/* * CS4270 ALSA SoC (ASoC) codec driver * * Author: Timur Tabi * * 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 not supported. * 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) */ #include #include #include #include #include #include #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) /* 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_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) */ }; /** * 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[] = { {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) { printk(KERN_ERR "cs4270: 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; 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"); 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 | 0x80, CS4270_NUMREGS, cache); if (length != CS4270_NUMREGS) { printk(KERN_ERR "cs4270: 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)) { printk(KERN_ERR "cs4270: 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 */ printk(KERN_ERR "cs4270: 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 */ 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; ret = snd_soc_write(codec, CS4270_MODE, reg); if (ret < 0) { printk(KERN_ERR "cs4270: I2C write failed\n"); return ret; } /* Program the format register */ 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: printk(KERN_ERR "cs4270: unknown 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"); return ret; } return ret; } #ifdef CONFIG_SND_SOC_CS4270_HWMUTE /** * 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 * board does not have the MUTEA or MUTEB pins connected to such circuitry, * then this function will do nothing. */ static int cs4270_mute(struct snd_soc_dai *dai, int mute) { struct snd_soc_codec *codec = dai->codec; int reg6; 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; else reg6 &= ~(CS4270_MUTE_ADC_A | CS4270_MUTE_ADC_B | CS4270_MUTE_DAC_A | CS4270_MUTE_DAC_B); return snd_soc_write(codec, CS4270_MUTE, reg6); } #else #define cs4270_mute NULL #endif /* 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) }; /* * 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; 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 = { .hw_params = cs4270_hw_params, .set_sysclk = cs4270_set_dai_sysclk, .set_fmt = cs4270_set_dai_fmt, .digital_mute = cs4270_mute, }, }; 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; unsigned int i; 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) { printk(KERN_ERR "cs4270: failed to create PCMs\n"); return ret; } /* Add the non-DAPM controls */ for (i = 0; i < ARRAY_SIZE(cs4270_snd_controls); i++) { struct snd_kcontrol *kctrl; kctrl = snd_soc_cnew(&cs4270_snd_controls[i], codec, NULL); if (!kctrl) { printk(KERN_ERR "cs4270: error creating control '%s'\n", cs4270_snd_controls[i].name); ret = -ENOMEM; goto error_free_pcms; } ret = snd_ctl_add(codec->card, kctrl); if (ret < 0) { printk(KERN_ERR "cs4270: error adding control '%s'\n", cs4270_snd_controls[i].name); goto error_free_pcms; } } /* And finally, register the socdev */ ret = snd_soc_init_card(socdev); if (ret < 0) { printk(KERN_ERR "cs4270: 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; int ret; /* For now, we only support one cs4270 device in the system. See the * comment for cs4270_codec. */ if (cs4270_codec) { printk(KERN_ERR "cs4270: ignoring CS4270 at addr %X\n", i2c_client->addr); printk(KERN_ERR "cs4270: only one CS4270 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) { printk(KERN_ERR "cs4270: 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) { printk(KERN_ERR "cs4270: device at addr %X is not a CS4270\n", i2c_client->addr); return -ENODEV; } printk(KERN_INFO "cs4270: found device at I2C address %X\n", i2c_client->addr); printk(KERN_INFO "cs4270: 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) { printk(KERN_ERR "cs4270: Could not allocate codec structure\n"); return -ENOMEM; } codec = &cs4270->codec; cs4270_codec = codec; mutex_init(&codec->mutex); INIT_LIST_HEAD(&codec->dapm_widgets); INIT_LIST_HEAD(&codec->dapm_paths); 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) { printk(KERN_ERR "cs4270: failed to fill register cache\n"); goto error_free_codec; } /* 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. */ ret = snd_soc_register_dai(&cs4270_dai); if (ret < 0) { printk(KERN_ERR "cs4270: failed to register DAIe\n"); goto error_free_codec; } i2c_set_clientdata(i2c_client, cs4270); return 0; error_free_codec: kfree(cs4270); 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); 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 * snd_soc_device structure. */ struct snd_soc_codec_device soc_codec_device_cs4270 = { .probe = cs4270_probe, .remove = cs4270_remove }; EXPORT_SYMBOL_GPL(soc_codec_device_cs4270); static int __init cs4270_init(void) { printk(KERN_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 "); MODULE_DESCRIPTION("Cirrus Logic CS4270 ALSA SoC Codec Driver"); MODULE_LICENSE("GPL");