Messages in this thread | | | Date | Sun, 16 Dec 2012 14:27:58 +0800 | Subject | Re: [PATCH] clk: factor: calculate rate by do_div | From | Haojian Zhuang <> |
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On Sun, Dec 16, 2012 at 4:54 AM, Mike Turquette <mturquette@linaro.org> wrote: > On Sat, Dec 15, 2012 at 8:41 AM, Haojian Zhuang > <haojian.zhuang@gmail.com> wrote: >> On Tue, Dec 4, 2012 at 9:32 AM, Haojian Zhuang <haojian.zhuang@gmail.com> wrote: >>> On Mon, Dec 3, 2012 at 4:14 PM, Haojian Zhuang <haojian.zhuang@gmail.com> wrote: >>>> clk->rate = parent->rate / div * mult >>>> >>>> The formula is OK. But it may overflow while we do operate with >>>> unsigned long. So use do_div instead. >>>> >>>> Signed-off-by: Haojian Zhuang <haojian.zhuang@gmail.com> >>>> --- >>>> drivers/clk/clk-fixed-factor.c | 5 ++++- >>>> 1 file changed, 4 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/clk/clk-fixed-factor.c b/drivers/clk/clk-fixed-factor.c >>>> index a489985..1ef271e 100644 >>>> --- a/drivers/clk/clk-fixed-factor.c >>>> +++ b/drivers/clk/clk-fixed-factor.c >>>> @@ -28,8 +28,11 @@ static unsigned long clk_factor_recalc_rate(struct clk_hw *hw, >>>> unsigned long parent_rate) >>>> { >>>> struct clk_fixed_factor *fix = to_clk_fixed_factor(hw); >>>> + unsigned long long int rate; >>>> >>>> - return parent_rate * fix->mult / fix->div; >>>> + rate = (unsigned long long int)parent_rate * fix->mult; >>>> + do_div(rate, fix->div); >>>> + return (unsigned long)rate; >>>> } >>>> >>>> static long clk_factor_round_rate(struct clk_hw *hw, unsigned long rate, >>>> -- >>>> 1.7.10.4 >>>> >>> >>> Correct Mike's email address. >> >> Any comments? Does it mean that nobody want to fix the bug? > > Thanks for the patch. My apologies for letting this one slip through > the cracks but my normal email workflow was unavoidably disrupted and > I find myself playing catch-up with pending patches. > > The patch looks good to me but I'll change the $SUBJECT to "clk: > fixed-factor: round_rate should use do_div" and do some testing before > taking it in. > > Regards, > Mike
It's nice. Thank you.
Best Regards Haojian
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