sound/soc/codecs/cx20442.c - third_party/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * cx20442.c  --  CX20442 ALSA Soc Audio driver
  *
  * Copyright 2009 Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
  *
  * Initially based on sound/soc/codecs/wm8400.c
  * Copyright 2008, 2009 Wolfson Microelectronics PLC.
  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
  */

 #include <linux/tty.h>
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/regulator/consumer.h>

 #include <sound/core.h>
 #include <sound/initval.h>
 #include <sound/soc.h>

 #include "cx20442.h"


 struct cx20442_priv {
 	struct tty_struct *tty;
 	struct regulator *por;
 	u8 reg_cache;
 };

 #define CX20442_PM		0x0

 #define CX20442_TELIN		0
 #define CX20442_TELOUT		1
 #define CX20442_MIC		2
 #define CX20442_SPKOUT		3
 #define CX20442_AGC		4

 static const struct snd_soc_dapm_widget cx20442_dapm_widgets[] = {
 	SND_SOC_DAPM_OUTPUT("TELOUT"),
 	SND_SOC_DAPM_OUTPUT("SPKOUT"),
 	SND_SOC_DAPM_OUTPUT("AGCOUT"),

 	SND_SOC_DAPM_MIXER("SPKOUT Mixer", SND_SOC_NOPM, 0, 0, NULL, 0),

 	SND_SOC_DAPM_PGA("TELOUT Amp", CX20442_PM, CX20442_TELOUT, 0, NULL, 0),
 	SND_SOC_DAPM_PGA("SPKOUT Amp", CX20442_PM, CX20442_SPKOUT, 0, NULL, 0),
 	SND_SOC_DAPM_PGA("SPKOUT AGC", CX20442_PM, CX20442_AGC, 0, NULL, 0),

 	SND_SOC_DAPM_DAC("DAC", "Playback", SND_SOC_NOPM, 0, 0),
 	SND_SOC_DAPM_ADC("ADC", "Capture", SND_SOC_NOPM, 0, 0),

 	SND_SOC_DAPM_MIXER("Input Mixer", SND_SOC_NOPM, 0, 0, NULL, 0),

 	SND_SOC_DAPM_MICBIAS("TELIN Bias", CX20442_PM, CX20442_TELIN, 0),
 	SND_SOC_DAPM_MICBIAS("MIC Bias", CX20442_PM, CX20442_MIC, 0),

 	SND_SOC_DAPM_PGA("MIC AGC", CX20442_PM, CX20442_AGC, 0, NULL, 0),

 	SND_SOC_DAPM_INPUT("TELIN"),
 	SND_SOC_DAPM_INPUT("MIC"),
 	SND_SOC_DAPM_INPUT("AGCIN"),
 };

 static const struct snd_soc_dapm_route cx20442_audio_map[] = {
 	{"TELOUT", NULL, "TELOUT Amp"},

 	{"SPKOUT", NULL, "SPKOUT Mixer"},
 	{"SPKOUT Mixer", NULL, "SPKOUT Amp"},

 	{"TELOUT Amp", NULL, "DAC"},
 	{"SPKOUT Amp", NULL, "DAC"},

 	{"SPKOUT Mixer", NULL, "SPKOUT AGC"},
 	{"SPKOUT AGC", NULL, "AGCIN"},

 	{"AGCOUT", NULL, "MIC AGC"},
 	{"MIC AGC", NULL, "MIC"},

 	{"MIC Bias", NULL, "MIC"},
 	{"Input Mixer", NULL, "MIC Bias"},

 	{"TELIN Bias", NULL, "TELIN"},
 	{"Input Mixer", NULL, "TELIN Bias"},

 	{"ADC", NULL, "Input Mixer"},
 };

 static unsigned int cx20442_read_reg_cache(struct snd_soc_component *component,
 					   unsigned int reg)
 {
 	struct cx20442_priv *cx20442 = snd_soc_component_get_drvdata(component);

 	if (reg >= 1)
 		return -EINVAL;

 	return cx20442->reg_cache;
 }

 enum v253_vls {
 	V253_VLS_NONE = 0,
 	V253_VLS_T,
 	V253_VLS_L,
 	V253_VLS_LT,
 	V253_VLS_S,
 	V253_VLS_ST,
 	V253_VLS_M,
 	V253_VLS_MST,
 	V253_VLS_S1,
 	V253_VLS_S1T,
 	V253_VLS_MS1T,
 	V253_VLS_M1,
 	V253_VLS_M1ST,
 	V253_VLS_M1S1T,
 	V253_VLS_H,
 	V253_VLS_HT,
 	V253_VLS_MS,
 	V253_VLS_MS1,
 	V253_VLS_M1S,
 	V253_VLS_M1S1,
 	V253_VLS_TEST,
 };

