| Message ID | 20190211135858.23635-4-horms+renesas@verge.net.au (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Geert Uytterhoeven |
| Headers | show |
| Series | clk: renesas: r8a77990, r8a774c0: Add Z2 clock | expand |
On 02/11/2019 04:58 PM, Simon Horman wrote: > Provide DIV64_U64_ROUND_CLOSEST helper which performs division rounded to > the closes integer using an unsigned 64bit dividend and divisor. Closest? > This will be used in a follow-up patch to allow calculation of clock > divisors with high frequency parents in the R-Car Gen3 CPG MSSR driver > where ovefolow occurs if either the dividend or divisor is 32bit. > > Signed-off-by: Simon Horman <horms+renesas@verge.net.au> [...] MBR, Sergei
On Mon, Feb 11, 2019 at 4:22 PM Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> wrote: > On 02/11/2019 04:58 PM, Simon Horman wrote: > > Provide DIV64_U64_ROUND_CLOSEST helper which performs division rounded to > > the closes integer using an unsigned 64bit dividend and divisor. > > Closest? > > > This will be used in a follow-up patch to allow calculation of clock > > divisors with high frequency parents in the R-Car Gen3 CPG MSSR driver > > where ovefolow occurs if either the dividend or divisor is 32bit. overflow > > Signed-off-by: Simon Horman <horms+renesas@verge.net.au> With the above fixed: Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Note that I can fix the above while applying to my clk-renesas branch. Andrew: an Acked-by would be appreciated. Thanks! Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
diff --git a/include/linux/math64.h b/include/linux/math64.h index bb2c84afb80c..65bef21cdddb 100644 --- a/include/linux/math64.h +++ b/include/linux/math64.h @@ -284,4 +284,17 @@ static inline u64 mul_u64_u32_div(u64 a, u32 mul, u32 divisor) #define DIV64_U64_ROUND_UP(ll, d) \ ({ u64 _tmp = (d); div64_u64((ll) + _tmp - 1, _tmp); }) +/** + * DIV64_U64_ROUND_CLOSEST - unsigned 64bit divide with 64bit divisor rounded to nearest integer + * @dividend: unsigned 64bit dividend + * @divisor: unsigned 64bit divisor + * + * Divide unsigned 64bit dividend by unsigned 64bit divisor + * and round to closest integer. + * + * Return: dividend / divisor rounded to nearest integer + */ +#define DIV64_U64_ROUND_CLOSEST(dividend, divisor) \ + ({ u64 _tmp = (divisor); div64_u64((dividend) + _tmp / 2, _tmp); }) + #endif /* _LINUX_MATH64_H */
Provide DIV64_U64_ROUND_CLOSEST helper which performs division rounded to the closes integer using an unsigned 64bit dividend and divisor. This will be used in a follow-up patch to allow calculation of clock divisors with high frequency parents in the R-Car Gen3 CPG MSSR driver where ovefolow occurs if either the dividend or divisor is 32bit. Signed-off-by: Simon Horman <horms+renesas@verge.net.au> --- v5: New separate patch to add DIV64_U64_ROUND_CLOSEST --- include/linux/math64.h | 13 +++++++++++++ 1 file changed, 13 insertions(+)