ASoC: nau8315: add codec driver

diff --git a/Documentation/devicetree/bindings/sound/nau8315.txt b/Documentation/devicetree/bindings/sound/nau8315.txt
new file mode 100644
index 000000000000..6eaec46f384c
--- /dev/null
+++ b/Documentation/devicetree/bindings/sound/nau8315.txt
@@ -0,0 +1,18 @@ 
+Nuvoton NAU8315 Mono Class-D Amplifier
+
+Required properties:
+- compatible   : "nuvoton,nau8315"
+
+Optional properties:
+- enable-gpios : GPIO specifier for the chip's device enable input(EN) pin.
+        If this option is not specified then driver does not manage
+        the pin state (e.g. chip is always on).
+
+Example:
+
+#include <dt-bindings/gpio/gpio.h>
+
+nau8315 {
+	compatible = "nuvoton,nau8315";
+	enable-gpios = <&gpio1 5 GPIO_ACTIVE_HIGH>;
+};
diff --git a/sound/soc/codecs/Kconfig b/sound/soc/codecs/Kconfig
index 5791b7056af6..2b6eceb3573c 100644
--- a/sound/soc/codecs/Kconfig
+++ b/sound/soc/codecs/Kconfig
@@ -130,6 +130,7 @@  config SND_SOC_ALL_CODECS
 	imply SND_SOC_MT6358
 	imply SND_SOC_MT6359
 	imply SND_SOC_MT6660
+	imply SND_SOC_NAU8315
 	imply SND_SOC_NAU8540
 	imply SND_SOC_NAU8810
 	imply SND_SOC_NAU8822
@@ -1760,6 +1761,10 @@  config SND_SOC_MT6660
 	  Select N if you don't have MT6660 on board.
 	  Select M to build this as module.
 
+config SND_SOC_NAU8315
+	tristate "Nuvoton Technology Corporation NAU8315 CODEC"
+	depends on GPIOLIB
+
 config SND_SOC_NAU8540
        tristate "Nuvoton Technology Corporation NAU85L40 CODEC"
        depends on I2C
diff --git a/sound/soc/codecs/Makefile b/sound/soc/codecs/Makefile
index 11ce98c25d6c..144d9256d4d5 100644
--- a/sound/soc/codecs/Makefile
+++ b/sound/soc/codecs/Makefile
@@ -129,6 +129,7 @@  snd-soc-mt6351-objs := mt6351.o
 snd-soc-mt6358-objs := mt6358.o
 snd-soc-mt6359-objs := mt6359.o
 snd-soc-mt6660-objs := mt6660.o
+snd-soc-nau8315-objs := nau8315.o
 snd-soc-nau8540-objs := nau8540.o
 snd-soc-nau8810-objs := nau8810.o
 snd-soc-nau8822-objs := nau8822.o
@@ -438,6 +439,7 @@  obj-$(CONFIG_SND_SOC_MT6351)	+= snd-soc-mt6351.o
 obj-$(CONFIG_SND_SOC_MT6358)	+= snd-soc-mt6358.o
 obj-$(CONFIG_SND_SOC_MT6359)	+= snd-soc-mt6359.o
 obj-$(CONFIG_SND_SOC_MT6660)	+= snd-soc-mt6660.o
+obj-$(CONFIG_SND_SOC_NAU8315)   += snd-soc-nau8315.o
 obj-$(CONFIG_SND_SOC_NAU8540)   += snd-soc-nau8540.o
 obj-$(CONFIG_SND_SOC_NAU8810)   += snd-soc-nau8810.o
 obj-$(CONFIG_SND_SOC_NAU8822)   += snd-soc-nau8822.o
diff --git a/sound/soc/codecs/nau8315.c b/sound/soc/codecs/nau8315.c
new file mode 100644
index 000000000000..e6bc5c0a5036
--- /dev/null
+++ b/sound/soc/codecs/nau8315.c
@@ -0,0 +1,166 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+//
+// nau8315.c  --  NAU8315 ALSA SoC Audio Amplifier Driver
+//
+// Copyright 2020 Nuvoton Technology Crop.
