ASoC: meson: aiu: add i2s and spdif support

Add support for the i2s and spdif audio outputs (AIU) found in the
amlogic Gx SoC family

Signed-off-by: Jerome Brunet <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

sound/soc/meson/Kconfig

···
 menu "ASoC support for Amlogic platforms"
 	depends on ARCH_MESON || COMPILE_TEST
 
+config SND_MESON_AIU
+	tristate "Amlogic AIU"
+	select SND_PCM_IEC958
+	help
+	  Select Y or M to add support for the Audio output subsystem found
+	  in the Amlogic GX SoC family
+
 config SND_MESON_AXG_FIFO
 	tristate
 	select REGMAP_MMIO

sound/soc/meson/Makefile

···
 # SPDX-License-Identifier: (GPL-2.0 OR MIT)
 
+snd-soc-meson-aiu-objs := aiu.o
+snd-soc-meson-aiu-objs += aiu-encoder-i2s.o
+snd-soc-meson-aiu-objs += aiu-encoder-spdif.o
+snd-soc-meson-aiu-objs += aiu-fifo.o
+snd-soc-meson-aiu-objs += aiu-fifo-i2s.o
+snd-soc-meson-aiu-objs += aiu-fifo-spdif.o
 snd-soc-meson-axg-fifo-objs := axg-fifo.o
 snd-soc-meson-axg-frddr-objs := axg-frddr.o
 snd-soc-meson-axg-toddr-objs := axg-toddr.o
···
 snd-soc-meson-codec-glue-objs := meson-codec-glue.o
 snd-soc-meson-g12a-tohdmitx-objs := g12a-tohdmitx.o
 
+obj-$(CONFIG_SND_MESON_AIU) += snd-soc-meson-aiu.o
 obj-$(CONFIG_SND_MESON_AXG_FIFO) += snd-soc-meson-axg-fifo.o
 obj-$(CONFIG_SND_MESON_AXG_FRDDR) += snd-soc-meson-axg-frddr.o
 obj-$(CONFIG_SND_MESON_AXG_TODDR) += snd-soc-meson-axg-toddr.o

