1 files changed, 338 insertions, 329 deletions

diff --git a/sound/soc/codecs/cs4270.c b/sound/soc/codecs/cs4270.c
index f1aa0c34421c..7fa09a387622 100644
--- a/sound/soc/codecs/cs4270.c
+++ b/sound/soc/codecs/cs4270.c
@@ -3,27 +3,22 @@
  *
  * Author: Timur Tabi <timur@freescale.com>
  *
- * Copyright 2007 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.
+ * 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:
  *
- * 1) Software mode is supported.  Stand-alone mode is automatically
- *    selected if I2C is disabled or if a CS4270 is not found on the I2C
- *    bus.  However, stand-alone mode is only partially implemented because
- *    there is no mechanism yet for this driver and the machine driver to
- *    communicate the values of the M0, M1, MCLK1, and MCLK2 pins.
- * 2) Only I2C is supported, not SPI
- * 3) Only Master mode is supported, not Slave.
- * 4) The machine driver's 'startup' function must call
- *    cs4270_set_dai_sysclk() with the value of MCLK.
- * 5) Only I2S and left-justified modes are supported
- * 6) Power management is not supported
- * 7) The only supported control is volume and hardware mute (if enabled)
+ * - 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 not supported
  */
 
 #include <linux/module.h>
@@ -35,18 +30,6 @@
 
 #include "cs4270.h"
 
-/* If I2C is defined, then we support software mode.  However, if we're
-   not compiled as module but I2C is, then we can't use I2C calls. */
-#if defined(CONFIG_I2C) || (defined(CONFIG_I2C_MODULE) && defined(MODULE))
-#define USE_I2C
-#endif
-
-/* Private data for the CS4270 */
-struct cs4270_private {
-        unsigned int mclk; /* Input frequency of the MCLK pin */
-        unsigned int mode; /* The mode (I2S or left-justified) */
-};
-
 /*
  * The codec isn't really big-endian or little-endian, since the I2S
  * interface requires data to be sent serially with the MSbit first.
@@ -60,8 +43,6 @@ struct cs4270_private {
                         SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE | \
                         SNDRV_PCM_FMTBIT_S24_LE  | SNDRV_PCM_FMTBIT_S24_BE)
 
-#ifdef USE_I2C
-
 /* CS4270 registers addresses */
 #define CS4270_CHIPID   0x01    /* Chip ID */
 #define CS4270_PWRCTL   0x02    /* Power Control */
@@ -121,8 +102,22 @@ struct cs4270_private {
 #define CS4270_MUTE_DAC_A       0x01
 #define CS4270_MUTE_DAC_B       0x02
 
-/*
- * Clock Ratio Selection for Master Mode with I2C enabled
+/* 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;
+};
+
+/**
+ * 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.
@@ -131,31 +126,30 @@ struct cs4270_private {
  * It is also used by cs4270_set_dai_sysclk() to tell ALSA which sampling
  * rates the CS4270 currently supports.
  *
- * Each element in this array corresponds to the ratios in mclk_ratios[].
- * These two arrays need to be in sync.
- *
- * 'speed_mode' is the corresponding bit pattern to be written to the
+ * @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
+ * @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
+ * 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 = 3.3V.  If this effects you, select the
+ * 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.
  */
-static struct {
+struct cs4270_mode_ratios {
         unsigned int ratio;
         u8 speed_mode;
         u8 mclk;
-} cs4270_mode_ratios[] = {
+};
+
+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},
@@ -172,34 +166,27 @@ static struct {
 /* The number of MCLK/LRCK ratios supported by the CS4270 */
 #define NUM_MCLK_RATIOS         ARRAY_SIZE(cs4270_mode_ratios)
 
-/*
- * Determine the CS4270 samples rates.
+/**
+ * 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)
  *
- * 'freq' is the input frequency to MCLK.  The other parameters are 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
- * support values: 64, 96, 128, 192, 256, 384, 512, 768, and 1024.
+ * 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 support sample rates.
+ * 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.
- *
- * Note that in stand-alone mode, the sample rate is determined by input
- * pins M0, M1, MDIV1, and MDIV2.  Also in stand-alone mode, divide-by-3
- * is not a programmable option.  However, divide-by-3 is not an available
- * option in stand-alone mode.  This cases two problems: a ratio of 768 is
- * not available (it requires divide-by-3) and B) ratios 192 and 384 can
- * only be selected with divide-by-1.5, but there is an errate that make
- * this selection difficult.
- *
- * In addition, there is no mechanism for communicating with the machine
- * driver what the input settings can be.  This would need to be implemented
- * for stand-alone mode to work.
  */
 static int cs4270_set_dai_sysclk(struct snd_soc_dai *codec_dai,
                                  int clk_id, unsigned int freq, int dir)
@@ -225,7 +212,7 @@ static int cs4270_set_dai_sysclk(struct snd_soc_dai *codec_dai,
         rates &= ~SNDRV_PCM_RATE_KNOT;
 
         if (!rates) {
-                printk(KERN_ERR "cs4270: could not find a valid sample rate\n");
+                dev_err(codec->dev, "could not find a valid sample rate\n");
                 return -EINVAL;
         }
 
