Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754349Ab0FZMMV (ORCPT ); Sat, 26 Jun 2010 08:12:21 -0400 Received: from mail-fx0-f66.google.com ([209.85.161.66]:36710 "EHLO mail-fx0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753461Ab0FZMMU (ORCPT ); Sat, 26 Jun 2010 08:12:20 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references; b=xr5VqQTLmUCCcXYMfTd6oACeypnPbu0nDjZmfeHenqLriLeaS3PT/1JwVucBJyJajf 9yMuUsvleO11Q8t49ogb55JlS0kfWUp/1bcZJbb/oHoHULRuRq4PFgTKyVgNq7qJ4XXg cp9w4gxyQCv8sbUOcYJIvqFmxW0rwQj0esnPs= From: Christoph Mair To: Andrew Morton Cc: linux-kernel@vger.kernel.org, Jonathan Cameron , Stefan Schmidt , Datta Shubhrajyoti , Christoph Mair Subject: [PATCH 2/2] bmp085: Add interface documentation and link to datasheet. Date: Sat, 26 Jun 2010 13:10:24 +0200 Message-Id: <1277550624-13879-3-git-send-email-christoph.mair@gmail.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <20100621144958.d5fc694e.akpm@linux-foundation.org> References: <20100621144958.d5fc694e.akpm@linux-foundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2360 Lines: 50 Signed-off-by: Christoph Mair --- drivers/misc/bmp085.c | 27 +++++++++++++++++++++++++++ 1 files changed, 27 insertions(+), 0 deletions(-) diff --git a/drivers/misc/bmp085.c b/drivers/misc/bmp085.c index 16a2b2c..67ed8b2 100644 --- a/drivers/misc/bmp085.c +++ b/drivers/misc/bmp085.c @@ -1,5 +1,32 @@ /* Copyright (c) 2010 Christoph Mair + This driver supports the bmp085 digital barometric pressure + and temperature sensor from Bosch Sensortec. The datasheet + is avaliable from their website: + http://www.bosch-sensortec.com/content/language1/downloads/BST-BMP085-DS000-05.pdf + + A pressure measurement is issued by reading from pressure0_input. + The return value ranges from 30000 to 110000 pascal with a resulution + of 1 pascal (0.01 millibar) which enables measurements from 9000m above + to 500m below sea level. + + The temperature can be read from temp0_input. Values range from + -400 to 850 representing the ambient temperature in degree celsius + multiplied by 10.The resolution is 0.1 celsius. + + Because ambient pressure is temperature dependent, a temperature + measurement will be executed automatically even if the user is reading + from pressure0_input. This happens if the last temperature measurement + has been executed more then one second ago. + + To decrease RMS noise from pressure measurements, the bmp085 can + autonomously calculate the average of up to eight samples. This is + set up by writing to the oversampling sysfs file. Accepted values + are 0, 1, 2 and 3. 2^x when x is the value written to this file + specifies the number of samples used to calculate the ambient pressure. + RMS noise is specified with six pascal (without averaging) and decreases + down to 3 pascal when using an oversampling setting of 3. + This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or -- 1.7.1 -- 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/