From 7d0f3fbb93cfebd7b5dc5635166e48ab998c4f82 Mon Sep 17 00:00:00 2001 From: Tero Kristo Date: Fri, 11 Jun 2021 11:45:02 +0300 Subject: 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 Reviewed-by: Tom Rini Signed-off-by: Tero Kristo --- include/linux/rational.h | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) create mode 100644 include/linux/rational.h (limited to 'include/linux') diff --git a/include/linux/rational.h b/include/linux/rational.h new file mode 100644 index 00000000000..33f5f5fc3e3 --- /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 + * + * 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 */ -- cgit v1.2.3