@@ -240,8 +227,10 @@ static int cs4270_set_dai_sysclk(struct snd_soc_dai *codec_dai,
         return 0;
 }
 
-/*
- * Configure the codec for the selected audio format
+/**
+ * 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.
@@ -258,32 +247,43 @@ static int cs4270_set_dai_fmt(struct snd_soc_dai *codec_dai,
         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:
-                printk(KERN_ERR "cs4270: invalid DAI format\n");
+                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;
 }
 
-/*
- * A list of addresses on which this CS4270 could use.  I2C addresses are
- * 7 bits.  For the CS4270, the upper four bits are always 1001, and the
- * lower three bits are determined via the AD2, AD1, and AD0 pins
- * (respectively).
- */
-static const unsigned short normal_i2c[] = {
-        0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, I2C_CLIENT_END
-};
-I2C_CLIENT_INSMOD;
-
-/*
- * Pre-fill the CS4270 register cache.
+/**
+ * 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.
@@ -298,7 +298,7 @@ static int cs4270_fill_cache(struct snd_soc_codec *codec)
                 CS4270_FIRSTREG | 0x80, CS4270_NUMREGS, cache);
 
         if (length != CS4270_NUMREGS) {
-                printk(KERN_ERR "cs4270: I2C read failure, addr=0x%x\n",
+                dev_err(codec->dev, "i2c read failure, addr=0x%x\n",
                        i2c_client->addr);
                 return -EIO;
         }
@@ -306,12 +306,17 @@ static int cs4270_fill_cache(struct snd_soc_codec *codec)
         return 0;
 }
 
-/*
- * Read from the CS4270 register cache.
+/**
+ * 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 coherncy problem.
+ * 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)
@@ -324,8 +329,11 @@ static unsigned int cs4270_read_reg_cache(struct snd_soc_codec *codec,
         return cache[reg - CS4270_FIRSTREG];
 }
 
-/*
- * Write to a CS4270 register via the I2C bus.
+/**
+ * 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.
@@ -346,7 +354,7 @@ static int cs4270_i2c_write(struct snd_soc_codec *codec, unsigned int reg,
         if (cache[reg - CS4270_FIRSTREG] != value) {
                 struct i2c_client *client = codec->control_data;
                 if (i2c_smbus_write_byte_data(client, reg, value)) {
-                        printk(KERN_ERR "cs4270: I2C write failed\n");
+                        dev_err(codec->dev, "i2c write failed\n");
                         return -EIO;
                 }
 
@@ -357,11 +365,17 @@ static int cs4270_i2c_write(struct snd_soc_codec *codec, unsigned int reg,
         return 0;
 }
 
-/*
- * Program the CS4270 with the given hardware parameters.
+/**
+ * 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,
+ * 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.
  */
@@ -371,7 +385,7 @@ static int cs4270_hw_params(struct snd_pcm_substream *substream,
 {
         struct snd_soc_pcm_runtime *rtd = substream->private_data;
         struct snd_soc_device *socdev = rtd->socdev;
-        struct snd_soc_codec *codec = socdev->codec;
+        struct snd_soc_codec *codec = socdev->card->codec;
         struct cs4270_private *cs4270 = codec->private_data;
         int ret;
         unsigned int i;
@@ -391,33 +405,28 @@ static int cs4270_hw_params(struct snd_pcm_substream *substream,
 
         if (i == NUM_MCLK_RATIOS) {
                 /* We did not find a matching ratio */
-                printk(KERN_ERR "cs4270: could not find matching ratio\n");
+                dev_err(codec->dev, "could not find matching ratio\n");
                 return -EINVAL;
         }
 
