| Message ID | 20240530171225.2749312-1-devarsht@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add V4L2 M2M Driver for E5010 JPEG Encoder | expand |
On Thu, May 30, 2024 at 10:42:25PM +0530, Devarsh Thakkar wrote: > Add below rounding related macros: > > round_closest_up(x, y) : Rounds x to closest multiple of y where y is a > power of 2, with a preference to round up in case two nearest values are > possible. > > round_closest_down(x, y) : Rounds x to closest multiple of y where y is a > power of 2, with a preference to round down in case two nearest values are > possible. > > roundclosest(x, y) : Rounds x to closest multiple of y, this macro should > generally be used only when y is not multiple of 2 as otherwise > round_closest* macros should be used which are much faster. > > Examples: > * round_closest_up(17, 4) = 16 > * round_closest_up(15, 4) = 16 > * round_closest_up(14, 4) = 16 > * round_closest_down(17, 4) = 16 > * round_closest_down(15, 4) = 16 > * round_closest_down(14, 4) = 12 > * roundclosest(21, 5) = 20 > * roundclosest(19, 5) = 20 > * roundclosest(17, 5) = 15 ... > + * Examples : It's inconsistent with the other one below. > + * round_closest_up(17, 4) = 16 > + * > + * round_closest_up(15, 4) = 16 > + * > + * round_closest_up(14, 4) = 16 The three have TABs/spaces mixture. I believe you wanted: * Examples:: * * round_closest_up(17, 4) = 16 * * round_closest_up(15, 4) = 16 * * round_closest_up(14, 4) = 16 ... > + * Examples: > + * > + * round_closest_down(17, 4) = 16 > + * > + * round_closest_down(15, 4) = 16 > + * > + * round_closest_down(14, 4) = 12 As per above ... > + * Examples : > + * > + * roundclosest(21, 5) = 20 > + * > + * roundclosest(19, 5) = 20 > + * > + * roundclosest(17, 5) = 15 As per above.
Hi Andy, Thanks for the review. On 31/05/24 00:49, Andy Shevchenko wrote: > On Thu, May 30, 2024 at 10:42:25PM +0530, Devarsh Thakkar wrote: >> Add below rounding related macros: >> >> round_closest_up(x, y) : Rounds x to closest multiple of y where y is a >> power of 2, with a preference to round up in case two nearest values are >> possible. >> >> round_closest_down(x, y) : Rounds x to closest multiple of y where y is a >> power of 2, with a preference to round down in case two nearest values are >> possible. >> >> roundclosest(x, y) : Rounds x to closest multiple of y, this macro should >> generally be used only when y is not multiple of 2 as otherwise >> round_closest* macros should be used which are much faster. >> >> Examples: >> * round_closest_up(17, 4) = 16 >> * round_closest_up(15, 4) = 16 >> * round_closest_up(14, 4) = 16 >> * round_closest_down(17, 4) = 16 >> * round_closest_down(15, 4) = 16 >> * round_closest_down(14, 4) = 12 >> * roundclosest(21, 5) = 20 >> * roundclosest(19, 5) = 20 >> * roundclosest(17, 5) = 15 > > ... > >> + * Examples : > > It's inconsistent with the other one below. > >> + * round_closest_up(17, 4) = 16 >> + * >> + * round_closest_up(15, 4) = 16 >> + * >> + * round_closest_up(14, 4) = 16 > > The three have TABs/spaces mixture. > > I believe you wanted: > > * Examples:: > * * round_closest_up(17, 4) = 16 > * * round_closest_up(15, 4) = 16 > * * round_closest_up(14, 4) = 16 > I initially referred the style from this link [1] but probably missed to remove extra space from my patch. But what you suggested looks better, I will go with what you suggested. [1] https://elixir.bootlin.com/linux/v6.9/source/include/linux/int_log.h#L22 Regards Devarsh
