ASoC: tas6424: Add support for TAS6424 digital amplifier

The Texas Instruments TAS6424 device is a high-efficiency quad-channel
Class-D audio power amplifier. Its digital time division multiplexed
(TDM) interface enables up to 2 devices to share the same bus,
supporting a total of eight channels from one audio serial port.

Signed-off-by: Andreas Dannenberg <dannenberg@ti.com>
Signed-off-by: Michael Stecklein <m-stecklein@ti.com>
Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 707 insertions, 0 deletions

diff --git a/sound/soc/codecs/tas6424.c b/sound/soc/codecs/tas6424.c
new file mode 100644
index 000000000000..49b87f6e85bf
--- /dev/null
+++ b/sound/soc/codecs/tas6424.c
@@ -0,0 +1,707 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ALSA SoC Texas Instruments TAS6424 Quad-Channel Audio Amplifier
+ *
+ * Copyright (C) 2016-2017 Texas Instruments Incorporated - http://www.ti.com/
+ *	Author: Andreas Dannenberg <dannenberg@ti.com>
+ *	Andrew F. Davis <afd@ti.com>
+ */
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/regulator/consumer.h>
+#include <linux/delay.h>
+
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+#include <sound/soc-dapm.h>
+#include <sound/tlv.h>
+
+#include "tas6424.h"
+
+/* Define how often to check (and clear) the fault status register (in ms) */
+#define TAS6424_FAULT_CHECK_INTERVAL 200
+
+static const char * const tas6424_supply_names[] = {
+	"dvdd", /* Digital power supply. Connect to 3.3-V supply. */
+	"vbat", /* Supply used for higher voltage analog circuits. */
+	"pvdd", /* Class-D amp output FETs supply. */
+};
+#define TAS6424_NUM_SUPPLIES ARRAY_SIZE(tas6424_supply_names)
+
+struct tas6424_data {
+	struct device *dev;
+	struct regmap *regmap;
+	struct regulator_bulk_data supplies[TAS6424_NUM_SUPPLIES];
+	struct delayed_work fault_check_work;
+	unsigned int last_fault1;
+	unsigned int last_fault2;
+	unsigned int last_warn;
+};
+
+/*
+ * DAC digital volumes. From -103.5 to 24 dB in 0.5 dB steps. Note that
+ * setting the gain below -100 dB (register value <0x7) is effectively a MUTE
+ * as per device datasheet.
+ */
+static DECLARE_TLV_DB_SCALE(dac_tlv, -10350, 50, 0);
+
+static const struct snd_kcontrol_new tas6424_snd_controls[] = {
+	SOC_SINGLE_TLV("Speaker Driver CH1 Playback Volume",
+		       TAS6424_CH1_VOL_CTRL, 0, 0xff, 0, dac_tlv),
+	SOC_SINGLE_TLV("Speaker Driver CH2 Playback Volume",
+		       TAS6424_CH2_VOL_CTRL, 0, 0xff, 0, dac_tlv),
+	SOC_SINGLE_TLV("Speaker Driver CH3 Playback Volume",
+		       TAS6424_CH3_VOL_CTRL, 0, 0xff, 0, dac_tlv),
+	SOC_SINGLE_TLV("Speaker Driver CH4 Playback Volume",
+		       TAS6424_CH4_VOL_CTRL, 0, 0xff, 0, dac_tlv),
+};
+
+static int tas6424_dac_event(struct snd_soc_dapm_widget *w,
+			     struct snd_kcontrol *kcontrol, int event)
+{
+	struct snd_soc_codec *codec = snd_soc_dapm_to_codec(w->dapm);
+	struct tas6424_data *tas6424 = snd_soc_codec_get_drvdata(codec);
+
+	dev_dbg(codec->dev, "%s() event=0x%0x\n", __func__, event);
+
+	if (event & SND_SOC_DAPM_POST_PMU) {
+		/* Observe codec shutdown-to-active time */
