From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BB28910E0; Tue, 26 Aug 2025 14:43:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756219398; cv=none; b=DYOZlRu2BBBGLWyz7jqs/JFt5KbHcMjVb1UjJZ5Oz1eITRKHifRNSNCrbzYzxyMPt4Vv7hEhej4heP7EatnrMZqEcRF0ZYZ1qZwwdlf+dvbiE1Qdv4tihQwC2Hj4EGtgkEm3vUog0YRDB8T8uPsm3QD7cb2BjgATx6jtNMatRh0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756219398; c=relaxed/simple; bh=cxTJC3oByel+qc/kaxje/PtyTcjYKQLDxbCLCKuQFRs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=BeobHrIVyy3AIcNS1cywSW4YAp9CRemWRpBir+msk8jH57SqE5eZdMKo9ng5mFEX3Rn66VS4WBCncwmvEm0pMuYICC64tbWiYgz2yQXNyBMqdAXGLjWg1TkiC8I3u0jgtaKwrtyOqTc3gRXx+g7kZmo9liHbCKLCnKeVTxKqhI0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=EWJmJkDU; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="EWJmJkDU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4CD86C113CF; Tue, 26 Aug 2025 14:43:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756219398; bh=cxTJC3oByel+qc/kaxje/PtyTcjYKQLDxbCLCKuQFRs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EWJmJkDUwPrF+vIN/9mZx/us+XtGru6SvDLdf6xYlmWwymRYi6bfbiSl03HYcERg5 HO5edPwq5cqcdpM8ZKWho7dcoAHRv26Dw6bCenKnWyf+AawJ1/GSz6FPEYyff+xsxd 48ay2Wh89AIpdt2yWxZYhuySunRqyWF8lvR8u7/8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= , AngeloGioacchino Del Regno , =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= , Sasha Levin Subject: [PATCH 5.4 367/403] pwm: mediatek: Fix duty and period setting Date: Tue, 26 Aug 2025 13:11:33 +0200 Message-ID: <20250826110917.144011112@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250826110905.607690791@linuxfoundation.org> References: <20250826110905.607690791@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Uwe Kleine-König [ Upstream commit f21d136caf8171f94159d975ea4620c164431bd9 ] The period generated by the hardware is (PWMDWIDTH + 1) << CLKDIV) / freq according to my tests with a signal analyser and also the documentation. The current algorithm doesn't consider the `+ 1` part and so configures slightly too high periods. The same issue exists for the duty cycle setting. So subtract 1 from both the register values for period and duty cycle. If period is 0, bail out, if duty_cycle is 0, just disable the PWM which results in a constant low output. Fixes: caf065f8fd58 ("pwm: Add MediaTek PWM support") Signed-off-by: Uwe Kleine-König Reviewed-by: AngeloGioacchino Del Regno Link: https://lore.kernel.org/r/6d1fa87a76f8020bfe3171529b8e19baffceab10.1753717973.git.u.kleine-koenig@baylibre.com Cc: stable@vger.kernel.org Signed-off-by: Uwe Kleine-König Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/pwm/pwm-mediatek.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) --- a/drivers/pwm/pwm-mediatek.c +++ b/drivers/pwm/pwm-mediatek.c @@ -168,7 +168,10 @@ static int pwm_mediatek_config(struct pw do_div(resolution, clk_rate); cnt_period = DIV_ROUND_CLOSEST_ULL((u64)period_ns * 1000, resolution); - while (cnt_period > 8191) { + if (!cnt_period) + return -EINVAL; + + while (cnt_period > 8192) { resolution *= 2; clkdiv++; cnt_period = DIV_ROUND_CLOSEST_ULL((u64)period_ns * 1000, @@ -191,9 +194,16 @@ static int pwm_mediatek_config(struct pw } cnt_duty = DIV_ROUND_CLOSEST_ULL((u64)duty_ns * 1000, resolution); + pwm_mediatek_writel(pc, pwm->hwpwm, PWMCON, BIT(15) | clkdiv); - pwm_mediatek_writel(pc, pwm->hwpwm, reg_width, cnt_period); - pwm_mediatek_writel(pc, pwm->hwpwm, reg_thres, cnt_duty); + pwm_mediatek_writel(pc, pwm->hwpwm, reg_width, cnt_period - 1); + + if (cnt_duty) { + pwm_mediatek_writel(pc, pwm->hwpwm, reg_thres, cnt_duty - 1); + pwm_mediatek_enable(chip, pwm); + } else { + pwm_mediatek_disable(chip, pwm); + } out: pwm_mediatek_clk_disable(chip, pwm); @@ -222,11 +232,8 @@ static int pwm_mediatek_apply(struct pwm if (err) return err; - if (!pwm->state.enabled) { + if (!pwm->state.enabled) err = pwm_mediatek_clk_enable(chip, pwm); - if (!err) - pwm_mediatek_enable(chip, pwm); - } return err; }