 static int cx20442_pm_to_v253_vls(u8 value)
 {
 	switch (value & ~(1 << CX20442_AGC)) {
 	case 0:
 		return V253_VLS_T;
 	case (1 << CX20442_SPKOUT):
 	case (1 << CX20442_MIC):
 	case (1 << CX20442_SPKOUT) | (1 << CX20442_MIC):
 		return V253_VLS_M1S1;
 	case (1 << CX20442_TELOUT):
 	case (1 << CX20442_TELIN):
 	case (1 << CX20442_TELOUT) | (1 << CX20442_TELIN):
 		return V253_VLS_L;
 	case (1 << CX20442_TELOUT) | (1 << CX20442_MIC):
 		return V253_VLS_NONE;
 	}
 	return -EINVAL;
 }
 static int cx20442_pm_to_v253_vsp(u8 value)
 {
 	switch (value & ~(1 << CX20442_AGC)) {
 	case (1 << CX20442_SPKOUT):
 	case (1 << CX20442_MIC):
 	case (1 << CX20442_SPKOUT) | (1 << CX20442_MIC):
 		return (bool)(value & (1 << CX20442_AGC));
 	}
 	return (value & (1 << CX20442_AGC)) ? -EINVAL : 0;
 }

 static int cx20442_write(struct snd_soc_component *component, unsigned int reg,
 							unsigned int value)
 {
 	struct cx20442_priv *cx20442 = snd_soc_component_get_drvdata(component);
 	int vls, vsp, old, len;
 	char buf[18];

 	if (reg >= 1)
 		return -EINVAL;

 	/* tty and write pointers required for talking to the modem
 	 * are expected to be set by the line discipline initialization code */
 	if (!cx20442->tty || !cx20442->tty->ops->write)
 		return -EIO;

 	old = cx20442->reg_cache;
 	cx20442->reg_cache = value;

 	vls = cx20442_pm_to_v253_vls(value);
 	if (vls < 0)
 		return vls;

 	vsp = cx20442_pm_to_v253_vsp(value);
 	if (vsp < 0)
 		return vsp;

 	if ((vls == V253_VLS_T) ||
 			(vls == cx20442_pm_to_v253_vls(old))) {
 		if (vsp == cx20442_pm_to_v253_vsp(old))
 			return 0;
 		len = snprintf(buf, ARRAY_SIZE(buf), "at+vsp=%d\r", vsp);
 	} else if (vsp == cx20442_pm_to_v253_vsp(old))
 		len = snprintf(buf, ARRAY_SIZE(buf), "at+vls=%d\r", vls);
 	else
 		len = snprintf(buf, ARRAY_SIZE(buf),
 					"at+vls=%d;+vsp=%d\r", vls, vsp);

 	if (unlikely(len > (ARRAY_SIZE(buf) - 1)))
 		return -ENOMEM;

 	dev_dbg(component->dev, "%s: %s\n", __func__, buf);
 	if (cx20442->tty->ops->write(cx20442->tty, buf, len) != len)
 		return -EIO;

 	return 0;
 }

 /*
  * Line discpline related code
  *
  * Any of the callback functions below can be used in two ways:
  * 1) registerd by a machine driver as one of line discipline operations,
  * 2) called from a machine's provided line discipline callback function
  *    in case when extra machine specific code must be run as well.
  */

 /* Modem init: echo off, digital speaker off, quiet off, voice mode */
 static const char *v253_init = "ate0m0q0+fclass=8\r";

 /* Line discipline .open() */
 static int v253_open(struct tty_struct *tty)
 {
 	int ret, len = strlen(v253_init);

 	/* Doesn't make sense without write callback */
 	if (!tty->ops->write)
 		return -EINVAL;

 	/* Won't work if no codec pointer has been passed by a card driver */
 	if (!tty->disc_data)
 		return -ENODEV;

 	tty->receive_room = 16;
 	if (tty->ops->write(tty, v253_init, len) != len) {
 		ret = -EIO;
 		goto err;
 	}
 	/* Actual setup will be performed after the modem responds. */
 	return 0;
 err:
 	tty->disc_data = NULL;
 	return ret;
 }

