From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 14B71CD5BB0 for ; Fri, 22 May 2026 19:14:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:Message-ID:Date:Subject:Cc:To:From:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=bcQfxlYT0WdkNlclpO13skLK1pFgoPq0lf6iXLyTJ4A=; b=ANCxPELcK47AjmTTuPKJzOm5wd +HfdpwnqqJ+wQQwjya+vMgZLjxC5IW5K4KNGjf8tGL1hTsBAqXYruTL4nMcfgTvRnr+K4tQmVQcq3 gJhjXwSuI/NJooj1FwzVvkoSGWKsQ7ZJhUqu93j0iTexi9nleHx1Yann2n0vSJUYSIhSlyuJ5qBTO Q3IveSy0/rR1fwwssnr0RGJ1GIzDBhmYAoXBypHys/73Ol2HkN7ZFLUPI7t2NezFbZ4ebkqBS7eme l5ISI3LpQYhVgRwUb9Fe/EWEDigecT4sirbeB4mGbDMk5wghDT5b3Qu2ARluEmw5XiFgqljDzvJJh Nr9r2Pmg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wQVKA-0000000BkUe-3fw9; Fri, 22 May 2026 19:14:22 +0000 Received: from mail-vk1-xa36.google.com ([2607:f8b0:4864:20::a36]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wQVK8-0000000BkU8-3fQY for linux-arm-kernel@lists.infradead.org; Fri, 22 May 2026 19:14:22 +0000 Received: by mail-vk1-xa36.google.com with SMTP id 71dfb90a1353d-57611a6a69eso2308512e0c.3 for ; Fri, 22 May 2026 12:14:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=baylibre.com; s=google; t=1779477259; x=1780082059; darn=lists.infradead.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=bcQfxlYT0WdkNlclpO13skLK1pFgoPq0lf6iXLyTJ4A=; b=eRn9N9mYmMGapBGUd4RtVpLfJMRPaL6NW7xPiyQPGAzLNHLqi7p83hQKj1CDK+COH6 6vW4WO+7o/yuWRFT5IM7IlFqqwc4hGb2RvG6G+ZtFgoO7NMnxvQadLKsvBm/gZbjBuJ+ JmfR7MEWmzNjaDMq5xozltZWs3DjZU0/hSjitYi2KHZAsu3IyHYi527UONyGhjrAr520 FyzPXfuvjSNY46RVZjx6U4IMU3WZIoZdq67bI6VX1BHDe9cX4hK76VjhvDTSxFQpUuRE Cdlc7MoA4mdQoqGh0xhen5610Q6cjsoaKEP9rxKLlROsb0oaKBb3EKTqtvShhJ9XS9+3 X+Dw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779477259; x=1780082059; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=bcQfxlYT0WdkNlclpO13skLK1pFgoPq0lf6iXLyTJ4A=; b=qU6vM0hFY92g3ZUaKDq5AzPs7/fVZrVf0FFVyFJbUL3D5DijG2YtKRMMqkcx6/5nq8 XId3UhygeoFSkgUx8Fhn6owmf60T/KWrLx952gvZSMaujaeM+/MHB7TU/XQ94ZwMpQ3j F0uf+PvPmnEpvXaIeK/URujk8x+WTUJd4fqOCDio9m55RZHfYhgBNsLiruoevONN2oox d3Fo5BawaohpvZKw+/gCFM31vH9q8h+2ECT918jSRoiBWBnbsBptDmO7R4jMVbAOBcmc 4XLy84C+PsVCs8B2fG4k1ufMm0nRJ7NDppvSelCbXAz8h1hgBmCkas+QDUb7A8n/+fXJ P1uA== X-Forwarded-Encrypted: i=1; AFNElJ/Sr/xE1WB4+QI/eSxm1H55CGdbeb2KGi7Zu+FVv8l7+ctQ630fWm5MpJkBdcfMz2HqD6El8hS+PvmlIKeX0vZ+@lists.infradead.org X-Gm-Message-State: AOJu0YyWD4zQGyRy8jyhidei1DZ1o77pYyztIfnD2kC8zarWCKtFb/Qd i3HRLvV/zF7DPOWyMfE8qluzorE9dVdltr781D0uTxhPT5Lb6aBToA0vylEu/HdfkQ4= X-Gm-Gg: Acq92OGq/fTPVMbjGRG5PkXUqxpeanFu4qwWjgoYxMclD/w5SM8pxt9AYpI76cTF2hr /zF/HDcmmpVQMeyxJfmkon0LfrfEBmpc+Gz4lYN8tkau93jqbQIt4nEzGrNOIsrjGP4h1zbAvuK V8orXcXDwZxAGanNX97kHftQ5dIj8jCEACmz8njNp87ubXaj0QVlOf86u1dHZuNrvw4dmWHx6ri yyE/5C3saNNUPiYqLwE6HoSTK+VpAHU23HHohyFPp4EQ7zQsa0QlZ0ljxOCf4e7ndn67ib5he/D zQD7+msAQ9gWIXQZr71lltsFbkmSTx+sssWA6Mzpu5AgQ1Q5TxmoUf9gZ5dbSBBFO7099sIvBK5 cDuTOQgNVD7vYVKL3xX9mkyxCYahM12wwUcFpvfnX17dfBLFxHR2Pmjp/Mr8N/cyNW3AQKMFzSg SxnRHIo1Eek70mDo6BbCe5htbJabmBkUEbOwxsSdfXew== X-Received: by 2002:a05:6122:330a:b0:56f:adb8:7c54 with SMTP id 71dfb90a1353d-5865e3aff5emr3335785e0c.3.1779477259066; Fri, 22 May 2026 12:14:19 -0700 (PDT) Received: from acer-e1.tail6c460f.ts.net ([2804:7f0:7542:7b16:2880:ed6d:f5c:8b9e]) by smtp.gmail.com with ESMTPSA id a1e0cc1a2514c-96173af3e82sm2741013241.10.2026.05.22.12.14.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 22 May 2026 12:14:18 -0700 (PDT) From: Ronaldo Nunez To: linux-pwm@vger.kernel.org Cc: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= , Frank Li , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Ronaldo Nunez Subject: [PATCH v2] pwm: imx27: Fix variable truncation in .apply() Date: Fri, 22 May 2026 16:13:48 -0300 Message-ID: <20260522191348.6227-1-rnunez@baylibre.com> X-Mailer: git-send-email 2.53.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260522_121420_923493_2E0E87C3 X-CRM114-Status: GOOD ( 12.17 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 --- Changes in v2: - Added example with actual PWMPR/prescaler values per Frank Li's feedback - Dropped testing section --- 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 3d34cdc4a3a5..c8b801fcb525 100644 --- a/drivers/pwm/pwm-imx27.c +++ b/drivers/pwm/pwm-imx27.c @@ -200,7 +200,7 @@ 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); unsigned long long c; unsigned long long clkrate; @@ -208,6 +208,7 @@ static int pwm_imx27_apply(struct pwm_chip *chip, struct pwm_device *pwm, int val; int ret; u32 cr; + u64 tmp; clkrate = clk_get_rate(imx->clks[PWM_IMX27_PER].clk); c = clkrate * state->period; @@ -249,6 +250,11 @@ 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