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
  15 #include "rl6231.h"
  16
  17 /**
  18  * rl6231_calc_dmic_clk - Calculate the parameter of dmic.
  19  *
  20  * @rate: base clock rate.
  21  *
  22  * Choose dmic clock between 1MHz and 3MHz.
  23  * It is better for clock to approximate 3MHz.
  24  */
  25 int rl6231_calc_dmic_clk(int rate)
  26 {
  27         int div[] = {2, 3, 4, 6, 8, 12}, idx = -EINVAL;
  28         int i, red, bound, temp;
  29
  30         red = 3000000 * 12;
  31         for (i = 0; i < ARRAY_SIZE(div); i++) {
  32                 bound = div[i] * 3000000;
  33                 if (rate > bound)
  34                         continue;
  35                 temp = bound - rate;
  36                 if (temp < red) {
  37                         red = temp;
  38                         idx = i;
  39                 }
  40         }
  41
  42         return idx;
  43 }
  44 EXPORT_SYMBOL_GPL(rl6231_calc_dmic_clk);
  45
  46 /**
  47  * rl6231_pll_calc - Calcualte PLL M/N/K code.
  48  * @freq_in: external clock provided to codec.
  49  * @freq_out: target clock which codec works on.
  50  * @pll_code: Pointer to structure with M, N, K and bypass flag.
  51  *
  52  * Calcualte M/N/K code to configure PLL for codec.
  53  *
  54  * Returns 0 for success or negative error code.
  55  */
  56 int rl6231_pll_calc(const unsigned int freq_in,
  57         const unsigned int freq_out, struct rl6231_pll_code *pll_code)
  58 {
  59         int max_n = RL6231_PLL_N_MAX, max_m = RL6231_PLL_M_MAX;
  60         int k, red, n_t, pll_out, in_t, out_t;
  61         int n = 0, m = 0, m_t = 0;
  62         int red_t = abs(freq_out - freq_in);
  63         bool bypass = false;
  64
  65         if (RL6231_PLL_INP_MAX < freq_in || RL6231_PLL_INP_MIN > freq_in)
  66                 return -EINVAL;
  67
  68         k = 100000000 / freq_out - 2;
  69         if (k > RL6231_PLL_K_MAX)
  70                 k = RL6231_PLL_K_MAX;
  71         for (n_t = 0; n_t <= max_n; n_t++) {
  72                 in_t = freq_in / (k + 2);
  73                 pll_out = freq_out / (n_t + 2);
  74                 if (in_t < 0)
  75                         continue;
  76                 if (in_t == pll_out) {
  77                         bypass = true;
  78                         n = n_t;
  79                         goto code_find;
  80                 }
  81                 red = abs(in_t - pll_out);
  82                 if (red < red_t) {
  83                         bypass = true;
  84                         n = n_t;
  85                         m = m_t;
  86                         if (red == 0)
  87                                 goto code_find;
  88                         red_t = red;
  89                 }
  90                 for (m_t = 0; m_t <= max_m; m_t++) {
  91                         out_t = in_t / (m_t + 2);
  92                         red = abs(out_t - pll_out);
  93                         if (red < red_t) {
  94                                 bypass = false;
  95                                 n = n_t;
  96                                 m = m_t;
  97                                 if (red == 0)
  98                                         goto code_find;
  99                                 red_t = red;
 100                         }
 101                 }
 102         }
 103         pr_debug("Only get approximation about PLL\n");
 104
 105 code_find:
 106
 107         pll_code->m_bp = bypass;
 108         pll_code->m_code = m;
 109         pll_code->n_code = n;
 110         pll_code->k_code = k;
 111         return 0;
 112 }
 113 EXPORT_SYMBOL_GPL(rl6231_pll_calc);
 114
 115 int rl6231_get_clk_info(int sclk, int rate)
 116 {
 117         int i, pd[] = {1, 2, 3, 4, 6, 8, 12, 16};
 118
 119         if (sclk <= 0 || rate <= 0)
 120                 return -EINVAL;
 121
 122         rate = rate << 8;
 123         for (i = 0; i < ARRAY_SIZE(pd); i++)
 124                 if (sclk == rate * pd[i])
 125                         return i;
 126
 127         return -EINVAL;
 128 }
 129 EXPORT_SYMBOL_GPL(rl6231_get_clk_info);
 130
 131 MODULE_DESCRIPTION("RL6231 class device shared support");
 132 MODULE_AUTHOR("Oder Chiou <oder_chiou@realtek.com>");
 133 MODULE_LICENSE("GPL v2");