From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 C7DFA3BD63B; Tue, 21 Jul 2026 22:04:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784671462; cv=none; b=QVtK3DmQukGzFURgukcD6EpxdgEmi8GOKNQagKE48VKoOMhqdK0Rr2UZUxbPmqvNEmVgFpSxgKs668EFtl8K3EwOoRYlDwcw3FoZANmRD+zEzcbOaJu0S0mJzMlotGN9TRDaQALY+cP5EPGvnx4MMIhJ0xwVl0ohpeFpg2xilCA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784671462; c=relaxed/simple; bh=I/eGE9zAVdVXzCadtEIi++rS/igFgAcgPRK1UvUp/tM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=BNDobYNSqhzyAitbh+N1+CJiGDnWHeGct07bqfWpgQTcDpGVF3kL22mCD3FKfHW95Aw3wnlYgrvmUq9KmlLrM/+CR1ZeMgkpQu4NvVBCCgzSHQa9zIfWUwBPstfJojk6vHUmtXaD+JvBMhOkgHEzN+RTNBJT7lieO6bwRlm/7Bc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=e9Q/0xsa; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="e9Q/0xsa" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 38FE41F000E9; Tue, 21 Jul 2026 22:04:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784671461; bh=lkcPqwO7v33AIzipChhyOfeGmkknhFKBbcc5XtRixb0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=e9Q/0xsa9jm7dhdzsoqfK9Nt27WxBVZgm/bEsr7SdgUy0wiXw4UaYCUBbafvroO7v j3SExr/GJ137pcvHFrY9t1VxAGaZu3J3ZdcBVKPc4Bt2ifalDmR3HzFgVmjK/YE8ud Gu8l+gqLmA0JYAFQGe3sUeUSx6D0pJYyMNKdNf9Q= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ronaldo Nunez , Frank Li , =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= , Sasha Levin Subject: [PATCH 5.15 254/843] pwm: imx27: Fix variable truncation in .apply() Date: Tue, 21 Jul 2026 17:18:09 +0200 Message-ID: <20260721152411.738144358@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152405.946368001@linuxfoundation.org> References: <20260721152405.946368001@linuxfoundation.org> User-Agent: quilt/0.69 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 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ronaldo Nunez [ Upstream commit dc9e08fdbcc3eb08a1d2b868b535081c44425e27 ] Fix a variable truncation when calculating period in microseconds as part of the solution for the ERR051198 in .apply() callback. Example scenario: - Period of 3us (PWMPR = 196 and prescaler = 1) - Expected value in tmp: 198000000000 (NSEC_PER_SEC * (196 + 2) * 1) - Actual value is 431504384 (truncation to u32) Signed-off-by: Ronaldo Nunez Reviewed-by: Frank Li Link: https://patch.msgid.link/20260522191348.6227-1-rnunez@baylibre.com Fixes: a25351e4c774 ("pwm: imx27: Workaround of the pwm output bug when decrease the duty cycle") Signed-off-by: Uwe Kleine-König Signed-off-by: Sasha Levin --- drivers/pwm/pwm-imx27.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/pwm/pwm-imx27.c b/drivers/pwm/pwm-imx27.c index ce8dbd5d174f64..2db2c53300fb14 100644 --- a/drivers/pwm/pwm-imx27.c +++ b/drivers/pwm/pwm-imx27.c @@ -216,7 +216,7 @@ static void pwm_imx27_wait_fifo_slot(struct pwm_chip *chip, static int pwm_imx27_apply(struct pwm_chip *chip, struct pwm_device *pwm, const struct pwm_state *state) { - unsigned long period_cycles, duty_cycles, prescale, period_us, tmp; + unsigned long period_cycles, duty_cycles, prescale, period_us; struct pwm_imx27_chip *imx = to_pwm_imx27_chip(chip); struct pwm_state cstate; unsigned long long c; @@ -225,6 +225,7 @@ static int pwm_imx27_apply(struct pwm_chip *chip, struct pwm_device *pwm, int val; int ret; u32 cr; + u64 tmp; pwm_get_state(pwm, &cstate); @@ -268,6 +269,11 @@ static int pwm_imx27_apply(struct pwm_chip *chip, struct pwm_device *pwm, val = readl(imx->mmio_base + MX3_PWMPR); val = val >= MX3_PWMPR_MAX ? MX3_PWMPR_MAX : val; cr = readl(imx->mmio_base + MX3_PWMCR); + + /* + * tmp stores period in nanoseconds. Result fits in u64 since + * val <= 0xfffe and prescaler in [1, 0x1000]. + */ tmp = NSEC_PER_SEC * (u64)(val + 2) * MX3_PWMCR_PRESCALER_GET(cr); tmp = DIV_ROUND_UP_ULL(tmp, clkrate); period_us = DIV_ROUND_UP_ULL(tmp, 1000); -- 2.53.0