sound/soc/meson/aiu-encoder-i2s.c

···
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (c) 2020 BayLibre, SAS.
+// Author: Jerome Brunet <[e-mail]>
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+#include <sound/soc-dai.h>
+
+#include "aiu.h"
+
+#define AIU_I2S_SOURCE_DESC_MODE_8CH	BIT(0)
+#define AIU_I2S_SOURCE_DESC_MODE_24BIT	BIT(5)
+#define AIU_I2S_SOURCE_DESC_MODE_32BIT	BIT(9)
+#define AIU_I2S_SOURCE_DESC_MODE_SPLIT	BIT(11)
+#define AIU_RST_SOFT_I2S_FAST		BIT(0)
+
+#define AIU_I2S_DAC_CFG_MSB_FIRST	BIT(2)
+#define AIU_I2S_MISC_HOLD_EN		BIT(2)
+#define AIU_CLK_CTRL_I2S_DIV_EN		BIT(0)
+#define AIU_CLK_CTRL_I2S_DIV		GENMASK(3, 2)
+#define AIU_CLK_CTRL_AOCLK_INVERT	BIT(6)
+#define AIU_CLK_CTRL_LRCLK_INVERT	BIT(7)
+#define AIU_CLK_CTRL_LRCLK_SKEW		GENMASK(9, 8)
+#define AIU_CLK_CTRL_MORE_HDMI_AMCLK	BIT(6)
+#define AIU_CLK_CTRL_MORE_I2S_DIV	GENMASK(5, 0)
+#define AIU_CODEC_DAC_LRCLK_CTRL_DIV	GENMASK(11, 0)
+
+struct aiu_encoder_i2s {
+	struct clk *aoclk;
+	struct clk *mclk;
+	struct clk *mixer;
+	struct clk *pclk;
+};
+
+static void aiu_encoder_i2s_divider_enable(struct snd_soc_component *component,
+					   bool enable)
+{
+	snd_soc_component_update_bits(component, AIU_CLK_CTRL,
+				      AIU_CLK_CTRL_I2S_DIV_EN,
+				      enable ? AIU_CLK_CTRL_I2S_DIV_EN : 0);
+}
+
+static void aiu_encoder_i2s_hold(struct snd_soc_component *component,
+				 bool enable)
+{
+	snd_soc_component_update_bits(component, AIU_I2S_MISC,
+				      AIU_I2S_MISC_HOLD_EN,
+				      enable ? AIU_I2S_MISC_HOLD_EN : 0);
+}
+
+static int aiu_encoder_i2s_trigger(struct snd_pcm_substream *substream, int cmd,
+				   struct snd_soc_dai *dai)
+{
+	struct snd_soc_component *component = dai->component;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		aiu_encoder_i2s_hold(component, false);
+		return 0;
+
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		aiu_encoder_i2s_hold(component, true);
+		return 0;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int aiu_encoder_i2s_setup_desc(struct snd_soc_component *component,
+				      struct snd_pcm_hw_params *params)
+{
+	/* Always operate in split (classic interleaved) mode */
+	unsigned int desc = AIU_I2S_SOURCE_DESC_MODE_SPLIT;
+	unsigned int val;
+
+	/* Reset required to update the pipeline */
+	snd_soc_component_write(component, AIU_RST_SOFT, AIU_RST_SOFT_I2S_FAST);
+	snd_soc_component_read(component, AIU_I2S_SYNC, &val);
+
+	switch (params_physical_width(params)) {
+	case 16: /* Nothing to do */
+		break;
+
+	case 32:
+		desc |= (AIU_I2S_SOURCE_DESC_MODE_24BIT |
+			 AIU_I2S_SOURCE_DESC_MODE_32BIT);
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	switch (params_channels(params)) {
+	case 2: /* Nothing to do */
+		break;
+	case 8:
+		desc |= AIU_I2S_SOURCE_DESC_MODE_8CH;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	snd_soc_component_update_bits(component, AIU_I2S_SOURCE_DESC,
+				      AIU_I2S_SOURCE_DESC_MODE_8CH |
+				      AIU_I2S_SOURCE_DESC_MODE_24BIT |
+				      AIU_I2S_SOURCE_DESC_MODE_32BIT |
+				      AIU_I2S_SOURCE_DESC_MODE_SPLIT,
+				      desc);
+
+	return 0;
+}
+
+static int aiu_encoder_i2s_set_clocks(struct snd_soc_component *component,
+				      struct snd_pcm_hw_params *params)
+{
+	struct aiu *aiu = snd_soc_component_get_drvdata(component);
+	unsigned int srate = params_rate(params);
+	unsigned int fs, bs;
+
+	/* Get the oversampling factor */
+	fs = DIV_ROUND_CLOSEST(clk_get_rate(aiu->i2s.clks[MCLK].clk), srate);
+
+	if (fs % 64)
+		return -EINVAL;
+
+	/* Send data MSB first */
+	snd_soc_component_update_bits(component, AIU_I2S_DAC_CFG,
+				      AIU_I2S_DAC_CFG_MSB_FIRST,
+				      AIU_I2S_DAC_CFG_MSB_FIRST);
+
+	/* Set bclk to lrlck ratio */
+	snd_soc_component_update_bits(component, AIU_CODEC_DAC_LRCLK_CTRL,
+				      AIU_CODEC_DAC_LRCLK_CTRL_DIV,
+				      FIELD_PREP(AIU_CODEC_DAC_LRCLK_CTRL_DIV,
+						 64 - 1));
+
+	/* Use CLK_MORE for mclk to bclk divider */
+	snd_soc_component_update_bits(component, AIU_CLK_CTRL,
+				      AIU_CLK_CTRL_I2S_DIV, 0);
+
+	/*
+	 * NOTE: this HW is odd.
+	 * In most configuration, the i2s divider is 'mclk / blck'.
+	 * However, in 16 bits - 8ch mode, this factor needs to be
+	 * increased by 50% to get the correct output rate.
+	 * No idea why !
+	 */
+	bs = fs / 64;
+	if (params_width(params) == 16 && params_channels(params) == 8) {
