[RFC,2/2] ASoC: codecs: Add driver for NXP/Goodix TFA989x (TFA1) amplifiers

diff --git a/MAINTAINERS b/MAINTAINERS
index bd7aff0c120f..33079fddc7b8 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13204,6 +13204,13 @@  S:	Maintained
 F:	Documentation/devicetree/bindings/sound/tfa9879.txt
 F:	sound/soc/codecs/tfa9879*
 
+NXP/Goodix TFA989X (TFA1) DRIVER
+M:	Stephan Gerhold <stephan@gerhold.net>
+L:	alsa-devel@alsa-project.org (moderated for non-subscribers)
+S:	Maintained
+F:	Documentation/devicetree/bindings/sound/nxp,tfa989x.yaml
+F:	sound/soc/codecs/tfa989x.c
+
 NXP-NCI NFC DRIVER
 M:	Clément Perrochaud <clement.perrochaud@effinnov.com>
 R:	Charles Gorand <charles.gorand@effinnov.com>
diff --git a/sound/soc/codecs/Kconfig b/sound/soc/codecs/Kconfig
index 2a7b3e363069..196919bc27ab 100644
--- a/sound/soc/codecs/Kconfig
+++ b/sound/soc/codecs/Kconfig
@@ -211,6 +211,7 @@  config SND_SOC_ALL_CODECS
 	imply SND_SOC_TAS6424
 	imply SND_SOC_TDA7419
 	imply SND_SOC_TFA9879
+	imply SND_SOC_TFA989X
 	imply SND_SOC_TLV320ADCX140
 	imply SND_SOC_TLV320AIC23_I2C
 	imply SND_SOC_TLV320AIC23_SPI
@@ -1408,6 +1409,16 @@  config SND_SOC_TFA9879
 	tristate "NXP Semiconductors TFA9879 amplifier"
 	depends on I2C
 
+config SND_SOC_TFA989X
+	tristate "NXP/Goodix TFA989X (TFA1) amplifiers"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  Enable support for NXP (now Goodix) TFA989X (TFA1 family) speaker
+	  amplifiers, e.g. TFA9895.
+	  Note that the driver currently bypasses the built-in "CoolFlux DSP"
+	  and does not support (hardware) volume control.
+
 config SND_SOC_TLV320AIC23
 	tristate
 
diff --git a/sound/soc/codecs/Makefile b/sound/soc/codecs/Makefile
index 0efdba609048..8c7257035e4c 100644
--- a/sound/soc/codecs/Makefile
+++ b/sound/soc/codecs/Makefile
@@ -229,6 +229,7 @@  snd-soc-tas6424-objs := tas6424.o
 snd-soc-tda7419-objs := tda7419.o
 snd-soc-tas2770-objs := tas2770.o
 snd-soc-tfa9879-objs := tfa9879.o
+snd-soc-tfa989x-objs := tfa989x.o
 snd-soc-tlv320aic23-objs := tlv320aic23.o
 snd-soc-tlv320aic23-i2c-objs := tlv320aic23-i2c.o
 snd-soc-tlv320aic23-spi-objs := tlv320aic23-spi.o
@@ -551,6 +552,7 @@  obj-$(CONFIG_SND_SOC_TAS6424)	+= snd-soc-tas6424.o
 obj-$(CONFIG_SND_SOC_TDA7419)	+= snd-soc-tda7419.o
 obj-$(CONFIG_SND_SOC_TAS2770) += snd-soc-tas2770.o
 obj-$(CONFIG_SND_SOC_TFA9879)	+= snd-soc-tfa9879.o
+obj-$(CONFIG_SND_SOC_TFA989X)	+= snd-soc-tfa989x.o
 obj-$(CONFIG_SND_SOC_TLV320AIC23)	+= snd-soc-tlv320aic23.o
 obj-$(CONFIG_SND_SOC_TLV320AIC23_I2C)	+= snd-soc-tlv320aic23-i2c.o
 obj-$(CONFIG_SND_SOC_TLV320AIC23_SPI)	+= snd-soc-tlv320aic23-spi.o
diff --git a/sound/soc/codecs/tfa989x.c b/sound/soc/codecs/tfa989x.c
new file mode 100644
index 000000000000..408e26eee108
--- /dev/null
+++ b/sound/soc/codecs/tfa989x.c
@@ -0,0 +1,298 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2021 Stephan Gerhold
+ *
+ * Register definitions/sequences taken from various tfa98xx kernel drivers:
+ * Copyright (C) 2014-2020 NXP Semiconductors, All Rights Reserved.
