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From: Chaitanya Sabnis <chaitanya.msabnis@gmail.com>
To: brgl@kernel.org, andi.shyti@kernel.org
Cc: linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Chaitanya Sabnis <chaitanya.msabnis@gmail.com>,
	Sashiko <sashiko-bot@kernel.org>
Subject: [PATCH] i2c: davinci: fix division by zero on missing clock-frequency
Date: Thu, 14 May 2026 16:07:40 +0530	[thread overview]
Message-ID: <20260514103740.5416-1-chaitanya.msabnis@gmail.com> (raw)

When the 'clock-frequency' property is missing from the device tree,
the driver falls back to DAVINCI_I2C_DEFAULT_BUS_FREQ. However, this
macro is defined in kHz (100), whereas the device tree property is
expected in Hz.

The probe function blindly divided the fallback value by 1000, causing
integer truncation that resulted in dev->bus_freq = 0. This triggered
a deterministic division-by-zero kernel panic when calculating clock
dividers later in the probe sequence.

Fix this by isolating the division so it only applies to the Hz value
read from the device tree, cleanly assigning the kHz default otherwise.

Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://lore.kernel.org/all/20260514044726.57297C2BCB7@smtp.kernel.org/
Signed-off-by: Chaitanya Sabnis <chaitanya.msabnis@gmail.com>
---
 drivers/i2c/busses/i2c-davinci.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index a773ba082321..bd0754abdcb7 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -760,9 +760,9 @@ static int davinci_i2c_probe(struct platform_device *pdev)
 
 	r = device_property_read_u32(&pdev->dev, "clock-frequency", &prop);
 	if (r)
-		prop = DAVINCI_I2C_DEFAULT_BUS_FREQ;
-
-	dev->bus_freq = prop / 1000;
+		dev->bus_freq = DAVINCI_I2C_DEFAULT_BUS_FREQ;
+	else
+		dev->bus_freq = prop / 1000;
 
 	dev->has_pfunc = device_property_present(&pdev->dev, "ti,has-pfunc");
 
-- 
2.43.0



             reply	other threads:[~2026-05-14 10:38 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-14 10:37 Chaitanya Sabnis [this message]
2026-05-14 12:16 ` [PATCH] i2c: davinci: fix division by zero on missing clock-frequency Andrew Lunn

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