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
adau_calc_pll_cfg(unsigned int freq_in,unsigned int freq_out,uint8_t regs[5])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");
61