LXR linux/sound/soc/codecs/adau-utils.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Shared helper functions for devices from the ADAU family
   4 *
   5 * Copyright 2011-2016 Analog Devices Inc.
   6 * Author: Lars-Peter Clausen <lars@metafoo.de>
   7 */
   8
   9#include <linux/gcd.h>
  10#include <linux/kernel.h>
  11#include <linux/module.h>
  12
  13#include "adau-utils.h"
  14
  15int adau_calc_pll_cfg(unsigned int freq_in, unsigned int freq_out,
  16        uint8_t regs[5])
  17{
  18        unsigned int r, n, m, i, j;
  19        unsigned int div;
  20
  21        if (!freq_out) {
  22                r = 0;
  23                n = 0;
  24                m = 0;
  25                div = 0;
  26        } else {
  27                if (freq_out % freq_in != 0) {
  28                        div = DIV_ROUND_UP(freq_in, 13500000);
  29                        freq_in /= div;
  30                        r = freq_out / freq_in;
  31                        i = freq_out % freq_in;
  32                        j = gcd(i, freq_in);
  33                        n = i / j;
  34                        m = freq_in / j;
  35                        div--;
  36                } else {
  37                        r = freq_out / freq_in;
  38                        n = 0;
  39                        m = 0;
  40                        div = 0;
  41                }
  42                if (n > 0xffff || m > 0xffff || div > 3 || r > 8 || r < 2)
  43                        return -EINVAL;
  44        }
  45
  46        regs[0] = m >> 8;
  47        regs[1] = m & 0xff;
  48        regs[2] = n >> 8;
  49        regs[3] = n & 0xff;
  50        regs[4] = (r << 3) | (div << 1);
  51        if (m != 0)
  52                regs[4] |= 1; /* Fractional mode */
  53
  54        return 0;
  55}
  56EXPORT_SYMBOL_GPL(adau_calc_pll_cfg);
  57
  58MODULE_DESCRIPTION("ASoC ADAU audio CODECs shared helper functions");
  59MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
  60MODULE_LICENSE("GPL v2");
  61