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ak4104.c

/*
 * AK4104 ALSA SoC (ASoC) driver
 *
 * Copyright (c) 2009 Daniel Mack <daniel@caiaq.de>
 *
 *  This program is free software; you can redistribute  it and/or modify it
 *  under the terms of  the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the  License, or (at your
 *  option) any later version.
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <sound/core.h>
#include <sound/soc.h>
#include <sound/initval.h>
#include <linux/spi/spi.h>
#include <sound/asoundef.h>

#include "ak4104.h"

/* AK4104 registers addresses */
#define AK4104_REG_CONTROL1         0x00
#define AK4104_REG_RESERVED         0x01
#define AK4104_REG_CONTROL2         0x02
#define AK4104_REG_TX               0x03
#define AK4104_REG_CHN_STATUS(x)    ((x) + 0x04)
#define AK4104_NUM_REGS             10

#define AK4104_REG_MASK             0x1f
#define AK4104_READ                 0xc0
#define AK4104_WRITE                0xe0
#define AK4104_RESERVED_VAL         0x5b

/* Bit masks for AK4104 registers */
#define AK4104_CONTROL1_RSTN        (1 << 0)
#define AK4104_CONTROL1_PW          (1 << 1)
#define AK4104_CONTROL1_DIF0        (1 << 2)
#define AK4104_CONTROL1_DIF1        (1 << 3)

#define AK4104_CONTROL2_SEL0        (1 << 0)
#define AK4104_CONTROL2_SEL1        (1 << 1)
#define AK4104_CONTROL2_MODE        (1 << 2)

#define AK4104_TX_TXE               (1 << 0)
#define AK4104_TX_V                 (1 << 1)

#define DRV_NAME "ak4104"

struct ak4104_private {
      struct snd_soc_codec codec;
      u8 reg_cache[AK4104_NUM_REGS];
};

static int ak4104_fill_cache(struct snd_soc_codec *codec)
{
      int i;
      u8 *reg_cache = codec->reg_cache;
      struct spi_device *spi = codec->control_data;

      for (i = 0; i < codec->reg_cache_size; i++) {
            int ret = spi_w8r8(spi, i | AK4104_READ);
            if (ret < 0) {
                  dev_err(&spi->dev, "SPI write failure\n");
                  return ret;
            }

            reg_cache[i] = ret;
      }

      return 0;
}

static unsigned int ak4104_read_reg_cache(struct snd_soc_codec *codec,
                                unsigned int reg)
{
      u8 *reg_cache = codec->reg_cache;

      if (reg >= codec->reg_cache_size)
            return -EINVAL;

      return reg_cache[reg];
}

static int ak4104_spi_write(struct snd_soc_codec *codec, unsigned int reg,
                      unsigned int value)
{
      u8 *cache = codec->reg_cache;
      struct spi_device *spi = codec->control_data;

      if (reg >= codec->reg_cache_size)
            return -EINVAL;

      /* only write to the hardware if value has changed */
      if (cache[reg] != value) {
            u8 tmp[2] = { (reg & AK4104_REG_MASK) | AK4104_WRITE, value };

            if (spi_write(spi, tmp, sizeof(tmp))) {
                  dev_err(&spi->dev, "SPI write failed\n");
                  return -EIO;
            }

            cache[reg] = value;
      }

      return 0;
}

static int ak4104_set_dai_fmt(struct snd_soc_dai *codec_dai,
                        unsigned int format)
{
      struct snd_soc_codec *codec = codec_dai->codec;
      int val = 0;

      val = ak4104_read_reg_cache(codec, AK4104_REG_CONTROL1);
      if (val < 0)
            return val;

      val &= ~(AK4104_CONTROL1_DIF0 | AK4104_CONTROL1_DIF1);

