From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guenter Roeck Subject: Re: Driver for pca9541 bus master selector Date: Tue, 28 Sep 2010 10:16:27 -0700 Message-ID: <20100928171627.GA8415@ericsson.com> References: <20100928143302.GA7593@ericsson.com> <20100928171607.395f7736@endymion.delvare> <20100928160746.GB7976@ericsson.com> <20100928184215.00f82717@endymion.delvare> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Return-path: Content-Disposition: inline In-Reply-To: <20100928184215.00f82717-R0o5gVi9kd7kN2dkZ6Wm7A@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jean Delvare Cc: "linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Michael Lawnick , Rodolfo Giometti List-Id: linux-i2c@vger.kernel.org Hi Jean, On Tue, Sep 28, 2010 at 12:42:15PM -0400, Jean Delvare wrote: > On Tue, 28 Sep 2010 09:07:46 -0700, Guenter Roeck wrote: > > On Tue, Sep 28, 2010 at 11:16:07AM -0400, Jean Delvare wrote: > > > Hi Guenter, > > > > > > On Tue, 28 Sep 2010 07:33:02 -0700, Guenter Roeck wrote: > > > > I am in the process of writing a driver for the pca9541 bus master selector. > > > > I using the i2c multiplexer framework, which fits the requirements quite nicely. > > > > > > > > If anyone happens to know about an existing driver for this chip, please let me know. > > > > I would love to get some input for the arbitration mechanism needed to determine > > > > if and when to switch bus ownership from one master to the other. > > > > > > See drivers/i2c/muxes/pca954x.c in 2.6.36-rc2 and later. > > > > > Yes, I know. I use it as basis. But it doesn't support pca9541, unfortunately. > > Oh, my bad. I had not noticed the PCA9541 was of a totally different kind. > Actually, I fell into the same trap. I was quite happy that someone else wrote the driver for me ... until I realized that the chips solve the opposite problem. Time goes by ... have a look at http://lists.lm-sensors.org/pipermail/lm-sensors/2004-June/008023.html I wasn't sure if you (or someone else) ever had a driver for 9541, or if you referred to 9540 in above post. The links in the post don't work anymore. Thanks, Guenter