 /* Line discipline .close() */
 static void v253_close(struct tty_struct *tty)
 {
 	struct snd_soc_component *component = tty->disc_data;
 	struct cx20442_priv *cx20442;

 	tty->disc_data = NULL;

 	if (!component)
 		return;

 	cx20442 = snd_soc_component_get_drvdata(component);

 	/* Prevent the codec driver from further accessing the modem */
 	cx20442->tty = NULL;
 	component->card->pop_time = 0;
 }

 /* Line discipline .hangup() */
 static int v253_hangup(struct tty_struct *tty)
 {
 	v253_close(tty);
 	return 0;
 }

 /* Line discipline .receive_buf() */
 static void v253_receive(struct tty_struct *tty,
 				const unsigned char *cp, char *fp, int count)
 {
 	struct snd_soc_component *component = tty->disc_data;
 	struct cx20442_priv *cx20442;

 	if (!component)
 		return;

 	cx20442 = snd_soc_component_get_drvdata(component);

 	if (!cx20442->tty) {
 		/* First modem response, complete setup procedure */

 		/* Set up codec driver access to modem controls */
 		cx20442->tty = tty;
 		component->card->pop_time = 1;
 	}
 }

 /* Line discipline .write_wakeup() */
 static void v253_wakeup(struct tty_struct *tty)
 {
 }

 struct tty_ldisc_ops v253_ops = {
 	.magic = TTY_LDISC_MAGIC,
 	.name = "cx20442",
 	.owner = THIS_MODULE,
 	.open = v253_open,
 	.close = v253_close,
 	.hangup = v253_hangup,
 	.receive_buf = v253_receive,
 	.write_wakeup = v253_wakeup,
 };
 EXPORT_SYMBOL_GPL(v253_ops);


 /*
  * Codec DAI
  */

 static struct snd_soc_dai_driver cx20442_dai = {
 	.name = "cx20442-voice",
 	.playback = {
 		.stream_name = "Playback",
 		.channels_min = 1,
 		.channels_max = 1,
 		.rates = SNDRV_PCM_RATE_8000,
 		.formats = SNDRV_PCM_FMTBIT_S16_LE,
 	},
 	.capture = {
 		.stream_name = "Capture",
 		.channels_min = 1,
 		.channels_max = 1,
 		.rates = SNDRV_PCM_RATE_8000,
 		.formats = SNDRV_PCM_FMTBIT_S16_LE,
 	},
 };

 static int cx20442_set_bias_level(struct snd_soc_component *component,
 		enum snd_soc_bias_level level)
 {
 	struct cx20442_priv *cx20442 = snd_soc_component_get_drvdata(component);
 	int err = 0;

 	switch (level) {
 	case SND_SOC_BIAS_PREPARE:
 		if (snd_soc_component_get_bias_level(component) != SND_SOC_BIAS_STANDBY)
 			break;
 		if (IS_ERR(cx20442->por))
 			err = PTR_ERR(cx20442->por);
 		else
 			err = regulator_enable(cx20442->por);
 		break;
 	case SND_SOC_BIAS_STANDBY:
 		if (snd_soc_component_get_bias_level(component) != SND_SOC_BIAS_PREPARE)
 			break;
 		if (IS_ERR(cx20442->por))
 			err = PTR_ERR(cx20442->por);
 		else
 			err = regulator_disable(cx20442->por);
 		break;
 	default:
 		break;
 	}

 	return err;
 }

 static int cx20442_component_probe(struct snd_soc_component *component)
 {
 	struct cx20442_priv *cx20442;

 	cx20442 = kzalloc(sizeof(struct cx20442_priv), GFP_KERNEL);
 	if (cx20442 == NULL)
 		return -ENOMEM;

 	cx20442->por = regulator_get(component->dev, "POR");
 	if (IS_ERR(cx20442->por)) {
 		int err = PTR_ERR(cx20442->por);

 		dev_warn(component->dev, "failed to get POR supply (%d)", err);
 		/*
 		 * When running on a non-dt platform and requested regulator
 		 * is not available, regulator_get() never returns
 		 * -EPROBE_DEFER as it is not able to justify if the regulator
 		 * may still appear later.  On the other hand, the board can
 		 * still set full constraints flag at late_initcall in order
 		 * to instruct regulator_get() to return a dummy one if
 		 * sufficient.  Hence, if we get -ENODEV here, let's convert
 		 * it to -EPROBE_DEFER and wait for the board to decide or
 		 * let Deferred Probe infrastructure handle this error.
 		 */
 		if (err == -ENODEV)
 			err = -EPROBE_DEFER;
 		kfree(cx20442);
 		return err;
 	}