      /* set DAI format */
      switch (format & SND_SOC_DAIFMT_FORMAT_MASK) {
      case SND_SOC_DAIFMT_RIGHT_J:
            break;
      case SND_SOC_DAIFMT_LEFT_J:
            val |= AK4104_CONTROL1_DIF0;
            break;
      case SND_SOC_DAIFMT_I2S:
            val |= AK4104_CONTROL1_DIF0 | AK4104_CONTROL1_DIF1;
            break;
      default:
            dev_err(codec->dev, "invalid dai format\n");
            return -EINVAL;
      }

      /* This device can only be slave */
      if ((format & SND_SOC_DAIFMT_MASTER_MASK) != SND_SOC_DAIFMT_CBS_CFS)
            return -EINVAL;

      return ak4104_spi_write(codec, AK4104_REG_CONTROL1, val);
}

static int ak4104_hw_params(struct snd_pcm_substream *substream,
                      struct snd_pcm_hw_params *params,
                      struct snd_soc_dai *dai)
{
      struct snd_soc_pcm_runtime *rtd = substream->private_data;
      struct snd_soc_device *socdev = rtd->socdev;
      struct snd_soc_codec *codec = socdev->card->codec;
      int val = 0;

      /* set the IEC958 bits: consumer mode, no copyright bit */
      val |= IEC958_AES0_CON_NOT_COPYRIGHT;
      ak4104_spi_write(codec, AK4104_REG_CHN_STATUS(0), val);

      val = 0;

      switch (params_rate(params)) {
      case 44100:
            val |= IEC958_AES3_CON_FS_44100;
            break;
      case 48000:
            val |= IEC958_AES3_CON_FS_48000;
            break;
      case 32000:
            val |= IEC958_AES3_CON_FS_32000;
            break;
      default:
            dev_err(codec->dev, "unsupported sampling rate\n");
            return -EINVAL;
      }

      return ak4104_spi_write(codec, AK4104_REG_CHN_STATUS(3), val);
}

static struct snd_soc_dai_ops ak4101_dai_ops = {
      .hw_params = ak4104_hw_params,
      .set_fmt = ak4104_set_dai_fmt,
};

struct snd_soc_dai ak4104_dai = {
      .name = DRV_NAME,
      .playback = {
            .stream_name = "Playback",
            .channels_min = 2,
            .channels_max = 2,
            .rates = SNDRV_PCM_RATE_8000_192000,
            .formats = SNDRV_PCM_FMTBIT_S16_LE  |
                     SNDRV_PCM_FMTBIT_S24_3LE |
                     SNDRV_PCM_FMTBIT_S24_LE
      },
      .ops = &ak4101_dai_ops,
};

static struct snd_soc_codec *ak4104_codec;

static int ak4104_spi_probe(struct spi_device *spi)
{
      struct snd_soc_codec *codec;
      struct ak4104_private *ak4104;
      int ret, val;

      spi->bits_per_word = 8;
      spi->mode = SPI_MODE_0;
      ret = spi_setup(spi);
      if (ret < 0)
            return ret;

      ak4104 = kzalloc(sizeof(struct ak4104_private), GFP_KERNEL);
      if (!ak4104) {
            dev_err(&spi->dev, "could not allocate codec\n");
            return -ENOMEM;
      }

      codec = &ak4104->codec;
      mutex_init(&codec->mutex);
      INIT_LIST_HEAD(&codec->dapm_widgets);
      INIT_LIST_HEAD(&codec->dapm_paths);

      codec->dev = &spi->dev;
      codec->name = DRV_NAME;
      codec->owner = THIS_MODULE;
      codec->dai = &ak4104_dai;
      codec->num_dai = 1;
      codec->private_data = ak4104;
      codec->control_data = spi;
      codec->reg_cache = ak4104->reg_cache;
      codec->reg_cache_size = AK4104_NUM_REGS;

      /* read all regs and fill the cache */
      ret = ak4104_fill_cache(codec);
      if (ret < 0) {
            dev_err(&spi->dev, "failed to fill register cache\n");
            return ret;
      }

