sound/soc/codecs/max98373.c

// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2017, Maxim Integrated

#include <linux/acpi.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/cdev.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>
#include <linux/gpio.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <sound/tlv.h>
#include "max98373.h"

static int max98373_dac_event(struct snd_soc_dapm_widget *w,
	struct snd_kcontrol *kcontrol, int event)
{
	struct snd_soc_component *component = snd_soc_dapm_to_component(w->dapm);
	struct max98373_priv *max98373 = snd_soc_component_get_drvdata(component);

	switch (event) {
	case SND_SOC_DAPM_POST_PMU:
		regmap_update_bits(max98373->regmap,
			MAX98373_R20FF_GLOBAL_SHDN,
			MAX98373_GLOBAL_EN_MASK, 1);
		usleep_range(30000, 31000);
		break;
	case SND_SOC_DAPM_POST_PMD:
		regmap_update_bits(max98373->regmap,
			MAX98373_R20FF_GLOBAL_SHDN,
			MAX98373_GLOBAL_EN_MASK, 0);
		usleep_range(30000, 31000);
		max98373->tdm_mode = false;
		break;
	default:
		return 0;
	}
	return 0;
}

static const char * const max98373_switch_text[] = {
	"Left", "Right", "LeftRight"};

static const struct soc_enum dai_sel_enum =
	SOC_ENUM_SINGLE(MAX98373_R2029_PCM_TO_SPK_MONO_MIX_1,
		MAX98373_PCM_TO_SPK_MONOMIX_CFG_SHIFT,
		3, max98373_switch_text);

static const struct snd_kcontrol_new max98373_dai_controls =
	SOC_DAPM_ENUM("DAI Sel", dai_sel_enum);

static const struct snd_kcontrol_new max98373_vi_control =
	SOC_DAPM_SINGLE("Switch", MAX98373_R202C_PCM_TX_EN, 0, 1, 0);

static const struct snd_kcontrol_new max98373_spkfb_control =
	SOC_DAPM_SINGLE("Switch", MAX98373_R2043_AMP_EN, 1, 1, 0);

static const struct snd_soc_dapm_widget max98373_dapm_widgets[] = {
SND_SOC_DAPM_DAC_E("Amp Enable", "HiFi Playback",
	MAX98373_R202B_PCM_RX_EN, 0, 0, max98373_dac_event,
	SND_SOC_DAPM_POST_PMU | SND_SOC_DAPM_POST_PMD),
SND_SOC_DAPM_MUX("DAI Sel Mux", SND_SOC_NOPM, 0, 0,
	&max98373_dai_controls),
SND_SOC_DAPM_OUTPUT("BE_OUT"),
SND_SOC_DAPM_AIF_OUT("Voltage Sense", "HiFi Capture", 0,
	MAX98373_R2047_IV_SENSE_ADC_EN, 0, 0),
SND_SOC_DAPM_AIF_OUT("Current Sense", "HiFi Capture", 0,
	MAX98373_R2047_IV_SENSE_ADC_EN, 1, 0),
SND_SOC_DAPM_AIF_OUT("Speaker FB Sense", "HiFi Capture", 0,
	SND_SOC_NOPM, 0, 0),
SND_SOC_DAPM_SWITCH("VI Sense", SND_SOC_NOPM, 0, 0,
	&max98373_vi_control),
SND_SOC_DAPM_SWITCH("SpkFB Sense", SND_SOC_NOPM, 0, 0,
	&max98373_spkfb_control),
SND_SOC_DAPM_SIGGEN("VMON"),
SND_SOC_DAPM_SIGGEN("IMON"),
SND_SOC_DAPM_SIGGEN("FBMON"),
};