 	cx20442->tty = NULL;

 	snd_soc_component_set_drvdata(component, cx20442);
 	component->card->pop_time = 0;

 	return 0;
 }

 /* power down chip */
 static void cx20442_component_remove(struct snd_soc_component *component)
 {
 	struct cx20442_priv *cx20442 = snd_soc_component_get_drvdata(component);

 	if (cx20442->tty) {
 		struct tty_struct *tty = cx20442->tty;
 		tty_hangup(tty);
 	}

 	if (!IS_ERR(cx20442->por)) {
 		/* should be already in STANDBY, hence disabled */
 		regulator_put(cx20442->por);
 	}

 	snd_soc_component_set_drvdata(component, NULL);
 	kfree(cx20442);
 }

 static const struct snd_soc_component_driver cx20442_component_dev = {
 	.probe			= cx20442_component_probe,
 	.remove			= cx20442_component_remove,
 	.set_bias_level		= cx20442_set_bias_level,
 	.read			= cx20442_read_reg_cache,
 	.write			= cx20442_write,
 	.dapm_widgets		= cx20442_dapm_widgets,
 	.num_dapm_widgets	= ARRAY_SIZE(cx20442_dapm_widgets),
 	.dapm_routes		= cx20442_audio_map,
 	.num_dapm_routes	= ARRAY_SIZE(cx20442_audio_map),
 	.idle_bias_on		= 1,
 	.use_pmdown_time	= 1,
 	.endianness		= 1,
 	.non_legacy_dai_naming	= 1,
 };

 static int cx20442_platform_probe(struct platform_device *pdev)
 {
 	return devm_snd_soc_register_component(&pdev->dev,
 			&cx20442_component_dev, &cx20442_dai, 1);
 }

 static struct platform_driver cx20442_platform_driver = {
 	.driver = {
 		.name = "cx20442-codec",
 		},
 	.probe = cx20442_platform_probe,
 };

 module_platform_driver(cx20442_platform_driver);

 MODULE_DESCRIPTION("ASoC CX20442-11 voice modem codec driver");
 MODULE_AUTHOR("Janusz Krzysztofik");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("platform:cx20442-codec");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* cx20442.c -- CX20442 ALSA Soc Audio driver
	*
	* Copyright 2009 Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
	*
	* Initially based on sound/soc/codecs/wm8400.c
	* Copyright 2008, 2009 Wolfson Microelectronics PLC.
	* Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
	*/

	#include <linux/tty.h>
	#include <linux/slab.h>
	#include <linux/module.h>
	#include <linux/regulator/consumer.h>

	#include <sound/core.h>
	#include <sound/initval.h>
	#include <sound/soc.h>

	#include "cx20442.h"


	struct cx20442_priv {
	struct tty_struct *tty;
	struct regulator *por;
	u8 reg_cache;
	};

	#define CX20442_PM 0x0

	#define CX20442_TELIN 0
	#define CX20442_TELOUT 1
	#define CX20442_MIC 2
	#define CX20442_SPKOUT 3
	#define CX20442_AGC 4

	static const struct snd_soc_dapm_widget cx20442_dapm_widgets[] = {
	SND_SOC_DAPM_OUTPUT("TELOUT"),
	SND_SOC_DAPM_OUTPUT("SPKOUT"),
	SND_SOC_DAPM_OUTPUT("AGCOUT"),

	SND_SOC_DAPM_MIXER("SPKOUT Mixer", SND_SOC_NOPM, 0, 0, NULL, 0),

	SND_SOC_DAPM_PGA("TELOUT Amp", CX20442_PM, CX20442_TELOUT, 0, NULL, 0),
	SND_SOC_DAPM_PGA("SPKOUT Amp", CX20442_PM, CX20442_SPKOUT, 0, NULL, 0),
	SND_SOC_DAPM_PGA("SPKOUT AGC", CX20442_PM, CX20442_AGC, 0, NULL, 0),

