[PATCH 3/4] ASoC: codecs: Add support for the GPIOs driven amplifier

[Herve Codina]

Some amplifiers driven by GPIOs can be present in the audio path.

In order to be fully integrated in the audio path and to have audio
mixer items available to control those amplifiers, an audio component
is needed.

This support allows to handle those GPIO driven amplifiers as auxiliary
audio devices and so control them using audio mixer controls.

Signed-off-by: Herve Codina <herve.codina@xxxxxxxxxxx>
---
 sound/soc/codecs/Kconfig          |  12 +
 sound/soc/codecs/Makefile         |   2 +
 sound/soc/codecs/audio-gpio-amp.c | 765 ++++++++++++++++++++++++++++++
 3 files changed, 779 insertions(+)
 create mode 100644 sound/soc/codecs/audio-gpio-amp.c

diff --git a/sound/soc/codecs/Kconfig b/sound/soc/codecs/Kconfig
index adb3fb923be3..9c51519d6eea 100644
--- a/sound/soc/codecs/Kconfig
+++ b/sound/soc/codecs/Kconfig
@@ -52,6 +52,7 @@ config SND_SOC_ALL_CODECS
 	imply SND_SOC_AK5558
 	imply SND_SOC_ALC5623
 	imply SND_SOC_ALC5632
+	imply SND_SOC_AUDIO_GPIO_AMP
 	imply SND_SOC_AUDIO_IIO_AUX
 	imply SND_SOC_AW8738
 	imply SND_SOC_AW87390
@@ -648,6 +649,17 @@ config SND_SOC_ALC5632
 	tristate
 	depends on I2C
 
+config SND_SOC_AUDIO_GPIO_AMP
+	tristate "Audio GPIO Amplifier"
+	select GPIOLIB
+	help
+	  Enable support for GPIO amplifier.
+	  This allows to have an amplifier driven by GPIOs in the audio path and
+	  controlled using mixer controls.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called snd-soc-audio-gpio-amp.
+
 config SND_SOC_AUDIO_IIO_AUX
 	tristate "Audio IIO Auxiliary device"
 	depends on IIO
diff --git a/sound/soc/codecs/Makefile b/sound/soc/codecs/Makefile
index 3ddee5298721..e1794a3368ab 100644
--- a/sound/soc/codecs/Makefile
+++ b/sound/soc/codecs/Makefile
@@ -423,6 +423,7 @@ snd-soc-wsa883x-y := wsa883x.o
 snd-soc-wsa884x-y := wsa884x.o
 snd-soc-zl38060-y := zl38060.o
 # Amp
+snd-soc-audio-gpio-amp-y := audio-gpio-amp.o
 snd-soc-max9877-y := max9877.o
 snd-soc-max98504-y := max98504.o
 snd-soc-simple-amplifier-y := simple-amplifier.o
@@ -869,6 +870,7 @@ obj-$(CONFIG_SND_SOC_WSA884X)	+= snd-soc-wsa884x.o
 obj-$(CONFIG_SND_SOC_ZL38060)	+= snd-soc-zl38060.o
 
 # Amp
+obj-$(CONFIG_SND_SOC_AUDIO_GPIO_AMP)	+= snd-soc-audio-gpio-amp.o
 obj-$(CONFIG_SND_SOC_MAX9877)	+= snd-soc-max9877.o
 obj-$(CONFIG_SND_SOC_MAX98504)	+= snd-soc-max98504.o
 obj-$(CONFIG_SND_SOC_SIMPLE_AMPLIFIER)	+= snd-soc-simple-amplifier.o
diff --git a/sound/soc/codecs/audio-gpio-amp.c b/sound/soc/codecs/audio-gpio-amp.c
new file mode 100644
index 000000000000..053501cfa5d6
--- /dev/null
+++ b/sound/soc/codecs/audio-gpio-amp.c
@@ -0,0 +1,765 @@
+// SPDX-License-Identifier: GPL-2.0-only
+//
+// GPIOs controlled amplifier ALSA SoC driver
+//
+// Copyright 2026 CS GROUP France
+//
+// Author: Herve Codina <herve.codina@xxxxxxxxxxx>
