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 CEDFC3C9EF3; Sun, 13 Sep 2026 06:49:05 +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=1789282147; cv=none; b=qXxnScZUl8pZJ9IV73vMGGPsxrTPRFe4VO8u3QzEQwXa4R9HTUOYTdes6N5Fb02aOPLOlfA5YKHZROKCoKaLngYZfcObwhn+WdeLYiwd6CYYvWGDI2wYNP2AhUAruTD8kpF0tdH2sYXuJDyhFwPAGbFjxJBKQcQuCXxTwFu4PrQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789282147; c=relaxed/simple; bh=LhYpJ485ik2w81eWufq8H1TOWNuj5hgG26G3w9ZImN0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=IAv2p5DeMTkD7hI3CYtFZnkPvqh4SC0xCHNz7MfyPTIyvpsdsRs9UnzqBhqs3uaGgZzospqthZ0fFCwjqHwGpICsGqPjoA2s+aZLnWU662KLfAfobqXrZ/3sJX0G3BYaLeBdmwR2UtVDtOWm0JRZX4LAP1nNahuypGXFBl0YULA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BK3kBiin; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="BK3kBiin" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 48BC01F00898; Sun, 13 Sep 2026 06:49:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789282145; bh=XKqnaSQmKuSO22y7wuizhyR47ub2Nz2pDtirMarQmXk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=BK3kBiinbza54tXVCGMTi/ymbCbFXEU04osBef/03viMesZ+PPQiAQ7l7FnSLkJmk RrJEp3IQoHBR1hNO8wgiEf8AfGEF0uEMKGJIT3YpsRB4xyYJMkpLvE1HoDa61mhpZp CX1APxHKbUox4RBNj+o+0yK9u+Ib4EVBqEYRw3TOaAV1kJxOy/QyJKQZafLXknr56t yikfx1RT6iXqt7sN9172Z2EkY982D0JoIZtYLFE+DZAXaDaTPgoZr5pEMvj6yH4EF0 3o6QpahtKkCmTMppOLE/dzaQuBILTWF6brBVKFhB9eFy5n9uEWZZqcXioc0fTFkEjh EGSc17Z13eEfA== From: Tzung-Bi Shih To: Wim Van Sebroeck , Guenter Roeck Cc: Baruch Siach , linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org, tzungbi@kernel.org Subject: [PATCH 1/3] watchdog: digicolor: Avoid division by zero Date: Sun, 13 Sep 2026 14:48:49 +0800 Message-ID: <20260913064851.8239-2-tzungbi@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260913064851.8239-1-tzungbi@kernel.org> References: <20260913064851.8239-1-tzungbi@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit clk_get_rate() could return 0. Avoid a division by zero panic. Since get_timeleft() cannot propagate errors, check the clock rate early in probe() and cache the rate in the driver data as it is unlikely to change at runtime. Fixes: 336694a01dae ("watchdog: digicolor: driver for Conexant Digicolor CX92755 SoC") Signed-off-by: Tzung-Bi Shih --- drivers/watchdog/digicolor_wdt.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/watchdog/digicolor_wdt.c b/drivers/watchdog/digicolor_wdt.c index 073d37867f47..de1a3267a972 100644 --- a/drivers/watchdog/digicolor_wdt.c +++ b/drivers/watchdog/digicolor_wdt.c @@ -25,6 +25,7 @@ struct dc_wdt { void __iomem *base; struct clk *clk; spinlock_t lock; + unsigned long rate; }; static unsigned timeout; @@ -61,7 +62,7 @@ static int dc_wdt_start(struct watchdog_device *wdog) { struct dc_wdt *wdt = watchdog_get_drvdata(wdog); - dc_wdt_set(wdt, wdog->timeout * clk_get_rate(wdt->clk)); + dc_wdt_set(wdt, wdog->timeout * wdt->rate); return 0; } @@ -79,7 +80,7 @@ static int dc_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t) { struct dc_wdt *wdt = watchdog_get_drvdata(wdog); - dc_wdt_set(wdt, t * clk_get_rate(wdt->clk)); + dc_wdt_set(wdt, t * wdt->rate); wdog->timeout = t; return 0; @@ -90,7 +91,7 @@ static unsigned int dc_wdt_get_timeleft(struct watchdog_device *wdog) struct dc_wdt *wdt = watchdog_get_drvdata(wdog); uint32_t count = readl_relaxed(wdt->base + TIMER_A_COUNT); - return count / clk_get_rate(wdt->clk); + return count / wdt->rate; } static const struct watchdog_ops dc_wdt_ops = { @@ -130,7 +131,11 @@ static int dc_wdt_probe(struct platform_device *pdev) wdt->clk = devm_clk_get(dev, NULL); if (IS_ERR(wdt->clk)) return PTR_ERR(wdt->clk); - dc_wdt_wdd.max_timeout = U32_MAX / clk_get_rate(wdt->clk); + + wdt->rate = clk_get_rate(wdt->clk); + if (!wdt->rate) + return -EINVAL; + dc_wdt_wdd.max_timeout = U32_MAX / wdt->rate; dc_wdt_wdd.timeout = dc_wdt_wdd.max_timeout; dc_wdt_wdd.parent = dev; -- 2.53.0