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62 lines
1.2 KiB
C
62 lines
1.2 KiB
C
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/*
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* Shared helper functions for devices from the ADAU family
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*
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* Copyright 2011-2016 Analog Devices Inc.
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* Author: Lars-Peter Clausen <lars@metafoo.de>
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*
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* Licensed under the GPL-2 or later.
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*/
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#include <linux/gcd.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include "adau-utils.h"
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int adau_calc_pll_cfg(unsigned int freq_in, unsigned int freq_out,
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uint8_t regs[5])
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{
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unsigned int r, n, m, i, j;
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unsigned int div;
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if (!freq_out) {
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r = 0;
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n = 0;
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m = 0;
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div = 0;
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} else {
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if (freq_out % freq_in != 0) {
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div = DIV_ROUND_UP(freq_in, 13500000);
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freq_in /= div;
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r = freq_out / freq_in;
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i = freq_out % freq_in;
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j = gcd(i, freq_in);
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n = i / j;
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m = freq_in / j;
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div--;
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} else {
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r = freq_out / freq_in;
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n = 0;
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m = 0;
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div = 0;
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}
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if (n > 0xffff || m > 0xffff || div > 3 || r > 8 || r < 2)
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return -EINVAL;
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}
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regs[0] = m >> 8;
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regs[1] = m & 0xff;
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regs[2] = n >> 8;
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regs[3] = n & 0xff;
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regs[4] = (r << 3) | (div << 1);
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if (m != 0)
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regs[4] |= 1; /* Fractional mode */
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return 0;
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}
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EXPORT_SYMBOL_GPL(adau_calc_pll_cfg);
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MODULE_DESCRIPTION("ASoC ADAU audio CODECs shared helper functions");
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MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
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MODULE_LICENSE("GPL v2");
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