+
+#include <linux/bitmap.h>
+#include <linux/gpio/consumer.h>
+#include <linux/minmax.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+#include <linux/sort.h>
+#include <sound/soc.h>
+#include <sound/tlv.h>
+
+struct audio_gpio_single {
+	struct gpio_desc *gpio;
+	bool is_inverted;
+	int kctrl_val;
+	const char *control_name;
+};
+
+struct audio_gpio_point {
+	u32 gpio_val;
+	int gain_db;
+};
+
+struct audio_gpio_points {
+	unsigned int nb_points;
+	struct audio_gpio_point *tab_points;
+};
+
+struct audio_gpio_range {
+	int min_db;
+	int max_db;
+};
+
+struct audio_gpio_labels {
+	unsigned int nb_labels;
+	const char **tab_labels;
+};
+
+enum audio_gpio_mode {
+	AUDIO_GPIO_MODE_NONE,
+	AUDIO_GPIO_MODE_RANGE,
+	AUDIO_GPIO_MODE_LABELS,
+	AUDIO_GPIO_MODE_POINTS,
+};
+
+struct audio_gpio_multi {
+	struct gpio_descs *gpios;
+	bool is_inverted;
+	u32 kctrl_val;
+	u32 kctrl_max;
+	const char *control_name;
+	unsigned int *tlv_array;
+	enum audio_gpio_mode mode;
+	union {
+		struct audio_gpio_range range;
+		struct audio_gpio_points points;
+		struct audio_gpio_labels labels;
+	};
+};
+
+struct audio_gpio_amp {
+	struct audio_gpio_single mute;
+	struct audio_gpio_single bypass;
+	struct audio_gpio_multi gain;
+};
+
+static const struct snd_soc_dapm_widget audio_gpio_amp_dapm_widgets[] = {
+	SND_SOC_DAPM_INPUT("IN"),
+	SND_SOC_DAPM_OUTPUT("OUT"),
+	SND_SOC_DAPM_PGA("PGA", SND_SOC_NOPM, 0, 0, NULL, 0),
+	SND_SOC_DAPM_REGULATOR_SUPPLY("vdd", 0, 0),
+};
+
+static const struct snd_soc_dapm_route audio_gpio_amp_dapm_routes[] = {
+	{ "PGA", NULL, "IN" },
+	{ "PGA", NULL, "vdd" },
+	{ "OUT", NULL, "PGA" },
+};
+
+static int audio_gpio_amp_single_kctrl_write_gpio(struct audio_gpio_single *single,
+						  int kctrl_val)
+{
+	int gpio_val;
+
+	gpio_val = single->is_inverted ? !kctrl_val : kctrl_val;
+
+	return gpiod_set_value_cansleep(single->gpio, gpio_val);
+}
+
+static int audio_gpio_amp_single_kctrl_info(struct snd_kcontrol *kcontrol,
+					    struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->count = 1;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = 1;
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
+	return 0;
+}
+
+static int audio_gpio_amp_single_kctrl_get(struct snd_kcontrol *kcontrol,
+					   struct snd_ctl_elem_value *ucontrol)
+{
+	struct audio_gpio_single *single = (struct audio_gpio_single *)kcontrol->private_value;
+
+	ucontrol->value.integer.value[0] = single->kctrl_val;
+
+	return 0;
+}
+
+static int audio_gpio_amp_single_kctrl_put(struct snd_kcontrol *kcontrol,
+					   struct snd_ctl_elem_value *ucontrol)
+{
+	struct audio_gpio_single *single = (struct audio_gpio_single *)kcontrol->private_value;
+	int kctrl_val;
+	int err;
+
+	kctrl_val = ucontrol->value.integer.value[0];
+
+	if (kctrl_val == single->kctrl_val)
+		return 0;
+
+	err = audio_gpio_amp_single_kctrl_write_gpio(single, kctrl_val);