+		if (bs % 2) {
+			dev_err(component->dev,
+				"Cannot increase i2s divider by 50%%\n");
+			return -EINVAL;
+		}
+		bs += bs / 2;
+	}
+
+	snd_soc_component_update_bits(component, AIU_CLK_CTRL_MORE,
+				      AIU_CLK_CTRL_MORE_I2S_DIV,
+				      FIELD_PREP(AIU_CLK_CTRL_MORE_I2S_DIV,
+						 bs - 1));
+
+	/* Make sure amclk is used for HDMI i2s as well */
+	snd_soc_component_update_bits(component, AIU_CLK_CTRL_MORE,
+				      AIU_CLK_CTRL_MORE_HDMI_AMCLK,
+				      AIU_CLK_CTRL_MORE_HDMI_AMCLK);
+
+	return 0;
+}
+
+static int aiu_encoder_i2s_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 ret;
+
+	/* Disable the clock while changing the settings */
+	aiu_encoder_i2s_divider_enable(component, false);
+
+	ret = aiu_encoder_i2s_setup_desc(component, params);
+	if (ret) {
+		dev_err(dai->dev, "setting i2s desc failed\n");
+		return ret;
+	}
+
+	ret = aiu_encoder_i2s_set_clocks(component, params);
+	if (ret) {
+		dev_err(dai->dev, "setting i2s clocks failed\n");
+		return ret;
+	}
+
+	aiu_encoder_i2s_divider_enable(component, true);
+
+	return 0;
+}
+
+static int aiu_encoder_i2s_hw_free(struct snd_pcm_substream *substream,
+				   struct snd_soc_dai *dai)
+{
+	struct snd_soc_component *component = dai->component;
+
+	aiu_encoder_i2s_divider_enable(component, false);
+
+	return 0;
+}
+
+static int aiu_encoder_i2s_set_fmt(struct snd_soc_dai *dai, unsigned int fmt)
+{
+	struct snd_soc_component *component = dai->component;
+	unsigned int inv = fmt & SND_SOC_DAIFMT_INV_MASK;
+	unsigned int val = 0;
+	unsigned int skew;
+
+	/* Only CPU Master / Codec Slave supported ATM */
+	if ((fmt & SND_SOC_DAIFMT_MASTER_MASK) != SND_SOC_DAIFMT_CBS_CFS)
+		return -EINVAL;
+
+	if (inv == SND_SOC_DAIFMT_NB_IF ||
+	    inv == SND_SOC_DAIFMT_IB_IF)
+		val |= AIU_CLK_CTRL_LRCLK_INVERT;
+
+	if (inv == SND_SOC_DAIFMT_IB_NF ||
+	    inv == SND_SOC_DAIFMT_IB_IF)
+		val |= AIU_CLK_CTRL_AOCLK_INVERT;
+
+	/* Signal skew */
+	switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
+	case SND_SOC_DAIFMT_I2S:
+		/* Invert sample clock for i2s */
+		val ^= AIU_CLK_CTRL_LRCLK_INVERT;
+		skew = 1;
+		break;
+	case SND_SOC_DAIFMT_LEFT_J:
+		skew = 0;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	val |= FIELD_PREP(AIU_CLK_CTRL_LRCLK_SKEW, skew);
+	snd_soc_component_update_bits(component, AIU_CLK_CTRL,
+				      AIU_CLK_CTRL_LRCLK_INVERT |
+				      AIU_CLK_CTRL_AOCLK_INVERT |
+				      AIU_CLK_CTRL_LRCLK_SKEW,
+				      val);
+
+	return 0;
+}
+
+static int aiu_encoder_i2s_set_sysclk(struct snd_soc_dai *dai, int clk_id,
+				      unsigned int freq, int dir)
+{
+	struct aiu *aiu = snd_soc_component_get_drvdata(dai->component);
+	int ret;
+
+	if (WARN_ON(clk_id != 0))
+		return -EINVAL;
+
+	if (dir == SND_SOC_CLOCK_IN)
+		return 0;
+
+	ret = clk_set_rate(aiu->i2s.clks[MCLK].clk, freq);
+	if (ret)
+		dev_err(dai->dev, "Failed to set sysclk to %uHz", freq);
+
+	return ret;
+}
+
+static const unsigned int hw_channels[] = {2, 8};
+static const struct snd_pcm_hw_constraint_list hw_channel_constraints = {
+	.list = hw_channels,
+	.count = ARRAY_SIZE(hw_channels),
+	.mask = 0,
+};
+
+static int aiu_encoder_i2s_startup(struct snd_pcm_substream *substream,
+				   struct snd_soc_dai *dai)
+{
+	struct aiu *aiu = snd_soc_component_get_drvdata(dai->component);
+	int ret;
+
+	/* Make sure the encoder gets either 2 or 8 channels */
+	ret = snd_pcm_hw_constraint_list(substream->runtime, 0,
+					 SNDRV_PCM_HW_PARAM_CHANNELS,
+					 &hw_channel_constraints);
+	if (ret) {
+		dev_err(dai->dev, "adding channels constraints failed\n");
+		return ret;
+	}
+
+	ret = clk_bulk_prepare_enable(aiu->i2s.clk_num, aiu->i2s.clks);
+	if (ret)
+		dev_err(dai->dev, "failed to enable i2s clocks\n");
+
+	return ret;
+}
+
+static void aiu_encoder_i2s_shutdown(struct snd_pcm_substream *substream,
+				     struct snd_soc_dai *dai)
+{
+	struct aiu *aiu = snd_soc_component_get_drvdata(dai->component);
+
+	clk_bulk_disable_unprepare(aiu->i2s.clk_num, aiu->i2s.clks);
+}
+
+const struct snd_soc_dai_ops aiu_encoder_i2s_dai_ops = {
+	.trigger	= aiu_encoder_i2s_trigger,
+	.hw_params	= aiu_encoder_i2s_hw_params,
+	.hw_free	= aiu_encoder_i2s_hw_free,
+	.set_fmt	= aiu_encoder_i2s_set_fmt,
+	.set_sysclk	= aiu_encoder_i2s_set_sysclk,
+	.startup	= aiu_encoder_i2s_startup,
+	.shutdown	= aiu_encoder_i2s_shutdown,
+};
+

