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[2001:14bb:ae:539c:1782:dd68:b0c1:c1a4]) by smtp.gmail.com with ESMTPSA id a10-20020a195f4a000000b0048a891e4d88sm1275440lfj.193.2022.08.15.23.01.14 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 15 Aug 2022 23:01:15 -0700 (PDT) Message-ID: <039566a7-5c65-b2d8-7b45-c616863cb292@linaro.org> Date: Tue, 16 Aug 2022 09:01:13 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.12.0 Subject: Re: [PATCH 0/6] i2c-imx-lpi2c: add IPG clock Content-Language: en-US To: Peng Fan , "Peng Fan (OSS)" , Aisheng Dong , "robh+dt@kernel.org" , "krzysztof.kozlowski+dt@linaro.org" , "shawnguo@kernel.org" , "s.hauer@pengutronix.de" Cc: "kernel@pengutronix.de" , "festevam@gmail.com" , dl-linux-imx , "linux-i2c@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Clark Wang References: <20220812043424.4078034-1-peng.fan@oss.nxp.com> From: Krzysztof Kozlowski In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 15/08/2022 03:52, Peng Fan wrote: > Hi Krzysztof, > >> Subject: Re: [PATCH 0/6] i2c-imx-lpi2c: add IPG clock >> >> On 12/08/2022 07:34, Peng Fan (OSS) wrote: >>> From: Peng Fan >>> >>> The i.MX LPI2C needs PER and IPG clock, not just PER or IPG clock. >>> This patch is to enable both PER and IPG clock for imx-i2c-lpi2c. >> >> This patchset breaks the ABI and is not bisectable. The justification is very >> limited (one sentence), so not really enough. > > ARM32 i.MX7ULP and ARM64 i.MX8QXP/i.MX8ULP all need to use two > clocks, PER and IPG. But current dt-bindings and dts, use one clock. > > This patchset includes dts changes patch 4 and patch 5. > Patch 6 is to update driver use two clocks. > > I think the patch order in this patchset would not break git bisect, it > just break ABI. But I not find good way how could not break ABI, > because only use one clock is wrong whether in dt-bindings or dtbs. Driver changes always go via separate branch than DTS, so your patch breaks git bisect. I already pointed it out in other patch. This is not really acceptable. Breaking ABI is another problem which could be justified with your explanation in other cases... but not in this one, since it is easy to make it backwards compatible, > Should I use a fixes tag to dt-bindings, then break ABI is allowed? No. For such patch ABI break is also not allowed in that case. Just make the driver backwards compatible and both problems - non bisectability and ABI break - go away. Best regards, Krzysztof