static DECLARE_TLV_DB_SCALE(max98373_digital_tlv, -6350, 50, 1);
static const DECLARE_TLV_DB_RANGE(max98373_spk_tlv,
	0, 8, TLV_DB_SCALE_ITEM(0, 50, 0),
	9, 10, TLV_DB_SCALE_ITEM(500, 100, 0),
);
static const DECLARE_TLV_DB_RANGE(max98373_spkgain_max_tlv,
	0, 9, TLV_DB_SCALE_ITEM(800, 100, 0),
);
static const DECLARE_TLV_DB_RANGE(max98373_dht_step_size_tlv,
	0, 1, TLV_DB_SCALE_ITEM(25, 25, 0),
	2, 4, TLV_DB_SCALE_ITEM(100, 100, 0),
);
static const DECLARE_TLV_DB_RANGE(max98373_dht_spkgain_min_tlv,
	0, 9, TLV_DB_SCALE_ITEM(800, 100, 0),
);
static const DECLARE_TLV_DB_RANGE(max98373_dht_rotation_point_tlv,
	0, 1, TLV_DB_SCALE_ITEM(-3000, 500, 0),
	2, 4, TLV_DB_SCALE_ITEM(-2200, 200, 0),
	5, 6, TLV_DB_SCALE_ITEM(-1500, 300, 0),
	7, 9, TLV_DB_SCALE_ITEM(-1000, 200, 0),
	10, 13, TLV_DB_SCALE_ITEM(-500, 100, 0),
	14, 15, TLV_DB_SCALE_ITEM(-100, 50, 0),
);
static const DECLARE_TLV_DB_RANGE(max98373_limiter_thresh_tlv,
	0, 15, TLV_DB_SCALE_ITEM(-1500, 100, 0),
);

static const DECLARE_TLV_DB_RANGE(max98373_bde_gain_tlv,
	0, 60, TLV_DB_SCALE_ITEM(-1500, 25, 0),
);

static const char * const max98373_output_voltage_lvl_text[] = {
	"5.43V", "6.09V", "6.83V", "7.67V", "8.60V",
	"9.65V", "10.83V", "12.15V", "13.63V", "15.29V"
};

static SOC_ENUM_SINGLE_DECL(max98373_out_volt_enum,
			    MAX98373_R203E_AMP_PATH_GAIN, 0,
			    max98373_output_voltage_lvl_text);

static const char * const max98373_dht_attack_rate_text[] = {
	"17.5us", "35us", "70us", "140us",
	"280us", "560us", "1120us", "2240us"
};

static SOC_ENUM_SINGLE_DECL(max98373_dht_attack_rate_enum,
			    MAX98373_R20D2_DHT_ATTACK_CFG, 0,
			    max98373_dht_attack_rate_text);

static const char * const max98373_dht_release_rate_text[] = {
	"45ms", "225ms", "450ms", "1150ms",
	"2250ms", "3100ms", "4500ms", "6750ms"
};

static SOC_ENUM_SINGLE_DECL(max98373_dht_release_rate_enum,
			    MAX98373_R20D3_DHT_RELEASE_CFG, 0,
			    max98373_dht_release_rate_text);

static const char * const max98373_limiter_attack_rate_text[] = {
	"10us", "20us", "40us", "80us",
	"160us", "320us", "640us", "1.28ms",
	"2.56ms", "5.12ms", "10.24ms", "20.48ms",
	"40.96ms", "81.92ms", "16.384ms", "32.768ms"
};

static SOC_ENUM_SINGLE_DECL(max98373_limiter_attack_rate_enum,
			    MAX98373_R20E1_LIMITER_ATK_REL_RATES, 4,
			    max98373_limiter_attack_rate_text);

static const char * const max98373_limiter_release_rate_text[] = {
	"40us", "80us", "160us", "320us",
	"640us", "1.28ms", "2.56ms", "5.120ms",
	"10.24ms", "20.48ms", "40.96ms", "81.92ms",
	"163.84ms", "327.68ms", "655.36ms", "1310.72ms"
};

static SOC_ENUM_SINGLE_DECL(max98373_limiter_release_rate_enum,
			    MAX98373_R20E1_LIMITER_ATK_REL_RATES, 0,
			    max98373_limiter_release_rate_text);

static const char * const max98373_ADC_samplerate_text[] = {
	"333kHz", "192kHz", "64kHz", "48kHz"
};

static SOC_ENUM_SINGLE_DECL(max98373_adc_samplerate_enum,
			    MAX98373_R2051_MEAS_ADC_SAMPLING_RATE, 0,
			    max98373_ADC_samplerate_text);

