From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 41A0AC433EF for ; Fri, 28 Jan 2022 10:37:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243945AbiA1Khp (ORCPT ); Fri, 28 Jan 2022 05:37:45 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:47404 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229462AbiA1Khl (ORCPT ); Fri, 28 Jan 2022 05:37:41 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 71CF9B82500 for ; Fri, 28 Jan 2022 10:37:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4D1E5C340E0; Fri, 28 Jan 2022 10:37:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1643366259; bh=Uy+++PWtPa7zd1qw+wNw6uYGotVQJL/yndlPtdBNAKA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=PQkofFD8DV9FsWWisPsOGCebQWLmXohOa6g5KLqDjfD/kM3agoP5q9+pUnf1JDK5k r3cQeKDzXXLXEVNL5UYeQFwdQeCnkl1nELVsDPnXcOPLJEfiisq58Btqvevnt+8d07 oR+qKMSGb+4PRVht+IWSGXnkDFtj0RfQwgZ2/LLW95FERP5XXiUvsUkzJKZLc8F9o5 w/HBTEvJ7A+kXJ9AZn/eW8mseIO3vo4e9Z51OZAml9PR1T9/OBqOSPkUbAlvz0Mw5A NwSgiV7MZCQKo452jqnctnVbEqnAWQK8xlrz0DUZJmGBzmHkANur5t3hAxm8rQSPGH JN+q7gKk8C9xg== Date: Fri, 28 Jan 2022 11:37:31 +0100 From: Wolfram Sang To: "Ivan T. Ivanov" Cc: Florian Fainelli , Ray Jui , Scott Branden , Nicolas Saenz Julienne , linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Phil Elwell Subject: Re: [PATCH] i2c: bcm2835: Set clock-stretch timeout to 35ms Message-ID: Mail-Followup-To: Wolfram Sang , "Ivan T. Ivanov" , Florian Fainelli , Ray Jui , Scott Branden , Nicolas Saenz Julienne , linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Phil Elwell References: <20220117102504.90585-1-iivanov@suse.de> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="tNNl2xM7+YgU3NMO" Content-Disposition: inline In-Reply-To: <20220117102504.90585-1-iivanov@suse.de> Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org --tNNl2xM7+YgU3NMO Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi Ivan, > The BCM2835 I2C blocks have a register to set the clock-stretch > timeout - how long the device is allowed to hold SCL low - in bus > cycles. The current driver doesn't write to the register, therefore > the default value of 64 cycles is being used for all devices. >=20 > Set the timeout to the value recommended for SMBus - 35ms. By default, busses are I2C and not SMBus, so it looks like we should finally apply this patch which disables CLKT: http://patchwork.ozlabs.org/project/linux-i2c/patch/1519422151-6218-1-git-s= end-email-stefan.wahren@i2se.com/ If you really want the SMBus timeout applied, you can check for a "smbus" property in DT and then set CLKT accordingly in a seperate patch. Kind regards, Wolfram --tNNl2xM7+YgU3NMO Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEOZGx6rniZ1Gk92RdFA3kzBSgKbYFAmHzx2cACgkQFA3kzBSg KbbiUhAAibR16ghawqi+04Dq+II/mrR+2C1nKSZduVNKyzZOtw93Z5X4LS213VTU geHA1RE+OoWG4sIMRijjvMGuYoyF/3F/czyoMBUGFyJZpWtQCz/iRj+nNmJBG3l3 Bqd1SeAAWc0ePewgTe3j4024Yn/v1RddUAgXsZ7JFmgQqy3APMdTo5WzfXoTAa4X S+hh52VN1+hlIx3bqlfna29JrQPU1aH+fggqHJkC2L7TZQs0NVFzq0kkAcQqn3gO VHEHFTlXDQPLe1Wncha7fs1ADx8pNdmd55YFer/FCPEqtvxn5RCJltDzojWhG11P vWjJCmmJAy4uqeYjx8QE6jGnKW6rZWCTalru5A2NB8hci+vuoxqEBpzM9QtESdIJ CFpSLtg9lJx29s0rrG6ixu+3YJ5j85TEwGTHrtBi2J+GjFYdDnCl9/Yhl6gjgrwI IETqYZLCv4vAflVzc8zbo4gzthdcB4CHRiD8FfHRP5iqT+JAg6a9i4mT82cLVX6y zUyhWJAPV2QlVUN6rHR1zU4bTcCqymkyxbl7KRZNUuE0O+/1k2AIBzeHLXq4292u 5baiB0EJ0xs7z24OOhkReAuXbsWo4x8HY9dSLgrkTZGkfRyioS+SU/h3P7Hzf7IO L8IaGZgUEzxRvspuFFuQfcvkiQStWiLcoiJW8mjdCe03sF2MKOQ= =SuZW -----END PGP SIGNATURE----- --tNNl2xM7+YgU3NMO--