+		msleep(12);
+
+		/* Turn on TAS6424 periodic fault checking/handling */
+		tas6424->last_fault1 = 0;
+		tas6424->last_fault2 = 0;
+		tas6424->last_warn = 0;
+		schedule_delayed_work(&tas6424->fault_check_work,
+				      msecs_to_jiffies(TAS6424_FAULT_CHECK_INTERVAL));
+	} else if (event & SND_SOC_DAPM_PRE_PMD) {
+		/* Disable TAS6424 periodic fault checking/handling */
+		cancel_delayed_work_sync(&tas6424->fault_check_work);
+	}
+
+	return 0;
+}
+
+static const struct snd_soc_dapm_widget tas6424_dapm_widgets[] = {
+	SND_SOC_DAPM_AIF_IN("DAC IN", "Playback", 0, SND_SOC_NOPM, 0, 0),
+	SND_SOC_DAPM_DAC_E("DAC", NULL, SND_SOC_NOPM, 0, 0, tas6424_dac_event,
+			   SND_SOC_DAPM_POST_PMU | SND_SOC_DAPM_PRE_PMD),
+	SND_SOC_DAPM_OUTPUT("OUT")
+};
+
+static const struct snd_soc_dapm_route tas6424_audio_map[] = {
+	{ "DAC", NULL, "DAC IN" },
+	{ "OUT", NULL, "DAC" },
+};
+
+static int tas6424_hw_params(struct snd_pcm_substream *substream,
+			     struct snd_pcm_hw_params *params,
+			     struct snd_soc_dai *dai)
+{
+	struct snd_soc_codec *codec = dai->codec;
+	unsigned int rate = params_rate(params);
+	unsigned int width = params_width(params);
+	u8 sap_ctrl = 0;
+
+	dev_dbg(codec->dev, "%s() rate=%u width=%u\n", __func__, rate, width);
+
+	switch (rate) {
+	case 44100:
+		sap_ctrl |= TAS6424_SAP_RATE_44100;
+		break;
+	case 48000:
+		sap_ctrl |= TAS6424_SAP_RATE_48000;
+		break;
+	case 96000:
+		sap_ctrl |= TAS6424_SAP_RATE_96000;
+		break;
+	default:
+		dev_err(codec->dev, "unsupported sample rate: %u\n", rate);
+		return -EINVAL;
+	}
+
+	switch (width) {
+	case 16:
+		sap_ctrl |= TAS6424_SAP_TDM_SLOT_SZ_16;
+		break;
+	case 24:
+		break;
+	default:
+		dev_err(codec->dev, "unsupported sample width: %u\n", width);
+		return -EINVAL;
+	}
+
+	snd_soc_update_bits(codec, TAS6424_SAP_CTRL,
+			    TAS6424_SAP_RATE_MASK |
+			    TAS6424_SAP_TDM_SLOT_SZ_16,
+			    sap_ctrl);
+
+	return 0;
+}
+
+static int tas6424_set_dai_fmt(struct snd_soc_dai *dai, unsigned int fmt)
+{
+	struct snd_soc_codec *codec = dai->codec;
+	u8 serial_format = 0;
+
+	dev_dbg(codec->dev, "%s() fmt=0x%0x\n", __func__, fmt);
+
+	/* clock masters */
+	switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
+	case SND_SOC_DAIFMT_CBS_CFS:
+		break;
+	default:
+		dev_err(codec->dev, "Invalid DAI master/slave interface\n");
+		return -EINVAL;
+	}
+
+	/* signal polarity */
+	switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
+	case SND_SOC_DAIFMT_NB_NF:
+		break;
+	default:
+		dev_err(codec->dev, "Invalid DAI clock signal polarity\n");
+		return -EINVAL;
+	}
+
+	/* interface format */
+	switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
+	case SND_SOC_DAIFMT_I2S:
+		serial_format |= TAS6424_SAP_I2S;
+		break;
+	case SND_SOC_DAIFMT_DSP_A:
+		serial_format |= TAS6424_SAP_DSP;
+		break;
+	case SND_SOC_DAIFMT_DSP_B:
+		/*
+		 * We can use the fact that the TAS6424 does not care about the
+		 * LRCLK duty cycle during TDM to receive DSP_B formatted data
+		 * in LEFTJ mode (no delaying of the 1st data bit).
