Logo Search packages:      
Sourcecode: alsa-driver version File versions

cs4270.c

/*
 * CS4270 ALSA SoC (ASoC) codec driver
 *
 * Author: Timur Tabi <timur@freescale.com>
 *
 * Copyright 2007-2009 Freescale Semiconductor, Inc.  This file is licensed
 * under the terms of the GNU General Public License version 2.  This
 * program is licensed "as is" without any warranty of any kind, whether
 * express or implied.
 *
 * This is an ASoC device driver for the Cirrus Logic CS4270 codec.
 *
 * Current features/limitations:
 *
 * - Software mode is supported.  Stand-alone mode is not supported.
 * - Only I2C is supported, not SPI
 * - Support for master and slave mode
 * - The machine driver's 'startup' function must call
 *   cs4270_set_dai_sysclk() with the value of MCLK.
 * - Only I2S and left-justified modes are supported
 * - Power management is supported
 */

#include <linux/module.h>
#include <linux/platform_device.h>
#include <sound/core.h>
#include <sound/soc.h>
#include <sound/initval.h>
#include <linux/i2c.h>
#include <linux/delay.h>

#include "cs4270.h"

/*
 * The codec isn't really big-endian or little-endian, since the I2S
 * interface requires data to be sent serially with the MSbit first.
 * However, to support BE and LE I2S devices, we specify both here.  That
 * way, ALSA will always match the bit patterns.
 */
#define CS4270_FORMATS (SNDRV_PCM_FMTBIT_S8      | \
                  SNDRV_PCM_FMTBIT_S16_LE  | SNDRV_PCM_FMTBIT_S16_BE  | \
                  SNDRV_PCM_FMTBIT_S18_3LE | SNDRV_PCM_FMTBIT_S18_3BE | \
                  SNDRV_PCM_FMTBIT_S20_3LE | SNDRV_PCM_FMTBIT_S20_3BE | \
                  SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE | \
                  SNDRV_PCM_FMTBIT_S24_LE  | SNDRV_PCM_FMTBIT_S24_BE)

/* CS4270 registers addresses */
#define CS4270_CHIPID   0x01  /* Chip ID */
#define CS4270_PWRCTL   0x02  /* Power Control */
#define CS4270_MODE     0x03  /* Mode Control */
#define CS4270_FORMAT   0x04  /* Serial Format, ADC/DAC Control */
#define CS4270_TRANS    0x05  /* Transition Control */
#define CS4270_MUTE     0x06  /* Mute Control */
#define CS4270_VOLA     0x07  /* DAC Channel A Volume Control */
#define CS4270_VOLB     0x08  /* DAC Channel B Volume Control */

#define CS4270_FIRSTREG 0x01
#define CS4270_LASTREG  0x08
#define CS4270_NUMREGS  (CS4270_LASTREG - CS4270_FIRSTREG + 1)
#define CS4270_I2C_INCR 0x80

/* Bit masks for the CS4270 registers */
#define CS4270_CHIPID_ID      0xF0
#define CS4270_CHIPID_REV     0x0F
#define CS4270_PWRCTL_FREEZE  0x80
#define CS4270_PWRCTL_PDN_ADC 0x20
#define CS4270_PWRCTL_PDN_DAC 0x02
#define CS4270_PWRCTL_PDN     0x01
#define CS4270_PWRCTL_PDN_ALL \
      (CS4270_PWRCTL_PDN_ADC | CS4270_PWRCTL_PDN_DAC | CS4270_PWRCTL_PDN)
#define CS4270_MODE_SPEED_MASK      0x30
#define CS4270_MODE_1X        0x00
#define CS4270_MODE_2X        0x10
#define CS4270_MODE_4X        0x20
#define CS4270_MODE_SLAVE     0x30
#define CS4270_MODE_DIV_MASK  0x0E
#define CS4270_MODE_DIV1      0x00
#define CS4270_MODE_DIV15     0x02
#define CS4270_MODE_DIV2      0x04
#define CS4270_MODE_DIV3      0x06
#define CS4270_MODE_DIV4      0x08
#define CS4270_MODE_POPGUARD  0x01
#define CS4270_FORMAT_FREEZE_A      0x80
#define CS4270_FORMAT_FREEZE_B      0x40
#define CS4270_FORMAT_LOOPBACK      0x20
#define CS4270_FORMAT_DAC_MASK      0x18
#define CS4270_FORMAT_DAC_LJ  0x00
#define CS4270_FORMAT_DAC_I2S 0x08
#define CS4270_FORMAT_DAC_RJ16      0x18
#define CS4270_FORMAT_DAC_RJ24      0x10
#define CS4270_FORMAT_ADC_MASK      0x01
#define CS4270_FORMAT_ADC_LJ  0x00
#define CS4270_FORMAT_ADC_I2S 0x01
#define CS4270_TRANS_ONE_VOL  0x80
#define CS4270_TRANS_SOFT     0x40
#define CS4270_TRANS_ZERO     0x20
#define CS4270_TRANS_INV_ADC_A      0x08
#define CS4270_TRANS_INV_ADC_B      0x10
#define CS4270_TRANS_INV_DAC_A      0x02
#define CS4270_TRANS_INV_DAC_B      0x04
#define CS4270_TRANS_DEEMPH   0x01
#define CS4270_MUTE_AUTO      0x20
#define CS4270_MUTE_ADC_A     0x08
#define CS4270_MUTE_ADC_B     0x10
#define CS4270_MUTE_POLARITY  0x04
#define CS4270_MUTE_DAC_A     0x01
#define CS4270_MUTE_DAC_B     0x02

