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=-9.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 ECA47ECDE44 for ; Sun, 4 Nov 2018 14:01:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B5C3B204FD for ; Sun, 4 Nov 2018 14:01:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="SUFksidy" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B5C3B204FD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.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 S1731443AbeKDXRD (ORCPT ); Sun, 4 Nov 2018 18:17:03 -0500 Received: from mail.kernel.org ([198.145.29.99]:47052 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731011AbeKDXIX (ORCPT ); Sun, 4 Nov 2018 18:08:23 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C2C852087A; Sun, 4 Nov 2018 13:53:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1541339599; bh=SHl783TBq4tAYy5T+nh1+3DQfbKJ4E2UVL2LGQdwyiM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SUFksidydT2PxH32xzL4uLJYVGbA+PKGt9vHCJIeDqXTph+ojMujlNukRzkwqp10V 2sPp50wVy+4umxDUYiQ3nh05yuOzPYOcdJl+UvBz6VTRBDGpNSUGmIc0YZbEtsIOQI ESP2VUtvu7cPaVLG6/SwNy5kIJ/FOfvv+zxoqiLI= From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Alexandru Ardelean , Jonathan Cameron , Sasha Levin Subject: [PATCH AUTOSEL 4.18 38/45] staging:iio:ad7606: fix voltage scales Date: Sun, 4 Nov 2018 08:52:33 -0500 Message-Id: <20181104135240.88431-38-sashal@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181104135240.88431-1-sashal@kernel.org> References: <20181104135240.88431-1-sashal@kernel.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Alexandru Ardelean [ Upstream commit 4ee033301c898dd0835d035d0e0eb768a3d35da1 ] Fixes commit 17be2a2905a6ec9aa27cd59521495e2f490d2af0 ("staging: iio: ad7606: replace range/range_available with corresponding scale"). The AD7606 devices don't have a 2.5V voltage range, they have 5V & 10V voltage range, which is selectable via the `gpio_range` descriptor. The scales also seem to have been miscomputed, because when they were applied to the raw values, the results differ from the expected values. After checking the ADC transfer function in the datasheet, these were re-computed. Signed-off-by: Alexandru Ardelean Signed-off-by: Jonathan Cameron Signed-off-by: Sasha Levin --- drivers/staging/iio/adc/ad7606.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/staging/iio/adc/ad7606.c b/drivers/staging/iio/adc/ad7606.c index 25b9fcd5e3a4..ce3351832fb1 100644 --- a/drivers/staging/iio/adc/ad7606.c +++ b/drivers/staging/iio/adc/ad7606.c @@ -26,9 +26,12 @@ #include "ad7606.h" -/* Scales are computed as 2.5/2**16 and 5/2**16 respectively */ +/* + * Scales are computed as 5000/32768 and 10000/32768 respectively, + * so that when applied to the raw values they provide mV values + */ static const unsigned int scale_avail[2][2] = { - {0, 38147}, {0, 76294} + {0, 152588}, {0, 305176} }; static int ad7606_reset(struct ad7606_state *st) -- 2.17.1