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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 D4357C2D0DB for ; Tue, 28 Jan 2020 14:24:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A1C752468A for ; Tue, 28 Jan 2020 14:24:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580221487; bh=rz9au/x2/LhW2l2P+rOP9AVynizyhC9avk5oBjR3xvU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=G+XSZrghY0gkqde3iBjUObiDUlV1qwU29NboQAf7+7gsk32liDHEstbRKWXRc2dSg l5k9Om6CQX2+Yb3wBA0IKW3wykULD/ddzBrv5BsxK/9mZLvKn8eHyF5FEibVZ/tmD3 ZMYKhjEXeApC4gspsvQR2rf2DI58gWlyug+Pka2M= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732762AbgA1OYq (ORCPT ); Tue, 28 Jan 2020 09:24:46 -0500 Received: from mail.kernel.org ([198.145.29.99]:51536 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732370AbgA1OYn (ORCPT ); Tue, 28 Jan 2020 09:24:43 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.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 1526B24686; Tue, 28 Jan 2020 14:24:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580221482; bh=rz9au/x2/LhW2l2P+rOP9AVynizyhC9avk5oBjR3xvU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Tq9/JJHRXKXfdRf8S2IO9gOU/4Mod38jzESjnLUkEQ8Xfs8u5xWW4+Q41ckhgDGc1 4CpukFcisw9iQC1vDJlvdEibMvM+kQOvOjk0C1CmzTVUhVfrm6AXLrGM6vBnt9G7ga N8CtmCWZZdfSYXXSpRYqYnqtJ9o2tJVeNwhkGtGE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Luuk Paulussen , Guenter Roeck Subject: [PATCH 4.9 243/271] hwmon: (adt7475) Make volt2reg return same reg as reg2volt input Date: Tue, 28 Jan 2020 15:06:32 +0100 Message-Id: <20200128135910.618534426@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200128135852.449088278@linuxfoundation.org> References: <20200128135852.449088278@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Luuk Paulussen commit cf3ca1877574a306c0207cbf7fdf25419d9229df upstream. reg2volt returns the voltage that matches a given register value. Converting this back the other way with volt2reg didn't return the same register value because it used truncation instead of rounding. This meant that values read from sysfs could not be written back to sysfs to set back the same register value. With this change, volt2reg will return the same value for every voltage previously returned by reg2volt (for the set of possible input values) Signed-off-by: Luuk Paulussen Link: https://lore.kernel.org/r/20191205231659.1301-1-luuk.paulussen@alliedtelesis.co.nz cc: stable@vger.kernel.org Signed-off-by: Guenter Roeck Signed-off-by: Greg Kroah-Hartman --- drivers/hwmon/adt7475.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/drivers/hwmon/adt7475.c +++ b/drivers/hwmon/adt7475.c @@ -268,9 +268,10 @@ static inline u16 volt2reg(int channel, long reg; if (bypass_attn & (1 << channel)) - reg = (volt * 1024) / 2250; + reg = DIV_ROUND_CLOSEST(volt * 1024, 2250); else - reg = (volt * r[1] * 1024) / ((r[0] + r[1]) * 2250); + reg = DIV_ROUND_CLOSEST(volt * r[1] * 1024, + (r[0] + r[1]) * 2250); return clamp_val(reg, 0, 1023) & (0xff << 2); }