/* Private data for the CS4270 */
struct cs4270_private {
      struct snd_soc_codec codec;
      u8 reg_cache[CS4270_NUMREGS];
      unsigned int mclk; /* Input frequency of the MCLK pin */
      unsigned int mode; /* The mode (I2S or left-justified) */
      unsigned int slave_mode;
      unsigned int manual_mute;
};

/**
 * struct cs4270_mode_ratios - clock ratio tables
 * @ratio: the ratio of MCLK to the sample rate
 * @speed_mode: the Speed Mode bits to set in the Mode Control register for
 *              this ratio
 * @mclk: the Ratio Select bits to set in the Mode Control register for this
 *        ratio
 *
 * The data for this chart is taken from Table 5 of the CS4270 reference
 * manual.
 *
 * This table is used to determine how to program the Mode Control register.
 * It is also used by cs4270_set_dai_sysclk() to tell ALSA which sampling
 * rates the CS4270 currently supports.
 *
 * @speed_mode is the corresponding bit pattern to be written to the
 * MODE bits of the Mode Control Register
 *
 * @mclk is the corresponding bit pattern to be wirten to the MCLK bits of
 * the Mode Control Register.
 *
 * In situations where a single ratio is represented by multiple speed
 * modes, we favor the slowest speed.  E.g, for a ratio of 128, we pick
 * double-speed instead of quad-speed.  However, the CS4270 errata states
 * that divide-By-1.5 can cause failures, so we avoid that mode where
 * possible.
 *
 * Errata: There is an errata for the CS4270 where divide-by-1.5 does not
 * work if Vd is 3.3V.  If this effects you, select the
 * CONFIG_SND_SOC_CS4270_VD33_ERRATA Kconfig option, and the driver will
 * never select any sample rates that require divide-by-1.5.
 */
struct cs4270_mode_ratios {
      unsigned int ratio;
      u8 speed_mode;
      u8 mclk;
};

static struct cs4270_mode_ratios cs4270_mode_ratios[] = {
      {64, CS4270_MODE_4X, CS4270_MODE_DIV1},
#ifndef CONFIG_SND_SOC_CS4270_VD33_ERRATA
      {96, CS4270_MODE_4X, CS4270_MODE_DIV15},
#endif
      {128, CS4270_MODE_2X, CS4270_MODE_DIV1},
      {192, CS4270_MODE_4X, CS4270_MODE_DIV3},
      {256, CS4270_MODE_1X, CS4270_MODE_DIV1},
      {384, CS4270_MODE_2X, CS4270_MODE_DIV3},
      {512, CS4270_MODE_1X, CS4270_MODE_DIV2},
      {768, CS4270_MODE_1X, CS4270_MODE_DIV3},
      {1024, CS4270_MODE_1X, CS4270_MODE_DIV4}
};

/* The number of MCLK/LRCK ratios supported by the CS4270 */
#define NUM_MCLK_RATIOS       ARRAY_SIZE(cs4270_mode_ratios)

