From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936122AbYEVJfX (ORCPT ); Thu, 22 May 2008 05:35:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932795AbYEVJfH (ORCPT ); Thu, 22 May 2008 05:35:07 -0400 Received: from ppsw-5.csi.cam.ac.uk ([131.111.8.135]:42704 "EHLO ppsw-5.csi.cam.ac.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760509AbYEVJfG (ORCPT ); Thu, 22 May 2008 05:35:06 -0400 X-Cam-SpamDetails: Not scanned X-Cam-AntiVirus: No virus found X-Cam-ScannerInfo: http://www.cam.ac.uk/cs/email/scanner/ Message-ID: <48353E45.2080903@cam.ac.uk> Date: Thu, 22 May 2008 10:35:01 +0100 From: Jonathan Cameron User-Agent: Thunderbird 2.0.0.0 (X11/20070423) MIME-Version: 1.0 To: David Brownell CC: Jean Delvare , spi-devel-general@lists.sourceforge.net, Jonathan Cameron , LM Sensors , linux-kernel@vger.kernel.org, Dmitry Torokhov Subject: Re: [spi-devel-general] Accelerometer, Gyros and ADC's etc within the kernel. References: <4832A211.4040206@gmail.com> <20080520132817.03fb74ea@hyperion.delvare> <200805211752.15670.david-b@pacbell.net> In-Reply-To: <200805211752.15670.david-b@pacbell.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi David, > On Tuesday 20 May 2008, Jean Delvare wrote: >> This all sounds quite different from our hwmon drivers. Our hwmon >> drivers read all the sensor values at once and cache the readings for a >> couple seconds, so you can't get an instant reading at any time, and >> they also don't support interrupts in general. > > That's something of an issue when the hardware monitor > triggers alarms though, right? I couldn't figure out > how to get a TMP75 alert out to any userspace code that > would care, to pick one example, even after teaching > the i2c core how to handle SMBus alerts. ;) > > I suppose this just emphasizes the point made by Hans > that we kind of need (industrial) "control" components > (or "data acquisition"?) not just "monitoring" ones. I get the feeling even the name is going to evolve for some time to come, getting broader as and when we add more classes of device. > Such alarms are of course different from the "data > ready" signals of an accelerometer. Whilst this is true, most accelerometers also have "alarm" triggers, for example the ST LIS3L02DQ will raise a pin on configurable conditions such as thresholds and even a double click detector (though I've never tried them!). I suppose we will ideally support this functionality as well. -- Jonathan Cameron