linux-kernel - Re: [PATCH v4 1/1] i2c: designware: use casting of u64 in clock multiplication to avoid overflow

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Message-ID: <Y6HtH0RWNYc1gT2+@smile.fi.intel.com>
Date:   Tue, 20 Dec 2022 19:13:03 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Hanna Hawa <hhhawa@...zon.com>
Cc:     wsa@...nel.org, jarkko.nikula@...ux.intel.com,
        mika.westerberg@...ux.intel.com, jsd@...ihalf.com,
        linus.walleij@...aro.org, ben-linux@...ff.org,
        linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org,
        dwmw@...zon.co.uk, benh@...zon.com, ronenk@...zon.com,
        talel@...zon.com, jonnyc@...zon.com, hanochu@...zon.com,
        farbere@...zon.com, itamark@...zon.com,
        Lareine Khawaly <lareine@...zon.com>
Subject: Re: [PATCH v4 1/1] i2c: designware: use casting of u64 in clock
 multiplication to avoid overflow

On Tue, Dec 20, 2022 at 07:11:51PM +0200, Andy Shevchenko wrote:
> On Tue, Dec 20, 2022 at 04:48:06PM +0000, Hanna Hawa wrote:

...

> > -		return DIV_ROUND_CLOSEST(ic_clk * tSYMBOL, MICRO) - 8 + offset;
> > +		return DIV_ROUND_CLOSEST_ULL((u64)ic_clk * tSYMBOL, MICRO) - 8 +
> > +			offset;
> 
> Broken indentation.
> 
> ...
> 
> > -		return DIV_ROUND_CLOSEST(ic_clk * (tSYMBOL + tf), MICRO) - 3 + offset;
> > +		return DIV_ROUND_CLOSEST_ULL((u64)ic_clk * (tSYMBOL + tf),
> > +					     MICRO) - 3 + offset;
> 
> I would still go with 'MICRO) -' part to be on the previous line despite being
> over 80, this is logical split which increases readability.
> 
> > -	return DIV_ROUND_CLOSEST(ic_clk * (tLOW + tf), MICRO) - 1 + offset;
> > +	return DIV_ROUND_CLOSEST_ULL((u64)ic_clk * (tLOW + tf), MICRO) - 1 +
> > +		offset;
> 
> Broken indentation.

That said, can you just follow what I have said in a review of v3?

-- 
With Best Regards,
Andy Shevchenko