ASoC: rl6231: get better PLL parameters
For those which can only get approximation PLL out cases, this patch will use higher resolution to get a better PLL parameter. Signed-off-by: Bard Liao <bardliao@realtek.com> Signed-off-by: Mark Brown <broonie@kernel.org>
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@ -13,6 +13,7 @@
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#include <linux/module.h>
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#include <linux/regmap.h>
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#include <linux/gcd.h>
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#include "rl6231.h"
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/**
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@ -106,6 +107,25 @@ static const struct pll_calc_map pll_preset_table[] = {
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{19200000, 24576000, 3, 30, 3, false},
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};
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static unsigned int find_best_div(unsigned int in,
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unsigned int max, unsigned int div)
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{
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unsigned int d;
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if (in <= max)
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return 1;
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d = in / max;
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if (in % max)
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d++;
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while (div % d != 0)
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d++;
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return d;
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}
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/**
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* rl6231_pll_calc - Calcualte PLL M/N/K code.
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* @freq_in: external clock provided to codec.
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@ -120,9 +140,11 @@ int rl6231_pll_calc(const unsigned int freq_in,
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const unsigned int freq_out, struct rl6231_pll_code *pll_code)
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{
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int max_n = RL6231_PLL_N_MAX, max_m = RL6231_PLL_M_MAX;
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int i, k, red, n_t, pll_out, in_t, out_t;
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int n = 0, m = 0, m_t = 0;
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int red_t = abs(freq_out - freq_in);
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int i, k, n_t;
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int k_t, min_k, max_k, n = 0, m = 0, m_t = 0;
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unsigned int red, pll_out, in_t, out_t, div, div_t;
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unsigned int red_t = abs(freq_out - freq_in);
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unsigned int f_in, f_out, f_max;
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bool bypass = false;
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if (RL6231_PLL_INP_MAX < freq_in || RL6231_PLL_INP_MIN > freq_in)
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@ -140,39 +162,54 @@ int rl6231_pll_calc(const unsigned int freq_in,
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}
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}
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k = 100000000 / freq_out - 2;
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if (k > RL6231_PLL_K_MAX)
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k = RL6231_PLL_K_MAX;
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for (n_t = 0; n_t <= max_n; n_t++) {
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in_t = freq_in / (k + 2);
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pll_out = freq_out / (n_t + 2);
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if (in_t < 0)
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continue;
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if (in_t == pll_out) {
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bypass = true;
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n = n_t;
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goto code_find;
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}
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red = abs(in_t - pll_out);
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if (red < red_t) {
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bypass = true;
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n = n_t;
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m = m_t;
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if (red == 0)
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goto code_find;
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red_t = red;
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}
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for (m_t = 0; m_t <= max_m; m_t++) {
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out_t = in_t / (m_t + 2);
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red = abs(out_t - pll_out);
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if (red < red_t) {
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bypass = false;
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min_k = 80000000 / freq_out - 2;
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max_k = 150000000 / freq_out - 2;
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if (max_k > RL6231_PLL_K_MAX)
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max_k = RL6231_PLL_K_MAX;
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if (min_k > RL6231_PLL_K_MAX)
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min_k = max_k = RL6231_PLL_K_MAX;
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div_t = gcd(freq_in, freq_out);
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f_max = 0xffffffff / RL6231_PLL_N_MAX;
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div = find_best_div(freq_in, f_max, div_t);
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f_in = freq_in / div;
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f_out = freq_out / div;
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k = min_k;
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for (k_t = min_k; k_t <= max_k; k_t++) {
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for (n_t = 0; n_t <= max_n; n_t++) {
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in_t = f_in * (n_t + 2);
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pll_out = f_out * (k_t + 2);
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if (in_t < 0)
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continue;
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if (in_t == pll_out) {
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bypass = true;
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n = n_t;
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m = m_t;
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k = k_t;
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goto code_find;
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}
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out_t = in_t / (k_t + 2);
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red = abs(f_out - out_t);
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if (red < red_t) {
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bypass = true;
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n = n_t;
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m = 0;
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k = k_t;
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if (red == 0)
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goto code_find;
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red_t = red;
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}
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for (m_t = 0; m_t <= max_m; m_t++) {
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out_t = in_t / ((m_t + 2) * (k_t + 2));
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red = abs(f_out - out_t);
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if (red < red_t) {
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bypass = false;
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n = n_t;
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m = m_t;
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k = k_t;
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if (red == 0)
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goto code_find;
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red_t = red;
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}
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}
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}
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}
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pr_debug("Only get approximation about PLL\n");
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