root/sound/soc/codecs/rl6231.c

DEFINITIONS

1. rl6231_get_pre_div
2. rl6231_calc_dmic_clk
3. find_best_div
4. rl6231_pll_calc
5. rl6231_get_clk_info

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * rl6231.c - RL6231 class device shared support
   4  *
   5  * Copyright 2014 Realtek Semiconductor Corp.
   6  *
   7  * Author: Oder Chiou <oder_chiou@realtek.com>
   8  */
   9 
  10 #include <linux/module.h>
  11 #include <linux/regmap.h>
  12 
  13 #include <linux/gcd.h>
  14 #include "rl6231.h"
  15 
  16 /**
  17  * rl6231_get_pre_div - Return the value of pre divider.
  18  *
  19  * @map: map for setting.
  20  * @reg: register.
  21  * @sft: shift.
  22  *
  23  * Return the value of pre divider from given register value.
  24  * Return negative error code for unexpected register value.
  25  */
  26 int rl6231_get_pre_div(struct regmap *map, unsigned int reg, int sft)
  27 {
  28         int pd, val;
  29 
  30         regmap_read(map, reg, &val);
  31 
  32         val = (val >> sft) & 0x7;
  33 
  34         switch (val) {
  35         case 0:
  36         case 1:
  37         case 2:
  38         case 3:
  39                 pd = val + 1;
  40                 break;
  41         case 4:
  42                 pd = 6;
  43                 break;
  44         case 5:
  45                 pd = 8;
  46                 break;
  47         case 6:
  48                 pd = 12;
  49                 break;
  50         case 7:
  51                 pd = 16;
  52                 break;
  53         default:
  54                 pd = -EINVAL;
  55                 break;
  56         }
  57 
  58         return pd;
  59 }
  60 EXPORT_SYMBOL_GPL(rl6231_get_pre_div);
  61 
  62 /**
  63  * rl6231_calc_dmic_clk - Calculate the frequency divider parameter of dmic.
  64  *
  65  * @rate: base clock rate.
  66  *
  67  * Choose divider parameter that gives the highest possible DMIC frequency in
  68  * 1MHz - 3MHz range.
  69  */
  70 int rl6231_calc_dmic_clk(int rate)
  71 {
  72         static const int div[] = {2, 3, 4, 6, 8, 12};
  73         int i;
  74 
  75         if (rate < 1000000 * div[0]) {
  76                 pr_warn("Base clock rate %d is too low\n", rate);
  77                 return -EINVAL;
  78         }
  79 
  80         for (i = 0; i < ARRAY_SIZE(div); i++) {
  81                 if ((div[i] % 3) == 0)
  82                         continue;
  83                 /* find divider that gives DMIC frequency below 3.072MHz */
  84                 if (3072000 * div[i] >= rate)
  85                         return i;
  86         }
  87 
  88         pr_warn("Base clock rate %d is too high\n", rate);
  89         return -EINVAL;
  90 }
  91 EXPORT_SYMBOL_GPL(rl6231_calc_dmic_clk);
  92 
  93 struct pll_calc_map {
  94         unsigned int pll_in;
  95         unsigned int pll_out;
  96         int k;
  97         int n;
  98         int m;
  99         bool m_bp;
 100 };
 101 
 102 static const struct pll_calc_map pll_preset_table[] = {
 103         {19200000,  4096000,  23, 14, 1, false},
 104         {19200000,  24576000,  3, 30, 3, false},
 105 };
 106 
 107 static unsigned int find_best_div(unsigned int in,
 108         unsigned int max, unsigned int div)
 109 {
 110         unsigned int d;
 111 
 112         if (in <= max)
 113                 return 1;
 114 
 115         d = in / max;
 116         if (in % max)
 117                 d++;
 118 
 119         while (div % d != 0)
 120                 d++;
 121 
 122 
 123         return d;
 124 }
 125 
 126 /**
 127  * rl6231_pll_calc - Calcualte PLL M/N/K code.
 128  * @freq_in: external clock provided to codec.
 129  * @freq_out: target clock which codec works on.
 130  * @pll_code: Pointer to structure with M, N, K and bypass flag.
 131  *
 132  * Calcualte M/N/K code to configure PLL for codec.
 133  *
 134  * Returns 0 for success or negative error code.
 135  */
 136 int rl6231_pll_calc(const unsigned int freq_in,
 137         const unsigned int freq_out, struct rl6231_pll_code *pll_code)
 138 {
 139         int max_n = RL6231_PLL_N_MAX, max_m = RL6231_PLL_M_MAX;
 140         int i, k, n_t;
 141         int k_t, min_k, max_k, n = 0, m = 0, m_t = 0;