/**
 * cs4270_set_dai_sysclk - determine the CS4270 samples rates.
 * @codec_dai: the codec DAI
 * @clk_id: the clock ID (ignored)
 * @freq: the MCLK input frequency
 * @dir: the clock direction (ignored)
 *
 * This function is used to tell the codec driver what the input MCLK
 * frequency is.
 *
 * The value of MCLK is used to determine which sample rates are supported
 * by the CS4270.  The ratio of MCLK / Fs must be equal to one of nine
 * supported values - 64, 96, 128, 192, 256, 384, 512, 768, and 1024.
 *
 * This function calculates the nine ratios and determines which ones match
 * a standard sample rate.  If there's a match, then it is added to the list
 * of supported sample rates.
 *
 * This function must be called by the machine driver's 'startup' function,
 * otherwise the list of supported sample rates will not be available in
 * time for ALSA.
 */
static int cs4270_set_dai_sysclk(struct snd_soc_dai *codec_dai,
                         int clk_id, unsigned int freq, int dir)
{
      struct snd_soc_codec *codec = codec_dai->codec;
      struct cs4270_private *cs4270 = codec->private_data;
      unsigned int rates = 0;
      unsigned int rate_min = -1;
      unsigned int rate_max = 0;
      unsigned int i;

      cs4270->mclk = freq;

      for (i = 0; i < NUM_MCLK_RATIOS; i++) {
            unsigned int rate = freq / cs4270_mode_ratios[i].ratio;
            rates |= snd_pcm_rate_to_rate_bit(rate);
            if (rate < rate_min)
                  rate_min = rate;
            if (rate > rate_max)
                  rate_max = rate;
      }
      /* FIXME: soc should support a rate list */
      rates &= ~SNDRV_PCM_RATE_KNOT;

      if (!rates) {
            dev_err(codec->dev, "could not find a valid sample rate\n");
            return -EINVAL;
      }

      codec_dai->playback.rates = rates;
      codec_dai->playback.rate_min = rate_min;
      codec_dai->playback.rate_max = rate_max;

      codec_dai->capture.rates = rates;
      codec_dai->capture.rate_min = rate_min;
      codec_dai->capture.rate_max = rate_max;

      return 0;
}

/**
 * cs4270_set_dai_fmt - configure the codec for the selected audio format
 * @codec_dai: the codec DAI
 * @format: a SND_SOC_DAIFMT_x value indicating the data format
 *
 * This function takes a bitmask of SND_SOC_DAIFMT_x bits and programs the
 * codec accordingly.
 *
 * Currently, this function only supports SND_SOC_DAIFMT_I2S and
 * SND_SOC_DAIFMT_LEFT_J.  The CS4270 codec also supports right-justified
 * data for playback only, but ASoC currently does not support different
 * formats for playback vs. record.
 */
static int cs4270_set_dai_fmt(struct snd_soc_dai *codec_dai,
                        unsigned int format)
{
      struct snd_soc_codec *codec = codec_dai->codec;
      struct cs4270_private *cs4270 = codec->private_data;
      int ret = 0;

      /* set DAI format */
      switch (format & SND_SOC_DAIFMT_FORMAT_MASK) {
      case SND_SOC_DAIFMT_I2S:
      case SND_SOC_DAIFMT_LEFT_J:
            cs4270->mode = format & SND_SOC_DAIFMT_FORMAT_MASK;
            break;
      default:
            dev_err(codec->dev, "invalid dai format\n");
            ret = -EINVAL;
      }

      /* set master/slave audio interface */
      switch (format & SND_SOC_DAIFMT_MASTER_MASK) {
      case SND_SOC_DAIFMT_CBS_CFS:
            cs4270->slave_mode = 1;
            break;
      case SND_SOC_DAIFMT_CBM_CFM:
            cs4270->slave_mode = 0;
            break;
      default:
            /* all other modes are unsupported by the hardware */
            ret = -EINVAL;
      }

