From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.zeus03.de (zeus03.de [194.117.254.33]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 93409280A49 for ; Thu, 10 Apr 2025 10:16:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=194.117.254.33 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744280164; cv=none; b=alKpsTfH7mO/yowymI4KveMfGFSRAZwtqd72zLOqarvkH7TUX7JwpwnueajixYe70MMQA2efH5ljQnQDrFhyOANNYOgIpWzNerD85vlF92zXdas/jmtjvqPbQ8hWLmGtPRFfY5mapjlMHTFQW1P/gxAJczset+TLufE+2sbUfz4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744280164; c=relaxed/simple; bh=UOP7nn5Bvkb1xuqmR+wH5tW8BtJBPXYRK7Rb4gkU9YE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=hH4gkn4rJDLdIIgNI2oxSpxIJJPERvKCanKbsXd2PzgGhoocONUN4QjsyZ0RlHZtTT3qYQsmWTiIe9r5T6oSwtSb1R3l4G2CwSDki5YL0PO6Oe+sVEdE7s8rybbU/RdhV0CT8iRSelo9+s7JUuahHzeukzZoyD/xBYIgJM8zdqw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sang-engineering.com; spf=pass smtp.mailfrom=sang-engineering.com; dkim=pass (2048-bit key) header.d=sang-engineering.com header.i=@sang-engineering.com header.b=il0MjVZf; arc=none smtp.client-ip=194.117.254.33 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sang-engineering.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sang-engineering.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=sang-engineering.com header.i=@sang-engineering.com header.b="il0MjVZf" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= sang-engineering.com; h=date:from:to:cc:subject:message-id :references:mime-version:content-type:in-reply-to; s=k1; bh=UOP7 nn5Bvkb1xuqmR+wH5tW8BtJBPXYRK7Rb4gkU9YE=; b=il0MjVZfBDRZbpGI8xmH BLL6mvPDRca1jjXnjKe76ofx09QOM9s1sauM0Hnqz7Zn2EmyeRGR6m8cn0o+4DK/ nbkppE5VuGfgw4x9BZ2QaMjTXMLIbah1fnQ8B9cTw3OHBYvKDjit055EzBC2itER N7udd6VSPrAwJ3s4tjKY5zdJxBFxYdahcn7fAZRlbc9U3Zzp0CdUWFBsp9ePBEEc wxZNm4VHddXYvdKYhGKhp34xjjaoJjlraoTlOkfvzJF1r14KDjWRIzKeGw8ABTNQ 3Y7CxQzYNkYDhqc/G2bR16VdHJCghmSCBWPCxJtpPwPHcjJzLSjtjps3BNAK38P8 Jw== Received: (qmail 850729 invoked from network); 10 Apr 2025 12:15:58 +0200 Received: by mail.zeus03.de with UTF8SMTPSA (TLS_AES_256_GCM_SHA384 encrypted, authenticated); 10 Apr 2025 12:15:58 +0200 X-UD-Smtp-Session: l3s3148p1@p1M932kyNLAgAwDPXyfYALbiJ46yNPq3 Date: Thu, 10 Apr 2025 12:15:58 +0200 From: Wolfram Sang To: Vladimir Kondratiev Cc: "linux-i2c@vger.kernel.org" Subject: Re: [RFC] Handle targets with different speed by the same I2C master Message-ID: Mail-Followup-To: Wolfram Sang , Vladimir Kondratiev , "linux-i2c@vger.kernel.org" References: Precedence: bulk X-Mailing-List: linux-i2c@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="dXTP4yqwJYawQ6JB" Content-Disposition: inline In-Reply-To: --dXTP4yqwJYawQ6JB Content-Type: text/plain; charset=us-ascii Content-Disposition: inline > In my case it is bus powered by 1.8V VCC with lots of FM+ targets and this EEPROM: > https://www.onsemi.com/download/data-sheet/pdf/nv24m01muw-d.pdf > This EEPROM supports 1MHz at VCC >= 2.5v and 400 KHz at VCC >= 1.8v. > Our experiments confirm it can stay silent when bus is clocked at 1MHz Okay, I get the picture, thanks. Still, this is a corner case which is furthermore based only on experiments, not on specifications. This is way too vague to have this added to a generic OS. For most people, it won't work. And this will add some complexity to the code base which I don't want to maintain. Because the underlying principle is unreliable itself. Sorry that the HW design is flawed on your device. If you can still influence the process, you could get the EERPOM replaced. If you still want your software solution in your device (I don't recommend it), you have to carry it out-of-tree, I am afraid. --dXTP4yqwJYawQ6JB Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEOZGx6rniZ1Gk92RdFA3kzBSgKbYFAmf3mloACgkQFA3kzBSg KbbPgQ/+KgY7bsVzVn6ITbexfc3V8WMrPcwc4jDKRv6d1LrszFSFvfubEXsSnvFL m7TqVSJyYtaFsncF2WLZIov57bFdugbC7QnUmOInS19vdEqhUhPdvnHDs+r1fKtY CawQ8v0bZORao/EOqaMmnSyva6ejqzl39BNcPqA5jFtOcK0klYwROiWjI1s5G1Re IyqFJXnR/zKuRhESG8BJyf9pjhhxEXi60Y2njOkrn+0s2R/2M2oP/NFPhD614Gft glFi5ZMFESg2biZizrKlhV83+5mSTN2U6b7wX1xE0n47g/f2j8CVAlOtOi94FXau wImM6R0iXhvBLzcmex1Zc+gC+0tcgQULflbU8jKxA2bEjgwFN8lZSlqZE1poNF0q KPTSEkCenz4KNof/ob92Z1SzwxeWycbdkugFg57+0JYbgdX22KdhBIyTjfuPVBAI iPflYJp2Wobzhe9UHZf5+b0osfSlssk4UyfQc+7czNp7GKwDhO8Hp3zh59+9cD+0 L7f9tCUJ5MD/rqnuZ+bfKT1ZqwoNzTXnm3DIlh9v1MyJToZnp6l13Wx4J0c8UcGb DNUZRYCXZ82BTuHEecYA35d0RRT+xD6OcrQJEuKqEjS0AMrIBkN1nA4XD6Ht87dU dBR4Fn/FC8aAXion1DDl141VuaESi4JVOMOAXMYDqZVlEEkopZw= =6VBN -----END PGP SIGNATURE----- --dXTP4yqwJYawQ6JB--