+ * Copyright (C) 2013 Sony Mobile Communications Inc.
+ */
+
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <sound/soc.h>
+
+#define TFA989X_STATUSREG		0x00
+#define TFA989X_BATTERYVOLTAGE		0x01
+#define TFA989X_TEMPERATURE		0x02
+#define TFA989X_REVISIONNUMBER		0x03
+#define TFA989X_REVISIONNUMBER_REV_MSK	GENMASK(7, 0)	/* device revision */
+#define TFA989X_I2SREG			0x04
+#define TFA989X_I2SREG_CHSA		6	/* amplifier input select */
+#define TFA989X_I2SREG_CHSA_MSK		GENMASK(7, 6)
+#define TFA989X_I2SREG_I2SSR		12	/* sample rate */
+#define TFA989X_I2SREG_I2SSR_MSK	GENMASK(15, 12)
+#define TFA989X_BAT_PROT		0x05
+#define TFA989X_AUDIO_CTR		0x06
+#define TFA989X_DCDCBOOST		0x07
+#define TFA989X_SPKR_CALIBRATION	0x08
+#define TFA989X_SYS_CTRL		0x09
+#define TFA989X_SYS_CTRL_PWDN		0	/* power down */
+#define TFA989X_SYS_CTRL_I2CR		1	/* I2C reset */
+#define TFA989X_SYS_CTRL_CFE		2	/* enable CoolFlux DSP */
+#define TFA989X_SYS_CTRL_AMPE		3	/* enable amplifier */
+#define TFA989X_SYS_CTRL_DCA		4	/* enable boost */
+#define TFA989X_SYS_CTRL_SBSL		5	/* DSP configured */
+#define TFA989X_SYS_CTRL_AMPC		6	/* amplifier enabled by DSP */
+#define TFA989X_I2S_SEL_REG		0x0a
+#define TFA989X_I2S_SEL_REG_SPKR_MSK	GENMASK(10, 9)	/* speaker impedance */
+#define TFA989X_I2S_SEL_REG_DCFG_MSK	GENMASK(14, 11)	/* DCDC compensation */
+#define TFA989X_PWM_CONTROL		0x41
+#define TFA989X_CURRENTSENSE1		0x46
+#define TFA989X_CURRENTSENSE2		0x47
+#define TFA989X_CURRENTSENSE3		0x48
+#define TFA989X_CURRENTSENSE4		0x49
+
+#define TFA9895_REVISION		0x12
+
+struct tfa989x_rev {
+	unsigned int rev;
+	int (*init)(struct regmap *regmap);
+};
+
+static bool tfa989x_writeable_reg(struct device *dev, unsigned int reg)
+{
+	return reg > TFA989X_REVISIONNUMBER;
+}
+
+static bool tfa989x_volatile_reg(struct device *dev, unsigned int reg)
+{
+	return reg < TFA989X_REVISIONNUMBER;
+}
+
+static const struct regmap_config tfa989x_regmap = {
+	.reg_bits = 8,
+	.val_bits = 16,
+
+	.writeable_reg	= tfa989x_writeable_reg,
+	.volatile_reg	= tfa989x_volatile_reg,
+	.cache_type	= REGCACHE_RBTREE,
+};
+
+static const char * const chsa_text[] = { "Left", "Right", /* "DSP" */ };
+static SOC_ENUM_SINGLE_DECL(chsa_enum, TFA989X_I2SREG, TFA989X_I2SREG_CHSA, chsa_text);
+static const struct snd_kcontrol_new chsa_mux = SOC_DAPM_ENUM("Amp Input", chsa_enum);
+
+static const struct snd_soc_dapm_widget tfa989x_dapm_widgets[] = {
+	SND_SOC_DAPM_OUTPUT("OUT"),
+	SND_SOC_DAPM_SUPPLY("POWER", TFA989X_SYS_CTRL, TFA989X_SYS_CTRL_PWDN, 1, NULL, 0),
+	SND_SOC_DAPM_OUT_DRV("AMPE", TFA989X_SYS_CTRL, TFA989X_SYS_CTRL_AMPE, 0, NULL, 0),
+
+	SND_SOC_DAPM_MUX("Amp Input", SND_SOC_NOPM, 0, 0, &chsa_mux),
+	SND_SOC_DAPM_AIF_IN("AIFINL", "HiFi Playback", 0, SND_SOC_NOPM, 0, 0),
+	SND_SOC_DAPM_AIF_IN("AIFINR", "HiFi Playback", 1, SND_SOC_NOPM, 0, 0),
+};
+
+static const struct snd_soc_dapm_route tfa989x_dapm_routes[] = {