      return ret;
}

/**
 * cs4270_fill_cache - pre-fill the CS4270 register cache.
 * @codec: the codec for this CS4270
 *
 * This function fills in the CS4270 register cache by reading the register
 * values from the hardware.
 *
 * This CS4270 registers are cached to avoid excessive I2C I/O operations.
 * After the initial read to pre-fill the cache, the CS4270 never updates
 * the register values, so we won't have a cache coherency problem.
 *
 * We use the auto-increment feature of the CS4270 to read all registers in
 * one shot.
 */
static int cs4270_fill_cache(struct snd_soc_codec *codec)
{
      u8 *cache = codec->reg_cache;
      struct i2c_client *i2c_client = codec->control_data;
      s32 length;

      length = i2c_smbus_read_i2c_block_data(i2c_client,
            CS4270_FIRSTREG | CS4270_I2C_INCR, CS4270_NUMREGS, cache);

      if (length != CS4270_NUMREGS) {
            dev_err(codec->dev, "i2c read failure, addr=0x%x\n",
                   i2c_client->addr);
            return -EIO;
      }

      return 0;
}

/**
 * cs4270_read_reg_cache - read from the CS4270 register cache.
 * @codec: the codec for this CS4270
 * @reg: the register to read
 *
 * This function returns the value for a given register.  It reads only from
 * the register cache, not the hardware itself.
 *
 * This CS4270 registers are cached to avoid excessive I2C I/O operations.
 * After the initial read to pre-fill the cache, the CS4270 never updates
 * the register values, so we won't have a cache coherency problem.
 */
static unsigned int cs4270_read_reg_cache(struct snd_soc_codec *codec,
      unsigned int reg)
{
      u8 *cache = codec->reg_cache;

      if ((reg < CS4270_FIRSTREG) || (reg > CS4270_LASTREG))
            return -EIO;

      return cache[reg - CS4270_FIRSTREG];
}

/**
 * cs4270_i2c_write - write to a CS4270 register via the I2C bus.
 * @codec: the codec for this CS4270
 * @reg: the register to write
 * @value: the value to write to the register
 *
 * This function writes the given value to the given CS4270 register, and
 * also updates the register cache.
 *
 * Note that we don't use the hw_write function pointer of snd_soc_codec.
 * That's because it's too clunky: the hw_write_t prototype does not match
 * i2c_smbus_write_byte_data(), and it's just another layer of overhead.
 */
static int cs4270_i2c_write(struct snd_soc_codec *codec, unsigned int reg,
                      unsigned int value)
{
      u8 *cache = codec->reg_cache;

      if ((reg < CS4270_FIRSTREG) || (reg > CS4270_LASTREG))
            return -EIO;

      /* Only perform an I2C operation if the new value is different */
      if (cache[reg - CS4270_FIRSTREG] != value) {
            struct i2c_client *client = codec->control_data;
            if (i2c_smbus_write_byte_data(client, reg, value)) {
                  dev_err(codec->dev, "i2c write failed\n");
                  return -EIO;
            }

            /* We've written to the hardware, so update the cache */
            cache[reg - CS4270_FIRSTREG] = value;
      }

      return 0;
}

/**
 * cs4270_hw_params - program the CS4270 with the given hardware parameters.
 * @substream: the audio stream
 * @params: the hardware parameters to set
 * @dai: the SOC DAI (ignored)
 *
 * This function programs the hardware with the values provided.
 * Specifically, the sample rate and the data format.
 *
 * The .ops functions are used to provide board-specific data, like input
 * frequencies, to this driver.  This function takes that information,
 * combines it with the hardware parameters provided, and programs the
 * hardware accordingly.
 */
static int cs4270_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;
      struct cs4270_private *cs4270 = codec->private_data;
      int ret;
      unsigned int i;
      unsigned int rate;
      unsigned int ratio;
      int reg;

      /* Figure out which MCLK/LRCK ratio to use */

      rate = params_rate(params);   /* Sampling rate, in Hz */
      ratio = cs4270->mclk / rate;  /* MCLK/LRCK ratio */

      for (i = 0; i < NUM_MCLK_RATIOS; i++) {
            if (cs4270_mode_ratios[i].ratio == ratio)
                  break;
      }

      if (i == NUM_MCLK_RATIOS) {
            /* We did not find a matching ratio */
            dev_err(codec->dev, "could not find matching ratio\n");
            return -EINVAL;
      }

