soc/codecs/adau-utils.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * Shared helper functions for devices from the ADAU family
0004  *
0005  * Copyright 2011-2016 Analog Devices Inc.
0006  * Author: Lars-Peter Clausen <lars@metafoo.de>
0007  */
0008
0009 #include <linux/gcd.h>
0010 #include <linux/kernel.h>
0011 #include <linux/module.h>
0012
0013 #include "adau-utils.h"
0014
0015 int adau_calc_pll_cfg(unsigned int freq_in, unsigned int freq_out,
0016     uint8_t regs[5])
0017 {
0018     unsigned int r, n, m, i, j;
0019     unsigned int div;
0020
0021     if (!freq_out) {
0022         r = 0;
0023         n = 0;
0024         m = 0;
0025         div = 0;
0026     } else {
0027         if (freq_out % freq_in != 0) {
0028             div = DIV_ROUND_UP(freq_in, 13500000);
0029             freq_in /= div;
0030             r = freq_out / freq_in;
0031             i = freq_out % freq_in;
0032             j = gcd(i, freq_in);
0033             n = i / j;
0034             m = freq_in / j;
0035             div--;
0036         } else {
0037             r = freq_out / freq_in;
0038             n = 0;
0039             m = 0;
0040             div = 0;
0041         }
0042         if (n > 0xffff || m > 0xffff || div > 3 || r > 8 || r < 2)
0043             return -EINVAL;
0044     }
0045
0046     regs[0] = m >> 8;
0047     regs[1] = m & 0xff;
0048     regs[2] = n >> 8;
0049     regs[3] = n & 0xff;
0050     regs[4] = (r << 3) | (div << 1);
0051     if (m != 0)
0052         regs[4] |= 1; /* Fractional mode */
0053
0054     return 0;
0055 }
0056 EXPORT_SYMBOL_GPL(adau_calc_pll_cfg);
0057
0058 MODULE_DESCRIPTION("ASoC ADAU audio CODECs shared helper functions");
0059 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
0060 MODULE_LICENSE("GPL v2");