static const struct snd_kcontrol_new max98373_snd_controls[] = {
SOC_SINGLE("Digital Vol Sel Switch", MAX98373_R203F_AMP_DSP_CFG,
	MAX98373_AMP_VOL_SEL_SHIFT, 1, 0),
SOC_SINGLE("Volume Location Switch", MAX98373_R203F_AMP_DSP_CFG,
	MAX98373_AMP_VOL_SEL_SHIFT, 1, 0),
SOC_SINGLE("Ramp Up Switch", MAX98373_R203F_AMP_DSP_CFG,
	MAX98373_AMP_DSP_CFG_RMP_UP_SHIFT, 1, 0),
SOC_SINGLE("Ramp Down Switch", MAX98373_R203F_AMP_DSP_CFG,
	MAX98373_AMP_DSP_CFG_RMP_DN_SHIFT, 1, 0),
SOC_SINGLE("CLK Monitor Switch", MAX98373_R20FE_DEVICE_AUTO_RESTART_CFG,
	MAX98373_CLOCK_MON_SHIFT, 1, 0),
SOC_SINGLE("Dither Switch", MAX98373_R203F_AMP_DSP_CFG,
	MAX98373_AMP_DSP_CFG_DITH_SHIFT, 1, 0),
SOC_SINGLE("DC Blocker Switch", MAX98373_R203F_AMP_DSP_CFG,
	MAX98373_AMP_DSP_CFG_DCBLK_SHIFT, 1, 0),
SOC_SINGLE_TLV("Digital Volume", MAX98373_R203D_AMP_DIG_VOL_CTRL,
	0, 0x7F, 1, max98373_digital_tlv),
SOC_SINGLE_TLV("Speaker Volume", MAX98373_R203E_AMP_PATH_GAIN,
	MAX98373_SPK_DIGI_GAIN_SHIFT, 10, 0, max98373_spk_tlv),
SOC_SINGLE_TLV("FS Max Volume", MAX98373_R203E_AMP_PATH_GAIN,
	MAX98373_FS_GAIN_MAX_SHIFT, 9, 0, max98373_spkgain_max_tlv),
SOC_ENUM("Output Voltage", max98373_out_volt_enum),
/* Dynamic Headroom Tracking */
SOC_SINGLE("DHT Switch", MAX98373_R20D4_DHT_EN,
	MAX98373_DHT_EN_SHIFT, 1, 0),
SOC_SINGLE_TLV("DHT Min Volume", MAX98373_R20D1_DHT_CFG,
	MAX98373_DHT_SPK_GAIN_MIN_SHIFT, 9, 0, max98373_dht_spkgain_min_tlv),
SOC_SINGLE_TLV("DHT Rot Pnt Volume", MAX98373_R20D1_DHT_CFG,
	MAX98373_DHT_ROT_PNT_SHIFT, 15, 1, max98373_dht_rotation_point_tlv),
SOC_SINGLE_TLV("DHT Attack Step Volume", MAX98373_R20D2_DHT_ATTACK_CFG,
	MAX98373_DHT_ATTACK_STEP_SHIFT, 4, 0, max98373_dht_step_size_tlv),
SOC_SINGLE_TLV("DHT Release Step Volume", MAX98373_R20D3_DHT_RELEASE_CFG,
	MAX98373_DHT_RELEASE_STEP_SHIFT, 4, 0, max98373_dht_step_size_tlv),
SOC_ENUM("DHT Attack Rate", max98373_dht_attack_rate_enum),
SOC_ENUM("DHT Release Rate", max98373_dht_release_rate_enum),
/* ADC configuration */
SOC_SINGLE("ADC PVDD CH Switch", MAX98373_R2056_MEAS_ADC_PVDD_CH_EN, 0, 1, 0),
SOC_SINGLE("ADC PVDD FLT Switch", MAX98373_R2052_MEAS_ADC_PVDD_FLT_CFG,
	MAX98373_FLT_EN_SHIFT, 1, 0),
SOC_SINGLE("ADC TEMP FLT Switch", MAX98373_R2053_MEAS_ADC_THERM_FLT_CFG,
	MAX98373_FLT_EN_SHIFT, 1, 0),
SOC_SINGLE("ADC PVDD", MAX98373_R2054_MEAS_ADC_PVDD_CH_READBACK, 0, 0xFF, 0),
SOC_SINGLE("ADC TEMP", MAX98373_R2055_MEAS_ADC_THERM_CH_READBACK, 0, 0xFF, 0),
SOC_SINGLE("ADC PVDD FLT Coeff", MAX98373_R2052_MEAS_ADC_PVDD_FLT_CFG,
	0, 0x3, 0),
SOC_SINGLE("ADC TEMP FLT Coeff", MAX98373_R2053_MEAS_ADC_THERM_FLT_CFG,
	0, 0x3, 0),
SOC_ENUM("ADC SampleRate", max98373_adc_samplerate_enum),
/* Brownout Detection Engine */
SOC_SINGLE("BDE Switch", MAX98373_R20B5_BDE_EN, MAX98373_BDE_EN_SHIFT, 1, 0),
SOC_SINGLE("BDE LVL4 Mute Switch", MAX98373_R20B2_BDE_L4_CFG_2,