+	{"OUT", NULL, "AMPE"},
+	{"AMPE", NULL, "POWER"},
+	{"AMPE", NULL, "Amp Input"},
+	{"Amp Input", "Left", "AIFINL"},
+	{"Amp Input", "Right", "AIFINR"},
+};
+
+static const struct snd_soc_component_driver tfa989x_component = {
+	.dapm_widgets		= tfa989x_dapm_widgets,
+	.num_dapm_widgets	= ARRAY_SIZE(tfa989x_dapm_widgets),
+	.dapm_routes		= tfa989x_dapm_routes,
+	.num_dapm_routes	= ARRAY_SIZE(tfa989x_dapm_routes),
+	.use_pmdown_time	= 1,
+	.endianness		= 1,
+	.non_legacy_dai_naming	= 1,
+};
+
+static const unsigned int tfa989x_rates[] = {
+	8000, 11025, 12000, 16000, 22050, 24000, 32000, 44100, 48000
+};
+
+static int tfa989x_find_sample_rate(unsigned int rate)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(tfa989x_rates); ++i)
+		if (tfa989x_rates[i] == rate)
+			return i;
+
+	return -EINVAL;
+}
+
+static int tfa989x_hw_params(struct snd_pcm_substream *substream,
+			     struct snd_pcm_hw_params *params,
+			     struct snd_soc_dai *dai)
+{
+	struct snd_soc_component *component = dai->component;
+	int sr;
+
+	sr = tfa989x_find_sample_rate(params_rate(params));
+	if (sr < 0)
+		return sr;
+
+	return snd_soc_component_update_bits(component, TFA989X_I2SREG,
+					     TFA989X_I2SREG_I2SSR_MSK,
+					     sr << TFA989X_I2SREG_I2SSR);
+}
+
+static const struct snd_soc_dai_ops tfa989x_dai_ops = {
+	.hw_params = tfa989x_hw_params,
+};
+
+static struct snd_soc_dai_driver tfa989x_dai = {
+	.name = "tfa989x-hifi",
+	.playback = {
+		.stream_name	= "HiFi Playback",
+		.formats	= SNDRV_PCM_FMTBIT_S16_LE,
+		.rates		= SNDRV_PCM_RATE_8000_48000,
+		.rate_min	= 8000,
+		.rate_max	= 48000,
+		.channels_min	= 1,
+		.channels_max	= 2,
+	},
+	.ops = &tfa989x_dai_ops,
+};
+
+static const struct reg_sequence tfa9895_reg_init[] = {
+	/* some other registers must be set for optimal amplifier behaviour */
+	{ TFA989X_BAT_PROT, 0x13ab },
+	{ TFA989X_AUDIO_CTR, 0x001f },
+
+	/* peak voltage protection is always on, but may be written */
+	{ TFA989X_SPKR_CALIBRATION, 0x3c4e },
+
+	/* TFA989X_SYSCTRL_DCA = 0 */
+	{ TFA989X_SYS_CTRL, 0x024d },
+	{ TFA989X_PWM_CONTROL, 0x0308 },
+	{ TFA989X_CURRENTSENSE4, 0x0e82 },
+};
+
+static int tfa9895_init(struct regmap *regmap)
+{
+	return regmap_multi_reg_write(regmap, tfa9895_reg_init,
+				      ARRAY_SIZE(tfa9895_reg_init));
+}
+
+static const struct tfa989x_rev tfa9895_rev = {
+	.rev	= TFA9895_REVISION,
+	.init	= tfa9895_init,
+};
+
+/*
+ * Note: At the moment this driver bypasses the "CoolFlux DSP" built into the
+ * TFA989X amplifiers. Unfortunately, there seems to be absolutely
+ * no documentation for it - the public "short datasheets" do not provide
+ * any information about the DSP or available registers.
+ *
+ * Usually the TFA989X amplifiers are configured through proprietary userspace
+ * libraries. There are also some (rather complex) kernel drivers but even those
+ * rely on obscure firmware blobs for configuration (so-called "containers").
