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| author | Tero Kristo <t-kristo@ti.com> | 2021-06-11 11:45:02 +0300 |
|---|---|---|
| committer | Lokesh Vutla <lokeshvutla@ti.com> | 2021-06-11 16:34:52 +0530 |
| commit | 7d0f3fbb93cfebd7b5dc5635166e48ab998c4f82 (patch) | |
| tree | bdb88eb5255e85ff5e35815ce0ff85ea1bad0c87 /include/linux/rational.h | |
| parent | 08ea87a6de1b9357b6edcfafb90be5bcecfd31c0 (diff) | |
| download | u-boot-7d0f3fbb93cfebd7b5dc5635166e48ab998c4f82.zip u-boot-7d0f3fbb93cfebd7b5dc5635166e48ab998c4f82.tar.gz u-boot-7d0f3fbb93cfebd7b5dc5635166e48ab998c4f82.tar.bz2 | |
lib: rational: copy the rational fraction lib routines from Linux
Copy the best rational approximation calculation routines from Linux.
Typical usecase for these routines is to calculate the M/N divider
values for PLLs to reach a specific clock rate.
This is based on linux kernel commit:
"lib/math/rational.c: fix possible incorrect result from rational
fractions helper"
(sha1: 323dd2c3ed0641f49e89b4e420f9eef5d3d5a881)
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Tero Kristo <kristo@kernel.org>
Diffstat (limited to 'include/linux/rational.h')
| -rw-r--r-- | include/linux/rational.h | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/include/linux/rational.h b/include/linux/rational.h new file mode 100644 index 0000000..33f5f5f --- /dev/null +++ b/include/linux/rational.h @@ -0,0 +1,20 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * rational fractions + * + * Copyright (C) 2009 emlix GmbH, Oskar Schirmer <oskar@scara.com> + * + * helper functions when coping with rational numbers, + * e.g. when calculating optimum numerator/denominator pairs for + * pll configuration taking into account restricted register size + */ + +#ifndef _LINUX_RATIONAL_H +#define _LINUX_RATIONAL_H + +void rational_best_approximation( + unsigned long given_numerator, unsigned long given_denominator, + unsigned long max_numerator, unsigned long max_denominator, + unsigned long *best_numerator, unsigned long *best_denominator); + +#endif /* _LINUX_RATIONAL_H */ |