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0eadaa9c LPC |
1 | /* |
2 | * Shared helper functions for devices from the ADAU family | |
3 | * | |
4 | * Copyright 2011-2016 Analog Devices Inc. | |
5 | * Author: Lars-Peter Clausen <lars@metafoo.de> | |
6 | * | |
7 | * Licensed under the GPL-2 or later. | |
8 | */ | |
9 | ||
10 | #include <linux/gcd.h> | |
11 | #include <linux/kernel.h> | |
12 | #include <linux/module.h> | |
13 | ||
14 | #include "adau-utils.h" | |
15 | ||
16 | int adau_calc_pll_cfg(unsigned int freq_in, unsigned int freq_out, | |
17 | uint8_t regs[5]) | |
18 | { | |
19 | unsigned int r, n, m, i, j; | |
20 | unsigned int div; | |
21 | ||
22 | if (!freq_out) { | |
23 | r = 0; | |
24 | n = 0; | |
25 | m = 0; | |
26 | div = 0; | |
27 | } else { | |
28 | if (freq_out % freq_in != 0) { | |
29 | div = DIV_ROUND_UP(freq_in, 13500000); | |
30 | freq_in /= div; | |
31 | r = freq_out / freq_in; | |
32 | i = freq_out % freq_in; | |
33 | j = gcd(i, freq_in); | |
34 | n = i / j; | |
35 | m = freq_in / j; | |
36 | div--; | |
37 | } else { | |
38 | r = freq_out / freq_in; | |
39 | n = 0; | |
40 | m = 0; | |
41 | div = 0; | |
42 | } | |
43 | if (n > 0xffff || m > 0xffff || div > 3 || r > 8 || r < 2) | |
44 | return -EINVAL; | |
45 | } | |
46 | ||
47 | regs[0] = m >> 8; | |
48 | regs[1] = m & 0xff; | |
49 | regs[2] = n >> 8; | |
50 | regs[3] = n & 0xff; | |
51 | regs[4] = (r << 3) | (div << 1); | |
52 | if (m != 0) | |
53 | regs[4] |= 1; /* Fractional mode */ | |
54 | ||
55 | return 0; | |
56 | } | |
57 | EXPORT_SYMBOL_GPL(adau_calc_pll_cfg); | |
58 | ||
59 | MODULE_DESCRIPTION("ASoC ADAU audio CODECs shared helper functions"); | |
60 | MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); | |
61 | MODULE_LICENSE("GPL v2"); |