      /* read the 'reserved' register - according to the datasheet, it
       * should contain 0x5b. Not a good way to verify the presence of
       * the device, but there is no hardware ID register. */
      if (ak4104_read_reg_cache(codec, AK4104_REG_RESERVED) !=
                               AK4104_RESERVED_VAL) {
            ret = -ENODEV;
            goto error_free_codec;
      }

      /* set power-up and non-reset bits */
      val = ak4104_read_reg_cache(codec, AK4104_REG_CONTROL1);
      val |= AK4104_CONTROL1_PW | AK4104_CONTROL1_RSTN;
      ret = ak4104_spi_write(codec, AK4104_REG_CONTROL1, val);
      if (ret < 0)
            goto error_free_codec;

      /* enable transmitter */
      val = ak4104_read_reg_cache(codec, AK4104_REG_TX);
      val |= AK4104_TX_TXE;
      ret = ak4104_spi_write(codec, AK4104_REG_TX, val);
      if (ret < 0)
            goto error_free_codec;

      ak4104_codec = codec;
      ret = snd_soc_register_dai(&ak4104_dai);
      if (ret < 0) {
            dev_err(&spi->dev, "failed to register DAI\n");
            goto error_free_codec;
      }

      spi_set_drvdata(spi, ak4104);
      dev_info(&spi->dev, "SPI device initialized\n");
      return 0;

error_free_codec:
      kfree(ak4104);
      ak4104_dai.dev = NULL;
      return ret;
}

static int __devexit ak4104_spi_remove(struct spi_device *spi)
{
      int ret, val;
      struct ak4104_private *ak4104 = spi_get_drvdata(spi);

      val = ak4104_read_reg_cache(&ak4104->codec, AK4104_REG_CONTROL1);
      if (val < 0)
            return val;

      /* clear power-up and non-reset bits */
      val &= ~(AK4104_CONTROL1_PW | AK4104_CONTROL1_RSTN);
      ret = ak4104_spi_write(&ak4104->codec, AK4104_REG_CONTROL1, val);
      if (ret < 0)
            return ret;

      ak4104_codec = NULL;
      kfree(ak4104);
      return 0;
}

static int ak4104_probe(struct platform_device *pdev)
{
      struct snd_soc_device *socdev = platform_get_drvdata(pdev);
      struct snd_soc_codec *codec = ak4104_codec;
      int ret;

      /* Connect the codec to the socdev.  snd_soc_new_pcms() needs this. */
      socdev->card->codec = codec;

      /* Register PCMs */
      ret = snd_soc_new_pcms(socdev, SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1);
      if (ret < 0) {
            dev_err(codec->dev, "failed to create pcms\n");
            return ret;
      }

      return 0;
}

static int ak4104_remove(struct platform_device *pdev)
{
      struct snd_soc_device *socdev = platform_get_drvdata(pdev);
      snd_soc_free_pcms(socdev);
      return 0;
};

struct snd_soc_codec_device soc_codec_device_ak4104 = {
      .probe =    ak4104_probe,
      .remove =   ak4104_remove
};
EXPORT_SYMBOL_GPL(soc_codec_device_ak4104);

static struct spi_driver ak4104_spi_driver = {
      .driver  = {
            .name   = DRV_NAME,
            .owner  = THIS_MODULE,
      },
      .probe  = ak4104_spi_probe,
      .remove = __devexit_p(ak4104_spi_remove),
};

static int __init ak4104_init(void)
{
      pr_info("Asahi Kasei AK4104 ALSA SoC Codec Driver\n");
      return spi_register_driver(&ak4104_spi_driver);
}
module_init(ak4104_init);

static void __exit ak4104_exit(void)
{
      spi_unregister_driver(&ak4104_spi_driver);
}
module_exit(ak4104_exit);

MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
MODULE_DESCRIPTION("Asahi Kasei AK4104 ALSA SoC driver");
MODULE_LICENSE("GPL");


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