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Mon, 29 Dec 2025 09:20:08 +0800 (CST) X-QQ-SSF: 0000000000000000000000000000000 X-QQ-GoodBg: 0 X-BIZMAIL-ID: 16357926230597589350 EX-QQ-RecipientCnt: 13 Date: Mon, 29 Dec 2025 09:20:08 +0800 From: Troy Mitchell To: Alex Elder , Troy Mitchell , Lee Jones , Yixun Lan , Andi Shyti , Alexandre Belloni , Liam Girdwood , Mark Brown Cc: linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, spacemit@lists.linux.dev, linux-i2c@vger.kernel.org, linux-rtc@vger.kernel.org Subject: Re: [PATCH v3 1/4] i2c: spacemit: configure ILCR for accurate SCL frequency Message-ID: <20BB6D852C5C87DF+aVHXSI7Mn5GH-xBF@kernel.org> References: <20251118-p1-kconfig-fix-v3-0-8839c5ac5db3@linux.spacemit.com> <20251118-p1-kconfig-fix-v3-1-8839c5ac5db3@linux.spacemit.com> <81eca0ab-47a3-4b12-98ae-fbd46a15ff93@riscstar.com> <569E6DA87DE510D5+aU4-1Jl9XxjAWQq4@kernel.org> <4a76e9bf-926e-4b77-a2f8-ee4a72b2f1dd@riscstar.com> Precedence: bulk X-Mailing-List: linux-rtc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4a76e9bf-926e-4b77-a2f8-ee4a72b2f1dd@riscstar.com> X-QQ-SENDSIZE: 520 Feedback-ID: zesmtpgz:linux.spacemit.com:qybglogicsvrgz:qybglogicsvrgz3a-0 X-QQ-XMAILINFO: N7bzzhFwp0G2YD0j7RqdQnXHoyelMSBDh7H4v6fW+L47kj88oHfddz18 o1pGWMWIYEKcKr37sf5T4RBcLFnvYr1vj/Ih04pWKTX0T2LwUf7Luiv7f/ixv5tm1bVFblw gNADGebUTHrsHJdKowJNs+ZI7mT6BrTqs+eKt4tFf9NA9GYyLYCEf+cXmAS2nGZM8KvP3Uf Y5/fgplLZ9z+R1kaRyQtHVoFPxMT5+eB9A4C7jiqJf/Jxo2RTiFV8K11dUjP4V/gcnsVX1A e1/QzfUzFoXzm84uWAiNxoXjUFB35PZILUm2f0rwpbjcy1Qf/SKHnKSsxaTvABiD32XMb1F HlGMitW0T/zv5jeEHjl0vq2xFYmpVnT0TOgvaTcD9WkVvNSZzzrLk5ifAomS7Iv2mMvfcdp pEApkrb2fwB/FWATeB6x4exiMNAMjeuk+/VEDlExuO8DNN/a6SNX1g/hX9w/c3xPT+pUJdC HHnlWCKmLtxyDqAxjocx7qD1Lu64IUmCv0clxryphaVPsntZA37Is0H9Nx1fRaD95zFuTUB wOhHbjub9/F2DLEvtMFdkWCU+M1PIOvoY878tGtnaMtMSp1VaHUeKkn/BRM/NQJkacKDEYW 27nZBVCC/2E9h2fNZOBFWxJ5xigX+AlRb8SZeOt5zabVs6p1R+a5+q1giFLaus238asNx9J pt3j0LaNTzKKaa0+fKZDf0MwocYqvCRfp54w9uBo7Zths9uXGUcRFR06tYKpqpN2d9Zi28v aenDm1RqRx60gEyM7873Yk/abqGumfGeqvLoR4lGmw+ZFzGnbCe/L7Y6emQK+AFUOMAlAWa N8Sdf/hEQHq5HsK6Mw184QCwv9elu24erOiYudHJyInY/rug2vqDBHoYrJ5rBLFX2hmASD2 d91cQgUQHZyi6WrDjDSquhMyTHeG2H5YlGMaEVJTe3sCXCmCflf+TzNF4W3DckSCi2IFfcW 8CAIH3WkjMUIxIStIwPAqV3oJH2gox924fqoXzmgix3hpb/E31p4q2SkOZmdnA+GCtyKUMy igESOeeGXZFqRHjhWut3uh+F78S9eMW95ewmtfLzP6IZyqOgEo X-QQ-XMRINFO: M/715EihBoGS47X28/vv4NpnfpeBLnr4Qg== X-QQ-RECHKSPAM: 0 On Sun, Dec 28, 2025 at 06:58:00PM -0600, Alex Elder wrote: > On 12/26/25 1:52 AM, Troy Mitchell wrote: > > > > > +static int spacemit_i2c_clk_set_rate(struct clk_hw *hw, unsigned long rate, > > > > > + unsigned long parent_rate) > > > > > +{ > > > > > + struct spacemit_i2c_dev *i2c = container_of(hw, struct spacemit_i2c_dev, scl_clk_hw); > > > > > + u32 lv, lcr, mask, shift, max_lv; > > > > > + > > > > > + lv = DIV_ROUND_UP(parent_rate, rate); > > > > > > > > Would DIV_ROUND_CLOSEST() give a more accurate value? > > > I'll test it. > > Same result. So I'll keep it. > > Is that true for all clock rates? I only test 400k. > Anyway, it's not > a huge deal, but especially when the number of rates > isn't very high this can make a difference. I'll test more. Thanks! - Troy