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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,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 BE144C433E0 for ; Mon, 29 Jun 2020 20:33:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 95A3F2067D for ; Mon, 29 Jun 2020 20:33:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593462790; bh=XSTF3fm7DRjOxknTkfjWDogjJ1+ZAG3jH+aOYLkF0Mk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=kUr/bD/gWql0m6i/LeNzACMGpVqFf6KqVNW6KGlmuuHVcOGGco43Fknq3ScxcYAaL CmNshKkBL/hGu7lMaKE5DyzKduXaOXcyAEe9flQndT9qNn04tjWwSPOsUVZx1v1c4H aVjl9DxsLl9u8X1+v2QyOwFBa2tOa9zXTDh2M+6A= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389055AbgF2UdJ (ORCPT ); Mon, 29 Jun 2020 16:33:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:37016 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732302AbgF2TZR (ORCPT ); Mon, 29 Jun 2020 15:25:17 -0400 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 9BDC12535E; Mon, 29 Jun 2020 15:40:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593445223; bh=XSTF3fm7DRjOxknTkfjWDogjJ1+ZAG3jH+aOYLkF0Mk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JWTgJZuSm35s/zN5SandQKQ9pikRdarPFKjUSqoLLW+0wZjzbE7A8nZ3+2ua7rGve GMhBqura4I1SxMhKaSNinO6iW8RWL7ZDL6xDFrzSkZmUjGV8IxO9t4T/WtNGkwjhUr a/sd7FNW9nEVPHL21oSfTFxUUSN5ucvWOWF/vvLM= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Andreas Klinger , Jonathan Cameron , Sasha Levin Subject: [PATCH 4.9 010/191] iio: bmp280: fix compensation of humidity Date: Mon, 29 Jun 2020 11:37:06 -0400 Message-Id: <20200629154007.2495120-11-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200629154007.2495120-1-sashal@kernel.org> References: <20200629154007.2495120-1-sashal@kernel.org> MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.9.229-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-4.9.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 4.9.229-rc1 X-KernelTest-Deadline: 2020-07-01T15:39+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Andreas Klinger [ Upstream commit dee2dabc0e4115b80945fe2c91603e634f4b4686 ] Limit the output of humidity compensation to the range between 0 and 100 percent. Depending on the calibration parameters of the individual sensor it happens, that a humidity above 100 percent or below 0 percent is calculated, which don't make sense in terms of relative humidity. Add a clamp to the compensation formula as described in the datasheet of the sensor in chapter 4.2.3. Although this clamp is documented, it was never in the driver of the kernel. It depends on the circumstances (calibration parameters, temperature, humidity) if one can see a value above 100 percent without the clamp. The writer of this patch was working with this type of sensor without noting this error. So it seems to be a rare event when this bug occures. Signed-off-by: Andreas Klinger Signed-off-by: Jonathan Cameron Signed-off-by: Sasha Levin --- drivers/iio/pressure/bmp280-core.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/iio/pressure/bmp280-core.c b/drivers/iio/pressure/bmp280-core.c index 36f03fdf4d4f9..85b90b5939db2 100644 --- a/drivers/iio/pressure/bmp280-core.c +++ b/drivers/iio/pressure/bmp280-core.c @@ -182,6 +182,8 @@ static u32 bmp280_compensate_humidity(struct bmp280_data *data, + (s32)2097152) * H2 + 8192) >> 14); var -= ((((var >> 15) * (var >> 15)) >> 7) * (s32)H1) >> 4; + var = clamp_val(var, 0, 419430400); + return var >> 12; }; -- 2.25.1