From patchwork Wed Jan 20 16:16:25 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Baruch Siach X-Patchwork-Id: 12032809 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=-16.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,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 EA064C433E6 for ; Wed, 20 Jan 2021 16:18:34 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 976E0233CE for ; Wed, 20 Jan 2021 16:18:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 976E0233CE Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=tkos.co.il Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-Id:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=lCZOSKP3569LMWqPgTxKWKoYC81T9Gaiuq4C4n3FXc0=; b=T7gj8wknFgTLOXeZ+SDBUPVNU lhnqU66B+7tE9+9/Y8BadDMzk3StClI774K3N8ea1LP1ICPFIw4X5S2RPXRxLoq0wQKQlN/NDvQ4S BNWjQdXs6BxHk9JMURF+N+ujpQqoD3pN2aaWDpqcSLi7Tgo3a1dPJbMK9mc2nCIwAOBKnYpjjMSpc B7MEA+CZ3/E4cXL2UyitbNPQIkSSwUmYCsG/XVjnVqsQy3S9iUcJNZz9l4/3OUk/9G/a//LPYDOiP 88hEGJjgPi98FSPGFproDHBNSP7Lz6Drwg+OGx0YDrjSPGA5qfmX4ZqDCGXPZxyUbOsqlpaZa/n6x 3GmlGTU6g==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l2GAC-00060B-MO; Wed, 20 Jan 2021 16:16:56 +0000 Received: from guitar.tcltek.co.il ([192.115.133.116] helo=mx.tkos.co.il) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l2GA3-0005vX-CR for linux-arm-kernel@lists.infradead.org; Wed, 20 Jan 2021 16:16:48 +0000 Received: from tarshish.tkos.co.il (unknown [10.0.8.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx.tkos.co.il (Postfix) with ESMTPS id 545E744079E; Wed, 20 Jan 2021 18:16:38 +0200 (IST) From: Baruch Siach To: Thierry Reding , =?utf-8?q?Uwe_Kleine-K=C3=B6n?= =?utf-8?q?ig?= , Lee Jones , Linus Walleij , Bartosz Golaszewski Subject: [PATCH v5 1/4] gpio: mvebu: improve pwm period calculation accuracy Date: Wed, 20 Jan 2021 18:16:25 +0200 Message-Id: <0c70e683121eb6970cfce31aa105cd09d52297e6.1611128398.git.baruch@tkos.co.il> X-Mailer: git-send-email 2.29.2 In-Reply-To: References: MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210120_111647_614965_5C359380 X-CRM114-Status: GOOD ( 16.72 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Andrew Lunn , Baruch Siach , linux-pwm@vger.kernel.org, Gregory Clement , Russell King , linux-gpio@vger.kernel.org, Chris Packham , Thomas Petazzoni , Ralph Sennhauser , Sascha Hauer , linux-arm-kernel@lists.infradead.org, Sebastian Hesselbarth Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Change 'off' register value calculation from $off = (period - duty_cycle) * clkrate / NSEC_PER_SEC to $off = (period * clkrate / NSEC_PER_SEC) - $on That is, divide the full period value to reduce rounding error. Reported-by: Uwe Kleine-König Reviewed-by: Uwe Kleine-König Reviewed-by: Linus Walleij Signed-off-by: Baruch Siach --- drivers/gpio/gpio-mvebu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpio/gpio-mvebu.c b/drivers/gpio/gpio-mvebu.c index a912a8fed197..c424d88e9e2b 100644 --- a/drivers/gpio/gpio-mvebu.c +++ b/drivers/gpio/gpio-mvebu.c @@ -715,9 +715,9 @@ static int mvebu_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, else on = 1; - val = (unsigned long long) mvpwm->clk_rate * - (state->period - state->duty_cycle); + val = (unsigned long long) mvpwm->clk_rate * state->period; do_div(val, NSEC_PER_SEC); + val -= on; if (val > UINT_MAX) return -EINVAL; if (val)