From patchwork Mon Jan 11 11:17:03 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Baruch Siach X-Patchwork-Id: 12010257 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=-17.0 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 00653C433E6 for ; Mon, 11 Jan 2021 11:19:23 +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 B40D921D7F for ; Mon, 11 Jan 2021 11:19:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B40D921D7F 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=1d1MilsKsBxRr23pqE6C10KzWD22IQPg+8JHIBdfeJM=; b=ykypIxrD/vNthxEq5LwNbK7eV B5tetcWAcIpWkLTeofncBgnualWruBN1sKLEiOJVR76QBRAjun0BqjLaDnXyvTtt/D0XkY49VAbNV HLZ4J6mhvTmB957OnLa53jx7GfAV8k7pdkTAjYok0+kYPxc0SDc+htj8yZaTGouprWKeGZL2UKksW g9OPXF9EMNfmagGtBmDJ2laU6+kE3MqaB/Ba9+u6Ok87gnqz+J679uYYFDHGDzEprz6n88y4l2Q+i hjpDYPGuT2PK3Q1A65QAU8NnkZkZczGGJFIwQ30fXyEEAzc6fVkmN8u+gWVxwwLp4NNxo5t0MqW+j Erg8a0UJg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kyvCr-0001qq-U7; Mon, 11 Jan 2021 11:17:53 +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 1kyvCk-0001nz-0q for linux-arm-kernel@lists.infradead.org; Mon, 11 Jan 2021 11:17:47 +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 68D024403E5; Mon, 11 Jan 2021 13:17:41 +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 2/5] gpio: mvebu: improve pwm period calculation accuracy Date: Mon, 11 Jan 2021 13:17:03 +0200 Message-Id: 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-20210111_061746_250598_7C3F44B5 X-CRM114-Status: GOOD ( 16.32 ) 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 Divide the full period value to reduce rounding error. Reported-by: Uwe Kleine-König Signed-off-by: Baruch Siach Reviewed-by: Uwe Kleine-König --- 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)