	SND_SOC_DAPM_DAC("DAC", "Playback", SND_SOC_NOPM, 0, 0),
	SND_SOC_DAPM_ADC("ADC", "Capture", SND_SOC_NOPM, 0, 0),

	SND_SOC_DAPM_MIXER("Input Mixer", SND_SOC_NOPM, 0, 0, NULL, 0),

	SND_SOC_DAPM_MICBIAS("TELIN Bias", CX20442_PM, CX20442_TELIN, 0),
	SND_SOC_DAPM_MICBIAS("MIC Bias", CX20442_PM, CX20442_MIC, 0),

	SND_SOC_DAPM_PGA("MIC AGC", CX20442_PM, CX20442_AGC, 0, NULL, 0),

	SND_SOC_DAPM_INPUT("TELIN"),
	SND_SOC_DAPM_INPUT("MIC"),
	SND_SOC_DAPM_INPUT("AGCIN"),
	};

	static const struct snd_soc_dapm_route cx20442_audio_map[] = {
	{"TELOUT", NULL, "TELOUT Amp"},

	{"SPKOUT", NULL, "SPKOUT Mixer"},
	{"SPKOUT Mixer", NULL, "SPKOUT Amp"},

	{"TELOUT Amp", NULL, "DAC"},
	{"SPKOUT Amp", NULL, "DAC"},

	{"SPKOUT Mixer", NULL, "SPKOUT AGC"},
	{"SPKOUT AGC", NULL, "AGCIN"},

	{"AGCOUT", NULL, "MIC AGC"},
	{"MIC AGC", NULL, "MIC"},

	{"MIC Bias", NULL, "MIC"},
	{"Input Mixer", NULL, "MIC Bias"},

	{"TELIN Bias", NULL, "TELIN"},
	{"Input Mixer", NULL, "TELIN Bias"},

	{"ADC", NULL, "Input Mixer"},
	};

	static unsigned int cx20442_read_reg_cache(struct snd_soc_component *component,
	unsigned int reg)
	{
	struct cx20442_priv *cx20442 = snd_soc_component_get_drvdata(component);

	if (reg >= 1)
	return -EINVAL;

	return cx20442->reg_cache;
	}

	enum v253_vls {
	V253_VLS_NONE = 0,
	V253_VLS_T,
	V253_VLS_L,
	V253_VLS_LT,
	V253_VLS_S,
	V253_VLS_ST,
	V253_VLS_M,
	V253_VLS_MST,
	V253_VLS_S1,
	V253_VLS_S1T,
	V253_VLS_MS1T,
	V253_VLS_M1,
	V253_VLS_M1ST,
	V253_VLS_M1S1T,
	V253_VLS_H,
	V253_VLS_HT,
	V253_VLS_MS,
	V253_VLS_MS1,
	V253_VLS_M1S,
	V253_VLS_M1S1,
	V253_VLS_TEST,
	};

	static int cx20442_pm_to_v253_vls(u8 value)
	{
	switch (value & ~(1 << CX20442_AGC)) {
	case 0:
	return V253_VLS_T;
	case (1 << CX20442_SPKOUT):
	case (1 << CX20442_MIC):
	case (1 << CX20442_SPKOUT) \| (1 << CX20442_MIC):
	return V253_VLS_M1S1;
	case (1 << CX20442_TELOUT):
	case (1 << CX20442_TELIN):
	case (1 << CX20442_TELOUT) \| (1 << CX20442_TELIN):
	return V253_VLS_L;
	case (1 << CX20442_TELOUT) \| (1 << CX20442_MIC):
	return V253_VLS_NONE;
	}
	return -EINVAL;
	}
	static int cx20442_pm_to_v253_vsp(u8 value)
	{
	switch (value & ~(1 << CX20442_AGC)) {
	case (1 << CX20442_SPKOUT):
	case (1 << CX20442_MIC):
	case (1 << CX20442_SPKOUT) \| (1 << CX20442_MIC):
	return (bool)(value & (1 << CX20442_AGC));
	}
	return (value & (1 << CX20442_AGC)) ? -EINVAL : 0;
	}

	static int cx20442_write(struct snd_soc_component *component, unsigned int reg,
	unsigned int value)
	{
	struct cx20442_priv *cx20442 = snd_soc_component_get_drvdata(component);
	int vls, vsp, old, len;
	char buf[18];

	if (reg >= 1)
	return -EINVAL;

