From: Jonathan Cameron Subject: Re: Accelerometer, Gyros and ADC's etc within the kernel. Date: Thu, 22 May 2008 10:35:01 +0100 Message-ID: <48353E45.2080903@cam.ac.uk> References: <4832A211.4040206@gmail.com> <20080520132817.03fb74ea@hyperion.delvare> <200805211752.15670.david-b@pacbell.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Dmitry Torokhov , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, LM Sensors , Jonathan Cameron , Jean Delvare , spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: David Brownell Return-path: In-Reply-To: <200805211752.15670.david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: spi-devel-general-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: spi-devel-general-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: linux-spi.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 ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/