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([2a02:810d:15c0:828:a40b:9d8:1fa0:ecc5]) by smtp.gmail.com with ESMTPSA id h13-20020a170906718d00b0095386574c81sm17032945ejk.51.2023.05.03.00.40.24 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 03 May 2023 00:40:25 -0700 (PDT) Message-ID: <89276de5-ded8-2f38-bcea-708fdd35ca6d@linaro.org> Date: Wed, 3 May 2023 09:40:23 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.1 Subject: Re: [PATCH] ARM: zynq: dts: Setting default i2c clock frequency to 400kHz To: Michal Simek , linux-kernel@vger.kernel.org, monstr@monstr.eu, michal.simek@xilinx.com, git@xilinx.com Cc: Varalaxmi Bingi , Krzysztof Kozlowski , Rob Herring , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org References: <4dde5d1eb8e4572dae4295a19a4c83002a58e5da.1683035611.git.michal.simek@amd.com> <958f4336-8c38-4cc1-4313-06a54e397d42@amd.com> Content-Language: en-US From: Krzysztof Kozlowski In-Reply-To: <958f4336-8c38-4cc1-4313-06a54e397d42@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/05/2023 09:27, Michal Simek wrote: > > > On 5/2/23 22:13, Krzysztof Kozlowski wrote: >> CAUTION: This message has originated from an External Source. Please use proper judgment and caution when opening attachments, clicking links, or responding to this email. >> >> >> On 02/05/2023 15:53, Michal Simek wrote: >>> From: Varalaxmi Bingi >>> >>> Setting default i2c clock frequency for Zynq to maximum rate of 400kHz. >>> Current default value is 100kHz. >>> >>> Signed-off-by: Varalaxmi Bingi >>> Signed-off-by: Michal Simek >>> --- >>> >>> arch/arm/boot/dts/zynq-7000.dtsi | 2 ++ >>> 1 file changed, 2 insertions(+) >>> >>> diff --git a/arch/arm/boot/dts/zynq-7000.dtsi b/arch/arm/boot/dts/zynq-7000.dtsi >>> index cd9931f6bcbd..a7db3f3009f2 100644 >>> --- a/arch/arm/boot/dts/zynq-7000.dtsi >>> +++ b/arch/arm/boot/dts/zynq-7000.dtsi >>> @@ -149,6 +149,7 @@ i2c0: i2c@e0004000 { >>> clocks = <&clkc 38>; >>> interrupt-parent = <&intc>; >>> interrupts = <0 25 4>; >>> + clock-frequency = <400000>; >> >> I think this should be rather property of the board, because it depends >> on I2C devices, right? > > We have 15+ boards with i2c connected and from this count I am aware about only > one configuration which is not working on 400k. > It is a question if make sense to update all boards (except for 1 and not all in > kernel yet) to 400k or just say 400k is default and if there is any issue use > lower frequency. > Obviously this patch is setting up 400k as default and let "problematic" boards > to setup lower freq. > The same approach was used for modepin description. > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/arch/arm64/boot/dts/xilinx/zynqmp.dtsi?h=v6.3&id=53ba1b2bdaf7f481fdd878e9c18cd0e54081fac9 > > The next point is that 100k is default in Linux but doesn't mean it is default > in other projects. > > But if you think that it must be board property I think we should setup 100k as > default in this file too to make it clear. No, if it is conscious choice, it's fine. Best regards, Krzysztof