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=-20.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,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 1DEDDC6377C for ; Mon, 19 Jul 2021 17:43:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 135D26120F for ; Mon, 19 Jul 2021 17:43:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1359260AbhGSRBH (ORCPT ); Mon, 19 Jul 2021 13:01:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:59768 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347285AbhGSPfG (ORCPT ); Mon, 19 Jul 2021 11:35:06 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 38CA261461; Mon, 19 Jul 2021 16:12:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626711126; bh=jHaHEvBaMngbGlFOPVwwTzBpRwK1qt1DGNPYQrrnlQk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QmHvCyGqZ5eHe50TbCBwag8OONjYZDcI5Hp3bc+3n/aEywCdKZPUfN+4Yltv25D3N CVA15grp+OqfkzI9Le6wP4Bl70fk728tApuyWRV2NTIVEDcq60uR/StSKyjVWyL6vp /jm4+NidZ8uO2hXapWeljKInV582fK/8U2hLeM9Y= 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?= , Nobuhiro Iwamatsu , Thierry Reding , Sasha Levin Subject: [PATCH 5.13 204/351] pwm: visconti: Fix and simplify period calculation Date: Mon, 19 Jul 2021 16:52:30 +0200 Message-Id: <20210719144951.717684587@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210719144944.537151528@linuxfoundation.org> References: <20210719144944.537151528@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Uwe Kleine-König [ Upstream commit 937efa29e70f7f8424b74631375dcb35d82a4614 ] With the original code a request for period = 65536000 ns and period = 32768000 ns yields the same register settings (which results in 32768000 ns) because the value for pwmc0 was miscalculated. Also simplify using that fls(0) is 0. Fixes: 721b595744f1 ("pwm: visconti: Add Toshiba Visconti SoC PWM support") Signed-off-by: Uwe Kleine-König Acked-by: Nobuhiro Iwamatsu Signed-off-by: Thierry Reding Signed-off-by: Sasha Levin --- drivers/pwm/pwm-visconti.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-) diff --git a/drivers/pwm/pwm-visconti.c b/drivers/pwm/pwm-visconti.c index 46d903786366..af4e37d3e3a6 100644 --- a/drivers/pwm/pwm-visconti.c +++ b/drivers/pwm/pwm-visconti.c @@ -82,17 +82,14 @@ static int visconti_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, return -ERANGE; /* - * PWMC controls a divider that divides the input clk by a - * power of two between 1 and 8. As a smaller divider yields - * higher precision, pick the smallest possible one. + * PWMC controls a divider that divides the input clk by a power of two + * between 1 and 8. As a smaller divider yields higher precision, pick + * the smallest possible one. As period is at most 0xffff << 3, pwmc0 is + * in the intended range [0..3]. */ - if (period > 0xffff) { - pwmc0 = ilog2(period >> 16); - if (WARN_ON(pwmc0 > 3)) - return -EINVAL; - } else { - pwmc0 = 0; - } + pwmc0 = fls(period >> 16); + if (WARN_ON(pwmc0 > 3)) + return -EINVAL; period >>= pwmc0; duty_cycle >>= pwmc0; -- 2.30.2