	/* tty and write pointers required for talking to the modem
	* are expected to be set by the line discipline initialization code */
	if (!cx20442->tty \|\| !cx20442->tty->ops->write)
	return -EIO;

	old = cx20442->reg_cache;
	cx20442->reg_cache = value;

	vls = cx20442_pm_to_v253_vls(value);
	if (vls < 0)
	return vls;

	vsp = cx20442_pm_to_v253_vsp(value);
	if (vsp < 0)
	return vsp;

	if ((vls == V253_VLS_T) \|\|
	(vls == cx20442_pm_to_v253_vls(old))) {
	if (vsp == cx20442_pm_to_v253_vsp(old))
	return 0;
	len = snprintf(buf, ARRAY_SIZE(buf), "at+vsp=%d\r", vsp);
	} else if (vsp == cx20442_pm_to_v253_vsp(old))
	len = snprintf(buf, ARRAY_SIZE(buf), "at+vls=%d\r", vls);
	else
	len = snprintf(buf, ARRAY_SIZE(buf),
	"at+vls=%d;+vsp=%d\r", vls, vsp);

	if (unlikely(len > (ARRAY_SIZE(buf) - 1)))
	return -ENOMEM;

	dev_dbg(component->dev, "%s: %s\n", __func__, buf);
	if (cx20442->tty->ops->write(cx20442->tty, buf, len) != len)
	return -EIO;

	return 0;
	}

	/*
	* Line discpline related code
	*
	* Any of the callback functions below can be used in two ways:
	* 1) registerd by a machine driver as one of line discipline operations,
	* 2) called from a machine's provided line discipline callback function
	* in case when extra machine specific code must be run as well.
	*/

	/* Modem init: echo off, digital speaker off, quiet off, voice mode */
	static const char *v253_init = "ate0m0q0+fclass=8\r";

	/* Line discipline .open() */
	static int v253_open(struct tty_struct *tty)
	{
	int ret, len = strlen(v253_init);

	/* Doesn't make sense without write callback */
	if (!tty->ops->write)
	return -EINVAL;

	/* Won't work if no codec pointer has been passed by a card driver */
	if (!tty->disc_data)
	return -ENODEV;

	tty->receive_room = 16;
	if (tty->ops->write(tty, v253_init, len) != len) {
	ret = -EIO;
	goto err;
	}
	/* Actual setup will be performed after the modem responds. */
	return 0;
	err:
	tty->disc_data = NULL;
	return ret;
	}

	/* Line discipline .close() */
	static void v253_close(struct tty_struct *tty)
	{
	struct snd_soc_component *component = tty->disc_data;
	struct cx20442_priv *cx20442;

	tty->disc_data = NULL;

	if (!component)
	return;

	cx20442 = snd_soc_component_get_drvdata(component);

	/* Prevent the codec driver from further accessing the modem */
	cx20442->tty = NULL;
	component->card->pop_time = 0;
	}

	/* Line discipline .hangup() */
	static int v253_hangup(struct tty_struct *tty)
	{
	v253_close(tty);
	return 0;
	}

	/* Line discipline .receive_buf() */
	static void v253_receive(struct tty_struct *tty,
	const unsigned char cp, char fp, int count)
	{
	struct snd_soc_component *component = tty->disc_data;
	struct cx20442_priv *cx20442;

	if (!component)
	return;

	cx20442 = snd_soc_component_get_drvdata(component);

	if (!cx20442->tty) {
	/* First modem response, complete setup procedure */

	/* Set up codec driver access to modem controls */
	cx20442->tty = tty;
	component->card->pop_time = 1;
	}
	}

	/* Line discipline .write_wakeup() */
	static void v253_wakeup(struct tty_struct *tty)
	{
	}

	struct tty_ldisc_ops v253_ops = {
	.magic = TTY_LDISC_MAGIC,
	.name = "cx20442",
	.owner = THIS_MODULE,
	.open = v253_open,
	.close = v253_close,
	.hangup = v253_hangup,
	.receive_buf = v253_receive,
	.write_wakeup = v253_wakeup,
	};
	EXPORT_SYMBOL_GPL(v253_ops);


