// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Shared helper functions for devices from the ADAU family
 *
 * Copyright 2011-2016 Analog Devices Inc.
 * Author: Lars-Peter Clausen <lars@metafoo.de>
 */

#include <linux/gcd.h>
#include <linux/kernel.h>
#include <linux/module.h>

#include "adau-utils.h"

int adau_calc_pll_cfg(unsigned int freq_in, unsigned int freq_out,
        uint8_t regs[5])
{
        unsigned int r, n, m, i, j;
        unsigned int div;

        if (!freq_out) {
                r = 0;
                n = 0;
                m = 0;
                div = 0;
        } else {
                if (freq_out % freq_in != 0) {
                        div = DIV_ROUND_UP(freq_in, 13500000);
                        freq_in /= div;
                        r = freq_out / freq_in;
                        i = freq_out % freq_in;
                        j = gcd(i, freq_in);
                        n = i / j;
                        m = freq_in / j;
                        div--;
                } else {
                        r = freq_out / freq_in;
                        n = 0;
                        m = 0;
                        div = 0;
                }
                if (n > 0xffff || m > 0xffff || div > 3 || r > 8 || r < 2)
                        return -EINVAL;
        }

        regs[0] = m >> 8;
        regs[1] = m & 0xff;
        regs[2] = n >> 8;
        regs[3] = n & 0xff;
        regs[4] = (r << 3) | (div << 1);
        if (m != 0)
                regs[4] |= 1; /* Fractional mode */

        return 0;
}
EXPORT_SYMBOL_GPL(adau_calc_pll_cfg);

MODULE_DESCRIPTION("ASoC ADAU audio CODECs shared helper functions");
MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_LICENSE("GPL v2");