      /* Set the sample rate */

      reg = snd_soc_read(codec, CS4270_MODE);
      reg &= ~(CS4270_MODE_SPEED_MASK | CS4270_MODE_DIV_MASK);
      reg |= cs4270_mode_ratios[i].mclk;

      if (cs4270->slave_mode)
            reg |= CS4270_MODE_SLAVE;
      else
            reg |= cs4270_mode_ratios[i].speed_mode;

      ret = snd_soc_write(codec, CS4270_MODE, reg);
      if (ret < 0) {
            dev_err(codec->dev, "i2c write failed\n");
            return ret;
      }

      /* Set the DAI format */

      reg = snd_soc_read(codec, CS4270_FORMAT);
      reg &= ~(CS4270_FORMAT_DAC_MASK | CS4270_FORMAT_ADC_MASK);

      switch (cs4270->mode) {
      case SND_SOC_DAIFMT_I2S:
            reg |= CS4270_FORMAT_DAC_I2S | CS4270_FORMAT_ADC_I2S;
            break;
      case SND_SOC_DAIFMT_LEFT_J:
            reg |= CS4270_FORMAT_DAC_LJ | CS4270_FORMAT_ADC_LJ;
            break;
      default:
            dev_err(codec->dev, "unknown dai format\n");
            return -EINVAL;
      }

      ret = snd_soc_write(codec, CS4270_FORMAT, reg);
      if (ret < 0) {
            dev_err(codec->dev, "i2c write failed\n");
            return ret;
      }

      return ret;
}

/**
 * cs4270_dai_mute - enable/disable the CS4270 external mute
 * @dai: the SOC DAI
 * @mute: 0 = disable mute, 1 = enable mute
 *
 * This function toggles the mute bits in the MUTE register.  The CS4270's
 * mute capability is intended for external muting circuitry, so if the
 * board does not have the MUTEA or MUTEB pins connected to such circuitry,
 * then this function will do nothing.
 */
static int cs4270_dai_mute(struct snd_soc_dai *dai, int mute)
{
      struct snd_soc_codec *codec = dai->codec;
      struct cs4270_private *cs4270 = codec->private_data;
      int reg6;

      reg6 = snd_soc_read(codec, CS4270_MUTE);

      if (mute)
            reg6 |= CS4270_MUTE_DAC_A | CS4270_MUTE_DAC_B;
      else {
            reg6 &= ~(CS4270_MUTE_DAC_A | CS4270_MUTE_DAC_B);
            reg6 |= cs4270->manual_mute;
      }

      return snd_soc_write(codec, CS4270_MUTE, reg6);
}

/**
 * cs4270_soc_put_mute - put callback for the 'Master Playback switch'
 *                 alsa control.
 * @kcontrol: mixer control
 * @ucontrol: control element information
 *
 * This function basically passes the arguments on to the generic
 * snd_soc_put_volsw() function and saves the mute information in
 * our private data structure. This is because we want to prevent
 * cs4270_dai_mute() neglecting the user's decision to manually
 * mute the codec's output.
 *
 * Returns 0 for success.
 */
static int cs4270_soc_put_mute(struct snd_kcontrol *kcontrol,
                        struct snd_ctl_elem_value *ucontrol)
{
      struct snd_soc_codec *codec = snd_kcontrol_chip(kcontrol);
      struct cs4270_private *cs4270 = codec->private_data;
      int left = !ucontrol->value.integer.value[0];
      int right = !ucontrol->value.integer.value[1];

      cs4270->manual_mute = (left ? CS4270_MUTE_DAC_A : 0) |
                        (right ? CS4270_MUTE_DAC_B : 0);

      return snd_soc_put_volsw(kcontrol, ucontrol);
}

/* A list of non-DAPM controls that the CS4270 supports */
static const struct snd_kcontrol_new cs4270_snd_controls[] = {
      SOC_DOUBLE_R("Master Playback Volume",
            CS4270_VOLA, CS4270_VOLB, 0, 0xFF, 1),
      SOC_SINGLE("Digital Sidetone Switch", CS4270_FORMAT, 5, 1, 0),
      SOC_SINGLE("Soft Ramp Switch", CS4270_TRANS, 6, 1, 0),
      SOC_SINGLE("Zero Cross Switch", CS4270_TRANS, 5, 1, 0),
      SOC_SINGLE("Popguard Switch", CS4270_MODE, 0, 1, 1),
      SOC_SINGLE("Auto-Mute Switch", CS4270_MUTE, 5, 1, 0),
      SOC_DOUBLE("Master Capture Switch", CS4270_MUTE, 3, 4, 1, 1),
      SOC_DOUBLE_EXT("Master Playback Switch", CS4270_MUTE, 0, 1, 1, 1,
            snd_soc_get_volsw, cs4270_soc_put_mute),
};

