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Merge remote-tracking branch 'asoc/topic/rl6231' into asoc-next
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Mark Brown committed Jan 12, 2018
2 parents dc3f733 + 790dde2 commit bae4d02
Showing 1 changed file with 64 additions and 29 deletions.
93 changes: 64 additions & 29 deletions sound/soc/codecs/rl6231.c
Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,7 @@
#include <linux/module.h>
#include <linux/regmap.h>

#include <linux/gcd.h>
#include "rl6231.h"

/**
Expand Down Expand Up @@ -106,6 +107,25 @@ static const struct pll_calc_map pll_preset_table[] = {
{19200000, 24576000, 3, 30, 3, false},
};

static unsigned int find_best_div(unsigned int in,
unsigned int max, unsigned int div)
{
unsigned int d;

if (in <= max)
return 1;

d = in / max;
if (in % max)
d++;

while (div % d != 0)
d++;


return d;
}

/**
* rl6231_pll_calc - Calcualte PLL M/N/K code.
* @freq_in: external clock provided to codec.
Expand All @@ -120,9 +140,11 @@ int rl6231_pll_calc(const unsigned int freq_in,
const unsigned int freq_out, struct rl6231_pll_code *pll_code)
{
int max_n = RL6231_PLL_N_MAX, max_m = RL6231_PLL_M_MAX;
int i, k, red, n_t, pll_out, in_t, out_t;
int n = 0, m = 0, m_t = 0;
int red_t = abs(freq_out - freq_in);
int i, k, n_t;
int k_t, min_k, max_k, n = 0, m = 0, m_t = 0;
unsigned int red, pll_out, in_t, out_t, div, div_t;
unsigned int red_t = abs(freq_out - freq_in);
unsigned int f_in, f_out, f_max;
bool bypass = false;

if (RL6231_PLL_INP_MAX < freq_in || RL6231_PLL_INP_MIN > freq_in)
Expand All @@ -140,39 +162,52 @@ int rl6231_pll_calc(const unsigned int freq_in,
}
}

k = 100000000 / freq_out - 2;
if (k > RL6231_PLL_K_MAX)
k = RL6231_PLL_K_MAX;
for (n_t = 0; n_t <= max_n; n_t++) {
in_t = freq_in / (k + 2);
pll_out = freq_out / (n_t + 2);
if (in_t < 0)
continue;
if (in_t == pll_out) {
bypass = true;
n = n_t;
goto code_find;
}
red = abs(in_t - pll_out);
if (red < red_t) {
bypass = true;
n = n_t;
m = m_t;
if (red == 0)
min_k = 80000000 / freq_out - 2;
max_k = 150000000 / freq_out - 2;
if (max_k > RL6231_PLL_K_MAX)
max_k = RL6231_PLL_K_MAX;
if (min_k > RL6231_PLL_K_MAX)
min_k = max_k = RL6231_PLL_K_MAX;
div_t = gcd(freq_in, freq_out);
f_max = 0xffffffff / RL6231_PLL_N_MAX;
div = find_best_div(freq_in, f_max, div_t);
f_in = freq_in / div;
f_out = freq_out / div;
k = min_k;
for (k_t = min_k; k_t <= max_k; k_t++) {
for (n_t = 0; n_t <= max_n; n_t++) {
in_t = f_in * (n_t + 2);
pll_out = f_out * (k_t + 2);
if (in_t == pll_out) {
bypass = true;
n = n_t;
k = k_t;
goto code_find;
red_t = red;
}
for (m_t = 0; m_t <= max_m; m_t++) {
out_t = in_t / (m_t + 2);
red = abs(out_t - pll_out);
}
out_t = in_t / (k_t + 2);
red = abs(f_out - out_t);
if (red < red_t) {
bypass = false;
bypass = true;
n = n_t;
m = m_t;
m = 0;
k = k_t;
if (red == 0)
goto code_find;
red_t = red;
}
for (m_t = 0; m_t <= max_m; m_t++) {
out_t = in_t / ((m_t + 2) * (k_t + 2));
red = abs(f_out - out_t);
if (red < red_t) {
bypass = false;
n = n_t;
m = m_t;
k = k_t;
if (red == 0)
goto code_find;
red_t = red;
}
}
}
}
pr_debug("Only get approximation about PLL\n");
Expand Down

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