sound/soc/meson/aiu-encoder-spdif.c

···
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (c) 2020 BayLibre, SAS.
+// Author: Jerome Brunet <[e-mail]>
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <sound/pcm_params.h>
+#include <sound/pcm_iec958.h>
+#include <sound/soc.h>
+#include <sound/soc-dai.h>
+
+#include "aiu.h"
+
+#define AIU_958_MISC_NON_PCM		BIT(0)
+#define AIU_958_MISC_MODE_16BITS	BIT(1)
+#define AIU_958_MISC_16BITS_ALIGN	GENMASK(6, 5)
+#define AIU_958_MISC_MODE_32BITS	BIT(7)
+#define AIU_958_MISC_U_FROM_STREAM	BIT(12)
+#define AIU_958_MISC_FORCE_LR		BIT(13)
+#define AIU_958_CTRL_HOLD_EN		BIT(0)
+#define AIU_CLK_CTRL_958_DIV_EN		BIT(1)
+#define AIU_CLK_CTRL_958_DIV		GENMASK(5, 4)
+#define AIU_CLK_CTRL_958_DIV_MORE	BIT(12)
+
+#define AIU_CS_WORD_LEN			4
+#define AIU_958_INTERNAL_DIV		2
+
+static void
+aiu_encoder_spdif_divider_enable(struct snd_soc_component *component,
+				 bool enable)
+{
+	snd_soc_component_update_bits(component, AIU_CLK_CTRL,
+				      AIU_CLK_CTRL_958_DIV_EN,
+				      enable ? AIU_CLK_CTRL_958_DIV_EN : 0);
+}
+
+static void aiu_encoder_spdif_hold(struct snd_soc_component *component,
+				   bool enable)
+{
+	snd_soc_component_update_bits(component, AIU_958_CTRL,
+				      AIU_958_CTRL_HOLD_EN,
+				      enable ? AIU_958_CTRL_HOLD_EN : 0);
+}
+
+static int
+aiu_encoder_spdif_trigger(struct snd_pcm_substream *substream, int cmd,
+			  struct snd_soc_dai *dai)
+{
+	struct snd_soc_component *component = dai->component;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		aiu_encoder_spdif_hold(component, false);
+		return 0;
+
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		aiu_encoder_spdif_hold(component, true);
+		return 0;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int aiu_encoder_spdif_setup_cs_word(struct snd_soc_component *component,
+					   struct snd_pcm_hw_params *params)
+{
+	u8 cs[AIU_CS_WORD_LEN];
+	unsigned int val;
+	int ret;
+
+	ret = snd_pcm_create_iec958_consumer_hw_params(params, cs,
+						       AIU_CS_WORD_LEN);
+	if (ret < 0)
+		return ret;
+
+	/* Write the 1st half word */
+	val = cs[1] | cs[0] << 8;
+	snd_soc_component_write(component, AIU_958_CHSTAT_L0, val);
+	snd_soc_component_write(component, AIU_958_CHSTAT_R0, val);
+
+	/* Write the 2nd half word */
+	val = cs[3] | cs[2] << 8;
+	snd_soc_component_write(component, AIU_958_CHSTAT_L1, val);
+	snd_soc_component_write(component, AIU_958_CHSTAT_R1, val);
+
+	return 0;
+}
+
+static int aiu_encoder_spdif_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;
+	struct aiu *aiu = snd_soc_component_get_drvdata(component);
+	unsigned int val = 0, mrate;
+	int ret;
+
+	/* Disable the clock while changing the settings */
+	aiu_encoder_spdif_divider_enable(component, false);
+
+	switch (params_physical_width(params)) {
+	case 16:
+		val |= AIU_958_MISC_MODE_16BITS;
+		val |= FIELD_PREP(AIU_958_MISC_16BITS_ALIGN, 2);
+		break;
+	case 32:
+		val |= AIU_958_MISC_MODE_32BITS;
+		break;
+	default:
+		dev_err(dai->dev, "Unsupport physical width\n");
+		return -EINVAL;
+	}
+
+	snd_soc_component_update_bits(component, AIU_958_MISC,
+				      AIU_958_MISC_NON_PCM |
+				      AIU_958_MISC_MODE_16BITS |
