sound/soc/codecs/rl6231.c

   1 /*
   2  * rl6231.c - RL6231 class device shared support
   3  *
   4  * Copyright 2014 Realtek Semiconductor Corp.
   5  *
   6  * Author: Oder Chiou <oder_chiou@realtek.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/regmap.h>
  15
  16 #include "rl6231.h"
  17
  18 /**
  19  * rl6231_get_pre_div - Return the value of pre divider.
  20  *
  21  * @map: map for setting.
  22  * @reg: register.
  23  * @sft: shift.
  24  *
  25  * Return the value of pre divider from given register value.
  26  * Return negative error code for unexpected register value.
  27  */
  28 int rl6231_get_pre_div(struct regmap *map, unsigned int reg, int sft)
  29 {
  30         int pd, val;
  31
  32         regmap_read(map, reg, &val);
  33
  34         val = (val >> sft) & 0x7;
  35
  36         switch (val) {
  37         case 0:
  38         case 1:
  39         case 2:
  40         case 3:
  41                 pd = val + 1;
  42                 break;
  43         case 4:
  44                 pd = 6;
  45                 break;
  46         case 5:
  47                 pd = 8;
  48                 break;
  49         case 6:
  50                 pd = 12;
  51                 break;
  52         case 7:
  53                 pd = 16;
  54                 break;
  55         default:
  56                 pd = -EINVAL;
  57                 break;
  58         }
  59
  60         return pd;
  61 }
  62 EXPORT_SYMBOL_GPL(rl6231_get_pre_div);
  63
  64 /**
  65  * rl6231_calc_dmic_clk - Calculate the frequency divider parameter of dmic.
  66  *
  67  * @rate: base clock rate.
  68  *
  69  * Choose divider parameter that gives the highest possible DMIC frequency in
  70  * 1MHz - 3MHz range.
  71  */
  72 int rl6231_calc_dmic_clk(int rate)
  73 {
  74         int div[] = {2, 3, 4, 6, 8, 12};
  75         int i;
  76
  77         if (rate < 1000000 * div[0]) {
  78                 pr_warn("Base clock rate %d is too low\n", rate);
  79                 return -EINVAL;
  80         }
  81
  82         for (i = 0; i < ARRAY_SIZE(div); i++) {
  83                 if ((div[i] % 3) == 0)
  84                         continue;
  85                 /* find divider that gives DMIC frequency below 3.072MHz */
  86                 if (3072000 * div[i] >= rate)
  87                         return i;
  88         }
  89
  90         pr_warn("Base clock rate %d is too high\n", rate);
  91         return -EINVAL;
  92 }
  93 EXPORT_SYMBOL_GPL(rl6231_calc_dmic_clk);
  94
  95 struct pll_calc_map {
  96         unsigned int pll_in;
  97         unsigned int pll_out;
  98         int k;
  99         int n;
 100         int m;
 101         bool m_bp;
 102 };
 103
 104 static const struct pll_calc_map pll_preset_table[] = {
 105         {19200000,  4096000,  23, 14, 1, false},
 106         {19200000,  24576000,  3, 30, 3, false},
 107 };
 108
 109 /**
 110  * rl6231_pll_calc - Calcualte PLL M/N/K code.
 111  * @freq_in: external clock provided to codec.
 112  * @freq_out: target clock which codec works on.
 113  * @pll_code: Pointer to structure with M, N, K and bypass flag.
 114  *
 115  * Calcualte M/N/K code to configure PLL for codec.
 116  *
 117  * Returns 0 for success or negative error code.
 118  */
 119 int rl6231_pll_calc(const unsigned int freq_in,
 120         const unsigned int freq_out, struct rl6231_pll_code *pll_code)
 121 {
 122         int max_n = RL6231_PLL_N_MAX, max_m = RL6231_PLL_M_MAX;
 123         int i, k, red, n_t, pll_out, in_t, out_t;
 124         int n = 0, m = 0, m_t = 0;
 125         int red_t = abs(freq_out - freq_in);
 126         bool bypass = false;
 127
 128         if (RL6231_PLL_INP_MAX < freq_in || RL6231_PLL_INP_MIN > freq_in)
 129                 return -EINVAL;
 130
 131         for (i = 0; i < ARRAY_SIZE(pll_preset_table); i++) {
 132                 if (freq_in == pll_preset_table[i].pll_in &&
 133                         freq_out == pll_preset_table[i].pll_out) {
 134                         k = pll_preset_table[i].k;
 135                         m = pll_preset_table[i].m;
 136                         n = pll_preset_table[i].n;
 137                         bypass = pll_preset_table[i].m_bp;
 138                         pr_debug("Use preset PLL parameter table\n");
 139                         goto code_find;
 140                 }
 141         }
 142
 143         k = 100000000 / freq_out - 2;
 144         if (k > RL6231_PLL_K_MAX)
 145                 k = RL6231_PLL_K_MAX;
 146         for (n_t = 0; n_t <= max_n; n_t++) {
 147                 in_t = freq_in / (k + 2);
 148                 pll_out = freq_out / (n_t + 2);
 149                 if (in_t < 0)
 150                         continue;
 151                 if (in_t == pll_out) {
 152                         bypass = true;
 153                         n = n_t;
 154                         goto code_find;
 155                 }
 156                 red = abs(in_t - pll_out);
 157                 if (red < red_t) {
 158                         bypass = true;
 159                         n = n_t;
 160                         m = m_t;
 161                         if (red == 0)
 162                                 goto code_find;
 163                         red_t = red;
 164                 }
 165                 for (m_t = 0; m_t <= max_m; m_t++) {
 166                         out_t = in_t / (m_t + 2);
 167                         red = abs(out_t - pll_out);
 168                         if (red < red_t) {
 169                                 bypass = false;
 170                                 n = n_t;
 171                                 m = m_t;
 172                                 if (red == 0)
 173                                         goto code_find;
 174                                 red_t = red;
 175                         }
 176                 }
 177         }
 178         pr_debug("Only get approximation about PLL\n");
 179
 180 code_find:
 181
 182         pll_code->m_bp = bypass;
 183         pll_code->m_code = m;
 184         pll_code->n_code = n;
 185         pll_code->k_code = k;
 186         return 0;
 187 }
 188 EXPORT_SYMBOL_GPL(rl6231_pll_calc);
 189
 190 int rl6231_get_clk_info(int sclk, int rate)
 191 {
 192         int i, pd[] = {1, 2, 3, 4, 6, 8, 12, 16};
 193
 194         if (sclk <= 0 || rate <= 0)
 195                 return -EINVAL;
 196
 197         rate = rate << 8;
 198         for (i = 0; i < ARRAY_SIZE(pd); i++)
 199                 if (sclk == rate * pd[i])
 200                         return i;
 201
 202         return -EINVAL;
 203 }
 204 EXPORT_SYMBOL_GPL(rl6231_get_clk_info);
 205
 206 MODULE_DESCRIPTION("RL6231 class device shared support");
 207 MODULE_AUTHOR("Oder Chiou <oder_chiou@realtek.com>");
 208 MODULE_LICENSE("GPL v2");