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 71A733277BD for ; Thu, 21 Aug 2025 13:17:00 +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=1755782220; cv=none; b=NySFoQqStekFzxWh5Cyd+dNVbnWpyS8CwkebjCSizzpH3GMnDR/w78vdaFd92mf74Nxium6d9/XBgZtIS+5YZKtB9Xpd2yTYnAcqwp4QJ4D8WNDK+cyQ2xxLieHnlfRXj1UKGqmMVo1ws58Sik0nZ3UJGP0N/9GbcoKGNEHhEAM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755782220; c=relaxed/simple; bh=wLb5Ir4++BEuEDheNFzGHKuFlB3A3OQb7lM7wljGwy0=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=cZ+i+jais2/SjrwgpMmGTxDpocMEhG/szCUc/nXAR4argyAx5XlPymsvs1/w1qF3FlEr6q4Z25UQSJ/U80QPx0/k/uL1gf8wCo7/ndtixgDyvRvJ26OrZk005d87oTqkriTnc2zOg4g8pntPXfsbMTtnepVEJ/Lc5ZO/4g1H1no= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=rY47CnCj; 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="rY47CnCj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BBD1CC113CF; Thu, 21 Aug 2025 13:16:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1755782220; bh=wLb5Ir4++BEuEDheNFzGHKuFlB3A3OQb7lM7wljGwy0=; h=Subject:To:Cc:From:Date:From; b=rY47CnCjfh/5IvlSASz8c/k4TMQVy2htO3HEl5078WZ5uwQk273KI4/3bOlftzC5l 5hDRbaL8PPe5VTgRG+TB6ym9Euyf/RMyciIFTlvkbDL5qPh7mhizNky6+IX9PfpKSG hDfCATcNPJV+lW1FP38nVjYaYzFwbPWC/7n7O6uU= Subject: FAILED: patch "[PATCH] pwm: mediatek: Fix duty and period setting" failed to apply to 5.15-stable tree To: u.kleine-koenig@baylibre.com,angelogioacchino.delregno@collabora.com,ukleinek@kernel.org Cc: From: Date: Thu, 21 Aug 2025 15:16:42 +0200 Message-ID: <2025082142-splotchy-hypocrite-964a@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x f21d136caf8171f94159d975ea4620c164431bd9 # git commit -s git send-email --to '' --in-reply-to '2025082142-splotchy-hypocrite-964a@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From f21d136caf8171f94159d975ea4620c164431bd9 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= Date: Mon, 28 Jul 2025 18:00:18 +0200 Subject: [PATCH] pwm: mediatek: Fix duty and period setting MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 diff --git a/drivers/pwm/pwm-mediatek.c b/drivers/pwm/pwm-mediatek.c index b6560e52c803..e4b595fc5a5e 100644 --- a/drivers/pwm/pwm-mediatek.c +++ b/drivers/pwm/pwm-mediatek.c @@ -170,7 +170,10 @@ static int pwm_mediatek_config(struct pwm_chip *chip, struct pwm_device *pwm, 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, @@ -193,9 +196,16 @@ static int pwm_mediatek_config(struct pwm_chip *chip, struct pwm_device *pwm, } 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); @@ -224,11 +234,8 @@ static int pwm_mediatek_apply(struct pwm_chip *chip, struct pwm_device *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; }