[PATCH v3 1/3] clk: k210: remove an implicit 64-bit division
Conor Dooley
conor at kernel.org
Mon Mar 6 14:35:01 PST 2023
On Mon, Mar 06, 2023 at 02:31:00PM -0800, Stephen Boyd wrote:
> Quoting Jesse Taube (2023-02-28 16:26:55)
> > diff --git a/drivers/clk/clk-k210.c b/drivers/clk/clk-k210.c
> > index 67a7cb3503c3..4eed667eddaf 100644
> > --- a/drivers/clk/clk-k210.c
> > +++ b/drivers/clk/clk-k210.c
> > @@ -495,7 +495,7 @@ static unsigned long k210_pll_get_rate(struct clk_hw *hw,
> > f = FIELD_GET(K210_PLL_CLKF, reg) + 1;
> > od = FIELD_GET(K210_PLL_CLKOD, reg) + 1;
> >
> > - return (u64)parent_rate * f / (r * od);
> > + return div_u64((u64)parent_rate * f, r * od);
>
> The equation 'r * od' can't overflow 32-bits, right?
Yah, I checked that when writing the patch. They're 4-bit fields:
> /*
> * PLL control register bits.
> */
> #define K210_PLL_CLKR GENMASK(3, 0)
> #define K210_PLL_CLKF GENMASK(9, 4)
> #define K210_PLL_CLKOD GENMASK(13, 10)
Cheers,
Conor.
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