+	if (err)
+		return err;
+
+	single->kctrl_val = kctrl_val;
+
+	return 1; /* The value changed */
+}
+
+static int audio_gpio_amp_single_add_kcontrol(struct snd_soc_component *component,
+					      struct audio_gpio_single *single)
+{
+	struct snd_kcontrol_new control = {
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = single->control_name,
+		.info = audio_gpio_amp_single_kctrl_info,
+		.get = audio_gpio_amp_single_kctrl_get,
+		.put = audio_gpio_amp_single_kctrl_put,
+		.private_value = (unsigned long)single,
+	};
+	int ret;
+
+	/* Be consistent between single->kctrl_val value and the GPIO value */
+	ret = audio_gpio_amp_single_kctrl_write_gpio(single, single->kctrl_val);
+	if (ret)
+		return ret;
+
+	return snd_soc_add_component_controls(component, &control, 1);
+}
+
+static int audio_gpio_amp_multi_kctrl_write_gpios(struct audio_gpio_multi *multi,
+						  u32 kctrl_val)
+{
+	DECLARE_BITMAP(bm, 32);
+	u32 gpio_val;
+
+	if (multi->mode == AUDIO_GPIO_MODE_POINTS) {
+		if (kctrl_val >= multi->points.nb_points)
+			return -EINVAL;
+
+		gpio_val = multi->points.tab_points[kctrl_val].gpio_val;
+	} else {
+		if (kctrl_val > multi->kctrl_max)
+			return -EINVAL;
+
+		gpio_val = multi->is_inverted ?
+				multi->kctrl_max - kctrl_val :
+				kctrl_val;
+	}
+
+	bitmap_from_arr32(bm, &gpio_val, multi->gpios->ndescs);
+
+	return gpiod_multi_set_value_cansleep(multi->gpios, bm);
+}
+
+static int audio_gpio_amp_multi_kctrl_int_info(struct snd_kcontrol *kcontrol,
+					       struct snd_ctl_elem_info *uinfo)
+{
+	struct audio_gpio_multi *multi = (struct audio_gpio_multi *)kcontrol->private_value;
+
+	uinfo->count = 1;
+	uinfo->value.integer.min = 0;
+	if (multi->mode == AUDIO_GPIO_MODE_POINTS)
+		uinfo->value.integer.max = multi->points.nb_points - 1;
+	else
+		uinfo->value.integer.max = multi->kctrl_max;
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	return 0;
+}
+
+static int audio_gpio_amp_multi_kctrl_int_get(struct snd_kcontrol *kcontrol,
+					      struct snd_ctl_elem_value *ucontrol)
+{
+	struct audio_gpio_multi *multi = (struct audio_gpio_multi *)kcontrol->private_value;
+
+	ucontrol->value.integer.value[0] = multi->kctrl_val;
+	return 0;
+}
+
+static int audio_gpio_amp_multi_kctrl_int_put(struct snd_kcontrol *kcontrol,
+					      struct snd_ctl_elem_value *ucontrol)
+{
+	struct audio_gpio_multi *multi = (struct audio_gpio_multi *)kcontrol->private_value;
+	u32 kctrl_val;
+	int ret;
+
+	kctrl_val = ucontrol->value.integer.value[0];
+
+	if (kctrl_val == multi->kctrl_val)
+		return 0;
+
+	ret = audio_gpio_amp_multi_kctrl_write_gpios(multi, kctrl_val);
+	if (ret)
+		return ret;
+
+	multi->kctrl_val = kctrl_val;
+
+	return 1; /* The value changed */
+}
+
+static int audio_gpio_amp_multi_kctrl_enum_info(struct snd_kcontrol *kcontrol,
+						struct snd_ctl_elem_info *uinfo)
