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Subject[PATCH AUTOSEL 5.4 07/58] i2c: altera: Fix potential integer overflow
Date
From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>

[ Upstream commit 54498e8070e19e74498a72c7331348143e7e1f8c ]

Factor out 100 from the equation and do 32-bit arithmetic (3 * clk_mhz / 10)
instead of 64-bit.

Notice that clk_mhz is MHz, so the multiplication will never wrap 32 bits
and there is no need for div_u64().

Addresses-Coverity: 1458369 ("Unintentional integer overflow")
Fixes: 0560ad576268 ("i2c: altera: Add Altera I2C Controller driver")
Suggested-by: David Laight <David.Laight@ACULAB.COM>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Thor Thayer <thor.thayer@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/i2c/busses/i2c-altera.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-altera.c b/drivers/i2c/busses/i2c-altera.c
index 5255d3755411b..1de23b4f3809c 100644
--- a/drivers/i2c/busses/i2c-altera.c
+++ b/drivers/i2c/busses/i2c-altera.c
@@ -171,7 +171,7 @@ 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(3 * clk_mhz / 10, idev->base + ALTR_I2C_SDA_HOLD);

/* Mask all master interrupt bits */
altr_i2c_int_enable(idev, ALTR_I2C_ALL_IRQ, false);
--
2.20.1
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