From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1753828AbbIGIIu (ORCPT <rfc822;w@1wt.eu>);
	Mon, 7 Sep 2015 04:08:50 -0400
Received: from smtp-out-013.synserver.de ([212.40.185.13]:1090 "EHLO
	smtp-out-210.synserver.de" rhost-flags-OK-OK-OK-FAIL)
	by vger.kernel.org with ESMTP id S1753627AbbIGIIr (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Mon, 7 Sep 2015 04:08:47 -0400
X-SynServer-TrustedSrc: 1
X-SynServer-AuthUser: lars@metafoo.de
X-SynServer-PPID: 26732
Message-ID: <55ED460A.1080706@metafoo.de>
Date: Mon, 07 Sep 2015 10:08:42 +0200
From: Lars-Peter Clausen <lars@metafoo.de>
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.8.0
MIME-Version: 1.0
To: Matt Ranostay <mranostay@gmail.com>, Jonathan Cameron <jic23@kernel.org>
CC: Peter Meerwald <pmeerw@pmeerw.net>,
        "open list:IIO SUBSYSTEM AND..." <linux-iio@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>,
        "open list:OPEN FIRMWARE AND..." <devicetree@vger.kernel.org>,
        George McCollister <george.mccollister@gmail.com>
Subject: Re: [RFC v2 4/4] iio: chemical: add SGX VZ89x VOC sensor support
References: <1441593547-10896-1-git-send-email-mranostay@gmail.com>	<1441593547-10896-5-git-send-email-mranostay@gmail.com>	<CAFSKS=NvhBvwknAXs-Pfd-bJ4U6zrXD3zBZT0GaC+w5JUg24ig@mail.gmail.com>	<CAKzfze_UBjKauqqCLDSkUu-ee+ZC0VzQCaYpZEgpfRny_H4y1A@mail.gmail.com> <CAKzfze8sEkr5q6-X42Z24nqrqy8JMdqL3omRKOraz1G0BehyJg@mail.gmail.com>
In-Reply-To: <CAKzfze8sEkr5q6-X42Z24nqrqy8JMdqL3omRKOraz1G0BehyJg@mail.gmail.com>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 09/07/2015 06:27 AM, Matt Ranostay wrote:
> Thinking this over do we needed a IIO_CHAN_INFO_PROCESSED_OFFSET to
> signal that it needs to be after the (value - offset) * scale
> calculation?

Well, value * scale + offset = (value + offset/scale) * scale. So just scale
your offset inversely to the scale.