+ * They seem to contain different "profiles" with tuned speaker settings, sample
+ * rates and volume steps (which would be better exposed as separate ALSA mixers).
+ *
+ * Bypassing the DSP disables volume control (and perhaps some speaker
+ * optimization?), but at least allows using the speaker without obscure
+ * kernel drivers and firmware.
+ *
+ * Ideally NXP (or now Goodix) should release proper documentation for these
+ * amplifiers so that support for the "CoolFlux DSP" can be implemented properly.
+ */
+static int tfa989x_dsp_bypass(struct regmap *regmap)
+{
+	int ret;
+
+	/* Clear CHSA to bypass DSP and take input from I2S 1 left channel */
+	ret = regmap_clear_bits(regmap, TFA989X_I2SREG, TFA989X_I2SREG_CHSA_MSK);
+	if (ret)
+		return ret;
+
+	/* Set DCDC compensation to off and speaker impedance to 8 ohm */
+	ret = regmap_update_bits(regmap, TFA989X_I2S_SEL_REG,
+				 TFA989X_I2S_SEL_REG_DCFG_MSK |
+				 TFA989X_I2S_SEL_REG_SPKR_MSK,
+				 TFA989X_I2S_SEL_REG_SPKR_MSK);
+	if (ret)
+		return ret;
+
+	/* Set DCDC to follower mode and disable CoolFlux DSP */
+	return regmap_clear_bits(regmap, TFA989X_SYS_CTRL,
+				 BIT(TFA989X_SYS_CTRL_DCA) |
+				 BIT(TFA989X_SYS_CTRL_CFE) |
+				 BIT(TFA989X_SYS_CTRL_AMPC));
+}
+
+static int tfa989x_i2c_probe(struct i2c_client *i2c)
+{
+	struct device *dev = &i2c->dev;
+	const struct tfa989x_rev *rev;
+	struct regmap *regmap;
+	unsigned int val;
+	int ret;
+
+	rev = device_get_match_data(dev);
+	if (!rev) {
+		dev_err(dev, "unknown device revision\n");
+		return -ENODEV;
+	}
+
+	regmap = devm_regmap_init_i2c(i2c, &tfa989x_regmap);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	/* Bypass regcache for reset and init sequence */
+	regcache_cache_bypass(regmap, true);
+
+	/* Dummy read to generate i2c clocks, required on some devices */
+	regmap_read(regmap, TFA989X_REVISIONNUMBER, &val);
+
+	ret = regmap_read(regmap, TFA989X_REVISIONNUMBER, &val);
+	if (ret) {
+		dev_err(dev, "failed to read revision number: %d\n", ret);
+		return ret;
+	}
+
+	val &= TFA989X_REVISIONNUMBER_REV_MSK;
+	if (val != rev->rev) {
+		dev_err(dev, "invalid revision number, expected %#x, got %#x\n",
+			rev->rev, val);
+		return -ENODEV;
+	}
+
+	ret = regmap_write(regmap, TFA989X_SYS_CTRL, BIT(TFA989X_SYS_CTRL_I2CR));
+	if (ret) {
+		dev_err(dev, "failed to reset I2C registers: %d\n", ret);
+		return ret;
+	}
+
+	ret = rev->init(regmap);
+	if (ret) {
+		dev_err(dev, "failed to initialize registers: %d\n", ret);
+		return ret;
+	}
+
+	ret = tfa989x_dsp_bypass(regmap);
+	if (ret) {
+		dev_err(dev, "failed to enable DSP bypass: %d\n", ret);
+		return ret;
+	}
+	regcache_cache_bypass(regmap, false);
+
+	return devm_snd_soc_register_component(dev, &tfa989x_component,
+					       &tfa989x_dai, 1);
+}
+
+static const struct of_device_id tfa989x_of_match[] = {
+	{ .compatible = "nxp,tfa9895", .data = &tfa9895_rev },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, tfa989x_of_match);
+
+static struct i2c_driver tfa989x_i2c_driver = {
+	.driver = {
+		.name = "tfa989x",
+		.of_match_table = tfa989x_of_match,
+	},
+	.probe_new = tfa989x_i2c_probe,
+};
+module_i2c_driver(tfa989x_i2c_driver);
+
+MODULE_DESCRIPTION("ASoC NXP/Goodix TFA989X (TFA1) driver");
+MODULE_AUTHOR("Stephan Gerhold <stephan@gerhold.net>");
+MODULE_LICENSE("GPL");