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,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 5F28DC433DF for ; Fri, 19 Jun 2020 15:34:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 34BE320786 for ; Fri, 19 Jun 2020 15:34:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592580842; bh=9bceEJ9pJZhQjQluZuGetqYQXAYC7KXWl/AlOJEesNk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=KotXo6KDA8iFUcvj+ZkKQnZG22HHtmOAWa+RLwRgKKZaCYkYF+11sGvAXW7w2Fs22 BWf1m0ZPn2kEreIhLCh0RihI4j37DGR19VQul6+Jz99pZyIbqF4GrFuDwe2OCk279e adBvm9MBbxYuAsiqsPw8Ypn+0rd3E7SzP2H49cos= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393687AbgFSPdz (ORCPT ); Fri, 19 Jun 2020 11:33:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:37100 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404915AbgFSPdF (ORCPT ); Fri, 19 Jun 2020 11:33:05 -0400 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 4EAE920786; Fri, 19 Jun 2020 15:33:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592580784; bh=9bceEJ9pJZhQjQluZuGetqYQXAYC7KXWl/AlOJEesNk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=J1um2GMFMKAs7kOUqHyHkyaTaDaClE/iI7jyH6sHIyvzuo0b7zMFKlOp00MZFRRky PH5iTi5dX6NFwloMt+pWM81/xf+c0HqgRHgdKLB1durV1kar4r/2hbGv3Zf+uhBzyu GoC/hp2nw4mZxgQwheOYoA6NmH4PNP9qEs+jncqI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= , Paul Cercueil , Thierry Reding Subject: [PATCH 5.7 351/376] pwm: jz4740: Enhance precision in calculation of duty cycle Date: Fri, 19 Jun 2020 16:34:29 +0200 Message-Id: <20200619141726.940210748@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200619141710.350494719@linuxfoundation.org> References: <20200619141710.350494719@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: Paul Cercueil commit 9017dc4fbd59c09463019ce494cfe36d654495a8 upstream. Calculating the hardware value for the duty from the hardware value of the period resulted in a precision loss versus calculating it from the clock rate directly. (Also remove a cast that doesn't really need to be here) Fixes: f6b8a5700057 ("pwm: Add Ingenic JZ4740 support") Cc: Suggested-by: Uwe Kleine-König Reviewed-by: Uwe Kleine-König Signed-off-by: Paul Cercueil Signed-off-by: Thierry Reding Signed-off-by: Greg Kroah-Hartman --- drivers/pwm/pwm-jz4740.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/drivers/pwm/pwm-jz4740.c +++ b/drivers/pwm/pwm-jz4740.c @@ -158,11 +158,11 @@ static int jz4740_pwm_apply(struct pwm_c /* Calculate period value */ tmp = (unsigned long long)rate * state->period; do_div(tmp, NSEC_PER_SEC); - period = (unsigned long)tmp; + period = tmp; /* Calculate duty value */ - tmp = (unsigned long long)period * state->duty_cycle; - do_div(tmp, state->period); + tmp = (unsigned long long)rate * state->duty_cycle; + do_div(tmp, NSEC_PER_SEC); duty = period - tmp; if (duty >= period)