+		 */
+		serial_format |= TAS6424_SAP_LEFTJ;
+		break;
+	case SND_SOC_DAIFMT_LEFT_J:
+		serial_format |= TAS6424_SAP_LEFTJ;
+		break;
+	default:
+		dev_err(codec->dev, "Invalid DAI interface format\n");
+		return -EINVAL;
+	}
+
+	snd_soc_update_bits(codec, TAS6424_SAP_CTRL,
+			    TAS6424_SAP_FMT_MASK, serial_format);
+
+	return 0;
+}
+
+static int tas6424_set_dai_tdm_slot(struct snd_soc_dai *dai,
+				    unsigned int tx_mask, unsigned int rx_mask,
+				    int slots, int slot_width)
+{
+	struct snd_soc_codec *codec = dai->codec;
+	unsigned int first_slot, last_slot;
+	bool sap_tdm_slot_last;
+
+	dev_dbg(codec->dev, "%s() tx_mask=%d rx_mask=%d\n", __func__,
+		tx_mask, rx_mask);
+
+	if (!tx_mask || !rx_mask)
+		return 0; /* nothing needed to disable TDM mode */
+
+	/*
+	 * Determine the first slot and last slot that is being requested so
+	 * we'll be able to more easily enforce certain constraints as the
+	 * TAS6424's TDM interface is not fully configurable.
+	 */
+	first_slot = __ffs(tx_mask);
+	last_slot = __fls(rx_mask);
+
+	if (last_slot - first_slot != 4) {
+		dev_err(codec->dev, "tdm mask must cover 4 contiguous slots\n");
+		return -EINVAL;
+	}
+
+	switch (first_slot) {
+	case 0:
+		sap_tdm_slot_last = false;
+		break;
+	case 4:
+		sap_tdm_slot_last = true;
+		break;
+	default:
+		dev_err(codec->dev, "tdm mask must start at slot 0 or 4\n");
+		return -EINVAL;
+	}
+
+	snd_soc_update_bits(codec, TAS6424_SAP_CTRL, TAS6424_SAP_TDM_SLOT_LAST,
+			    sap_tdm_slot_last ? TAS6424_SAP_TDM_SLOT_LAST : 0);
+
+	return 0;
+}
+
+static int tas6424_mute(struct snd_soc_dai *dai, int mute)
+{
+	struct snd_soc_codec *codec = dai->codec;
+	unsigned int val;
+
+	dev_dbg(codec->dev, "%s() mute=%d\n", __func__, mute);
+
+	if (mute)
+		val = TAS6424_ALL_STATE_MUTE;
+	else
+		val = TAS6424_ALL_STATE_PLAY;
+
+	snd_soc_write(codec, TAS6424_CH_STATE_CTRL, val);
+
+	return 0;
+}
+
+static int tas6424_power_off(struct snd_soc_codec *codec)
+{
+	struct tas6424_data *tas6424 = snd_soc_codec_get_drvdata(codec);
+	int ret;
+
+	snd_soc_write(codec, TAS6424_CH_STATE_CTRL, TAS6424_ALL_STATE_HIZ);
+
+	regcache_cache_only(tas6424->regmap, true);
+	regcache_mark_dirty(tas6424->regmap);
+
+	ret = regulator_bulk_disable(ARRAY_SIZE(tas6424->supplies),
+				     tas6424->supplies);
+	if (ret < 0) {
+		dev_err(codec->dev, "failed to disable supplies: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int tas6424_power_on(struct snd_soc_codec *codec)
+{
+	struct tas6424_data *tas6424 = snd_soc_codec_get_drvdata(codec);
+	int ret;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(tas6424->supplies),
+				    tas6424->supplies);
+	if (ret < 0) {
+		dev_err(codec->dev, "failed to enable supplies: %d\n", ret);
+		return ret;
+	}
+
+	regcache_cache_only(tas6424->regmap, false);
+
+	ret = regcache_sync(tas6424->regmap);
+	if (ret < 0) {
