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 C353E1386DA; Tue, 11 Mar 2025 07:55:05 +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=1741679705; cv=none; b=sXqD5dwB988qKq/cGx1gLOqqEc/ur+YkHpN6+EgCo6TbpPLyKAWxlI/3wL5S+oo54aI/GaxmdtzDdPLRKvglBO2kzYqX8ISRdfVI/kInnOLupO7Qs15oHuDyiJyZPftinlTWQHLCuXifTCeorEUqg06CKEQeBHdB5UONdOBIcdw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741679705; c=relaxed/simple; bh=VUW7JbS09K3eHvnTUq5EVfSChPS6oMO+mH9yFSbdepM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=iTLuuq43PoaRl83ZrdMAwXkqtlUElnOCmpOxRdqt3HimEZRQXlZlHv5qbluVcixOLc6KKH85nEpIgMSo59NNbfXeAQUgW0KG/BFOSzxGEX0ramkstFlf89LIrjZOvOAkEO8vGlhxfMJT6nUqUMuh8nw5WooifYuVKhONr4o5mXI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Wx5Q8A9D; 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="Wx5Q8A9D" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 989A6C4CEE9; Tue, 11 Mar 2025 07:54:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741679705; bh=VUW7JbS09K3eHvnTUq5EVfSChPS6oMO+mH9yFSbdepM=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Wx5Q8A9DQaH3NN0kUB4+ZcFK4gFdfG0u+FX0hWXIr+HuxZx42aMFO8JZsZ3QRm3Uj ImmFlilYR7CjZW1qucYXZoVMyzLLSyPOcRkFN30gfn5XFDXP0B0bBihCTpsCucB0q3 leuzDdMyJVl7lRYH22GlFVKlpjz1BoXn2jneTMsT0Z//rTEz1M2NbeqvjaupmNGbly QBI/mUBhAB4cdKe7kwuuuwerkwRnALNEX2wRIM3vpa11W0YEq1TYHZ0KMg072M3ARW nJQN51eOTqKiKsIHumGChc/YF5Uvy1tm8fAHpK/lv5KyWiw7vodZU3d69u8iC3XrSw mURkGg3j8eAdQ== Message-ID: <01a7918b-dc4b-4ed3-8f74-bc59a9629ce9@kernel.org> Date: Tue, 11 Mar 2025 08:54:55 +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 v11 3/7] dt-bindings: PCI: qcom: Use sdx55 reg description for ipq9574 To: Varadarajan Narayanan , Krzysztof Kozlowski Cc: bhelgaas@google.com, lpieralisi@kernel.org, kw@linux.com, manivannan.sadhasivam@linaro.org, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, vkoul@kernel.org, kishon@kernel.org, andersson@kernel.org, konradybcio@kernel.org, p.zabel@pengutronix.de, quic_nsekar@quicinc.com, dmitry.baryshkov@linaro.org, linux-arm-msm@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-phy@lists.infradead.org References: <20250220094251.230936-1-quic_varada@quicinc.com> <20250220094251.230936-4-quic_varada@quicinc.com> <41b400fe-5e08-42c0-9bc6-a238d25d155a@kernel.org> <33bb1cb2-0c5e-402b-a5c6-9604b1dd8d99@kernel.org> <84456c70-e933-469f-ac7a-7d899f85e777@linaro.org> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 11/03/2025 06:01, Varadarajan Narayanan wrote: > On Mon, Mar 10, 2025 at 12:37:28PM +0100, Krzysztof Kozlowski wrote: >> On 10/03/2025 08:44, Varadarajan Narayanan wrote: >>> On Thu, Mar 06, 2025 at 01:06:13PM +0100, Krzysztof Kozlowski wrote: >>>> On 06/03/2025 12:52, Krzysztof Kozlowski wrote: >>>>> On 20/02/2025 10:42, Varadarajan Narayanan wrote: >>>>>> All DT entries except "reg" is similar between ipq5332 and ipq9574. ipq9574 >>>>>> has 5 registers while ipq5332 has 6. MHI is the additional (i.e. sixth >>>>>> entry). Since this matches with the sdx55's "reg" definition which allows >>>>>> for 5 or 6 registers, combine ipq9574 with sdx55. >>>>>> >>>>>> This change is to prepare ipq9574 to be used as ipq5332's fallback >>>>>> compatible. >>>>>> >>>>>> Acked-by: Manivannan Sadhasivam >>>>>> Reviewed-by: Krzysztof Kozlowski >>>>> >>>>> Unreviewed. >>>>> >>>>>> Signed-off-by: Varadarajan Narayanan >>>>>> --- >>>>>> v8: Add 'Reviewed-by: Krzysztof Kozlowski' >>>>>> --- >>>>>> Documentation/devicetree/bindings/pci/qcom,pcie.yaml | 2 +- >>>>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>>>> >>>>>> diff --git a/Documentation/devicetree/bindings/pci/qcom,pcie.yaml b/Documentation/devicetree/bindings/pci/qcom,pcie.yaml >>>>>> index 7235d6554cfb..4b4927178abc 100644 >>>>>> --- a/Documentation/devicetree/bindings/pci/qcom,pcie.yaml >>>>>> +++ b/Documentation/devicetree/bindings/pci/qcom,pcie.yaml >>>>>> @@ -169,7 +169,6 @@ allOf: >>>>>> enum: >>>>>> - qcom,pcie-ipq6018 >>>>>> - qcom,pcie-ipq8074-gen3 >>>>>> - - qcom,pcie-ipq9574 >>>>> >>>>> Why you did not explain that you are going to affect users of DTS? >>>>> >>>>> NAK >>> >>> Sorry for not explicitly calling this out. I thought that would be seen from the >>> following DTS related patches. >>> >>>> I did not connect the dots, but I pointed out that you break users and >>>> your DTS is wrong: >>>> https://lore.kernel.org/all/f7551daa-cce5-47b3-873f-21b9c5026ed2@kernel.org/ >>>> >>>> so you should come back with questions to clarify what to do, not keep >>>> pushing this incorrect patchset. >>>> >>>> My bad, I should really have zero trust. >>> >>> It looks like it is not possible to have ipq9574 as fallback (for ipq5332) >>> without making changes to ipq9574 since the "reg" constraint is different >>> between the two. And this in turn would break the ABI w.r.t. ipq9574. >> >> I don't get why this is not possible. You have one list for ipq9574 and >> existing compatible devices, and you add second list for new device. >> >> ... or you just keep existing order. Why you need to keep changing order >> every time you add new device? > > Presently, sdx55 and ipq9574 have the following reg/reg-names constraints. > > compatible | qcom,pcie-sdx55 | qcom,pcie-ipq9574 > ----------------+-----------------------+------------------ > reg minItems| 5 | 5 > maxItems| 6 | 5 > ----------------+-----------------------+------------------ > reg-names | | > minItems| 5 | 5 > ----------------+-----------------------+------------------ > maxItems| | 5 (6 for ipq5332) > ----------------+-----------------------+------------------ > items | | > | parf | dbi > | dbi | elbi > | elbi | atu > | atu | parf > | config | config > | mhi | (add mhi for ipq5332) > ----------------+-----------------------+------------------ > > To make ipq9574 as fallback for ipq5332, have to add "mhi" to reg-names of > ipq9574. only ipq5332 gets additional item, not ipq9574. Your sentence is not correct. You do not have to add mhi to ipq9574. Neither we, nor schema asked you to do this. > Once I add that, the sdx55 and ipq9574 is the same list but in > different order. > You cannot change the order in existing devices. > If this would not be considered as duplication of the same constraint, then I > can club ipq5332 with ipq9574. > > If this would be considered as duplication, then sdx55 and ipq9574 would have to > use the same reg-names list and sdx55 or ipq9574 reg-names order would change. > >>> To overcome this, two approaches seem to be availabe >>> >>> 1. Document that ipq9574 is impacted and rework these patches to >>> minimize the impact as much as possible >> >> What impact? What is the reason to impact ipq9574? What is the actual issue? > > By impact, I meant the change in the reg-names order as mentioned above (for > considered as duplication). Then you must eliminate the impact, not minimize it. > >>> (or) >>> >>> 2. Handle ipq5332 as a separate compatible (without fallback) and reuse >>> the constraints of sdx55 for "reg" and ipq9574 for the others (like >>> clock etc.). This approach will also have to revert [1], as it >>> assumes ipq9574 as fallback. >>> >>> Please advice which of the above would be appropriate. If there is a better 3rd >>> alternative please let me know, will align with that approach. >> >> Keep existing order. Why every time we see new device, it comes up with >> a different order? > > Will be able to do that based on the answer to 'duplication' question and how to > handle that. I don't understand what is duplication of something here. > > if (adding mhi to ipq9574 reg-names != duplication) > > /* Keep existing order */ > > * Append "mhi" to ipq9574 ipq9574 does not have mhi, does it? If it has, it should be separate patch with its own explanation of the hardware. Best regards, Krzysztof