diff --git a/include/linux/math.h b/include/linux/math.h index dd4152711de7..1f6177191b66 100644 --- a/include/linux/math.h +++ b/include/linux/math.h @@ -34,6 +34,58 @@ */ #define round_down(x, y) ((x) & ~__round_mask(x, y)) +/** + * round_closest_up - round closest to be multiple of specified value (which is + * power of 2) with preference to rounding up + * @x: the value to round + * @y: multiple to round closest to (must be a power of 2) + * + * Rounds @x to closest multiple of @y (which must be a power of 2). + * The value can be either rounded up or rounded down depending upon rounded + * value's closeness to the specified value. If there are two closest possible + * values, i.e. the difference between the specified value and it's rounded up + * and rounded down values is same then preference is given to rounded up + * value. + * + * To perform arbitrary rounding to closest value (not multiple of 2), use + * roundclosest(). + * + * Examples : + * + * round_closest_up(17, 4) = 16 + * + * round_closest_up(15, 4) = 16 + * + * round_closest_up(14, 4) = 16 + */ +#define round_closest_up(x, y) round_down((x) + (y) / 2, (y)) + +/** + * round_closest_down - round closest to be multiple of specified value (which + * is power of 2) with preference to rounding down + * @x: the value to round + * @y: multiple to round closest to (must be a power of 2) + * + * Rounds @x to closest multiple of @y (which must be a power of 2). + * The value can be either rounded up or rounded down depending upon rounded + * value's closeness to the specified value. If there are two closest possible + * values, i.e. the difference between the specified value and it's rounded up + * and rounded down values is same then preference is given to rounded up + * value. + * + * To perform arbitrary rounding to closest value (not multiple of 2), use + * roundclosest(). + * + * Examples: + * + * round_closest_down(17, 4) = 16 + * + * round_closest_down(15, 4) = 16 + * + * round_closest_down(14, 4) = 12 + */ +#define round_closest_down(x, y) round_up((x) - (y) / 2, (y)) + #define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP #define DIV_ROUND_DOWN_ULL(ll, d) \ @@ -77,6 +129,26 @@ } \ ) +/** + * roundclosest - round to nearest multiple + * @x: the value to round + * @y: multiple to round nearest to + * + * Rounds @x to nearest multiple of @y. + * The rounded value can be greater than or less than @x depending + * upon it's nearness to @x. If @y will always be a power of 2, consider + * using the faster round_closest_up() or round_closest_down(). + * + * Examples : + * + * roundclosest(21, 5) = 20 + * + * roundclosest(19, 5) = 20 + * + * roundclosest(17, 5) = 15 + */ +#define roundclosest(x, y) rounddown((x) + (y) / 2, (y)) + /* * Divide positive or negative dividend by positive or negative divisor * and round to closest integer. Result is undefined for negative
Add below rounding related macros: round_closest_up(x, y) : Rounds x to closest multiple of y where y is a power of 2, with a preference to round up in case two nearest values are possible. round_closest_down(x, y) : Rounds x to closest multiple of y where y is a power of 2, with a preference to round down in case two nearest values are possible. roundclosest(x, y) : Rounds x to closest multiple of y, this macro should generally be used only when y is not multiple of 2 as otherwise round_closest* macros should be used which are much faster. Examples: * round_closest_up(17, 4) = 16 * round_closest_up(15, 4) = 16 * round_closest_up(14, 4) = 16 * round_closest_down(17, 4) = 16 * round_closest_down(15, 4) = 16 * round_closest_down(14, 4) = 12 * roundclosest(21, 5) = 20 * roundclosest(19, 5) = 20 * roundclosest(17, 5) = 15 Signed-off-by: Devarsh Thakkar <devarsht@ti.com> --- NOTE: This patch is inspired from the Mentor Graphics IPU driver [1] which uses similar macro locally and which is updated in further patch in the series to use this generic macro instead along with other drivers having similar requirements. [1]: https://elixir.bootlin.com/linux/v6.8.9/source/drivers/gpu/ipu-v3/ipu-image-convert.c#L480 V10: - Update example comment to fix formatting issues as observed with html docs V9: - No change V8: - Add new macro to round to nearest value for non-multiple of 2 - Update commit message as suggested: V1->V6 (No change, patch introduced in V7) --- include/linux/math.h | 72 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 72 insertions(+)