-        /* Freeze and power-down the codec */
-
-        ret = snd_soc_write(codec, CS4270_PWRCTL, CS4270_PWRCTL_FREEZE |
-                            CS4270_PWRCTL_PDN_ADC | CS4270_PWRCTL_PDN_DAC |
-                            CS4270_PWRCTL_PDN);
-        if (ret < 0) {
-                printk(KERN_ERR "cs4270: I2C write failed\n");
-                return ret;
-        }
-
-        /* Program the mode control register */
+        /* 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].speed_mode | cs4270_mode_ratios[i].mclk;
+        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) {
-                printk(KERN_ERR "cs4270: I2C write failed\n");
+                dev_err(codec->dev, "i2c write failed\n");
                 return ret;
         }
 
-        /* Program the format register */
+        /* Set the DAI format */
 
         reg = snd_soc_read(codec, CS4270_FORMAT);
         reg &= ~(CS4270_FORMAT_DAC_MASK | CS4270_FORMAT_ADC_MASK);
@@ -430,55 +439,23 @@ static int cs4270_hw_params(struct snd_pcm_substream *substream,
                 reg |= CS4270_FORMAT_DAC_LJ | CS4270_FORMAT_ADC_LJ;
                 break;
         default:
-                printk(KERN_ERR "cs4270: unknown format\n");
+                dev_err(codec->dev, "unknown dai format\n");
                 return -EINVAL;
         }
 
         ret = snd_soc_write(codec, CS4270_FORMAT, reg);
         if (ret < 0) {
-                printk(KERN_ERR "cs4270: I2C write failed\n");
-                return ret;
-        }
-
-        /* Disable auto-mute.  This feature appears to be buggy, because in
-           some situations, auto-mute will not deactivate when it should. */
-
-        reg = snd_soc_read(codec, CS4270_MUTE);
-        reg &= ~CS4270_MUTE_AUTO;
-        ret = snd_soc_write(codec, CS4270_MUTE, reg);
-        if (ret < 0) {
-                printk(KERN_ERR "cs4270: I2C write failed\n");
-                return ret;
-        }
-
-        /* Disable automatic volume control.  It's enabled by default, and
-         * it causes volume change commands to be delayed, sometimes until
-         * after playback has started.
-         */
-
-        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) {
-                printk(KERN_ERR "I2C write failed\n");
-                return ret;
-        }
-
-        /* Thaw and power-up the codec */
-
-        ret = snd_soc_write(codec, CS4270_PWRCTL, 0);
-        if (ret < 0) {
-                printk(KERN_ERR "cs4270: I2C write failed\n");
+                dev_err(codec->dev, "i2c write failed\n");
                 return ret;
         }
 
         return ret;
 }
 
-#ifdef CONFIG_SND_SOC_CS4270_HWMUTE
-
-/*
- * Set the CS4270 external mute
+/**
+ * cs4270_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
@@ -493,276 +470,306 @@ static int cs4270_mute(struct snd_soc_dai *dai, int mute)
         reg6 = snd_soc_read(codec, CS4270_MUTE);
 
         if (mute)
-                reg6 |= CS4270_MUTE_ADC_A | CS4270_MUTE_ADC_B |
-                        CS4270_MUTE_DAC_A | CS4270_MUTE_DAC_B;
+                reg6 |= CS4270_MUTE_DAC_A | CS4270_MUTE_DAC_B;
         else
-                reg6 &= ~(CS4270_MUTE_ADC_A | CS4270_MUTE_ADC_B |
-                          CS4270_MUTE_DAC_A | CS4270_MUTE_DAC_B);
+                reg6 &= ~(CS4270_MUTE_DAC_A | CS4270_MUTE_DAC_B);
 
         return snd_soc_write(codec, CS4270_MUTE, reg6);
 }
 
-#endif
-
-static int cs4270_i2c_probe(struct i2c_client *, const struct i2c_device_id *);
-
 /* 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)
-};
-
-static const struct i2c_device_id cs4270_id[] = {
-        {"cs4270", 0},
-        {}
-};
-MODULE_DEVICE_TABLE(i2c, cs4270_id);
-
-static struct i2c_driver cs4270_i2c_driver = {
-        .driver = {
-                .name = "CS4270 I2C",
-                .owner = THIS_MODULE,
-        },
-        .id_table = cs4270_id,
-        .probe = cs4270_i2c_probe,
+                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, 0)
 };
 
 /*
- * Global variable to store socdev for i2c probe function.
+ * 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_socdec.  This is the only way to pass the socdev structure to
- * cs4270_i2c_probe().
- *
- * The real solution to cs4270_socdev is to create a mechanism
- * that maps I2C addresses to snd_soc_device structures.  Perhaps the
- * creation of the snd_soc_device object should be moved out of
- * cs4270_probe() and into cs4270_i2c_probe(), but that would make this
- * driver dependent on I2C.  The CS4270 supports "stand-alone" mode, whereby
- * the chip is *not* connected to the I2C bus, but is instead configured via
- * input pins.
+ * 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_device *cs4270_socdev;
+static struct snd_soc_codec *cs4270_codec;
 
