CVlBiS1EOYd9nVg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iMp/sCcu; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="iMp/sCcu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9D133C4CEF1; Mon, 27 Oct 2025 19:24:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761593087; bh=blBWTCT+SIFaa8+odPy1K2NT/1/JwxUEuNBKMUHBGBU=; h=Date:Subject:To:References:From:In-Reply-To:From; b=iMp/sCcuj8WkwVMinkWWHH+1WE5wIOctkxm4WmKkGOpFB3tlL6dXbKLgjwApaqArE H/00yx5LviCcddxMag8atyGdVYKVM8VcWEWhgOgiaaZbqc59TqNWXtibCQ9CJJzVd2 feIQMAR10vkDBV3ppruablnt24+Set2AftOQwXDEWLy4rgVCbUNBjgHIMTf8AIkLlE yl1M4m9ZBgjeF6YxKl2yGqKFQnMXi13P7ipQnSVbC8zaAk/xsLiLL+RADk4SUEF88j shnLsfHydVzjrwO6xQJ9eVMpGrk072ybXcWmo90tJSLurE/uo95Fk2aVAFyl59DNkl wp2ymHAgNiEGA== Message-ID: Date: Mon, 27 Oct 2025 20:24:41 +0100 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v21 3/4] i2c: ast2600: Add controller driver for new register layout To: Ryan Chen , bmc-sw@aspeedtech.com, benh@kernel.crashing.org, joel@jms.id.au, andi.shyti@kernel.org, jk@codeconstruct.com.au, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, andrew@codeconstruct.com.au, p.zabel@pengutronix.de, andriy.shevchenko@linux.intel.com, naresh.solanki@9elements.com, linux-i2c@vger.kernel.org, openbmc@lists.ozlabs.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org References: <20251027061240.3427875-1-ryan_chen@aspeedtech.com> <20251027061240.3427875-4-ryan_chen@aspeedtech.com> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 27/10/2025 07:12, Ryan Chen wrote: > Add i2c-ast2600 new register mode driver to support AST2600 > i2c new register mode. This i2c-ast2600 new driver and the > legacy i2c-aspeed driver both match the same compatible string > "aspeed,ast2600-i2c-bus" because they target the same I2C > controller IP on AST2600. However, AST2600 SoCs may configure Where did you document ABI compatibility of new driver with old DTS, which do not have required properties and uses old reg? I don't see that. I actually clearly see: > + i2c_bus = devm_kzalloc(dev, sizeof(*i2c_bus), GFP_KERNEL); > + if (!i2c_bus) > + return -ENOMEM; > + > + i2c_bus->reg_base = devm_platform_ioremap_resource(pdev, 0); > + if (IS_ERR(i2c_bus->reg_base)) > + return PTR_ERR(i2c_bus->reg_base); > + > + rst = devm_reset_control_get_shared_deasserted(dev, NULL); > + if (IS_ERR(rst)) > + return dev_err_probe(dev, PTR_ERR(rst), "Missing reset ctrl\n"); > + > + i2c_bus->global_regs = > + syscon_regmap_lookup_by_phandle(dev_of_node(dev), "aspeed,global-regs"); > + if (IS_ERR(i2c_bus->global_regs)) > + return PTR_ERR(i2c_bus->global_regs); ABI break. No explanation of that ABI break, not even mentioning it. There is no reason to break the ABI. Your new driver *must* support both interfaces and both DTB. You *cannot* (please listen carefully, because in the past we wasted a lot of time discussing simple statements) rely on legacy driver binding to old DTB, because it is the same compatible. You need to rewrite all this to handle both DTBs in backwards compatible way. NAK Best regards, Krzysztof