+{
+	struct audio_gpio_multi *multi = (struct audio_gpio_multi *)kcontrol->private_value;
+
+	return snd_ctl_enum_info(uinfo, 1, multi->labels.nb_labels,
+				 multi->labels.tab_labels);
+}
+
+static int audio_gpio_amp_multi_kctrl_enum_get(struct snd_kcontrol *kcontrol,
+					       struct snd_ctl_elem_value *ucontrol)
+{
+	struct audio_gpio_multi *multi = (struct audio_gpio_multi *)kcontrol->private_value;
+
+	ucontrol->value.enumerated.item[0] = multi->kctrl_val;
+	return 0;
+}
+
+static int audio_gpio_amp_multi_kctrl_enum_put(struct snd_kcontrol *kcontrol,
+					       struct snd_ctl_elem_value *ucontrol)
+{
+	struct audio_gpio_multi *multi = (struct audio_gpio_multi *)kcontrol->private_value;
+	u32 kctrl_val;
+	int ret;
+
+	kctrl_val = ucontrol->value.enumerated.item[0];
+
+	if (kctrl_val == multi->kctrl_val)
+		return 0;
+
+	ret = audio_gpio_amp_multi_kctrl_write_gpios(multi, kctrl_val);
+	if (ret)
+		return ret;
+
+	multi->kctrl_val = kctrl_val;
+
+	return 1; /* The value changed */
+}
+
+static int *audio_gpio_amp_alloc_tlv_range(const struct audio_gpio_range *range)
+{
+	DECLARE_TLV_DB_MINMAX(tmp, range->min_db, range->max_db);
+
+	return kmemdup(tmp, sizeof(tmp), GFP_KERNEL);
+}
+
+static int *audio_gpio_amp_alloc_tlv_points(struct audio_gpio_points *points)
+{
+	unsigned int *tlv;
+	unsigned int *t;
+	unsigned int i;
+
+	tlv = kzalloc_objs(*tlv, 2 + points->nb_points * 6, GFP_KERNEL);
+	if (!tlv)
+		return NULL;
+
+	t = tlv;
+
+	/* Fill first TLV */
+	*t++ = SNDRV_CTL_TLVT_DB_RANGE; /* Tag */
+	*t++ = points->nb_points * 6 * sizeof(*tlv); /* Len */
+	/* points are sorted from lower to higher value */
+	for (i = 0; i < points->nb_points; i++) {
+		/* Fill item i */
+		*t++ = i;  /* min */
+		*t++ = i;  /* max */
+		*t++ = SNDRV_CTL_TLVT_DB_MINMAX; /* Tag */
+		*t++ = 2 * sizeof(*tlv); /* Len */
+		*t++ = points->tab_points[i].gain_db; /* min_dB */
+		*t++ = points->tab_points[i].gain_db; /* max_dB */
+	}
+
+	return tlv;
+}
+
+static int audio_gpio_amp_multi_add_kcontrol(struct snd_soc_component *component,
+					     struct audio_gpio_multi *multi)
+{
+	struct snd_kcontrol_new control = {
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = multi->control_name,
+		.info = audio_gpio_amp_multi_kctrl_int_info,
+		.get = audio_gpio_amp_multi_kctrl_int_get,
+		.put = audio_gpio_amp_multi_kctrl_int_put,
+		.private_value = (unsigned long)multi,
+	};
+	int ret;
+
+	switch (multi->mode) {
+	case AUDIO_GPIO_MODE_RANGE:
+		multi->tlv_array = audio_gpio_amp_alloc_tlv_range(&multi->range);
+		if (!multi->tlv_array)
+			return -ENOMEM;
+
+		control.access = SNDRV_CTL_ELEM_ACCESS_TLV_READ |
+				 SNDRV_CTL_ELEM_ACCESS_READWRITE;
+		control.tlv.p = multi->tlv_array;
+		break;
+
+	case AUDIO_GPIO_MODE_POINTS:
+		multi->tlv_array = audio_gpio_amp_alloc_tlv_points(&multi->points);
