@@ -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)
+ 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;
+ 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");