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60 lines
1.2 KiB
60 lines
1.2 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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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 <[email protected]> |
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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 <[email protected]>"); |
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MODULE_LICENSE("GPL v2");
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