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 DFD7442C0B; Fri, 1 Nov 2024 09:47:46 +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=1730454467; cv=none; b=PWAkbv1u4P155GGKIohx72BfqoNeaGAcRJM8EBMueTRN/sn30PjVfJADdTTATNXkk3+O0t6RZRNdbpJib9cGxbeq80dD6wIMtSNDj5vsyvGeEZhIrIfptwcepARP9ora4yNqe3p7jV1pvhBKhSIGjnC69+ch0sHmNK9qWZEq7V8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730454467; c=relaxed/simple; bh=upm8WGdKhPggtEfpo7lQDsOK8xctqolSF2bsVJdhbhA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=fXG5ZCPmlNm2uJYVObd9zg4NqVWh+ADbCtqrKp+vY0wJb13qcUu4ITppHE/oOffSXwHSpDcVyxFGh7bUIVbkuvYa8weMtyhq2c1QDoESPNB/XocYCKk2QkYRlmqnGnxlUwE3QAlCG7O+3UESGLN6qAFHw4pW8APWQKNlhOw4cJg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KFu7XpOg; 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="KFu7XpOg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CF1A1C4CECD; Fri, 1 Nov 2024 09:47:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730454466; bh=upm8WGdKhPggtEfpo7lQDsOK8xctqolSF2bsVJdhbhA=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=KFu7XpOgTT+UYr/2hNWNxM8dEMGLVvXekSBH0vKDsa004yigZZJTzlKW5HhyFsVhK d8Xz5B5nYH4OtLTRsR3aDiCafo7kfvR2O1S6X9CxUMZrrNyIfxaUbVWmLSGAuJ36kt tW+gfIgT+FSkNJpIb9QaEiREYM2uIC6b9kUDUDm14nHOoDXOvfm2o7hcmR8Ms9PBeJ m9PFIHfVxLRWlCOCc/gfaDqH9wl8rE+Li/kL1HXR6VU47fxIeE7HeaxNGPNKMfpEpc cxddrE5s1HZfCBitcMoo0Mt3aF/0HQpMgrn50z4qR8kdFolT3SmM9cpSOZpRCygZkQ 3JMVNOzwi+USg== Message-ID: <364f2afb-fdaa-42b9-8921-70dbdc3f7085@kernel.org> Date: Fri, 1 Nov 2024 10:47:38 +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 v6 2/5] dt-bindings: media: camss: Add qcom,sdm670-camss To: Vladimir Zapolskiy , Rob Herring Cc: Bryan O'Donoghue , Richard Acayan , Bjorn Andersson , Michael Turquette , Stephen Boyd , Krzysztof Kozlowski , Conor Dooley , Robert Foss , Todor Tomov , Mauro Carvalho Chehab , Konrad Dybcio , linux-arm-msm@vger.kernel.org, linux-clk@vger.kernel.org, devicetree@vger.kernel.org, linux-media@vger.kernel.org References: <20241011023724.614584-7-mailingradian@gmail.com> <20241011023724.614584-9-mailingradian@gmail.com> <785c82d5-549d-454b-86bf-a00a39e6f521@linaro.org> <20241011144129.GA2295617-robh@kernel.org> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit On 30/10/2024 23:13, Vladimir Zapolskiy wrote: > On 10/30/24 23:06, Rob Herring wrote: >> On Wed, Oct 30, 2024 at 9:20 AM Vladimir Zapolskiy >> wrote: >>> >>> Hi Rob. >>> >>> On 10/11/24 17:41, Rob Herring wrote: >>>> On Fri, Oct 11, 2024 at 09:31:06AM +0100, Bryan O'Donoghue wrote: >>>>> On 11/10/2024 08:14, Vladimir Zapolskiy wrote: >>>>>> >>>>>> Two most recently added CAMSS IP descriptions (qcom,sm8250-camss.yaml and >>>>>> qcom,sc8280xp-camss.yaml) do implement sorting by reg values, I believe >>>>>> from now on >>>>>> it should be assumed that all subsequently added CAMSS IP descriptions >>>>>> to follow >>>>>> the same established policy. >>>>> >>>>> My preference is sort by address not sort by name => we sort the device >>>>> nodes themselves by address so it seems more consistent to sort by address >>>>> inside of the devices too. >>>> >>>> Strictly speaking, the values of addresses are unknown to the binding, >>>> so you can't sort by address. However, if something is truly a single >>>> block, then the offsets are probably fixed in order by offset makes >>>> sense. But when a block is changed, any rule on sorting may go out >>>> the window since we add new regions on the end. >>> >>> Exactly, and this is an argument why the sorting is a subject to a device >>> driver policy, kind of any sorting order is equally bad. Sorting 'reg' >>> values by addresses helps to avoid a notorious problem with unit addresses. >> >> What notorious problem? >> > > Here the problem I reference to is the problem of an incorrespondence between > device tree node unit address and the address of the first value of 'reg' > values. Sorting by unit address does not solve it. Sorting by anything else does not cause it. You repeat this statement multiple times already. Sorry, it's not true. You can sort by address and still put wrong unit address. Tools address it already, not sorting. > > Having a sorting by addresses allows to grasp IO ranges easily, and setting > device tree node unit addresses to some almost arbitrary chosen value from > the middle of IP's IO range is suspicious and confusing in my opinion. It's not arbitrary. It's the main, control address space often. At least it should be. Your sorting rule enforces putting irrelevant address as unit address, imagine: isp@1000 { reg = <0x1000 0x4>, <0x2000, 0x1000>; reg-names = "reset-control-block-one-unimportant-register", "main-control-block-with-99%-of-registers"; Sorry, this is just wrong coding style. Best regards, Krzysztof