-/*
- * Initialize the I2C interface of the CS4270
- *
- * This function is called for whenever the I2C subsystem finds a device
- * at a particular address.
+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_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
  *
- * Note: snd_soc_new_pcms() must be called before this function can be called,
- * because of snd_ctl_add().
+ * This function is called when ASoC has all the pieces it needs to
+ * instantiate a sound driver.
  */
-static int cs4270_i2c_probe(struct i2c_client *i2c_client,
-        const struct i2c_device_id *id)
+static int cs4270_probe(struct platform_device *pdev)
 {
-        struct snd_soc_device *socdev = cs4270_socdev;
-        struct snd_soc_codec *codec = socdev->codec;
-        int i;
-        int ret = 0;
-
-        /* Probing all possible addresses has one drawback: if there are
-           multiple CS4270s on the bus, then you cannot specify which
-           socdev is matched with which CS4270.  For now, we just reject
-           this I2C device if the socdev already has one attached. */
-        if (codec->control_data)
-                return -ENODEV;
-
-        /* Note: codec_dai->codec is NULL here */
-
-        codec->reg_cache = kzalloc(CS4270_NUMREGS, GFP_KERNEL);
-        if (!codec->reg_cache) {
-                printk(KERN_ERR "cs4270: could not allocate register cache\n");
-                ret = -ENOMEM;
-                goto error;
-        }
+        struct snd_soc_device *socdev = platform_get_drvdata(pdev);
+        struct snd_soc_codec *codec = cs4270_codec;
+        int ret;
 
-        /* Verify that we have a CS4270 */
+        /* Connect the codec to the socdev.  snd_soc_new_pcms() needs this. */
+        socdev->card->codec = codec;
 
-        ret = i2c_smbus_read_byte_data(i2c_client, CS4270_CHIPID);
+        /* Register PCMs */
+        ret = snd_soc_new_pcms(socdev, SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1);
         if (ret < 0) {
-                printk(KERN_ERR "cs4270: failed to read I2C\n");
-                goto error;
-        }
-        /* The top four bits of the chip ID should be 1100. */
-        if ((ret & 0xF0) != 0xC0) {
-                /* The device at this address is not a CS4270 codec */
-                ret = -ENODEV;
-                goto error;
+                dev_err(codec->dev, "failed to create pcms\n");
+                return ret;
         }
 
-        printk(KERN_INFO "cs4270: found device at I2C address %X\n",
-                i2c_client->addr);
-        printk(KERN_INFO "cs4270: hardware revision %X\n", ret & 0xF);
-
-        codec->control_data = i2c_client;
-        codec->read = cs4270_read_reg_cache;
-        codec->write = cs4270_i2c_write;
-        codec->reg_cache_size = CS4270_NUMREGS;
-
-        /* The I2C interface is set up, so pre-fill our register cache */
-
-        ret = cs4270_fill_cache(codec);
+        /* Add the non-DAPM controls */
+        ret = snd_soc_add_controls(codec, cs4270_snd_controls,
+                                ARRAY_SIZE(cs4270_snd_controls));
         if (ret < 0) {
-                printk(KERN_ERR "cs4270: failed to fill register cache\n");
-                goto error;
+                dev_err(codec->dev, "failed to add controls\n");
+                goto error_free_pcms;
         }
 
-        /* Add the non-DAPM controls */
-
-        for (i = 0; i < ARRAY_SIZE(cs4270_snd_controls); i++) {
-                struct snd_kcontrol *kctrl =
-                snd_soc_cnew(&cs4270_snd_controls[i], codec, NULL);
-
-                ret = snd_ctl_add(codec->card, kctrl);
-                if (ret < 0)
-                        goto error;
+        /* 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;
         }
 
-        i2c_set_clientdata(i2c_client, codec);
-
         return 0;
 
-error:
-        codec->control_data = NULL;
-
-        kfree(codec->reg_cache);
-        codec->reg_cache = NULL;
-        codec->reg_cache_size = 0;
+error_free_pcms:
+        snd_soc_free_pcms(socdev);
 
         return ret;
 }
 
-#endif /* USE_I2C*/
+/**
+ * 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);
 
-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,
-        },
+        snd_soc_free_pcms(socdev);
+
+        return 0;
 };
-EXPORT_SYMBOL_GPL(cs4270_dai);
 