	/*
	* Codec DAI
	*/

	static struct snd_soc_dai_driver cx20442_dai = {
	.name = "cx20442-voice",
	.playback = {
	.stream_name = "Playback",
	.channels_min = 1,
	.channels_max = 1,
	.rates = SNDRV_PCM_RATE_8000,
	.formats = SNDRV_PCM_FMTBIT_S16_LE,
	},
	.capture = {
	.stream_name = "Capture",
	.channels_min = 1,
	.channels_max = 1,
	.rates = SNDRV_PCM_RATE_8000,
	.formats = SNDRV_PCM_FMTBIT_S16_LE,
	},
	};

	static int cx20442_set_bias_level(struct snd_soc_component *component,
	enum snd_soc_bias_level level)
	{
	struct cx20442_priv *cx20442 = snd_soc_component_get_drvdata(component);
	int err = 0;

	switch (level) {
	case SND_SOC_BIAS_PREPARE:
	if (snd_soc_component_get_bias_level(component) != SND_SOC_BIAS_STANDBY)
	break;
	if (IS_ERR(cx20442->por))
	err = PTR_ERR(cx20442->por);
	else
	err = regulator_enable(cx20442->por);
	break;
	case SND_SOC_BIAS_STANDBY:
	if (snd_soc_component_get_bias_level(component) != SND_SOC_BIAS_PREPARE)
	break;
	if (IS_ERR(cx20442->por))
	err = PTR_ERR(cx20442->por);
	else
	err = regulator_disable(cx20442->por);
	break;
	default:
	break;
	}

	return err;
	}

	static int cx20442_component_probe(struct snd_soc_component *component)
	{
	struct cx20442_priv *cx20442;

	cx20442 = kzalloc(sizeof(struct cx20442_priv), GFP_KERNEL);
	if (cx20442 == NULL)
	return -ENOMEM;

	cx20442->por = regulator_get(component->dev, "POR");
	if (IS_ERR(cx20442->por)) {
	int err = PTR_ERR(cx20442->por);

	dev_warn(component->dev, "failed to get POR supply (%d)", err);
	/*
	* When running on a non-dt platform and requested regulator
	* is not available, regulator_get() never returns
	* -EPROBE_DEFER as it is not able to justify if the regulator
	* may still appear later. On the other hand, the board can
	* still set full constraints flag at late_initcall in order
	* to instruct regulator_get() to return a dummy one if
	* sufficient. Hence, if we get -ENODEV here, let's convert
	* it to -EPROBE_DEFER and wait for the board to decide or
	* let Deferred Probe infrastructure handle this error.
	*/
	if (err == -ENODEV)
	err = -EPROBE_DEFER;
	kfree(cx20442);
	return err;
	}

	cx20442->tty = NULL;

	snd_soc_component_set_drvdata(component, cx20442);
	component->card->pop_time = 0;

	return 0;
	}

	/* power down chip */
	static void cx20442_component_remove(struct snd_soc_component *component)
	{
	struct cx20442_priv *cx20442 = snd_soc_component_get_drvdata(component);

	if (cx20442->tty) {
	struct tty_struct *tty = cx20442->tty;
	tty_hangup(tty);
	}

	if (!IS_ERR(cx20442->por)) {
	/* should be already in STANDBY, hence disabled */
	regulator_put(cx20442->por);
	}

	snd_soc_component_set_drvdata(component, NULL);
	kfree(cx20442);
	}

	static const struct snd_soc_component_driver cx20442_component_dev = {
	.probe = cx20442_component_probe,
	.remove = cx20442_component_remove,
	.set_bias_level = cx20442_set_bias_level,
	.read = cx20442_read_reg_cache,
	.write = cx20442_write,
	.dapm_widgets = cx20442_dapm_widgets,
	.num_dapm_widgets = ARRAY_SIZE(cx20442_dapm_widgets),
	.dapm_routes = cx20442_audio_map,
	.num_dapm_routes = ARRAY_SIZE(cx20442_audio_map),
	.idle_bias_on = 1,
	.use_pmdown_time = 1,
	.endianness = 1,
	.non_legacy_dai_naming = 1,
	};

	static int cx20442_platform_probe(struct platform_device *pdev)
	{
	return devm_snd_soc_register_component(&pdev->dev,
	&cx20442_component_dev, &cx20442_dai, 1);
	}

	static struct platform_driver cx20442_platform_driver = {
	.driver = {
	.name = "cx20442-codec",
	},
	.probe = cx20442_platform_probe,
	};

	module_platform_driver(cx20442_platform_driver);

	MODULE_DESCRIPTION("ASoC CX20442-11 voice modem codec driver");
	MODULE_AUTHOR("Janusz Krzysztofik");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS("platform:cx20442-codec");