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=-9.1 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 6F70CC282CD for ; Mon, 28 Jan 2019 16:23:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 41E0820879 for ; Mon, 28 Jan 2019 16:23:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548692636; bh=vNGjbw7LC6HYlUIHZ6diKg8EF6tV4uJg2mI5GdI/Rqc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=RCJkdydN/XfKKcW+XMor4zcJj1B7dUQRTFWXG83MAIXK7+N0sqicY4tjF7NCtHy3v oapr9USu9p2kH/JbMB4iuSUbQxyPKt/ZTh37ovaj0/69EPF7dlTm5ffcBNt6/Ali/g vPG0O+4lTi0uV+wRgEOEw5olXvil4lBLqTd6ABp4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389555AbfA1QXy (ORCPT ); Mon, 28 Jan 2019 11:23:54 -0500 Received: from mail.kernel.org ([198.145.29.99]:60118 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389522AbfA1QXs (ORCPT ); Mon, 28 Jan 2019 11:23:48 -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 1E4C62171F; Mon, 28 Jan 2019 16:23:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548692628; bh=vNGjbw7LC6HYlUIHZ6diKg8EF6tV4uJg2mI5GdI/Rqc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NqQKWIswmNLEmGhAZdKdIpQHStR99TjP4pOsHygxcwaw71ZK0d2SOAAhhsXXyLdii HA59NuWkemkj8maX1XsMYH0/rbTtQQLUxhVP1MyaCnotwuOW6C8hHRqoNvL5rz9CIu dCbq3a/8XDKNLZRuC/6U4ucYCAsgoMZ21ledaZkc= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Bjorn Andersson , Laxman Dewangan , Eduardo Valentin , Sasha Levin , linux-pm@vger.kernel.org Subject: [PATCH AUTOSEL 4.9 101/107] thermal: generic-adc: Fix adc to temp interpolation Date: Mon, 28 Jan 2019 11:19:41 -0500 Message-Id: <20190128161947.57405-101-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190128161947.57405-1-sashal@kernel.org> References: <20190128161947.57405-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Bjorn Andersson [ 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 73f55d6a1721..ad601e5b4175 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