Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932358Ab2HWLeG (ORCPT ); Thu, 23 Aug 2012 07:34:06 -0400 Received: from mail-ob0-f174.google.com ([209.85.214.174]:58459 "EHLO mail-ob0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755448Ab2HWLeC convert rfc822-to-8bit (ORCPT ); Thu, 23 Aug 2012 07:34:02 -0400 MIME-Version: 1.0 In-Reply-To: <331ABD5ECB02734CA317220B2BBEABC13EA1EBF5@DBDE01.ent.ti.com> References: <1345617039-27469-1-git-send-email-anilkumar@ti.com> <201208220748.39106.arnd@arndb.de> <331ABD5ECB02734CA317220B2BBEABC13EA1B975@DBDE01.ent.ti.com> <331ABD5ECB02734CA317220B2BBEABC13EA1BDA9@DBDE01.ent.ti.com> <331ABD5ECB02734CA317220B2BBEABC13EA1EA53@DBDE01.ent.ti.com> <331ABD5ECB02734CA317220B2BBEABC13EA1EBF5@DBDE01.ent.ti.com> From: Chinmay V S Date: Thu, 23 Aug 2012 17:03:31 +0530 Message-ID: Subject: Re: [PATCH v2] lis3lv02d: Add STMicroelectronics lis331dlh digital accelerometer To: "AnilKumar, Chimata" Cc: Arnd Bergmann , "gregkh@linuxfoundation.org" , "eric.piel@tremplin-utc.net" , "jic23@cam.ac.uk" , "greg@kroah.com" , "akpm@linux-foundation.org" , "broonie@opensource.wolfsonmicro.com" , "dmitry.torokhov@gmail.com" , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2078 Lines: 56 12bit it IS then. :-) LGTM. +1. On Thu, Aug 23, 2012 at 4:45 PM, AnilKumar, Chimata wrote: > Chinmay, > > On Thu, Aug 23, 2012 at 15:53:10, Chinmay V S wrote: >> > Note from datasheet, "1LSb=4g/4096 at 12bit representation, >> > ±2g Full-scale" >> >> Precisely my point. All the datasheet says is : >> 1. It is +/-2G mode --> so Numerator is 4G. >> 2. We are using 12bits --> so Denominator is 2^12 = 4096. >> >> There is no clear reason/justification as to why 12bits was chosen in >> the first place. At this point unless someone from the >> design/original-driver team actually confirms why the 12bit >> representation was chosen, it is all conjecture on our part. >> >> If you have the actual LIS331DLH hardware, can you verify if the lower >> 4bits do actually contain any data (or are they always zero). This >> will help us decide whether to use them(16bit mode) or discard >> them(12bit mode)?... >> > > This is the outdata of accelerometer > > root@am335xevm:~# cat /sys/devices/platform/lis3lv02d/position > [ 16.323852] lis3lv02d: hi 0x1 low 0x50 val 0x15 > [ 16.329742] lis3lv02d: hi 0x0 low 0x0 val 0x0 > [ 16.335052] lis3lv02d: hi 0x3e low 0x50 val 0x3e5 > (20,0,973) > root@am335xevm:~# cat /sys/devices/platform/lis3lv02d/position > [ 25.777343] lis3lv02d: hi 0x2 low 0xa0 val 0x2a > [ 25.783203] lis3lv02d: hi 0xc1 low 0xf0 val 0xfffffc1f > [ 25.790130] lis3lv02d: hi 0xfd low 0x50 val 0xffffffd5 > (41,-969,-41) > root@am335xevm:~# cat /sys/devices/platform/lis3lv02d/position > [ 47.607330] lis3lv02d: hi 0xc0 low 0x60 val 0xfffffc06 > [ 47.613464] lis3lv02d: hi 0xfd low 0x90 val 0xffffffd9 > [ 47.619934] lis3lv02d: hi 0x2 low 0x40 val 0x24 > (-994,-38,35) > > Lower nibble always "0" > > Regards > AnilKumar -- regards ChinmayVS -- 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/