From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Lawnick Subject: Re: [PATCH] i2c-mux-pca954x: Disable mux after 200ms timeout Date: Mon, 25 Nov 2013 15:54:36 +0100 Message-ID: <529364AC.8000305@gmx.de> References: <1385387037-3710-1-git-send-email-mike.looijmans@topic.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1385387037-3710-1-git-send-email-mike.looijmans@topic.nl> Sender: linux-kernel-owner@vger.kernel.org To: Mike Looijmans Cc: Wolfram Sang , linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-i2c@vger.kernel.org Hi, Am 25.11.2013 14:43, schrieb Mike Looijmans: > Leaving the mux enabled causes needless I2C traffic on the downstream > bus. De-selecting after every request causes excess I2C traffic and > switching. > > This patch implements a hybrid solution: After 200ms of inactivity, > the mux is disabled. ... Have you checked against behavior on cascaded muxes? At least your desired timing will not look as expected. 200 ms: disable mux1 201 ms: enable mux1 - disable mux2 202 ms: enable mux2 - disable mux3 401 ms: disable mux1 402 ms: enable mux1 - disable mux2 602 ms: disable mux1 And on full second temperature sensor behind mux3 is read again ... KR Michael