mirror of
https://github.com/torvalds/linux.git
synced 2026-04-18 06:44:00 -04:00
118d86a324
The Baikal SoC and platform support was dropped from the kernel, remove the reference to non-exist file. While at it, fix spelling. Link: https://lkml.kernel.org/r/20260302092831.2267785-4-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Kuan-Wei Chiu <visitorckw@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
106 lines
3.5 KiB
C
106 lines
3.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* Generic polynomial calculation using integer coefficients.
|
|
*
|
|
* Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
|
|
*
|
|
* Authors:
|
|
* Maxim Kaurkin <maxim.kaurkin@baikalelectronics.ru>
|
|
* Serge Semin <Sergey.Semin@baikalelectronics.ru>
|
|
*
|
|
*/
|
|
|
|
#include <linux/export.h>
|
|
#include <linux/math.h>
|
|
#include <linux/module.h>
|
|
#include <linux/polynomial.h>
|
|
|
|
/*
|
|
* The following conversion is an example:
|
|
*
|
|
* The original translation formulae of the temperature (in degrees of Celsius)
|
|
* to PVT data and vice-versa are following:
|
|
*
|
|
* N = 1.8322e-8*(T^4) + 2.343e-5*(T^3) + 8.7018e-3*(T^2) + 3.9269*(T^1) + 1.7204e2
|
|
* T = -1.6743e-11*(N^4) + 8.1542e-8*(N^3) + -1.8201e-4*(N^2) + 3.1020e-1*(N^1) - 4.838e1
|
|
*
|
|
* where T = [-48.380, 147.438]C and N = [0, 1023].
|
|
*
|
|
* They must be accordingly altered to be suitable for the integer arithmetics.
|
|
* The technique is called 'factor redistribution', which just makes sure the
|
|
* multiplications and divisions are made so to have a result of the operations
|
|
* within the integer numbers limit. In addition we need to translate the
|
|
* formulae to accept millidegrees of Celsius. Here what they look like after
|
|
* the alterations:
|
|
*
|
|
* N = (18322e-20*(T^4) + 2343e-13*(T^3) + 87018e-9*(T^2) + 39269e-3*T + 17204e2) / 1e4
|
|
* T = -16743e-12*(D^4) + 81542e-9*(D^3) - 182010e-6*(D^2) + 310200e-3*D - 48380
|
|
*
|
|
* where T = [-48380, 147438] mC and N = [0, 1023].
|
|
*
|
|
* static const struct polynomial poly_temp_to_N = {
|
|
* .total_divider = 10000,
|
|
* .terms = {
|
|
* {4, 18322, 10000, 10000},
|
|
* {3, 2343, 10000, 10},
|
|
* {2, 87018, 10000, 10},
|
|
* {1, 39269, 1000, 1},
|
|
* {0, 1720400, 1, 1}
|
|
* }
|
|
* };
|
|
*
|
|
* static const struct polynomial poly_N_to_temp = {
|
|
* .total_divider = 1,
|
|
* .terms = {
|
|
* {4, -16743, 1000, 1},
|
|
* {3, 81542, 1000, 1},
|
|
* {2, -182010, 1000, 1},
|
|
* {1, 310200, 1000, 1},
|
|
* {0, -48380, 1, 1}
|
|
* }
|
|
* };
|
|
*/
|
|
|
|
/**
|
|
* polynomial_calc - calculate a polynomial using integer arithmetic
|
|
*
|
|
* @poly: pointer to the descriptor of the polynomial
|
|
* @data: input value of the polynomial
|
|
*
|
|
* Calculate the result of a polynomial using only integer arithmetic. For
|
|
* this to work without too much loss of precision the coefficients has to
|
|
* be altered. This is called factor redistribution.
|
|
*
|
|
* Return: the result of the polynomial calculation.
|
|
*/
|
|
long polynomial_calc(const struct polynomial *poly, long data)
|
|
{
|
|
const struct polynomial_term *term = poly->terms;
|
|
long total_divider = poly->total_divider ?: 1;
|
|
long tmp, ret = 0;
|
|
int deg;
|
|
|
|
/*
|
|
* Here is the polynomial calculation function, which performs the
|
|
* redistributed terms calculations. It's pretty straightforward.
|
|
* We walk over each degree term up to the free one, and perform
|
|
* the redistributed multiplication of the term coefficient, its
|
|
* divider (as for the rationale fraction representation), data
|
|
* power and the rational fraction divider leftover. Then all of
|
|
* this is collected in a total sum variable, which value is
|
|
* normalized by the total divider before being returned.
|
|
*/
|
|
do {
|
|
tmp = term->coef;
|
|
for (deg = 0; deg < term->deg; ++deg)
|
|
tmp = mult_frac(tmp, data, term->divider);
|
|
ret += tmp / term->divider_leftover;
|
|
} while ((term++)->deg);
|
|
|
|
return ret / total_divider;
|
|
}
|
|
EXPORT_SYMBOL_GPL(polynomial_calc);
|
|
|
|
MODULE_DESCRIPTION("Generic polynomial calculations");
|
|
MODULE_LICENSE("GPL");
|