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/moduleparam.h>
  15 #include <linux/init.h>
  16 #include <linux/delay.h>
  17 #include <linux/pm.h>
  18 #include <linux/gpio.h>
  19 #include <linux/i2c.h>
  20 #include <linux/regmap.h>
  21 #include <linux/of.h>
  22 #include <linux/of_gpio.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/spi/spi.h>
  25 #include <linux/acpi.h>
  26 #include <sound/core.h>
  27 #include <sound/pcm.h>
  28 #include <sound/pcm_params.h>
  29 #include <sound/soc.h>
  30 #include <sound/soc-dapm.h>
  31 #include <sound/initval.h>
  32 #include <sound/tlv.h>
  33
  34 #include "rl6231.h"
  35
  36 /**
  37  * rl6231_calc_dmic_clk - Calculate the parameter of dmic.
  38  *
  39  * @rate: base clock rate.
  40  *
  41  * Choose dmic clock between 1MHz and 3MHz.
  42  * It is better for clock to approximate 3MHz.
  43  */
  44 int rl6231_calc_dmic_clk(int rate)
  45 {
  46         int div[] = {2, 3, 4, 6, 8, 12}, idx = -EINVAL;
  47         int i, red, bound, temp;
  48
  49         red = 3000000 * 12;
  50         for (i = 0; i < ARRAY_SIZE(div); i++) {
  51                 bound = div[i] * 3000000;
  52                 if (rate > bound)
  53                         continue;
  54                 temp = bound - rate;
  55                 if (temp < red) {
  56                         red = temp;
  57                         idx = i;
  58                 }
  59         }
  60
  61         return idx;
  62 }
  63 EXPORT_SYMBOL_GPL(rl6231_calc_dmic_clk);
  64
  65 MODULE_DESCRIPTION("RL6231 class device shared support");
  66 MODULE_AUTHOR("Oder Chiou <oder_chiou@realtek.com>");
  67 MODULE_LICENSE("GPL v2");