+		dev_err(codec->dev, "failed to sync regcache: %d\n", ret);
+		return ret;
+	}
+
+	snd_soc_write(codec, TAS6424_CH_STATE_CTRL, TAS6424_ALL_STATE_MUTE);
+
+	/* any time we come out of HIZ, the output channels automatically run DC
+	 * load diagnostics, wait here until this completes
+	 */
+	msleep(230);
+
+	return 0;
+}
+
+static int tas6424_set_bias_level(struct snd_soc_codec *codec,
+				  enum snd_soc_bias_level level)
+{
+	dev_dbg(codec->dev, "%s() level=%d\n", __func__, level);
+
+	switch (level) {
+	case SND_SOC_BIAS_ON:
+	case SND_SOC_BIAS_PREPARE:
+		break;
+	case SND_SOC_BIAS_STANDBY:
+		if (snd_soc_codec_get_bias_level(codec) == SND_SOC_BIAS_OFF)
+			tas6424_power_on(codec);
+		break;
+	case SND_SOC_BIAS_OFF:
+		tas6424_power_off(codec);
+		break;
+	}
+
+	return 0;
+}
+
+static struct snd_soc_codec_driver soc_codec_dev_tas6424 = {
+	.set_bias_level = tas6424_set_bias_level,
+	.idle_bias_off = true,
+
+	.component_driver = {
+		.controls = tas6424_snd_controls,
+		.num_controls = ARRAY_SIZE(tas6424_snd_controls),
+		.dapm_widgets = tas6424_dapm_widgets,
+		.num_dapm_widgets = ARRAY_SIZE(tas6424_dapm_widgets),
+		.dapm_routes = tas6424_audio_map,
+		.num_dapm_routes = ARRAY_SIZE(tas6424_audio_map),
+	},
+};
+
+static struct snd_soc_dai_ops tas6424_speaker_dai_ops = {
+	.hw_params	= tas6424_hw_params,
+	.set_fmt	= tas6424_set_dai_fmt,
+	.set_tdm_slot	= tas6424_set_dai_tdm_slot,
+	.digital_mute	= tas6424_mute,
+};
+
+static struct snd_soc_dai_driver tas6424_dai[] = {
+	{
+		.name = "tas6424-amplifier",
+		.playback = {
+			.stream_name = "Playback",
+			.channels_min = 1,
+			.channels_max = 4,
+			.rates = TAS6424_RATES,
+			.formats = TAS6424_FORMATS,
+		},
+		.ops = &tas6424_speaker_dai_ops,
+	},
+};
+
+static void tas6424_fault_check_work(struct work_struct *work)
+{
+	struct tas6424_data *tas6424 = container_of(work, struct tas6424_data,
+						    fault_check_work.work);
+	struct device *dev = tas6424->dev;
+	unsigned int reg;
+	int ret;
+
+	ret = regmap_read(tas6424->regmap, TAS6424_GLOB_FAULT1, &reg);
+	if (ret < 0) {
+		dev_err(dev, "failed to read FAULT1 register: %d\n", ret);
+		goto out;
+	}
+
+	/*
+	 * Ignore any clock faults as there is no clean way to check for them.
+	 * We would need to start checking for those faults *after* the SAIF
+	 * stream has been setup, and stop checking *before* the stream is
+	 * stopped to avoid any false-positives. However there are no
+	 * appropriate hooks to monitor these events.
+	 */
+	reg &= TAS6424_FAULT_PVDD_OV |
+	       TAS6424_FAULT_VBAT_OV |
+	       TAS6424_FAULT_PVDD_UV |
+	       TAS6424_FAULT_VBAT_UV;
+
+	if (reg)
+		goto check_global_fault2_reg;
+
+	/*
+	 * Only flag errors once for a given occurrence. This is needed as
+	 * the TAS6424 will take time clearing the fault condition internally
+	 * during which we don't want to bombard the system with the same
+	 * error message over and over.