/*
 * cs4270_codec - global variable to store codec for the ASoC probe function
 *
 * If struct i2c_driver had a private_data field, we wouldn't need to use
 * cs4270_codec.  This is the only way to pass the codec structure from
 * cs4270_i2c_probe() to cs4270_probe().  Unfortunately, there is no good
 * way to synchronize these two functions.  cs4270_i2c_probe() can be called
 * multiple times before cs4270_probe() is called even once.  So for now, we
 * also only allow cs4270_i2c_probe() to be run once.  That means that we do
 * not support more than one cs4270 device in the system, at least for now.
 */
static struct snd_soc_codec *cs4270_codec;

static struct snd_soc_dai_ops cs4270_dai_ops = {
      .hw_params  = cs4270_hw_params,
      .set_sysclk = cs4270_set_dai_sysclk,
      .set_fmt    = cs4270_set_dai_fmt,
      .digital_mute     = cs4270_dai_mute,
};

struct snd_soc_dai cs4270_dai = {
      .name = "cs4270",
      .playback = {
            .stream_name = "Playback",
            .channels_min = 1,
            .channels_max = 2,
            .rates = 0,
            .formats = CS4270_FORMATS,
      },
      .capture = {
            .stream_name = "Capture",
            .channels_min = 1,
            .channels_max = 2,
            .rates = 0,
            .formats = CS4270_FORMATS,
      },
      .ops = &cs4270_dai_ops,
};
EXPORT_SYMBOL_GPL(cs4270_dai);

/**
 * cs4270_probe - ASoC probe function
 * @pdev: platform device
 *
 * This function is called when ASoC has all the pieces it needs to
 * instantiate a sound driver.
 */
static int cs4270_probe(struct platform_device *pdev)
{
      struct snd_soc_device *socdev = platform_get_drvdata(pdev);
      struct snd_soc_codec *codec = cs4270_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;
      }

      /* Add the non-DAPM controls */
      ret = snd_soc_add_controls(codec, cs4270_snd_controls,
                        ARRAY_SIZE(cs4270_snd_controls));
      if (ret < 0) {
            dev_err(codec->dev, "failed to add controls\n");
            goto error_free_pcms;
      }

      /* And finally, register the socdev */
      ret = snd_soc_init_card(socdev);
      if (ret < 0) {
            dev_err(codec->dev, "failed to register card\n");
            goto error_free_pcms;
      }

      return 0;

error_free_pcms:
      snd_soc_free_pcms(socdev);

      return ret;
}

/**
 * cs4270_remove - ASoC remove function
 * @pdev: platform device
 *
 * This function is the counterpart to cs4270_probe().
 */
static int cs4270_remove(struct platform_device *pdev)
{
      struct snd_soc_device *socdev = platform_get_drvdata(pdev);

      snd_soc_free_pcms(socdev);

      return 0;
};

/**
 * cs4270_i2c_probe - initialize the I2C interface of the CS4270
 * @i2c_client: the I2C client object
 * @id: the I2C device ID (ignored)
 *
 * This function is called whenever the I2C subsystem finds a device that
 * matches the device ID given via a prior call to i2c_add_driver().
 */
static int cs4270_i2c_probe(struct i2c_client *i2c_client,
      const struct i2c_device_id *id)
{
      struct snd_soc_codec *codec;
      struct cs4270_private *cs4270;
      unsigned int reg;
      int ret;

      /* For now, we only support one cs4270 device in the system.  See the
       * comment for cs4270_codec.
       */
      if (cs4270_codec) {
            dev_err(&i2c_client->dev, "ignoring CS4270 at addr %X\n",
                   i2c_client->addr);
            dev_err(&i2c_client->dev, "only one per board allowed\n");
            /* Should we return something other than ENODEV here? */
            return -ENODEV;
      }

