diff options
| author | Craig Tatlor <ctatlor97@gmail.com> | 2020-12-04 05:54:56 +0300 |
|---|---|---|
| committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2021-01-16 18:14:53 +0000 |
| commit | 8d502ef682fdbe0ddf2274dae903b07baf1140e0 (patch) | |
| tree | 40975646c1d54a580aa5df8770bc9944dc88e1f5 /include/linux/fixp-arith.h | |
| parent | 5c8fe583cce542aa0b84adc939ce85293de36e5e (diff) | |
fixp-arith: add a linear interpolation function
Adds a function to interpolate against two points,
this is carried arount as a helper function by tons of drivers.
Signed-off-by: Craig Tatlor <ctatlor97@gmail.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20201204025509.1075506-3-dmitry.baryshkov@linaro.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Diffstat (limited to 'include/linux/fixp-arith.h')
| -rw-r--r-- | include/linux/fixp-arith.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/include/linux/fixp-arith.h b/include/linux/fixp-arith.h index 8396013785ef..281cb4f83dbe 100644 --- a/include/linux/fixp-arith.h +++ b/include/linux/fixp-arith.h @@ -141,4 +141,23 @@ static inline s32 fixp_sin32_rad(u32 radians, u32 twopi) #define fixp_cos32_rad(rad, twopi) \ fixp_sin32_rad(rad + twopi / 4, twopi) +/** + * fixp_linear_interpolate() - interpolates a value from two known points + * + * @x0: x value of point 0 + * @y0: y value of point 0 + * @x1: x value of point 1 + * @y1: y value of point 1 + * @x: the linear interpolant + */ +static inline int fixp_linear_interpolate(int x0, int y0, int x1, int y1, int x) +{ + if (y0 == y1 || x == x0) + return y0; + if (x1 == x0 || x == x1) + return y1; + + return y0 + ((y1 - y0) * (x - x0) / (x1 - x0)); +} + #endif |