From patchwork Thu Apr 16 08:02:45 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= X-Patchwork-Id: 1271561 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-pwm-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 492sD33WSYz9sP7 for ; Thu, 16 Apr 2020 18:03:15 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2439837AbgDPIDF (ORCPT ); Thu, 16 Apr 2020 04:03:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33118 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S2439759AbgDPIC6 (ORCPT ); Thu, 16 Apr 2020 04:02:58 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 98CB3C061A0C for ; Thu, 16 Apr 2020 01:02:58 -0700 (PDT) Received: from pty.hi.pengutronix.de ([2001:67c:670:100:1d::c5]) by metis.ext.pengutronix.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jOzU6-0005Pu-Ox; Thu, 16 Apr 2020 10:02:54 +0200 Received: from ukl by pty.hi.pengutronix.de with local (Exim 4.89) (envelope-from ) id 1jOzU5-0005D8-Ge; Thu, 16 Apr 2020 10:02:53 +0200 From: =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= To: Thierry Reding Cc: Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , NXP Linux Team , linux-pwm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH] pwm: imx27: Fix rounding behavior Date: Thu, 16 Apr 2020 10:02:45 +0200 Message-Id: <20200416080245.3203-1-u.kleine-koenig@pengutronix.de> X-Mailer: git-send-email 2.26.0.rc2 MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c5 X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-pwm@vger.kernel.org Sender: linux-pwm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pwm@vger.kernel.org To not trigger the warnings provided by CONFIG_PWM_DEBUG - use up-rounding in .get_state() - don't divide by the result of a division - don't use the rounded counter value for the period length to calculate the counter value for the duty cycle Signed-off-by: Uwe Kleine-König --- drivers/pwm/pwm-imx27.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/drivers/pwm/pwm-imx27.c b/drivers/pwm/pwm-imx27.c index a6e40d4c485f..732a6f3701e8 100644 --- a/drivers/pwm/pwm-imx27.c +++ b/drivers/pwm/pwm-imx27.c @@ -150,13 +150,12 @@ static void pwm_imx27_get_state(struct pwm_chip *chip, prescaler = MX3_PWMCR_PRESCALER_GET(val); pwm_clk = clk_get_rate(imx->clk_per); - pwm_clk = DIV_ROUND_CLOSEST_ULL(pwm_clk, prescaler); val = readl(imx->mmio_base + MX3_PWMPR); period = val >= MX3_PWMPR_MAX ? MX3_PWMPR_MAX : val; /* PWMOUT (Hz) = PWMCLK / (PWMPR + 2) */ - tmp = NSEC_PER_SEC * (u64)(period + 2); - state->period = DIV_ROUND_CLOSEST_ULL(tmp, pwm_clk); + tmp = NSEC_PER_SEC * (u64)(period + 2) * prescaler; + state->period = DIV_ROUND_UP_ULL(tmp, pwm_clk); /* * PWMSAR can be read only if PWM is enabled. If the PWM is disabled, @@ -167,8 +166,8 @@ static void pwm_imx27_get_state(struct pwm_chip *chip, else val = imx->duty_cycle; - tmp = NSEC_PER_SEC * (u64)(val); - state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, pwm_clk); + tmp = NSEC_PER_SEC * (u64)(val) * prescaler; + state->duty_cycle = DIV_ROUND_UP_ULL(tmp, pwm_clk); pwm_imx27_clk_disable_unprepare(imx); } @@ -220,22 +219,23 @@ static int pwm_imx27_apply(struct pwm_chip *chip, struct pwm_device *pwm, struct pwm_imx27_chip *imx = to_pwm_imx27_chip(chip); struct pwm_state cstate; unsigned long long c; + unsigned long long clkrate; int ret; u32 cr; pwm_get_state(pwm, &cstate); - c = clk_get_rate(imx->clk_per); - c *= state->period; + clkrate = clk_get_rate(imx->clk_per); + c = clkrate * state->period; - do_div(c, 1000000000); + do_div(c, NSEC_PER_SEC); period_cycles = c; prescale = period_cycles / 0x10000 + 1; period_cycles /= prescale; - c = (unsigned long long)period_cycles * state->duty_cycle; - do_div(c, state->period); + c = clkrate * state->duty_cycle; + do_div(c, NSEC_PER_SEC * prescale); duty_cycles = c; /*