-/*
- * ASoC probe function
+/**
+ * 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 when the machine driver calls
- * platform_device_add().
+ * 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_probe(struct platform_device *pdev)
+static int cs4270_i2c_probe(struct i2c_client *i2c_client,
+        const struct i2c_device_id *id)
 {
-        struct snd_soc_device *socdev = platform_get_drvdata(pdev);
         struct snd_soc_codec *codec;
-        int ret = 0;
+        struct cs4270_private *cs4270;
+        unsigned int reg;
+        int ret;
 
-        printk(KERN_INFO "CS4270 ALSA SoC Codec\n");
+        /* 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. */
-        codec = kzalloc(ALIGN(sizeof(struct snd_soc_codec), 4) +
-                        sizeof(struct cs4270_private), GFP_KERNEL);
-        if (!codec) {
-                printk(KERN_ERR "cs4270: Could not allocate codec structure\n");
+        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 = (void *) codec +
-                ALIGN(sizeof(struct snd_soc_codec), 4);
-
-        socdev->codec = codec;
+        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;
 
-        /* Register PCMs */
+        /* The I2C interface is set up, so pre-fill our register cache */
 
-        ret = snd_soc_new_pcms(socdev, SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1);
+        ret = cs4270_fill_cache(codec);
         if (ret < 0) {
-                printk(KERN_ERR "cs4270: failed to create PCMs\n");
+                dev_err(&i2c_client->dev, "failed to fill register cache\n");
                 goto error_free_codec;
         }
 
-#ifdef USE_I2C
-        cs4270_socdev = socdev;
+        /* 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.
+         */
 
-        ret = i2c_add_driver(&cs4270_i2c_driver);
-        if (ret) {
-                printk(KERN_ERR "cs4270: failed to attach driver");
-                goto error_free_pcms;
+        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;
         }
 
-        /* Did we find a CS4270 on the I2C bus? */
-        if (codec->control_data) {
-                /* Initialize codec ops */
-                cs4270_dai.ops.hw_params = cs4270_hw_params;
-                cs4270_dai.ops.set_sysclk = cs4270_set_dai_sysclk;
-                cs4270_dai.ops.set_fmt = cs4270_set_dai_fmt;
-#ifdef CONFIG_SND_SOC_CS4270_HWMUTE
-                cs4270_dai.ops.digital_mute = cs4270_mute;
-#endif
-        } else
-                printk(KERN_INFO "cs4270: no I2C device found, "
-                        "using stand-alone mode\n");
-#else
-        printk(KERN_INFO "cs4270: I2C disabled, using stand-alone mode\n");
-#endif
+        /* 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.
+         */
 
-        ret = snd_soc_init_card(socdev);
+        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) {
-                printk(KERN_ERR "cs4270: failed to register card\n");
-                goto error_del_driver;
+                dev_err(&i2c_client->dev, "i2c write failed\n");
+                return ret;
         }
 
-        return 0;
+        /* 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;
 
-error_del_driver:
-#ifdef USE_I2C
-        i2c_del_driver(&cs4270_i2c_driver);
+        /* 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;
+        }
 
-error_free_pcms:
-#endif
-        snd_soc_free_pcms(socdev);
+        i2c_set_clientdata(i2c_client, cs4270);
+
+        return 0;
 
 error_free_codec:
-        kfree(socdev->codec);
-        socdev->codec = NULL;
+        kfree(cs4270);
+        cs4270_codec = NULL;
+        cs4270_dai.dev = NULL;
 
         return ret;
 }
 
-static int cs4270_remove(struct platform_device *pdev)
+/**
+ * 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 snd_soc_device *socdev = platform_get_drvdata(pdev);
-
-        snd_soc_free_pcms(socdev);
-
-#ifdef USE_I2C
-        i2c_del_driver(&cs4270_i2c_driver);
-#endif
+        struct cs4270_private *cs4270 = i2c_get_clientdata(i2c_client);
 
-        kfree(socdev->codec);
-        socdev->codec = NULL;
+        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);
+
+/*
+ * 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,
+};
+
+/*
  * ASoC codec device structure
  *
  * Assign this variable to the codec_dev field of the machine driver's
@@ -776,13 +783,15 @@ EXPORT_SYMBOL_GPL(soc_codec_device_cs4270);
 
 static int __init cs4270_init(void)
 {
-        return snd_soc_register_dai(&cs4270_dai);
+        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)
 {
-        snd_soc_unregister_dai(&cs4270_dai);
+        i2c_del_driver(&cs4270_i2c_driver);
 }
 module_exit(cs4270_exit);