From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ADC26C43441 for ; Wed, 28 Nov 2018 09:14:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6C1172081C for ; Wed, 28 Nov 2018 09:14:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linaro.org header.i=@linaro.org header.b="Hn5lQ0Um" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6C1172081C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728000AbeK1UPc (ORCPT ); Wed, 28 Nov 2018 15:15:32 -0500 Received: from mail-wm1-f67.google.com ([209.85.128.67]:40676 "EHLO mail-wm1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727527AbeK1UPc (ORCPT ); Wed, 28 Nov 2018 15:15:32 -0500 Received: by mail-wm1-f67.google.com with SMTP id q26so1731392wmf.5 for ; Wed, 28 Nov 2018 01:14:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to :user-agent; bh=vASiJ29iDdzzZSAwTyxtgFXmVhCZkejxpsR6NY1/uSs=; b=Hn5lQ0Um5ALaPhmxbPI8ksD54bvqp6FTk2GoW5xlD/aXnwS9qQQxKOlxmFd+yb69nf kfuX9vQS5kv63g0j0YbbwhRCaVfkU0cpabilu3TfBBrInkcfzvAzOR66SYRMFEJZecjN z9UbbWD2jY1tgGSQhbiqpyXEotFFSugOdMlus= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to:user-agent; bh=vASiJ29iDdzzZSAwTyxtgFXmVhCZkejxpsR6NY1/uSs=; b=FHx9qVBORFzV5zIfnB9VPI6eoskVxGsqaP2b4cKTYO0KK1njc1j90XUXtTTMuCHDek 7u2KVl2zvXcy77EhqvCSkQuw8CzAeaxwXAqMm7PBaIq0lhSQXiAZYoY5decSvwjAZ9QQ dUwFv+jl+5S3nsA0hD5RUK33aBi3S6TsbJchtGKYkkKoPBqIq6LI3pENdoNkWsJE2tw9 0vQC8uOpOTTtVS9ipC8FLUQoOLv6hZffH0CUVjzVIi7NTg/PFGJ0vtvcEHwZj3B9rfTG CTOSu8QNc9fVaxC095Q5GttYAXF/BeMAuVMXCzMub897MmjMoOOZdBrPj7wjXvoisf/D QgEw== X-Gm-Message-State: AA+aEWbYhgtJE0auUd3TOEyZlvev7ft7XKYF1jD6eYGnT/OIykrj9tEd aKa9kdPNQ+7jVmN5rDtaLJsu+Q== X-Google-Smtp-Source: AFSGD/UGI7RWZc1Ynx640s9OrKJNLB4rkk7/o1y7hOQD6JUWRltSMqrbscJzWtz5gAfsfwRVF4tWpw== X-Received: by 2002:a1c:83c8:: with SMTP id f191mr1938054wmd.134.1543396475259; Wed, 28 Nov 2018 01:14:35 -0800 (PST) Received: from dell ([2.31.167.233]) by smtp.gmail.com with ESMTPSA id n8sm6445513wrw.59.2018.11.28.01.14.34 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 28 Nov 2018 01:14:34 -0800 (PST) Date: Wed, 28 Nov 2018 09:14:32 +0000 From: Lee Jones To: Vignesh R Cc: Jonathan Cameron , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , linux-iio@vger.kernel.org, linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] iio: adc: ti_am335x_tscadc: Improve accuracy of measurement Message-ID: <20181128091432.GT4272@dell> References: <20181119064236.28902-1-vigneshr@ti.com> <20181119064236.28902-3-vigneshr@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20181119064236.28902-3-vigneshr@ti.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 19 Nov 2018, Vignesh R wrote: > When performing single ended measurements with TSCADC, its recommended > to set negative input (SEL_INM_SWC_3_0) of ADC step to ADC's VREFN in the > corresponding STEP_CONFIGx register. > Also, the positive(SEL_RFP_SWC_2_0) and negative(SEL_RFM_SWC_1_0) > reference voltage for ADC step needs to be set to VREFP and VREFN > respectively in STEP_CONFIGx register. > Without these changes, there may be variation of as much as ~2% in the > ADC's digital output which is bad for precise measurement. > > Signed-off-by: Vignesh R > --- > drivers/iio/adc/ti_am335x_adc.c | 5 ++++- > include/linux/mfd/ti_am335x_tscadc.h | 4 ++++ Acked-by: Lee Jones -- Lee Jones [李琼斯] Linaro Services Technical Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog