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=-9.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 62D8EC282CE for ; Mon, 11 Feb 2019 14:49:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 355802081B for ; Mon, 11 Feb 2019 14:49:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549896597; bh=L3awooXZvbEU+w+LgzGh6sv/BZRBv9D+wcAQTu7MPqQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=DGw4BB9WuhMPGauBaqFWj1K2XvOcqpCsH/idpCWZV35/sVNdfMgRQst7r7K4KGkFn 72JOvZmcfVt2Sm+tesxZHeRX1k1TAXYdljt3/wGo7KKuBa57j45btjZdubY91io51U D5OesHk4eReF5ihX3f4C5+limc+a+55tzv2SpwRw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733256AbfBKOt4 (ORCPT ); Mon, 11 Feb 2019 09:49:56 -0500 Received: from mail.kernel.org ([198.145.29.99]:35562 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387577AbfBKOtz (ORCPT ); Mon, 11 Feb 2019 09:49:55 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 436752081B; Mon, 11 Feb 2019 14:49:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549896594; bh=L3awooXZvbEU+w+LgzGh6sv/BZRBv9D+wcAQTu7MPqQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YUGeBBdSvjgggCglj6CGb+RNMPh3cfDFGmTiN+LiHTWABeV/Bp6DA38pLBOLKv0SX DxZ0kX+qi2vVgR+1CL80V+dsgHv1Kl/30CYg3Zb3hvmIYGHRWR6u/PQHu7b9im8tyw ktaO2CMWpmw0GNeY9/kxjCf15nDCNJcpbrIegxr0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Laxman Dewangan , Bjorn Andersson , Eduardo Valentin , Sasha Levin Subject: [PATCH 4.19 237/313] thermal: generic-adc: Fix adc to temp interpolation Date: Mon, 11 Feb 2019 15:18:37 +0100 Message-Id: <20190211141909.273048912@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190211141852.749630980@linuxfoundation.org> References: <20190211141852.749630980@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit 9d216211fded20fff301d0317af3238d8383634c ] First correct the edge case to return the last element if we're outside the range, rather than at the last element, so that interpolation is not omitted for points between the two last entries in the table. Then correct the formula to perform linear interpolation based the two points surrounding the read ADC value. The indices for temp are kept as "hi" and "lo" to pair with the adc indices, but there's no requirement that the temperature is provided in descendent order. mult_frac() is used to prevent issues with overflowing the int. Cc: Laxman Dewangan Signed-off-by: Bjorn Andersson Signed-off-by: Eduardo Valentin Signed-off-by: Sasha Levin --- drivers/thermal/thermal-generic-adc.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/thermal/thermal-generic-adc.c b/drivers/thermal/thermal-generic-adc.c index bf1c628d4a7a..e22fc60ad36d 100644 --- a/drivers/thermal/thermal-generic-adc.c +++ b/drivers/thermal/thermal-generic-adc.c @@ -26,7 +26,7 @@ struct gadc_thermal_info { static int gadc_thermal_adc_to_temp(struct gadc_thermal_info *gti, int val) { - int temp, adc_hi, adc_lo; + int temp, temp_hi, temp_lo, adc_hi, adc_lo; int i; for (i = 0; i < gti->nlookup_table; i++) { @@ -36,13 +36,17 @@ static int gadc_thermal_adc_to_temp(struct gadc_thermal_info *gti, int val) if (i == 0) { temp = gti->lookup_table[0]; - } else if (i >= (gti->nlookup_table - 1)) { + } else if (i >= gti->nlookup_table) { temp = gti->lookup_table[2 * (gti->nlookup_table - 1)]; } else { adc_hi = gti->lookup_table[2 * i - 1]; adc_lo = gti->lookup_table[2 * i + 1]; - temp = gti->lookup_table[2 * i]; - temp -= ((val - adc_lo) * 1000) / (adc_hi - adc_lo); + + temp_hi = gti->lookup_table[2 * i - 2]; + temp_lo = gti->lookup_table[2 * i]; + + temp = temp_hi + mult_frac(temp_lo - temp_hi, val - adc_hi, + adc_lo - adc_hi); } return temp; -- 2.19.1