      /* Verify that we have a CS4270 */

      ret = i2c_smbus_read_byte_data(i2c_client, CS4270_CHIPID);
      if (ret < 0) {
            dev_err(&i2c_client->dev, "failed to read i2c at addr %X\n",
                   i2c_client->addr);
            return ret;
      }
      /* The top four bits of the chip ID should be 1100. */
      if ((ret & 0xF0) != 0xC0) {
            dev_err(&i2c_client->dev, "device at addr %X is not a CS4270\n",
                   i2c_client->addr);
            return -ENODEV;
      }

      dev_info(&i2c_client->dev, "found device at i2c address %X\n",
            i2c_client->addr);
      dev_info(&i2c_client->dev, "hardware revision %X\n", ret & 0xF);

      /* Allocate enough space for the snd_soc_codec structure
         and our private data together. */
      cs4270 = kzalloc(sizeof(struct cs4270_private), GFP_KERNEL);
      if (!cs4270) {
            dev_err(&i2c_client->dev, "could not allocate codec\n");
            return -ENOMEM;
      }
      codec = &cs4270->codec;

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

      codec->dev = &i2c_client->dev;
      codec->name = "CS4270";
      codec->owner = THIS_MODULE;
      codec->dai = &cs4270_dai;
      codec->num_dai = 1;
      codec->private_data = cs4270;
      codec->control_data = i2c_client;
      codec->read = cs4270_read_reg_cache;
      codec->write = cs4270_i2c_write;
      codec->reg_cache = cs4270->reg_cache;
      codec->reg_cache_size = CS4270_NUMREGS;

      /* The I2C interface is set up, so pre-fill our register cache */

      ret = cs4270_fill_cache(codec);
      if (ret < 0) {
            dev_err(&i2c_client->dev, "failed to fill register cache\n");
            goto error_free_codec;
      }

      /* Disable auto-mute.  This feature appears to be buggy.  In some
       * situations, auto-mute will not deactivate when it should, so we want
       * this feature disabled by default.  An application (e.g. alsactl) can
       * re-enabled it by using the controls.
       */

      reg = cs4270_read_reg_cache(codec, CS4270_MUTE);
      reg &= ~CS4270_MUTE_AUTO;
      ret = cs4270_i2c_write(codec, CS4270_MUTE, reg);
      if (ret < 0) {
            dev_err(&i2c_client->dev, "i2c write failed\n");
            return ret;
      }

      /* Disable automatic volume control.  The hardware enables, and it
       * causes volume change commands to be delayed, sometimes until after
       * playback has started.  An application (e.g. alsactl) can
       * re-enabled it by using the controls.
       */

      reg = cs4270_read_reg_cache(codec, CS4270_TRANS);
      reg &= ~(CS4270_TRANS_SOFT | CS4270_TRANS_ZERO);
      ret = cs4270_i2c_write(codec, CS4270_TRANS, reg);
      if (ret < 0) {
            dev_err(&i2c_client->dev, "i2c write failed\n");
            return ret;
      }

      /* Initialize the DAI. Normally, we'd prefer to have a kmalloc'd DAI
       * structure for each CS4270 device, but the machine driver needs to
       * have a pointer to the DAI structure, so for now it must be a global
       * variable.
       */
      cs4270_dai.dev = &i2c_client->dev;

      /* Register the DAI.  If all the other ASoC driver have already
       * registered, then this will call our probe function, so
       * cs4270_codec needs to be ready.
       */
      cs4270_codec = codec;
      ret = snd_soc_register_dai(&cs4270_dai);
      if (ret < 0) {
            dev_err(&i2c_client->dev, "failed to register DAIe\n");
            goto error_free_codec;
      }

      i2c_set_clientdata(i2c_client, cs4270);

      return 0;

error_free_codec:
      kfree(cs4270);
      cs4270_codec = NULL;
      cs4270_dai.dev = NULL;

      return ret;
}

/**
 * cs4270_i2c_remove - remove an I2C device
 * @i2c_client: the I2C client object
 *
 * This function is the counterpart to cs4270_i2c_probe().
 */
static int cs4270_i2c_remove(struct i2c_client *i2c_client)
{
      struct cs4270_private *cs4270 = i2c_get_clientdata(i2c_client);

      kfree(cs4270);
      cs4270_codec = NULL;
      cs4270_dai.dev = NULL;

      return 0;
}

/*
 * cs4270_id - I2C device IDs supported by this driver
 */
static struct i2c_device_id cs4270_id[] = {
      {"cs4270", 0},
      {}
};
MODULE_DEVICE_TABLE(i2c, cs4270_id);

