LXR linux/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 */
  26int 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}
  60EXPORT_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 */
  70int 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}
  91EXPORT_SYMBOL_GPL(rl6231_calc_dmic_clk);
  92
  93struct 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
 102static 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
 108static 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 */
 137int 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
 213code_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}
 221EXPORT_SYMBOL_GPL(rl6231_pll_calc);
 222
 223int 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}
 238EXPORT_SYMBOL_GPL(rl6231_get_clk_info);
 239
 240MODULE_DESCRIPTION("RL6231 class device shared support");
 241MODULE_AUTHOR("Oder Chiou <oder_chiou@realtek.com>");
 242MODULE_LICENSE("GPL v2");
 243