Re: [PATCH v5 1/1] i2c: designware: use casting of u64 in clock multiplication to avoid overflow

From: Wolfram Sang
Date: Mon Jan 09 2023 - 07:08:06 EST


On Wed, Dec 21, 2022 at 07:59:00PM +0000, Hanna Hawa wrote:
> From: Lareine Khawaly <lareine@xxxxxxxxxx>
>
> In functions i2c_dw_scl_lcnt() and i2c_dw_scl_hcnt() may have overflow
> by depending on the values of the given parameters including the ic_clk.
> For example in our use case where ic_clk is larger than one million,
> multiplication of ic_clk * 4700 will result in 32 bit overflow.
>
> Add cast of u64 to the calculation to avoid multiplication overflow, and
> use the corresponding define for divide.
>
> Fixes: 2373f6b9744d ("i2c-designware: split of i2c-designware.c into core and bus specific parts")
> Signed-off-by: Lareine Khawaly <lareine@xxxxxxxxxx>
> Signed-off-by: Hanna Hawa <hhhawa@xxxxxxxxxx>

Applied to for-current, thanks!

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