	MAX98373_LVL4_MUTE_EN_SHIFT, 1, 0),
SOC_SINGLE("BDE LVL4 Hold Switch", MAX98373_R20B2_BDE_L4_CFG_2,
	MAX98373_LVL4_HOLD_EN_SHIFT, 1, 0),
SOC_SINGLE("BDE LVL1 Thresh", MAX98373_R2097_BDE_L1_THRESH, 0, 0xFF, 0),
SOC_SINGLE("BDE LVL2 Thresh", MAX98373_R2098_BDE_L2_THRESH, 0, 0xFF, 0),
SOC_SINGLE("BDE LVL3 Thresh", MAX98373_R2099_BDE_L3_THRESH, 0, 0xFF, 0),
SOC_SINGLE("BDE LVL4 Thresh", MAX98373_R209A_BDE_L4_THRESH, 0, 0xFF, 0),
SOC_SINGLE("BDE Active Level", MAX98373_R20B6_BDE_CUR_STATE_READBACK, 0, 8, 0),
SOC_SINGLE("BDE Clip Mode Switch", MAX98373_R2092_BDE_CLIPPER_MODE, 0, 1, 0),
SOC_SINGLE("BDE Thresh Hysteresis", MAX98373_R209B_BDE_THRESH_HYST, 0, 0xFF, 0),
SOC_SINGLE("BDE Hold Time", MAX98373_R2090_BDE_LVL_HOLD, 0, 0xFF, 0),
SOC_SINGLE("BDE Attack Rate", MAX98373_R2091_BDE_GAIN_ATK_REL_RATE, 4, 0xF, 0),
SOC_SINGLE("BDE Release Rate", MAX98373_R2091_BDE_GAIN_ATK_REL_RATE, 0, 0xF, 0),
SOC_SINGLE_TLV("BDE LVL1 Clip Thresh Volume", MAX98373_R20A9_BDE_L1_CFG_2,
	0, 0x3C, 1, max98373_bde_gain_tlv),
SOC_SINGLE_TLV("BDE LVL2 Clip Thresh Volume", MAX98373_R20AC_BDE_L2_CFG_2,
	0, 0x3C, 1, max98373_bde_gain_tlv),
SOC_SINGLE_TLV("BDE LVL3 Clip Thresh Volume", MAX98373_R20AF_BDE_L3_CFG_2,
	0, 0x3C, 1, max98373_bde_gain_tlv),
SOC_SINGLE_TLV("BDE LVL4 Clip Thresh Volume", MAX98373_R20B2_BDE_L4_CFG_2,
	0, 0x3C, 1, max98373_bde_gain_tlv),
SOC_SINGLE_TLV("BDE LVL1 Clip Reduction Volume", MAX98373_R20AA_BDE_L1_CFG_3,
	0, 0x3C, 1, max98373_bde_gain_tlv),
SOC_SINGLE_TLV("BDE LVL2 Clip Reduction Volume", MAX98373_R20AD_BDE_L2_CFG_3,
	0, 0x3C, 1, max98373_bde_gain_tlv),
SOC_SINGLE_TLV("BDE LVL3 Clip Reduction Volume", MAX98373_R20B0_BDE_L3_CFG_3,
	0, 0x3C, 1, max98373_bde_gain_tlv),
SOC_SINGLE_TLV("BDE LVL4 Clip Reduction Volume", MAX98373_R20B3_BDE_L4_CFG_3,
	0, 0x3C, 1, max98373_bde_gain_tlv),
SOC_SINGLE_TLV("BDE LVL1 Limiter Thresh Volume", MAX98373_R20A8_BDE_L1_CFG_1,
	0, 0xF, 1, max98373_limiter_thresh_tlv),
SOC_SINGLE_TLV("BDE LVL2 Limiter Thresh Volume", MAX98373_R20AB_BDE_L2_CFG_1,
	0, 0xF, 1, max98373_limiter_thresh_tlv),
SOC_SINGLE_TLV("BDE LVL3 Limiter Thresh Volume", MAX98373_R20AE_BDE_L3_CFG_1,
	0, 0xF, 1, max98373_limiter_thresh_tlv),
SOC_SINGLE_TLV("BDE LVL4 Limiter Thresh Volume", MAX98373_R20B1_BDE_L4_CFG_1,
	0, 0xF, 1, max98373_limiter_thresh_tlv),
/* Limiter */
SOC_SINGLE("Limiter Switch", MAX98373_R20E2_LIMITER_EN,
	MAX98373_LIMITER_EN_SHIFT, 1, 0),
SOC_SINGLE("Limiter Src Switch", MAX98373_R20E0_LIMITER_THRESH_CFG,
	MAX98373_LIMITER_THRESH_SRC_SHIFT, 1, 0),
SOC_SINGLE_TLV("Limiter Thresh Volume", MAX98373_R20E0_LIMITER_THRESH_CFG,
	MAX98373_LIMITER_THRESH_SHIFT, 15, 0, max98373_limiter_thresh_tlv),
SOC_ENUM("Limiter Attack Rate", max98373_limiter_attack_rate_enum),
SOC_ENUM("Limiter Release Rate", max98373_limiter_release_rate_enum),
};