+		if (!multi->tlv_array)
+			return -ENOMEM;
+
+		control.access = SNDRV_CTL_ELEM_ACCESS_TLV_READ |
+				 SNDRV_CTL_ELEM_ACCESS_READWRITE;
+		control.tlv.p = multi->tlv_array;
+		break;
+
+	case AUDIO_GPIO_MODE_LABELS:
+		/* Use enumerated values */
+		control.info = audio_gpio_amp_multi_kctrl_enum_info;
+		control.get = audio_gpio_amp_multi_kctrl_enum_get;
+		control.put = audio_gpio_amp_multi_kctrl_enum_put;
+		break;
+
+	case AUDIO_GPIO_MODE_NONE:
+		/* Already set control configuration is enough */
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	/* Be consistent between multi->kctrl_val value and the GPIOs value */
+	ret = audio_gpio_amp_multi_kctrl_write_gpios(multi, multi->kctrl_val);
+	if (ret)
+		return ret;
+
+	return snd_soc_add_component_controls(component, &control, 1);
+}
+
+struct audio_gpio_amp_supply {
+	const char *prop_name;
+	const struct snd_soc_dapm_widget dapm_widget;
+	const struct snd_soc_dapm_route dapm_route;
+};
+
+static const struct audio_gpio_amp_supply audio_gpio_amp_supplies[] = {
+	{
+		.prop_name = "vddio-supply",
+		.dapm_widget = SND_SOC_DAPM_REGULATOR_SUPPLY("vddio", 0, 0),
+		.dapm_route = { "PGA", NULL, "vddio" },
+	}, {
+		.prop_name = "vdda1-supply",
+		.dapm_widget = SND_SOC_DAPM_REGULATOR_SUPPLY("vdda1", 0, 0),
+		.dapm_route = { "PGA", NULL, "vdda1" },
+	}, {
+		.prop_name = "vdda2-supply",
+		.dapm_widget = SND_SOC_DAPM_REGULATOR_SUPPLY("vdda2", 0, 0),
+		.dapm_route = { "PGA", NULL, "vdda2" },
+	},
+	{ /* End of list */}
+};
+
+static int audio_gpio_amp_add_power_supplies(struct snd_soc_component *component)
+{
+	struct snd_soc_dapm_context *dapm = snd_soc_component_to_dapm(component);
+	const struct audio_gpio_amp_supply *supply;
+	struct device *dev = component->dev;
+	int ret;
+
+	supply = audio_gpio_amp_supplies;
+	do {
+		if (!of_property_present(dev->of_node, supply->prop_name))
+			continue;
+
+		ret = snd_soc_dapm_new_controls(dapm, &supply->dapm_widget, 1);
+		if (ret) {
+			dev_err(dev, "Failed to add control for '%s' (%d)\n",
+				supply->prop_name, ret);
+			return ret;
+		}
+		ret = snd_soc_dapm_add_routes(dapm, &supply->dapm_route, 1);
+		if (ret) {
+			dev_err(dev, "Failed to add route for '%s' (%d)\n",
+				supply->prop_name, ret);
+			return ret;
+		}
+	} while ((++supply)->prop_name);
+
+	return 0;
+}
+
+static int audio_gpio_amp_component_probe(struct snd_soc_component *component)
+{
+	struct audio_gpio_amp *gpio_amp = snd_soc_component_get_drvdata(component);
+	int ret;
+
+	ret = audio_gpio_amp_add_power_supplies(component);
+	if (ret)
+		return ret;
+
+	if (gpio_amp->mute.gpio) {
+		/*
+		 * The name of the GPIO used is mute. According to this name, 1
+		 * means muted and 0 means un-muted.
+		 *
+		 * An inversion is expected by ALSA. Indeed from ALSA point of
+		 * view, 1 means 'on' (un-muted) and 0 means 'off' (muted).
