Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752822Ab0H3WGI (ORCPT ); Mon, 30 Aug 2010 18:06:08 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:53745 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751724Ab0H3WGE (ORCPT ); Mon, 30 Aug 2010 18:06:04 -0400 MIME-Version: 1.0 In-Reply-To: <20100830214355.GB28865@core.coreip.homeip.net> References: <15445.10.24.255.17.1274424777.squirrel@dbdmail.itg.ti.com> <20100829184904.GC26209@core.coreip.homeip.net> <36abcb34cfbf34724d9a581a75b53e76@secure211.sgcpanel.com> <20100830214025.2f9677a1@lxorguk.ukuu.org.uk> <20100830204412.GA28711@core.coreip.homeip.net> <20100830214355.GB28865@core.coreip.homeip.net> Date: Mon, 30 Aug 2010 15:05:32 -0700 Message-ID: Subject: Re: Sensors and the input layer (was Re: [RFC] [PATCH V2 1/2] input: CMA3000 Accelerometer driver) From: Linus Torvalds To: Dmitry Torokhov Cc: Linus Torvalds , Alan Cox , Felipe Balbi , Hemanth V , "linux-input@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-omap@vger.kernel.org" , "igor.stoppa@nokia.com" , "kai.svahn@nokia.com" , "matthias.nyman@nokia.com" Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2003 Lines: 47 On Monday, August 30, 2010, Dmitry Torokhov wrote: > > That is why I started taking accelerometers in. But I am concerned that > taking accelerometers (which indeed are most often input devices) will > lead people to try and use the same for temperature, ALS and other > sensors that are more often used in industrial process controls. You're just being silly. Nobody writes a driver for a "temperature sensor" or "ambient light sensor". They write a driver for a specific *chip* that is used in cellphones etc, and that happens to have an ambient light and temperature sensor on it. And in that context, it really does make sense to see it as an input driver. And the fact that there are industrial uses for ALS sensors that aren't necessarily at all interested on the input layer should not matter at all. So don't bring up "ALS isn't always input" because within the context of a driver for some highly integrated cellphone model, it really IS input, and there is no ambiguity at all. So your "sometimes it is, and sometimes it isn't" argument is bogus. The ambiguity simply doesn't exist when seen in context. >> (or GPS device, for that matter) really be? > > But why GPS should be input device? It has nothing to do with user > input. What? OF COURSE it is an input driver. It's the user moving the device around. It's EXACTLY the same thing as an accelerometer in that respect. Sure, it's a bit less precise and measures movement wrt some external frame, but technically they are almost exactly the same. If you se doing a navigation app, the accelerometer, the compass and the GPS are all equally (but differently) important. Again - it's not a user touching buttons. But it IS a user moving around. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/