+	 */
+	if ((reg & TAS6424_FAULT_PVDD_OV) && !(tas6424->last_fault1 & TAS6424_FAULT_PVDD_OV))
+		dev_crit(dev, "experienced a PVDD overvoltage fault\n");
+
+	if ((reg & TAS6424_FAULT_VBAT_OV) && !(tas6424->last_fault1 & TAS6424_FAULT_VBAT_OV))
+		dev_crit(dev, "experienced a VBAT overvoltage fault\n");
+
+	if ((reg & TAS6424_FAULT_PVDD_UV) && !(tas6424->last_fault1 & TAS6424_FAULT_PVDD_UV))
+		dev_crit(dev, "experienced a PVDD undervoltage fault\n");
+
+	if ((reg & TAS6424_FAULT_VBAT_UV) && !(tas6424->last_fault1 & TAS6424_FAULT_VBAT_UV))
+		dev_crit(dev, "experienced a VBAT undervoltage fault\n");
+
+	/* Store current fault1 value so we can detect any changes next time */
+	tas6424->last_fault1 = reg;
+
+check_global_fault2_reg:
+	ret = regmap_read(tas6424->regmap, TAS6424_GLOB_FAULT2, &reg);
+	if (ret < 0) {
+		dev_err(dev, "failed to read FAULT2 register: %d\n", ret);
+		goto out;
+	}
+
+	reg &= TAS6424_FAULT_OTSD |
+	       TAS6424_FAULT_OTSD_CH1 |
+	       TAS6424_FAULT_OTSD_CH2 |
+	       TAS6424_FAULT_OTSD_CH3 |
+	       TAS6424_FAULT_OTSD_CH4;
+
+	if (!reg)
+		goto check_warn_reg;
+
+	if ((reg & TAS6424_FAULT_OTSD) && !(tas6424->last_fault2 & TAS6424_FAULT_OTSD))
+		dev_crit(dev, "experienced a global overtemp shutdown\n");
+
+	if ((reg & TAS6424_FAULT_OTSD_CH1) && !(tas6424->last_fault2 & TAS6424_FAULT_OTSD_CH1))
+		dev_crit(dev, "experienced an overtemp shutdown on CH1\n");
+
+	if ((reg & TAS6424_FAULT_OTSD_CH2) && !(tas6424->last_fault2 & TAS6424_FAULT_OTSD_CH2))
+		dev_crit(dev, "experienced an overtemp shutdown on CH2\n");
+
+	if ((reg & TAS6424_FAULT_OTSD_CH3) && !(tas6424->last_fault2 & TAS6424_FAULT_OTSD_CH3))
+		dev_crit(dev, "experienced an overtemp shutdown on CH3\n");
+
+	if ((reg & TAS6424_FAULT_OTSD_CH4) && !(tas6424->last_fault2 & TAS6424_FAULT_OTSD_CH4))
+		dev_crit(dev, "experienced an overtemp shutdown on CH4\n");
+
+	/* Store current fault2 value so we can detect any changes next time */
+	tas6424->last_fault2 = reg;
+
+check_warn_reg:
+	ret = regmap_read(tas6424->regmap, TAS6424_WARN, &reg);
+	if (ret < 0) {
+		dev_err(dev, "failed to read WARN register: %d\n", ret);
+		goto out;
+	}
+
+	reg &= TAS6424_WARN_VDD_UV |
+	       TAS6424_WARN_VDD_POR |
+	       TAS6424_WARN_VDD_OTW |
+	       TAS6424_WARN_VDD_OTW_CH1 |
+	       TAS6424_WARN_VDD_OTW_CH2 |
+	       TAS6424_WARN_VDD_OTW_CH3 |
+	       TAS6424_WARN_VDD_OTW_CH4;
+
+	if (!reg)
+		goto out;
+
+	if ((reg & TAS6424_WARN_VDD_UV) && !(tas6424->last_warn & TAS6424_WARN_VDD_UV))
+		dev_warn(dev, "experienced a VDD under voltage condition\n");
+
+	if ((reg & TAS6424_WARN_VDD_POR) && !(tas6424->last_warn & TAS6424_WARN_VDD_POR))
+		dev_warn(dev, "experienced a VDD POR condition\n");
+
+	if ((reg & TAS6424_WARN_VDD_OTW) && !(tas6424->last_warn & TAS6424_WARN_VDD_OTW))
+		dev_warn(dev, "experienced a global overtemp warning\n");
+
+	if ((reg & TAS6424_WARN_VDD_OTW_CH1) && !(tas6424->last_warn & TAS6424_WARN_VDD_OTW_CH1))
+		dev_warn(dev, "experienced an overtemp warning on CH1\n");
+
+	if ((reg & TAS6424_WARN_VDD_OTW_CH2) && !(tas6424->last_warn & TAS6424_WARN_VDD_OTW_CH2))