+		 */
+		gpio_amp->mute.is_inverted = true;
+		gpio_amp->mute.kctrl_val = 1; /* Un-muted */
+		ret = audio_gpio_amp_single_add_kcontrol(component, &gpio_amp->mute);
+		if (ret)
+			return ret;
+	}
+
+	if (gpio_amp->bypass.gpio) {
+		ret = audio_gpio_amp_single_add_kcontrol(component, &gpio_amp->bypass);
+		if (ret)
+			return ret;
+	}
+
+	if (gpio_amp->gain.gpios) {
+		ret = audio_gpio_amp_multi_add_kcontrol(component, &gpio_amp->gain);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static void audio_gpio_amp_component_remove(struct snd_soc_component *component)
+{
+	struct audio_gpio_amp *gpio_amp = snd_soc_component_get_drvdata(component);
+
+	kfree(gpio_amp->gain.tlv_array);
+	gpio_amp->gain.tlv_array = NULL;
+}
+
+static const struct snd_soc_component_driver audio_gpio_amp_component_driver = {
+	.dapm_widgets		= audio_gpio_amp_dapm_widgets,
+	.num_dapm_widgets	= ARRAY_SIZE(audio_gpio_amp_dapm_widgets),
+	.dapm_routes		= audio_gpio_amp_dapm_routes,
+	.num_dapm_routes	= ARRAY_SIZE(audio_gpio_amp_dapm_routes),
+	.probe = audio_gpio_amp_component_probe,
+	.remove = audio_gpio_amp_component_remove,
+};
+
+static int audio_gpio_amp_parse_labels(struct device *dev,
+				       struct audio_gpio_multi *multi,
+				       const char *labels_property)
+{
+	struct audio_gpio_labels *labels = &multi->labels;
+	struct device_node *np = dev->of_node;
+	int ret;
+
+	ret = of_property_count_strings(np, labels_property);
+	if (ret <= 0)
+		return ret;
+
+	labels->nb_labels = ret;
+	if (labels->nb_labels > (1 << multi->gpios->ndescs))
+		return -EINVAL;
+
+	labels->tab_labels = devm_kcalloc(dev, labels->nb_labels,
+					  sizeof(*labels->tab_labels),
+					  GFP_KERNEL);
+	if (!labels->tab_labels)
+		return -ENOMEM;
+
+	multi->kctrl_max = labels->nb_labels - 1;
+	multi->kctrl_val = 0;
+	multi->is_inverted = false;
+
+	return of_property_read_string_array(np, labels_property, labels->tab_labels,
+					     labels->nb_labels);
+}
+
+static int audio_gpio_amp_parse_range(struct device *dev,
+				      struct audio_gpio_multi *multi,
+				      const char *range_property)
+{
+	struct audio_gpio_range *range = &multi->range;
+	struct device_node *np = dev->of_node;
+	s32 tmp;
+	int ret;
+
+	ret = of_property_read_s32_index(np, range_property, 0, &tmp);
+	if (ret)
+		return ret;
+	range->min_db = tmp;
+
+	ret = of_property_read_s32_index(np, range_property, 1, &tmp);
+	if (ret)
+		return ret;
+	range->max_db = tmp;
+
+	multi->kctrl_max = (1 << multi->gpios->ndescs) - 1;
+	multi->kctrl_val = 0;
+	multi->is_inverted = false;
+
+	if (range->min_db > range->max_db) {
+		/* Invert range */
+		swap(range->min_db, range->max_db);
+		multi->is_inverted = 1;
+
+		/*
+		 * When the range is inverted, choose to have the initial
+		 * amplification set to max_db (i.e. all GPIOs inactive).