 142         unsigned int red, pll_out, in_t, out_t, div, div_t;
 143         unsigned int red_t = abs(freq_out - freq_in);
 144         unsigned int f_in, f_out, f_max;
 145         bool bypass = false;
 146 
 147         if (RL6231_PLL_INP_MAX < freq_in || RL6231_PLL_INP_MIN > freq_in)
 148                 return -EINVAL;
 149 
 150         for (i = 0; i < ARRAY_SIZE(pll_preset_table); i++) {
 151                 if (freq_in == pll_preset_table[i].pll_in &&
 152                         freq_out == pll_preset_table[i].pll_out) {
 153                         k = pll_preset_table[i].k;
 154                         m = pll_preset_table[i].m;
 155                         n = pll_preset_table[i].n;
 156                         bypass = pll_preset_table[i].m_bp;
 157                         pr_debug("Use preset PLL parameter table\n");
 158                         goto code_find;
 159                 }
 160         }
 161 
 162         min_k = 80000000 / freq_out - 2;
 163         max_k = 150000000 / freq_out - 2;
 164         if (max_k > RL6231_PLL_K_MAX)
 165                 max_k = RL6231_PLL_K_MAX;
 166         if (min_k > RL6231_PLL_K_MAX)
 167                 min_k = max_k = RL6231_PLL_K_MAX;
 168         div_t = gcd(freq_in, freq_out);
 169         f_max = 0xffffffff / RL6231_PLL_N_MAX;
 170         div = find_best_div(freq_in, f_max, div_t);
 171         f_in = freq_in / div;
 172         f_out = freq_out / div;
 173         k = min_k;
 174         for (k_t = min_k; k_t <= max_k; k_t++) {
 175                 for (n_t = 0; n_t <= max_n; n_t++) {
 176                         in_t = f_in * (n_t + 2);
 177                         pll_out = f_out * (k_t + 2);
 178                         if (in_t == pll_out) {
 179                                 bypass = true;
 180                                 n = n_t;
 181                                 k = k_t;
 182                                 goto code_find;
 183                         }
 184                         out_t = in_t / (k_t + 2);
 185                         red = abs(f_out - out_t);
 186                         if (red < red_t) {
 187                                 bypass = true;
 188                                 n = n_t;
 189                                 m = 0;
 190                                 k = k_t;
 191                                 if (red == 0)
 192                                         goto code_find;
 193                                 red_t = red;
 194                         }
 195                         for (m_t = 0; m_t <= max_m; m_t++) {
 196                                 out_t = in_t / ((m_t + 2) * (k_t + 2));
 197                                 red = abs(f_out - out_t);
 198                                 if (red < red_t) {
 199                                         bypass = false;
 200                                         n = n_t;
 201                                         m = m_t;
 202                                         k = k_t;
 203                                         if (red == 0)
 204                                                 goto code_find;
 205                                         red_t = red;
 206                                 }
 207                         }
 208                 }
 209         }
 210         pr_debug("Only get approximation about PLL\n");
 211 
 212 code_find:
 213 
 214         pll_code->m_bp = bypass;
 215         pll_code->m_code = m;
 216         pll_code->n_code = n;
 217         pll_code->k_code = k;
 218         return 0;
 219 }
 220 EXPORT_SYMBOL_GPL(rl6231_pll_calc);
 221 
 222 int rl6231_get_clk_info(int sclk, int rate)
 223 {
 224         int i;
 225         static const int pd[] = {1, 2, 3, 4, 6, 8, 12, 16};
 226 
 227         if (sclk <= 0 || rate <= 0)
 228                 return -EINVAL;
 229 
 230         rate = rate << 8;
 231         for (i = 0; i < ARRAY_SIZE(pd); i++)
 232                 if (sclk == rate * pd[i])
 233                         return i;
 234 
 235         return -EINVAL;
 236 }
 237 EXPORT_SYMBOL_GPL(rl6231_get_clk_info);
 238 
 239 MODULE_DESCRIPTION("RL6231 class device shared support");
 240 MODULE_AUTHOR("Oder Chiou <oder_chiou@realtek.com>");
 241 MODULE_LICENSE("GPL v2");