[{"id":3656491,"web_url":"http://patchwork.ozlabs.org/comment/3656491/","msgid":"<4be6f824-fa05-490b-8414-e08e654523ff@alliedtelesis.co.nz>","list_archive_url":null,"date":"2026-03-01T19:19:37","subject":"Re: [PATCH] i2c: rtl9300: add support for 50 kHz and 2.5 MHz bus\n speeds","submitter":{"id":27499,"url":"http://patchwork.ozlabs.org/api/people/27499/","name":"Chris Packham","email":"chris.packham@alliedtelesis.co.nz"},"content":"Hi Jan,\n\nOn 28/02/2026 00:11, Jan Kantert wrote:\n> Some SFP modules on certain switches (for example the ONTi ONT-S508CL-8S and\n> XikeStor SKS8300-8X) exhibit unreliable I2C communication at the currently\n> supported speeds. Add support for 50 kHz and 2.5 MHz I2C bus modes on the\n> RTL9300 to improve compatibility with these devices.\n>\n> Signed-off-by: Jan Kantert \n\nReviewed-by: Chris Packham \n\nThanks,\n\n> ---\n> drivers/i2c/busses/i2c-rtl9300.c | 16 ++++++++++++++--\n> 1 file changed, 14 insertions(+), 2 deletions(-)\n>\n> diff --git a/drivers/i2c/busses/i2c-rtl9300.c b/drivers/i2c/busses/i2c-rtl9300.c\n> index 672cb978066d..67a5c4228fc9 100644\n> --- a/drivers/i2c/busses/i2c-rtl9300.c\n> +++ b/drivers/i2c/busses/i2c-rtl9300.c\n> @@ -11,10 +11,16 @@\n> #include \n> \n> enum rtl9300_bus_freq {\n> -\tRTL9300_I2C_STD_FREQ,\n> -\tRTL9300_I2C_FAST_FREQ,\n> +\tRTL9300_I2C_STD_FREQ,\t\t\t// 100kHz\n> +\tRTL9300_I2C_FAST_FREQ,\t\t\t// 400kHz\n> +\tRTL9300_I2C_SUPER_FAST_FREQ,\t\t// 2.5MHz\n> +\tRTL9300_I2C_SLOW_FREQ,\t\t\t// 50kHz\n> };\n> \n> +#define RTL9300_I2C_MAX_SUPER_FAST_FREQ\t\t2500000\n> +#define RTL9300_I2C_MAX_SLOW_FREQ\t\t50000\n> +\n> +\n> struct rtl9300_i2c;\n> \n> struct rtl9300_i2c_chan {\n> @@ -433,6 +439,12 @@ static int rtl9300_i2c_probe(struct platform_device *pdev)\n> \t\tcase I2C_MAX_FAST_MODE_FREQ:\n> \t\t\tchan->bus_freq = RTL9300_I2C_FAST_FREQ;\n> \t\t\tbreak;\n> +\t\tcase RTL9300_I2C_MAX_SUPER_FAST_FREQ:\n> +\t\t\tchan->bus_freq = RTL9300_I2C_SUPER_FAST_FREQ;\n> +\t\t\tbreak;\n> +\t\tcase RTL9300_I2C_MAX_SLOW_FREQ:\n> +\t\t\tchan->bus_freq = RTL9300_I2C_SLOW_FREQ;\n> +\t\t\tbreak;\n> \t\tdefault:\n> \t\t\tdev_warn(i2c->dev, \"SDA%d clock-frequency %d not supported using default\\n\",\n> \t\t\t\t sda_num, clock_freq);","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-i2c@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=alliedtelesis.co.nz header.i=@alliedtelesis.co.nz\n header.a=rsa-sha256 header.s=mail181024 header.b=XPQKmITe;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c04:e001:36c::12fc:5321; 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Add support for 50 kHz and 2.5 MHz I2C bus modes on the\n> RTL9300 to improve compatibility with these devices.\n> \n> Signed-off-by: Jan Kantert \n\nmerged to i2c/i2c-host.