+		dev_warn(dev, "experienced an overtemp warning on CH2\n");
+
+	if ((reg & TAS6424_WARN_VDD_OTW_CH3) && !(tas6424->last_warn & TAS6424_WARN_VDD_OTW_CH3))
+		dev_warn(dev, "experienced an overtemp warning on CH3\n");
+
+	if ((reg & TAS6424_WARN_VDD_OTW_CH4) && !(tas6424->last_warn & TAS6424_WARN_VDD_OTW_CH4))
+		dev_warn(dev, "experienced an overtemp warning on CH4\n");
+
+	/* Store current warn value so we can detect any changes next time */
+	tas6424->last_warn = reg;
+
+	/* Clear any faults by toggling the CLEAR_FAULT control bit */
+	ret = regmap_write_bits(tas6424->regmap, TAS6424_MISC_CTRL3,
+				TAS6424_CLEAR_FAULT, TAS6424_CLEAR_FAULT);
+	if (ret < 0)
+		dev_err(dev, "failed to write MISC_CTRL3 register: %d\n", ret);
+
+	ret = regmap_write_bits(tas6424->regmap, TAS6424_MISC_CTRL3,
+				TAS6424_CLEAR_FAULT, 0);
+	if (ret < 0)
+		dev_err(dev, "failed to write MISC_CTRL3 register: %d\n", ret);
+
+out:
+	/* Schedule the next fault check at the specified interval */
+	schedule_delayed_work(&tas6424->fault_check_work,
+			      msecs_to_jiffies(TAS6424_FAULT_CHECK_INTERVAL));
+}
+
+static const struct reg_default tas6424_reg_defaults[] = {
+	{ TAS6424_MODE_CTRL,		0x00 },
+	{ TAS6424_MISC_CTRL1,		0x32 },
+	{ TAS6424_MISC_CTRL2,		0x62 },
+	{ TAS6424_SAP_CTRL,		0x04 },
+	{ TAS6424_CH_STATE_CTRL,	0x55 },
+	{ TAS6424_CH1_VOL_CTRL,		0xcf },
+	{ TAS6424_CH2_VOL_CTRL,		0xcf },
+	{ TAS6424_CH3_VOL_CTRL,		0xcf },
+	{ TAS6424_CH4_VOL_CTRL,		0xcf },
+	{ TAS6424_DC_DIAG_CTRL1,	0x00 },
+	{ TAS6424_DC_DIAG_CTRL2,	0x11 },
+	{ TAS6424_DC_DIAG_CTRL3,	0x11 },
+	{ TAS6424_PIN_CTRL,		0xff },
+	{ TAS6424_AC_DIAG_CTRL1,	0x00 },
+	{ TAS6424_MISC_CTRL3,		0x00 },
+	{ TAS6424_CLIP_CTRL,		0x01 },
+	{ TAS6424_CLIP_WINDOW,		0x14 },
+	{ TAS6424_CLIP_WARN,		0x00 },
+	{ TAS6424_CBC_STAT,		0x00 },
+	{ TAS6424_MISC_CTRL4,		0x40 },
+};
+
+static bool tas6424_is_writable_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case TAS6424_MODE_CTRL:
+	case TAS6424_MISC_CTRL1:
+	case TAS6424_MISC_CTRL2:
+	case TAS6424_SAP_CTRL:
+	case TAS6424_CH_STATE_CTRL:
+	case TAS6424_CH1_VOL_CTRL:
+	case TAS6424_CH2_VOL_CTRL:
+	case TAS6424_CH3_VOL_CTRL:
+	case TAS6424_CH4_VOL_CTRL:
+	case TAS6424_DC_DIAG_CTRL1:
+	case TAS6424_DC_DIAG_CTRL2:
+	case TAS6424_DC_DIAG_CTRL3:
+	case TAS6424_PIN_CTRL:
+	case TAS6424_AC_DIAG_CTRL1:
+	case TAS6424_MISC_CTRL3:
+	case TAS6424_CLIP_CTRL:
+	case TAS6424_CLIP_WINDOW:
+	case TAS6424_CLIP_WARN:
+	case TAS6424_CBC_STAT:
+	case TAS6424_MISC_CTRL4:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool tas6424_is_volatile_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case TAS6424_DC_LOAD_DIAG_REP12:
+	case TAS6424_DC_LOAD_DIAG_REP34:
+	case TAS6424_DC_LOAD_DIAG_REPLO:
+	case TAS6424_CHANNEL_STATE:
+	case TAS6424_CHANNEL_FAULT:
+	case TAS6424_GLOB_FAULT1:
+	case TAS6424_GLOB_FAULT2:
+	case TAS6424_WARN:
+	case TAS6424_AC_LOAD_DIAG_REP1:
+	case TAS6424_AC_LOAD_DIAG_REP2:
+	case TAS6424_AC_LOAD_DIAG_REP3:
+	case TAS6424_AC_LOAD_DIAG_REP4:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static const struct regmap_config tas6424_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+
