From: Jarkko Nikula <jarkko.nikula@linux.intel.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Hanna Hawa <hhhawa@amazon.com>
Cc: wsa@kernel.org, mika.westerberg@linux.intel.com,
jsd@semihalf.com, linus.walleij@linaro.org, ben-linux@fluff.org,
linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
dwmw@amazon.co.uk, benh@amazon.com, ronenk@amazon.com,
talel@amazon.com, jonnyc@amazon.com, hanochu@amazon.com,
farbere@amazon.com, itamark@amazon.com, lareine@amazon.com
Subject: Re: [PATCH v5 1/1] i2c: designware: use casting of u64 in clock multiplication to avoid overflow
Date: Thu, 22 Dec 2022 17:14:14 +0200 [thread overview]
Message-ID: <9c663363-49a0-da2f-508b-dbf3906b4d61@linux.intel.com> (raw)
In-Reply-To: <Y6NnkDwD9UUQ8Ro/@smile.fi.intel.com>
On 12/21/22 22:07, Andy Shevchenko wrote:
> On Wed, Dec 21, 2022 at 07:59:00PM +0000, Hanna Hawa wrote:
>> From: Lareine Khawaly <lareine@amazon.com>
>>
>> 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.
>
> Perfect, thank you!
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
next prev parent reply other threads:[~2022-12-22 15:14 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-21 19:59 [PATCH v5 1/1] i2c: designware: use casting of u64 in clock multiplication to avoid overflow Hanna Hawa
2022-12-21 20:07 ` Andy Shevchenko
2022-12-22 15:14 ` Jarkko Nikula [this message]
2023-01-09 12:07 ` Wolfram Sang
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