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ASoC: rl6231: get better PLL parameters

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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>
This commit is contained in:
Bard Liao 2017-11-27 20:03:14 +08:00 committed by Mark Brown
parent 4fbd8d194f
commit 2f8aab3d29
No known key found for this signature in database
GPG key ID: 24D68B725D5487D0
1 changed files with 68 additions and 31 deletions
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99
sound/soc/codecs/rl6231.c
View file

@ -13,6 +13,7 @@
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/gcd.h>
#include "rl6231.h"
/**
@ -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.
@ -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)
@ -140,39 +162,54 @@ 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)
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);
if (red < red_t) {
bypass = false;
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 < 0)
continue;
if (in_t == pll_out) {
bypass = true;
n = n_t;
m = m_t;
k = k_t;
goto code_find;
}
out_t = in_t / (k_t + 2);
red = abs(f_out - out_t);
if (red < red_t) {
bypass = true;
n = n_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");