+	.writeable_reg = tas6424_is_writable_reg,
+	.volatile_reg = tas6424_is_volatile_reg,
+
+	.max_register = TAS6424_MAX,
+	.reg_defaults = tas6424_reg_defaults,
+	.num_reg_defaults = ARRAY_SIZE(tas6424_reg_defaults),
+	.cache_type = REGCACHE_RBTREE,
+};
+
+#if IS_ENABLED(CONFIG_OF)
+static const struct of_device_id tas6424_of_ids[] = {
+	{ .compatible = "ti,tas6424", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, tas6424_of_ids);
+#endif
+
+static int tas6424_i2c_probe(struct i2c_client *client,
+			     const struct i2c_device_id *id)
+{
+	struct device *dev = &client->dev;
+	struct tas6424_data *tas6424;
+	int ret;
+	int i;
+
+	tas6424 = devm_kzalloc(dev, sizeof(*tas6424), GFP_KERNEL);
+	if (!tas6424)
+		return -ENOMEM;
+	dev_set_drvdata(dev, tas6424);
+
+	tas6424->dev = dev;
+
+	tas6424->regmap = devm_regmap_init_i2c(client, &tas6424_regmap_config);
+	if (IS_ERR(tas6424->regmap)) {
+		ret = PTR_ERR(tas6424->regmap);
+		dev_err(dev, "unable to allocate register map: %d\n", ret);
+		return ret;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(tas6424->supplies); i++)
+		tas6424->supplies[i].supply = tas6424_supply_names[i];
+	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(tas6424->supplies),
+				      tas6424->supplies);
+	if (ret) {
+		dev_err(dev, "unable to request supplies: %d\n", ret);
+		return ret;
+	}
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(tas6424->supplies),
+				    tas6424->supplies);
+	if (ret) {
+		dev_err(dev, "unable to enable supplies: %d\n", ret);
+		return ret;
+	}
+
+	/* Reset device to establish well-defined startup state */
+	ret = regmap_update_bits(tas6424->regmap, TAS6424_MODE_CTRL,
+				 TAS6424_RESET, TAS6424_RESET);
+	if (ret) {
+		dev_err(dev, "unable to reset device: %d\n", ret);
+		return ret;
+	}
+
+	INIT_DELAYED_WORK(&tas6424->fault_check_work, tas6424_fault_check_work);
+
+	ret = snd_soc_register_codec(dev, &soc_codec_dev_tas6424,
+				     tas6424_dai, ARRAY_SIZE(tas6424_dai));
+	if (ret < 0) {
+		dev_err(dev, "unable to register codec: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int tas6424_i2c_remove(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct tas6424_data *tas6424 = dev_get_drvdata(dev);
+	int ret;
+
+	snd_soc_unregister_codec(dev);
+
+	cancel_delayed_work_sync(&tas6424->fault_check_work);
+
+	ret = regulator_bulk_disable(ARRAY_SIZE(tas6424->supplies),
+				     tas6424->supplies);
+	if (ret < 0) {
+		dev_err(dev, "unable to disable supplies: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct i2c_device_id tas6424_i2c_ids[] = {
+	{ "tas6424", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, tas6424_i2c_ids);
+
+static struct i2c_driver tas6424_i2c_driver = {
+	.driver = {
+		.name = "tas6424",
+		.of_match_table = of_match_ptr(tas6424_of_ids),
+	},
+	.probe = tas6424_i2c_probe,
+	.remove = tas6424_i2c_remove,
+	.id_table = tas6424_i2c_ids,
+};
+module_i2c_driver(tas6424_i2c_driver);
+
+MODULE_AUTHOR("Andreas Dannenberg <dannenberg@ti.com>");
+MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
+MODULE_DESCRIPTION("TAS6424 Audio amplifier driver");
+MODULE_LICENSE("GPL v2");