+		 */
+		multi->kctrl_val = multi->kctrl_max;
+	}
+
+	return 0;
+}
+
+static int audio_gpio_amp_cmp_points(const void *a, const void *b)
+{
+	const struct audio_gpio_point *a_point = a;
+	const struct audio_gpio_point *b_point = b;
+
+	return a_point->gain_db - b_point->gain_db;
+}
+
+static int audio_gpio_amp_parse_points(struct device *dev,
+				       struct audio_gpio_multi *multi,
+				       const char *points_property)
+{
+	struct audio_gpio_points *points = &multi->points;
+	struct device_node *np = dev->of_node;
+	struct audio_gpio_point first_point;
+	unsigned int max_gpio_val;
+	unsigned int i;
+	int ret;
+	u32 u;
+	s32 s;
+
+	max_gpio_val = (1 << multi->gpios->ndescs) - 1;
+
+	ret = of_property_count_u32_elems(np, points_property);
+	if (ret <= 0)
+		return ret;
+
+	if (ret % 2)
+		return -EINVAL;
+
+	points->nb_points = ret / 2;
+	if (points->nb_points > max_gpio_val + 1)
+		return -EINVAL;
+
+	points->tab_points = devm_kcalloc(dev, points->nb_points,
+					  sizeof(*points->tab_points),
+					  GFP_KERNEL);
+	if (!points->tab_points)
+		return -ENOMEM;
+
+	for (i = 0; i < points->nb_points; i++) {
+		/* Gpio value */
+		ret = of_property_read_u32_index(np, points_property,
+						 i * 2, &u);
+		if (ret)
+			return ret;
+		if (u > max_gpio_val)
+			return -EINVAL;
+
+		points->tab_points[i].gpio_val = u;
+
+		/* Gain value */
+		ret = of_property_read_s32_index(np, points_property,
+						 i * 2 + 1, &s);
+		if (ret)
+			return ret;
+
+		points->tab_points[i].gain_db = s;
+	}
+
+	first_point = points->tab_points[0];
+
+	/* Sort the tab_point array by gain_db value */
+	sort(points->tab_points, points->nb_points, sizeof(*points->tab_points),
+	     audio_gpio_amp_cmp_points, NULL);
+
+	multi->kctrl_max = points->nb_points - 1;
+	multi->is_inverted = false;
+
+	/*
+	 * multi->kctrl_val is the index in tab_points.
+	 *
+	 * Choose to have the initial amplification value set to the first item
+	 * available in the tab_points array before sorting.
+	 *
+	 * This first point before sorting has been identified. Search for it in
+	 * the sorted array in order to set the multi->kctrl_val initial value.
+	 */
+	for (i = 0; i < points->nb_points; i++) {
+		if (points->tab_points[i].gpio_val == first_point.gpio_val &&
+		    points->tab_points[i].gain_db == first_point.gain_db) {
+			multi->kctrl_val = i;
+			break;
+		}
+	}
+
+	return 0;
+}
+
+static int audio_gpio_amp_parse_multi_gpio(struct device *dev,
+					   struct audio_gpio_multi *multi,
+					   const char *gpios_property,
+					   const char *range_property,
+					   const char *points_property,
+					   const char *labels_property)
+{
+	struct device_node *np = dev->of_node;
+	int ret;
+
+	/* Start with the value 0 (GPIO inactive). Can be changed later */
+	multi->is_inverted = false;
+	multi->kctrl_val = 0;
+	multi->gpios = devm_gpiod_get_array_optional(dev, gpios_property, GPIOD_OUT_LOW);
+	if (IS_ERR(multi->gpios))
+		return dev_err_probe(dev, PTR_ERR(multi->gpios),
+				     "Failed to get '%s' gpios\n",
+				     gpios_property);
+	if (!multi->gpios)
+		return 0;
+
+	if (multi->gpios->ndescs > 32)
+		return dev_err_probe(dev, -EINVAL,
+				     "Number of '%s' gpios limited to 32\n",
+				     labels_property);
+
+	/* Set default value for the kctrl_max. Can be changed later */
