From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: Thor Thayer <thor.thayer@linux.intel.com>
Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
"Gustavo A. R. Silva" <gustavo@embeddedor.com>
Subject: [PATCH] i2c: altera: Use 64-bit arithmetic instead of 32-bit
Date: Mon, 10 Feb 2020 13:26:56 -0600 [thread overview]
Message-ID: <20200210192656.GA8412@embeddedor> (raw)
Add suffix ULL to constant 300 in order to avoid a potential integer
overflow and give the compiler complete information about the proper
arithmetic to use. Notice that this constant is being used in a context
that expects an expression of type u64, but it's currently evaluated
using 32-bit arithmetic.
Addresses-Coverity: 1458369 ("Unintentional integer overflow")
Fixes: 0560ad576268 ("i2c: altera: Add Altera I2C Controller driver")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
drivers/i2c/busses/i2c-altera.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-altera.c b/drivers/i2c/busses/i2c-altera.c
index 5255d3755411..526f453f0ff7 100644
--- a/drivers/i2c/busses/i2c-altera.c
+++ b/drivers/i2c/busses/i2c-altera.c
@@ -171,7 +171,8 @@ static void altr_i2c_init(struct altr_i2c_dev *idev)
/* SCL Low Time */
writel(t_low, idev->base + ALTR_I2C_SCL_LOW);
/* SDA Hold Time, 300ns */
- writel(div_u64(300 * clk_mhz, 1000), idev->base + ALTR_I2C_SDA_HOLD);
+ writel(div_u64(300ULL * clk_mhz, 1000),
+ idev->base + ALTR_I2C_SDA_HOLD);
/* Mask all master interrupt bits */
altr_i2c_int_enable(idev, ALTR_I2C_ALL_IRQ, false);
--
2.25.0
next reply other threads:[~2020-02-10 19:44 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-10 19:26 Gustavo A. R. Silva [this message]
2020-02-10 20:42 ` [PATCH] i2c: altera: Use 64-bit arithmetic instead of 32-bit Thor Thayer
2020-02-11 11:44 ` David Laight
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