static const struct snd_soc_dapm_route max98373_audio_map[] = {
	/* Plabyack */
	{"DAI Sel Mux", "Left", "Amp Enable"},
	{"DAI Sel Mux", "Right", "Amp Enable"},
	{"DAI Sel Mux", "LeftRight", "Amp Enable"},
	{"BE_OUT", NULL, "DAI Sel Mux"},
	/* Capture */
	{ "VI Sense", "Switch", "VMON" },
	{ "VI Sense", "Switch", "IMON" },
	{ "SpkFB Sense", "Switch", "FBMON" },
	{ "Voltage Sense", NULL, "VI Sense" },
	{ "Current Sense", NULL, "VI Sense" },
	{ "Speaker FB Sense", NULL, "SpkFB Sense" },
};

void max98373_reset(struct max98373_priv *max98373, struct device *dev)
{
	int ret, reg, count;

	/* Software Reset */
	ret = regmap_update_bits(max98373->regmap,
		MAX98373_R2000_SW_RESET,
		MAX98373_SOFT_RESET,
		MAX98373_SOFT_RESET);
	if (ret)
		dev_err(dev, "Reset command failed. (ret:%d)\n", ret);

	count = 0;
	while (count < 3) {
		usleep_range(10000, 11000);
		/* Software Reset Verification */
		ret = regmap_read(max98373->regmap,
			MAX98373_R21FF_REV_ID, &reg);
		if (!ret) {
			dev_info(dev, "Reset completed (retry:%d)\n", count);
			return;
		}
		count++;
	}
	dev_err(dev, "Reset failed. (ret:%d)\n", ret);
}
EXPORT_SYMBOL_GPL(max98373_reset);

static int max98373_probe(struct snd_soc_component *component)
{
	struct max98373_priv *max98373 = snd_soc_component_get_drvdata(component);

	/* Software Reset */
	max98373_reset(max98373, component->dev);

	/* IV default slot configuration */
	regmap_write(max98373->regmap,
		MAX98373_R2020_PCM_TX_HIZ_EN_1,
		0xFF);
	regmap_write(max98373->regmap,
		MAX98373_R2021_PCM_TX_HIZ_EN_2,
		0xFF);
	/* L/R mix configuration */
	regmap_write(max98373->regmap,
		MAX98373_R2029_PCM_TO_SPK_MONO_MIX_1,
		0x80);
	regmap_write(max98373->regmap,
		MAX98373_R202A_PCM_TO_SPK_MONO_MIX_2,
		0x1);
	/* Enable DC blocker */
	regmap_write(max98373->regmap,
		MAX98373_R203F_AMP_DSP_CFG,
		0x3);
	/* Enable IMON VMON DC blocker */
	regmap_write(max98373->regmap,
		MAX98373_R2046_IV_SENSE_ADC_DSP_CFG,
		0x7);
	/* voltage, current slot configuration */
	regmap_write(max98373->regmap,
		MAX98373_R2022_PCM_TX_SRC_1,
		(max98373->i_slot << MAX98373_PCM_TX_CH_SRC_A_I_SHIFT |
		max98373->v_slot) & 0xFF);
	if (max98373->v_slot < 8)
		regmap_update_bits(max98373->regmap,
			MAX98373_R2020_PCM_TX_HIZ_EN_1,
			1 << max98373->v_slot, 0);
	else
		regmap_update_bits(max98373->regmap,
			MAX98373_R2021_PCM_TX_HIZ_EN_2,
			1 << (max98373->v_slot - 8), 0);