+//
+// Author: David Lin <ctlin0@nuvoton.com>
+//
+// Based on MAX98357A.c
+
+#include <linux/acpi.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <sound/pcm.h>
+#include <sound/soc.h>
+#include <sound/soc-dai.h>
+#include <sound/soc-dapm.h>
+
+struct nau8315_priv {
+	struct gpio_desc *enable;
+	int enpin_switch;
+};
+
+static int nau8315_daiops_trigger(struct snd_pcm_substream *substream,
+		int cmd, struct snd_soc_dai *dai)
+{
+	struct snd_soc_component *component = dai->component;
+	struct nau8315_priv *nau8315 =
+		snd_soc_component_get_drvdata(component);
+
+	if (!nau8315->enable)
+		return 0;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		if (nau8315->enpin_switch) {
+			gpiod_set_value(nau8315->enable, 1);
+			dev_dbg(component->dev, "set enable to 1");
+		}
+		break;
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		gpiod_set_value(nau8315->enable, 0);
+		dev_dbg(component->dev, "set enable to 0");
+		break;
+	}
+
+	return 0;
+}
+
+static int nau8315_enpin_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 nau8315_priv *nau8315 =
+		snd_soc_component_get_drvdata(component);
+
+	if (event & SND_SOC_DAPM_POST_PMU)
+		nau8315->enpin_switch = 1;
+	else if (event & SND_SOC_DAPM_POST_PMD)
+		nau8315->enpin_switch = 0;
+
+	return 0;
+}
+
+static const struct snd_soc_dapm_widget nau8315_dapm_widgets[] = {
+	SND_SOC_DAPM_OUTPUT("Speaker"),
+	SND_SOC_DAPM_OUT_DRV_E("EN_Pin", SND_SOC_NOPM, 0, 0, NULL, 0,
+			nau8315_enpin_event,
+			SND_SOC_DAPM_POST_PMU | SND_SOC_DAPM_POST_PMD),
+};
+
+static const struct snd_soc_dapm_route nau8315_dapm_routes[] = {
+	{"EN_Pin", NULL, "HiFi Playback"},
+	{"Speaker", NULL, "EN_Pin"},
+};
+
+static const struct snd_soc_component_driver nau8315_component_driver = {
+	.dapm_widgets		= nau8315_dapm_widgets,
+	.num_dapm_widgets	= ARRAY_SIZE(nau8315_dapm_widgets),
+	.dapm_routes		= nau8315_dapm_routes,
+	.num_dapm_routes	= ARRAY_SIZE(nau8315_dapm_routes),
+	.idle_bias_on		= 1,
+	.use_pmdown_time	= 1,
+	.endianness		= 1,
+	.non_legacy_dai_naming	= 1,
+};
+
+static const struct snd_soc_dai_ops nau8315_dai_ops = {
+	.trigger	= nau8315_daiops_trigger,
+};
+
+#define NAU8315_RATES SNDRV_PCM_RATE_8000_96000
+#define NAU8315_FORMATS (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S24_3LE)
+
+static struct snd_soc_dai_driver nau8315_dai_driver = {
+	.name = "nau8315-hifi",
+	.playback = {
+		.stream_name	= "HiFi Playback",
+		.formats	= NAU8315_FORMATS,
+		.rates		= NAU8315_RATES,
+		.channels_min	= 1,
+		.channels_max	= 2,
+	},
+	.ops    = &nau8315_dai_ops,
+};
+
+static int nau8315_platform_probe(struct platform_device *pdev)
+{
+	struct nau8315_priv *nau8315;
+
+	nau8315 = devm_kzalloc(&pdev->dev, sizeof(*nau8315), GFP_KERNEL);
+	if (!nau8315)
+		return -ENOMEM;
+
+	nau8315->enable = devm_gpiod_get_optional(&pdev->dev,
+				"enable", GPIOD_OUT_LOW);
+	if (IS_ERR(nau8315->enable))
+		return PTR_ERR(nau8315->enable);
+
+	dev_set_drvdata(&pdev->dev, nau8315);
+
+	return devm_snd_soc_register_component(&pdev->dev,
+			&nau8315_component_driver,
+			&nau8315_dai_driver, 1);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id nau8315_device_id[] = {
+	{ .compatible = "nuvoton,nau8315" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, nau8315_device_id);
+#endif
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id nau8315_acpi_match[] = {
+	{ "NVTN2010", 0 },
+	{},
+};
+MODULE_DEVICE_TABLE(acpi, nau8315_acpi_match);
+#endif
+
+static struct platform_driver nau8315_platform_driver = {
+	.driver = {
+		.name = "nau8315",
+		.of_match_table = of_match_ptr(nau8315_device_id),
+		.acpi_match_table = ACPI_PTR(nau8315_acpi_match),
+	},
+	.probe	= nau8315_platform_probe,
+};
+module_platform_driver(nau8315_platform_driver);
+
+MODULE_DESCRIPTION("ASoC NAU8315 Mono Class-D Amplifier Driver");
+MODULE_AUTHOR("David Lin <ctlin0@nuvoton.com>");
+MODULE_LICENSE("GPL v2");