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
  15 int 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 }
  56 EXPORT_SYMBOL_GPL(adau_calc_pll_cfg);
  57
  58 MODULE_DESCRIPTION("ASoC ADAU audio CODECs shared helper functions");
  59 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
  60 MODULE_LICENSE("GPL v2");