	if (max98373->i_slot < 8)
		regmap_update_bits(max98373->regmap,
			MAX98373_R2020_PCM_TX_HIZ_EN_1,
			1 << max98373->i_slot, 0);
	else
		regmap_update_bits(max98373->regmap,
			MAX98373_R2021_PCM_TX_HIZ_EN_2,
			1 << (max98373->i_slot - 8), 0);

	/* speaker feedback slot configuration */
	regmap_write(max98373->regmap,
		MAX98373_R2023_PCM_TX_SRC_2,
		max98373->spkfb_slot & 0xFF);

	/* Set interleave mode */
	if (max98373->interleave_mode)
		regmap_update_bits(max98373->regmap,
			MAX98373_R2024_PCM_DATA_FMT_CFG,
			MAX98373_PCM_TX_CH_INTERLEAVE_MASK,
			MAX98373_PCM_TX_CH_INTERLEAVE_MASK);

	/* Speaker enable */
	regmap_update_bits(max98373->regmap,
		MAX98373_R2043_AMP_EN,
		MAX98373_SPK_EN_MASK, 1);

	return 0;
}

const struct snd_soc_component_driver soc_codec_dev_max98373 = {
	.probe			= max98373_probe,
	.controls		= max98373_snd_controls,
	.num_controls		= ARRAY_SIZE(max98373_snd_controls),
	.dapm_widgets		= max98373_dapm_widgets,
	.num_dapm_widgets	= ARRAY_SIZE(max98373_dapm_widgets),
	.dapm_routes		= max98373_audio_map,
	.num_dapm_routes	= ARRAY_SIZE(max98373_audio_map),
	.use_pmdown_time	= 1,
	.endianness		= 1,
	.non_legacy_dai_naming	= 1,
};
EXPORT_SYMBOL_GPL(soc_codec_dev_max98373);

const struct snd_soc_component_driver soc_codec_dev_max98373_sdw = {
	.probe			= NULL,
	.controls		= max98373_snd_controls,
	.num_controls		= ARRAY_SIZE(max98373_snd_controls),
	.dapm_widgets		= max98373_dapm_widgets,
	.num_dapm_widgets	= ARRAY_SIZE(max98373_dapm_widgets),
	.dapm_routes		= max98373_audio_map,
	.num_dapm_routes	= ARRAY_SIZE(max98373_audio_map),
	.use_pmdown_time	= 1,
	.endianness		= 1,
	.non_legacy_dai_naming	= 1,
};
EXPORT_SYMBOL_GPL(soc_codec_dev_max98373_sdw);

void max98373_slot_config(struct device *dev,
			  struct max98373_priv *max98373)
{
	int value;

	if (!device_property_read_u32(dev, "maxim,vmon-slot-no", &value))
		max98373->v_slot = value & 0xF;
	else
		max98373->v_slot = 0;

	if (!device_property_read_u32(dev, "maxim,imon-slot-no", &value))
		max98373->i_slot = value & 0xF;
	else
		max98373->i_slot = 1;
	if (dev->of_node) {
		max98373->reset_gpio = of_get_named_gpio(dev->of_node,
						"maxim,reset-gpio", 0);
		if (!gpio_is_valid(max98373->reset_gpio)) {
			dev_err(dev, "Looking up %s property in node %s failed %d\n",
				"maxim,reset-gpio", dev->of_node->full_name,
				max98373->reset_gpio);
		} else {
			dev_dbg(dev, "maxim,reset-gpio=%d",
				max98373->reset_gpio);
		}
	} else {
		/* this makes reset_gpio as invalid */
		max98373->reset_gpio = -1;
	}

	if (!device_property_read_u32(dev, "maxim,spkfb-slot-no", &value))
		max98373->spkfb_slot = value & 0xF;
	else
		max98373->spkfb_slot = 2;
}
EXPORT_SYMBOL_GPL(max98373_slot_config);

MODULE_DESCRIPTION("ALSA SoC MAX98373 driver");
MODULE_AUTHOR("Ryan Lee <ryans.lee@maximintegrated.com>");
MODULE_LICENSE("GPL");