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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-i2c@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: OXvkGtaK08fGzVyBcvDPqJcIA53HT9A+ZpqG1btxeAnhOYGYpEPMnSfv DGcIhq5g6sZKK3vJAWTtne04ZOQZf0wbR/mNi4KJDfbl2N/KScZjlkpO986CQ5ZXGFPXIh2 ioZ31RNhXYNUrliC1i49dquCM/I+1VmEy5OvhaKnzZ9YuMW69lowfvbHm421qbdZz77yJ9Z 2c0xL1hKMdqFeAilR6kG6v1gDcsAW6r8mEa0zjetDJJTj7Vsn/q1GTeDkh4HNcVFGuZZGfx 1z/g0hyvAfMSd0AlKytiaZ/gCFsSQ2RMYKpl2St2K4267pvYcdpCHShDj81scxHacKQ1UdX LdZEjdxVYnxzbHE1jAR3rp48orvIBnkeXQLtpkJER/JcJ7Hn12I+I9ka+5cb/5BfxIvoqut 3BNB+DSfmrDKBarbE7cOtJ/A/13vzeYXawFnV2YIk61JQdGr+yJKcDMxD8XMC5ydutzL4JK kJnyc4xThYficgFm21pjvX0K9G6C7YfCsx5fm47mXiVUlMPtgZZZc6Aa1XKxY2mtQmffrJK re4yQsZkhJ2bt7mvtBPBZ1NH2k4G8+5C4jxYRt7eYaUtWvy7RLc+9a6fVS7LcUGnOpnOlhB 2Uf0zTNCU9jTdkjAlp/kwJJhzol7zikVaPstUAGni4Fd/xWAz4jVd8BEKMHEj79ZqIVf+TM nSJsE0kqRK0TLN6jAUJ3ZHLGGTAC8HjhCf1zUhuoAPrCcDAh5WB/fivyEdLTWsU1ijvCAKM 4V1lEzatn7S7NZNFizdcUQl0gM7w6GzhCJpYqo1xLcxZtOYoE6VJVxcgmrv42uIAL7+RuOP i5sxzZd49LDtE3DzkE3UGbLatJWn8aelU6qFOVUMMciafueaMlUIlJHNQX/k8EBtLr5CC3l xJnYAUAekK4F/JUI9miS35uFQMXXA5EzdozhP5RA2qUVedvSzrMT8VIFY332p5HGIVE/K72 Qac2whpmTxtzBrAv+7eTPtz9gN+E+FoYKBHKzGzjheDFhCmZsEbFtnjdy/r0mIUQ7nuWVWz +fzla//JJ8r3Awr2Re3NMWV7UpHjrxrk0G1bjTm9pzFx9n/uYW X-QQ-XMRINFO: NS+P29fieYNwqS3WCnRCOn9D1NpZuCnCRA== 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