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 90A4F22257E for ; Tue, 8 Apr 2025 11:53:21 +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=1744113210; cv=none; b=LSH8VH5A0rzeShEwMQMkotu7H5xZ0UuARnwMeUmp21PvtINy2E0AsT94RRW3FFPevlqXBx936B+FnDQj6l746Im5QY2KG3exeL7CLQxW5DF57mUIXnT1Zmgt+wOrvRYnYaRnDo+l28RSOcSpnvI/6xqFqFRDoow7jdiGbVOh14M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744113210; c=relaxed/simple; bh=Dxq2GkqloFK2OJHr/1+VdKJQbRBQvGcH9zXZstwKy78=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=dWGgKTao5120daqeiblFmSkauQmf1OVKWEe8PwNYlNuLR6rwGksNFSa8msEmiHCOKE4x6YN7sT+J+LNld4dPMjvTcHHNbWlVFlN3wUAb5bR0DES7gm0xgKU6wOuktxLwE4OeOOX4ZcJ4dAvo2kvbKkOxlmB/GD1t/vJjsMc/M+g= 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=ZYcRaR78; 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="ZYcRaR78" 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=Dxq2 GkqloFK2OJHr/1+VdKJQbRBQvGcH9zXZstwKy78=; b=ZYcRaR78i0b9XASP/cAj YvFstwp/0irVgkYQmZCWCUN9Wk4xIOSmOJ3HT5uyFx2SkJQ6+9j5k68xONGemKLj o9sownNV3JYibIJz2p1oBkLrICRJ9S21/q7SKsnrWsUFDT55gfcjJst8e3116tJ5 saE1OOjhS3/Oar1lDISfZgnNij+SVq7Q7lX7ZxBY+n1/rDkSy9w2HrP9zIiMz5Wr uveaBYbixY1so3FBSGs069I5z2wxz9e2E04tf9egKMlr/tJLGikT/HN4ifmRrn1z 3lBf2f1uQyKYnf1o1U7GRb2ZrGLF0xztxJOUPFSwevVyIfIqUAb1He2VdLm075GP QA== Received: (qmail 4182589 invoked from network); 8 Apr 2025 13:53:19 +0200 Received: by mail.zeus03.de with UTF8SMTPSA (TLS_AES_256_GCM_SHA384 encrypted, authenticated); 8 Apr 2025 13:53:19 +0200 X-UD-Smtp-Session: l3s3148p1@Suau/0Iy3qAujnsS Date: Tue, 8 Apr 2025 13:53:18 +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="52BEGUaTx0aSGpAm" Content-Disposition: inline In-Reply-To: --52BEGUaTx0aSGpAm Content-Type: text/plain; charset=us-ascii Content-Disposition: inline > We have a design where several I2C targets with different maximum speed capability > connected to the same I2C bus managed by one I2C master. > We want to communicate with each target with its speed. However there is no way to > specify the bus speed for the I2C message. Rightfully so. Devices with a lower max_freq may get confused and block the bus if you operate at a higher freq. You have to live with the lowest max_freq. Or put the slow devices to another adapter. Or behind a mux. Something like this. --52BEGUaTx0aSGpAm Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEOZGx6rniZ1Gk92RdFA3kzBSgKbYFAmf1DisACgkQFA3kzBSg KbZgvxAAo+Er/ESjZbNVE3yZH4xd8bCTYovMdUUySX4KuorJHe/ZqNtcWaFwnj56 IUon+RrdrY9gcSmXt7SvvISs15E70y6SF+oX54Blaqz//Ny5CTYfsxB5M3fPj/Hy xZK8z7KZbsTCHxBbI7nLSx413Ufx/ujY7Bqr5KBB55D1lkX+JRfloZ7gWuaoN5Nj CP2OtMKvBAXoS/axOel6OF6ypuwmQyJP6WMXOonN9FJ6xbkU58n6LgxVYbELGytC YwRLmAZkV53xKCTmL8qO+2t2rwVTUxo8qzF7hcLWiugfPt5kdKob1bSOO+aflmnN LkIWcShjok+vkz4mhQUO29nxHzKS8FuPAOvhVIcVxbcXmZ6QbYeeqSd4zLVq12VJ W+KsqPMTDCDJOyDEPZ5UmJ+8BM7KnzeQxD2ozZVAvrrbGMxAGyyLA1xZuu66Hfq2 7LMPv6+M7nzDrYBRY4bxz4hJTSKXy8D1o6KSLmCHXGyjorvBbV4lieGnTCUZ2VPa tzqlBBPxD9ol1NPnwFddBU/jpSCKAQiTwd/q5DMhlyw2JPQGvq/60A4fC6LWQXwx A4pOWfHfRrD8f7mvHFPNgsjhyXXgxQGDgXOFR9MxJ59jlLW1ytsPBvhRvRC3m9vP hCPhfmcebNX3LUJHE0a6wEi0lSwqmwKlUo8xUuW8mfdY0X+AvGs= =vnmS -----END PGP SIGNATURE----- --52BEGUaTx0aSGpAm--