\n\nThanks,\nAndi","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-i2c@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256\n header.s=k20201202 header.b=XU5G4DZV;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c15:e001:75::12fc:5321; helo=sin.lore.kernel.org;\n envelope-from=linux-i2c+bounces-16916-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)","smtp.subspace.kernel.org;\n\tdkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org\n header.b=\"XU5G4DZV\"","smtp.subspace.kernel.org;\n arc=none smtp.client-ip=10.30.226.201"],"Received":["from sin.lore.kernel.org (sin.lore.kernel.org\n [IPv6:2600:3c15:e001:75::12fc:5321])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fmJwm6Vgjz1yFv\n\tfor ; Thu, 02 Apr 2026 09:06:32 +1100 (AEDT)","from smtp.subspace.kernel.org (conduit.subspace.kernel.org\n [100.90.174.1])\n\tby sin.lore.kernel.org (Postfix) with ESMTP id 469DD3007293\n\tfor ; Wed, 1 Apr 2026 22:06:30 +0000 (UTC)","from localhost.localdomain (localhost.localdomain [127.0.0.1])\n\tby smtp.subspace.kernel.org (Postfix) with ESMTP id E0EAF317162;\n\tWed, 1 Apr 2026 22:06:28 +0000 (UTC)","from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org\n [10.30.226.201])\n\t(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby smtp.subspace.kernel.org (Postfix) with ESMTPS id 8A76830DEDC\n\tfor ; Wed, 1 Apr 2026 22:06:28 +0000 (UTC)","by smtp.kernel.org (Postfix) with ESMTPSA id 9E9CFC4CEF7;\n\tWed, 1 Apr 2026 22:06:27 +0000 (UTC)"],"ARC-Seal":"i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116;\n\tt=1775081188; cv=none;\n b=nUel12oi45qOl5YFHM6NhkJ157z3ikcjC1RWmUcCYyniw9kep0+kpDCfO84Zx9VetmnacHE5Vg8RWzHvEcJZ4YeF7zQTUyzILWN+RF/5f5BVaX8PerlJ0vSmjOAtnhipHYJHmtGn/DDTTLtiZdtxOv9YK8nKqx8wfsEO02nQ0pI=","ARC-Message-Signature":"i=1; a=rsa-sha256; d=subspace.kernel.org;\n\ts=arc-20240116; t=1775081188; c=relaxed/simple;\n\tbh=8vJKSGysDA+Db+T4KKo1vQ8Mi9ErglfPxx7WPr0AiQ8=;\n\th=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version:\n\t Content-Type:Content-Disposition:In-Reply-To;\n b=HQvSfw/Iu46olo7w6oAumLTRjstzlCL19+7xZA/F9iUy5i5hlmbLMQvuuArpkpAxtOWStmpAR8PdHU3EIzz79pbSjYXioMgzY0aY5xgxhPTX2Hi8jCkpjW97+/EFEJQi3Kx6tx1sJnwdPsFMJ/3v/4zYBihFfUFjgDR5fCkBl7E=","ARC-Authentication-Results":"i=1; smtp.subspace.kernel.org;\n dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org\n header.b=XU5G4DZV; arc=none smtp.client-ip=10.30.226.201","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org;\n\ts=k20201202; t=1775081188;\n\tbh=8vJKSGysDA+Db+T4KKo1vQ8Mi9ErglfPxx7WPr0AiQ8=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=XU5G4DZVbHJtG3eftyAkyT2nzohl/uX0nUWgirpVRO/HUOy7TNaZ3w2LHQnK6r2NB\n\t 172b9X6fxbdEBrfD8GO5IJn69MlwAOBkA5MsomxpBW+wzpAQK/hdWmduuNGVysVdC+\n\t Z8Gk8LZcaOqaqHnCEmLbbTy5HQNEUcIbqDKshPo8vze/IOVawFqF6HHkjjV8GhGuHX\n\t orUuM5Im636cnlSscnQmZAzsn3x0VAhAMouuLSeMvCi7V50AvT8/b7SMvzuOXgK0U+\n\t L/u8Yx2DtBAgZcQIEWWdnJEyVpgVENi5DJAKeacMrnOrbLEZR5tz12h+oN8+GYeV/e\n\t uKCO0BKp0ZbPw==","Date":"Thu, 2 Apr 2026 00:06:24 +0200","From":"Andi Shyti ","To":"Jan Kantert ","Cc":"chris.packham@alliedtelesis.co.nz, linux-i2c@vger.kernel.org","Subject":"Re: [PATCH] i2c: rtl9300: add support for 50 kHz and 2.5 MHz bus\n speeds","Message-ID":"","References":"<20260227111134.2163701-1-jan-kernel@kantert.net>","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":"<20260227111134.2163701-1-jan-kernel@kantert.net>"}}]