sound/soc/codecs/rl6231.c

   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         {3840000,   24576000,  3, 30, 0, true},
 106 };
 107
 108 static unsigned int find_best_div(unsigned int in,
 109         unsigned int max, unsigned int div)
 110 {
 111         unsigned int d;
 112
 113         if (in <= max)
 114                 return 1;
 115
 116         d = in / max;
 117         if (in % max)
 118                 d++;
 119
 120         while (div % d != 0)
 121                 d++;
 122
 123
 124         return d;
 125 }
 126
 127 /**
 128  * rl6231_pll_calc - Calcualte PLL M/N/K code.
 129  * @freq_in: external clock provided to codec.
 130  * @freq_out: target clock which codec works on.
 131  * @pll_code: Pointer to structure with M, N, K and bypass flag.
 132  *
 133  * Calcualte M/N/K code to configure PLL for codec.
 134  *
 135  * Returns 0 for success or negative error code.
 136  */
 137 int rl6231_pll_calc(const unsigned int freq_in,
 138         const unsigned int freq_out, struct rl6231_pll_code *pll_code)
 139 {
 140         int max_n = RL6231_PLL_N_MAX, max_m = RL6231_PLL_M_MAX;
 141         int i, k, n_t;
 142         int k_t, min_k, max_k, n = 0, m = 0, m_t = 0;
 143         unsigned int red, pll_out, in_t, out_t, div, div_t;
 144         unsigned int red_t = abs(freq_out - freq_in);
 145         unsigned int f_in, f_out, f_max;
 146         bool bypass = false;
 147
 148         if (RL6231_PLL_INP_MAX < freq_in || RL6231_PLL_INP_MIN > freq_in)
 149                 return -EINVAL;
 150
 151         for (i = 0; i < ARRAY_SIZE(pll_preset_table); i++) {
 152                 if (freq_in == pll_preset_table[i].pll_in &&
 153                         freq_out == pll_preset_table[i].pll_out) {
 154                         k = pll_preset_table[i].k;
 155                         m = pll_preset_table[i].m;
 156                         n = pll_preset_table[i].n;
 157                         bypass = pll_preset_table[i].m_bp;
 158                         pr_debug("Use preset PLL parameter table\n");
 159                         goto code_find;
 160                 }
 161         }
 162
 163         min_k = 80000000 / freq_out - 2;
 164         max_k = 150000000 / freq_out - 2;
 165         if (max_k > RL6231_PLL_K_MAX)
 166                 max_k = RL6231_PLL_K_MAX;
 167         if (min_k > RL6231_PLL_K_MAX)
 168                 min_k = max_k = RL6231_PLL_K_MAX;
 169         div_t = gcd(freq_in, freq_out);
 170         f_max = 0xffffffff / RL6231_PLL_N_MAX;
 171         div = find_best_div(freq_in, f_max, div_t);
 172         f_in = freq_in / div;
 173         f_out = freq_out / div;
 174         k = min_k;
 175         for (k_t = min_k; k_t <= max_k; k_t++) {
 176                 for (n_t = 0; n_t <= max_n; n_t++) {
 177                         in_t = f_in * (n_t + 2);
 178                         pll_out = f_out * (k_t + 2);
 179                         if (in_t == pll_out) {
 180                                 bypass = true;
 181                                 n = n_t;
 182                                 k = k_t;
 183                                 goto code_find;
 184                         }
 185                         out_t = in_t / (k_t + 2);
 186                         red = abs(f_out - out_t);
 187                         if (red < red_t) {
 188                                 bypass = true;
 189                                 n = n_t;
 190                                 m = 0;
 191                                 k = k_t;
 192                                 if (red == 0)
 193                                         goto code_find;
 194                                 red_t = red;
 195                         }
 196                         for (m_t = 0; m_t <= max_m; m_t++) {
 197                                 out_t = in_t / ((m_t + 2) * (k_t + 2));
 198                                 red = abs(f_out - out_t);
 199                                 if (red < red_t) {
 200                                         bypass = false;
 201                                         n = n_t;
 202                                         m = m_t;
 203                                         k = k_t;
 204                                         if (red == 0)
 205                                                 goto code_find;
 206                                         red_t = red;
 207                                 }
 208                         }
 209                 }
 210         }
 211         pr_debug("Only get approximation about PLL\n");
 212
 213 code_find:
 214
 215         pll_code->m_bp = bypass;
 216         pll_code->m_code = m;
 217         pll_code->n_code = n;
 218         pll_code->k_code = k;
 219         return 0;
 220 }
 221 EXPORT_SYMBOL_GPL(rl6231_pll_calc);
 222
 223 int rl6231_get_clk_info(int sclk, int rate)
 224 {
 225         int i;
 226         static const int pd[] = {1, 2, 3, 4, 6, 8, 12, 16};
 227
 228         if (sclk <= 0 || rate <= 0)
 229                 return -EINVAL;
 230
 231         rate = rate << 8;
 232         for (i = 0; i < ARRAY_SIZE(pd); i++)
 233                 if (sclk == rate * pd[i])
 234                         return i;
 235
 236         return -EINVAL;
 237 }
 238 EXPORT_SYMBOL_GPL(rl6231_get_clk_info);
 239
 240 MODULE_DESCRIPTION("RL6231 class device shared support");
 241 MODULE_AUTHOR("Oder Chiou <oder_chiou@realtek.com>");
 242 MODULE_LICENSE("GPL v2");