From patchwork Tue Feb 1 00:18:08 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zev Weiss X-Patchwork-Id: 1587031 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: bilbo.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=bewilderbeest.net header.i=@bewilderbeest.net header.a=rsa-sha256 header.s=thorn header.b=giilTykb; dkim-atps=neutral Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-i2c-owner@vger.kernel.org; receiver=) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by bilbo.ozlabs.org (Postfix) with ESMTP id 4JnlsR3y99z9sGN for ; Tue, 1 Feb 2022 11:18:51 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230300AbiBAASt (ORCPT ); Mon, 31 Jan 2022 19:18:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60036 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230290AbiBAASs (ORCPT ); Mon, 31 Jan 2022 19:18:48 -0500 Received: from thorn.bewilderbeest.net (thorn.bewilderbeest.net [IPv6:2605:2700:0:5::4713:9cab]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 184D9C06173B; Mon, 31 Jan 2022 16:18:48 -0800 (PST) Received: from hatter.bewilderbeest.net (174-21-190-118.tukw.qwest.net [174.21.190.118]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: zev) by thorn.bewilderbeest.net (Postfix) with ESMTPSA id 68340407; Mon, 31 Jan 2022 16:18:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bewilderbeest.net; s=thorn; t=1643674726; bh=vzPsNjZvndAyHxwYzpRfPbOzW25qWDh7MkzyvlonJCI=; h=From:To:Cc:Subject:Date:From; b=giilTykb2ELfTcPfC8n/+sJ0g9/UFXKa/W5nrtxv0TvhP63lm8znl5kNWAcGdvfNb qoxAzlFBuLgBsjc4UUzLMUH1V+QNdjxN9gvZ7MaHbF+fA7p1a6u/OD11gxEsUweeqe rdrvQvXDTuiT8d/pc9TynkRPqKeFXTQtrois/LQU= From: Zev Weiss To: linux-i2c@vger.kernel.org, Guenter Roeck , Peter Rosin , Rob Herring Cc: Zev Weiss , openbmc@lists.ozlabs.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org Subject: [PATCH v2 0/2] ic2: mux: pca9541: add delayed-release support Date: Mon, 31 Jan 2022 16:18:08 -0800 Message-Id: <20220201001810.19516-1-zev@bewilderbeest.net> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org Hello, This series adds support for a new pca9541 device-tree property ("release-delay-us"), which delays releasing ownership of the bus after a transaction for a configurable duration, anticipating that another transaction may follow shortly. By avoiding a release/reacquisition between transactions, this can provide a substantial performance improvement for back-to-back operations -- on a Delta AHE-50DC (ASPEED AST1250) system running OpenBMC with dozens of LM25066 PMICs on PCA9541-arbitrated busses, a setting of 10000 (10 ms) reduces the median latency the psusensor daemon's hwmon sysfs file reads from 2.28 ms to 0.99 ms (a 57% improvement). Thanks, Zev Changes since v1 [0]: - removed spurious #include line from dt-bindings example [0] https://lore.kernel.org/linux-i2c/20220124213850.3766-1-zev@bewilderbeest.net/ Zev Weiss (2): i2c: mux: pca9541: add delayed-release support dt-bindings: i2c: add nxp,pca9541 release-delay-us property .../devicetree/bindings/i2c/nxp,pca9541.txt | 9 +++ drivers/i2c/muxes/i2c-mux-pca9541.c | 56 ++++++++++++++++--- 2 files changed, 56 insertions(+), 9 deletions(-)