From owner-svn-src-all@freebsd.org Wed Oct 30 15:15:54 2019 Return-Path: Delivered-To: svn-src-all@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 4E5681A79E9; Wed, 30 Oct 2019 15:15:54 +0000 (UTC) (envelope-from avg@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 473BqG1M1wz43l8; Wed, 30 Oct 2019 15:15:54 +0000 (UTC) (envelope-from avg@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 115EDC3CC; Wed, 30 Oct 2019 15:15:54 +0000 (UTC) (envelope-from avg@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id x9UFFrXc084906; Wed, 30 Oct 2019 15:15:53 GMT (envelope-from avg@FreeBSD.org) Received: (from avg@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id x9UFFrI4084905; Wed, 30 Oct 2019 15:15:53 GMT (envelope-from avg@FreeBSD.org) Message-Id: <201910301515.x9UFFrI4084905@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: avg set sender to avg@FreeBSD.org using -f From: Andriy Gapon Date: Wed, 30 Oct 2019 15:15:53 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r354180 - head/sys/dev/ow X-SVN-Group: head X-SVN-Commit-Author: avg X-SVN-Commit-Paths: head/sys/dev/ow X-SVN-Commit-Revision: 354180 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 30 Oct 2019 15:15:54 -0000 Author: avg Date: Wed Oct 30 15:15:53 2019 New Revision: 354180 URL: https://svnweb.freebsd.org/changeset/base/354180 Log: ow(4): increase regular mode recovery time, t_rec, to 15 us Previously we used the minimal value of 1 us and it was really tight. Application Note 3829 has a table describing recommended t_rec values for various bus voltages, temperature conditions and numbers of slave devices. The new value decreases the maximum possible data rate from 16.3 Kbit/s to 13.3 Kbit/s, but it allows for up to four slaves on a 3.3V bus (under room temperature). References: - Maxim Integrated Application Note 3829 Determining the Recovery Time for Multiple-Slave 1-Wire(R) Networks - Maxim Integrated Application Note 937 Book of iButton Standards Discussed with: imp (D22108) MFC after: 3 weeks Modified: head/sys/dev/ow/ow.c Modified: head/sys/dev/ow/ow.c ============================================================================== --- head/sys/dev/ow/ow.c Wed Oct 30 14:05:50 2019 (r354179) +++ head/sys/dev/ow/ow.c Wed Oct 30 15:15:53 2019 (r354180) @@ -80,7 +80,7 @@ static struct ow_timing timing_regular = { .t_low0 = 60, /* really 60 to 120 */ .t_low1 = 1, /* really 1 to 15 */ .t_release = 45, /* <= 45us */ - .t_rec = 1, /* at least 1us */ + .t_rec = 15, /* at least 1us */ .t_rdv = 15, /* 15us */ .t_rstl = 480, /* 480us or more */ .t_rsth = 480, /* 480us or more */