+	multi->kctrl_max = (1 << multi->gpios->ndescs) - 1;
+
+	multi->mode = AUDIO_GPIO_MODE_NONE;
+	if (of_property_present(np, points_property)) {
+		ret = audio_gpio_amp_parse_points(dev, multi, points_property);
+		if (ret < 0)
+			return dev_err_probe(dev, ret, "Failed to parse '%s'\n",
+					     points_property);
+		multi->mode = AUDIO_GPIO_MODE_POINTS;
+
+	} else if (of_property_present(np, range_property)) {
+		ret = audio_gpio_amp_parse_range(dev, multi, range_property);
+		if (ret < 0)
+			return dev_err_probe(dev, ret, "Failed to parse '%s'\n",
+					     range_property);
+		multi->mode = AUDIO_GPIO_MODE_RANGE;
+
+	} else if (of_property_present(np, labels_property)) {
+		ret = audio_gpio_amp_parse_labels(dev, multi, labels_property);
+		if (ret < 0)
+			return dev_err_probe(dev, ret, "Failed to parse '%s'\n",
+					     labels_property);
+
+		multi->mode = AUDIO_GPIO_MODE_LABELS;
+	}
+
+	return 0;
+}
+
+static int audio_gpio_amp_parse_single_gpio(struct device *dev,
+					    struct audio_gpio_single *single,
+					    const char *gpio_property)
+{
+	/* Start with the inactive value */
+	single->is_inverted = false;
+	single->kctrl_val = 0;
+	single->gpio = devm_gpiod_get_optional(dev, gpio_property, GPIOD_OUT_LOW);
+	if (IS_ERR(single->gpio))
+		return dev_err_probe(dev, PTR_ERR(single->gpio),
+				     "Failed to get '%s' gpio\n",
+				     gpio_property);
+	return 0;
+}
+
+static int audio_gpio_amp_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct audio_gpio_amp *gpio_amp;
+	int ret;
+
+	gpio_amp = devm_kzalloc(dev, sizeof(*gpio_amp), GFP_KERNEL);
+	if (!gpio_amp)
+		return -ENOMEM;
+
+	ret = audio_gpio_amp_parse_single_gpio(dev, &gpio_amp->mute, "mute");
+	if (ret)
+		return ret;
+
+	ret = audio_gpio_amp_parse_single_gpio(dev, &gpio_amp->bypass, "bypass");
+	if (ret)
+		return ret;
+
+	ret = audio_gpio_amp_parse_multi_gpio(dev, &gpio_amp->gain, "gain",
+					      "gain-range", "gain-points", "gain-labels");
+	if (ret)
+		return ret;
+
+	/* Set controls name */
+	gpio_amp->gain.control_name = "Volume";
+	gpio_amp->mute.control_name = "Switch";
+	gpio_amp->bypass.control_name = "Bypass Switch";
+
+	if (gpio_amp->gain.mode == AUDIO_GPIO_MODE_LABELS) {
+		/*
+		 * The gain widget control will use enumerated values.
+		 *
+		 * Having just "Voltage" and "Switch" widget names with
+		 * enumerated values and boolean value can confuse ALSA in terms
+		 * of possible values (strings).
+		 *
+		 * Make things clear and avoid the just "Switch" name in that
+		 * case.
+		 */
+		gpio_amp->mute.control_name = "Out Switch";
+	}
+
+	platform_set_drvdata(pdev, gpio_amp);
+
+	return devm_snd_soc_register_component(dev,
+					       &audio_gpio_amp_component_driver,
+					       NULL, 0);
+}
+
+static const struct of_device_id audio_gpio_amp_ids[] = {
+	{ .compatible = "audio-gpio-amp" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, audio_gpio_amp_ids);
+
+static struct platform_driver audio_gpio_amp_driver = {
+	.driver = {
+		.name = "audio-gpio-amp",
+		.of_match_table = of_match_ptr(audio_gpio_amp_ids),
+	},
+	.probe = audio_gpio_amp_probe,
+};
+module_platform_driver(audio_gpio_amp_driver);
+
+MODULE_AUTHOR("Herve Codina <herve.codina@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("ASoC GPIOs controlled amplifier driver");
+MODULE_LICENSE("GPL");
-- 
2.53.0