| 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(a: i, b: 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 |