#ifdef CONFIG_PM

/* This suspend/resume implementation can handle both - a simple standby
 * where the codec remains powered, and a full suspend, where the voltage
 * domain the codec is connected to is teared down and/or any other hardware
 * reset condition is asserted.
 *
 * The codec's own power saving features are enabled in the suspend callback,
 * and all registers are written back to the hardware when resuming.
 */

static int cs4270_i2c_suspend(struct i2c_client *client, pm_message_t mesg)
{
      struct cs4270_private *cs4270 = i2c_get_clientdata(client);
      struct snd_soc_codec *codec = &cs4270->codec;

      return snd_soc_suspend_device(codec->dev);
}

static int cs4270_i2c_resume(struct i2c_client *client)
{
      struct cs4270_private *cs4270 = i2c_get_clientdata(client);
      struct snd_soc_codec *codec = &cs4270->codec;

      return snd_soc_resume_device(codec->dev);
}

static int cs4270_soc_suspend(struct platform_device *pdev, pm_message_t mesg)
{
      struct snd_soc_codec *codec = cs4270_codec;
      int reg = snd_soc_read(codec, CS4270_PWRCTL) | CS4270_PWRCTL_PDN_ALL;

      return snd_soc_write(codec, CS4270_PWRCTL, reg);
}

static int cs4270_soc_resume(struct platform_device *pdev)
{
      struct snd_soc_codec *codec = cs4270_codec;
      struct i2c_client *i2c_client = codec->control_data;
      int reg;

      /* In case the device was put to hard reset during sleep, we need to
       * wait 500ns here before any I2C communication. */
      ndelay(500);

      /* first restore the entire register cache ... */
      for (reg = CS4270_FIRSTREG; reg <= CS4270_LASTREG; reg++) {
            u8 val = snd_soc_read(codec, reg);

            if (i2c_smbus_write_byte_data(i2c_client, reg, val)) {
                  dev_err(codec->dev, "i2c write failed\n");
                  return -EIO;
            }
      }

      /* ... then disable the power-down bits */
      reg = snd_soc_read(codec, CS4270_PWRCTL);
      reg &= ~CS4270_PWRCTL_PDN_ALL;

      return snd_soc_write(codec, CS4270_PWRCTL, reg);
}
#else
#define cs4270_i2c_suspend    NULL
#define cs4270_i2c_resume     NULL
#define cs4270_soc_suspend    NULL
#define cs4270_soc_resume     NULL
#endif /* CONFIG_PM */

/*
 * cs4270_i2c_driver - I2C device identification
 *
 * This structure tells the I2C subsystem how to identify and support a
 * given I2C device type.
 */
static struct i2c_driver cs4270_i2c_driver = {
      .driver = {
            .name = "cs4270",
            .owner = THIS_MODULE,
      },
      .id_table = cs4270_id,
      .probe = cs4270_i2c_probe,
      .remove = cs4270_i2c_remove,
      .suspend = cs4270_i2c_suspend,
      .resume = cs4270_i2c_resume,
};

/*
 * ASoC codec device structure
 *
 * Assign this variable to the codec_dev field of the machine driver's
 * snd_soc_device structure.
 */
struct snd_soc_codec_device soc_codec_device_cs4270 = {
      .probe =    cs4270_probe,
      .remove =   cs4270_remove,
      .suspend =  cs4270_soc_suspend,
      .resume =   cs4270_soc_resume,
};
EXPORT_SYMBOL_GPL(soc_codec_device_cs4270);

static int __init cs4270_init(void)
{
      pr_info("Cirrus Logic CS4270 ALSA SoC Codec Driver\n");

      return i2c_add_driver(&cs4270_i2c_driver);
}
module_init(cs4270_init);

static void __exit cs4270_exit(void)
{
      i2c_del_driver(&cs4270_i2c_driver);
}
module_exit(cs4270_exit);

MODULE_AUTHOR("Timur Tabi <timur@freescale.com>");
MODULE_DESCRIPTION("Cirrus Logic CS4270 ALSA SoC Codec Driver");
MODULE_LICENSE("GPL");

Generated by  Doxygen 1.6.0   Back to index