+				      AIU_958_MISC_16BITS_ALIGN |
+				      AIU_958_MISC_MODE_32BITS |
+				      AIU_958_MISC_FORCE_LR |
+				      AIU_958_MISC_U_FROM_STREAM,
+				      val);
+
+	/* Set the stream channel status word */
+	ret = aiu_encoder_spdif_setup_cs_word(component, params);
+	if (ret) {
+		dev_err(dai->dev, "failed to set channel status word\n");
+		return ret;
+	}
+
+	snd_soc_component_update_bits(component, AIU_CLK_CTRL,
+				      AIU_CLK_CTRL_958_DIV |
+				      AIU_CLK_CTRL_958_DIV_MORE,
+				      FIELD_PREP(AIU_CLK_CTRL_958_DIV,
+						 __ffs(AIU_958_INTERNAL_DIV)));
+
+	/* 2 * 32bits per subframe * 2 channels = 128 */
+	mrate = params_rate(params) * 128 * AIU_958_INTERNAL_DIV;
+	ret = clk_set_rate(aiu->spdif.clks[MCLK].clk, mrate);
+	if (ret) {
+		dev_err(dai->dev, "failed to set mclk rate\n");
+		return ret;
+	}
+
+	aiu_encoder_spdif_divider_enable(component, true);
+
+	return 0;
+}
+
+static int aiu_encoder_spdif_hw_free(struct snd_pcm_substream *substream,
+				     struct snd_soc_dai *dai)
+{
+	struct snd_soc_component *component = dai->component;
+
+	aiu_encoder_spdif_divider_enable(component, false);
+
+	return 0;
+}
+
+static int aiu_encoder_spdif_startup(struct snd_pcm_substream *substream,
+				     struct snd_soc_dai *dai)
+{
+	struct aiu *aiu = snd_soc_component_get_drvdata(dai->component);
+	int ret;
+
+	/*
+	 * NOTE: Make sure the spdif block is on its own divider.
+	 *
+	 * The spdif can be clocked by the i2s master clock or its own
+	 * clock. We should (in theory) change the source depending on the
+	 * origin of the data.
+	 *
+	 * However, considering the clocking scheme used on these platforms,
+	 * the master clocks will pick the same PLL source when they are
+	 * playing from the same FIFO. The clock should be in sync so, it
+	 * should not be necessary to reparent the spdif master clock.
+	 */
+	ret = clk_set_parent(aiu->spdif.clks[MCLK].clk,
+			     aiu->spdif_mclk);
+	if (ret)
+		return ret;
+
+	ret = clk_bulk_prepare_enable(aiu->spdif.clk_num, aiu->spdif.clks);
+	if (ret)
+		dev_err(dai->dev, "failed to enable spdif clocks\n");
+
+	return ret;
+}
+
+static void aiu_encoder_spdif_shutdown(struct snd_pcm_substream *substream,
+				       struct snd_soc_dai *dai)
+{
+	struct aiu *aiu = snd_soc_component_get_drvdata(dai->component);
+
+	clk_bulk_disable_unprepare(aiu->spdif.clk_num, aiu->spdif.clks);
+}
+
+const struct snd_soc_dai_ops aiu_encoder_spdif_dai_ops = {
+	.trigger	= aiu_encoder_spdif_trigger,
+	.hw_params	= aiu_encoder_spdif_hw_params,
+	.hw_free	= aiu_encoder_spdif_hw_free,
+	.startup	= aiu_encoder_spdif_startup,
+	.shutdown	= aiu_encoder_spdif_shutdown,
+};

sound/soc/meson/aiu-fifo-i2s.c

···
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (c) 2020 BayLibre, SAS.
+// Author: Jerome Brunet <[e-mail]>
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+#include <sound/soc-dai.h>
+
+#include "aiu.h"
+#include "aiu-fifo.h"
+
+#define AIU_I2S_SOURCE_DESC_MODE_8CH	BIT(0)
+#define AIU_I2S_SOURCE_DESC_MODE_24BIT	BIT(5)
+#define AIU_I2S_SOURCE_DESC_MODE_32BIT	BIT(9)
+#define AIU_I2S_SOURCE_DESC_MODE_SPLIT	BIT(11)
+#define AIU_MEM_I2S_MASKS_IRQ_BLOCK	GENMASK(31, 16)
+#define AIU_MEM_I2S_CONTROL_MODE_16BIT	BIT(6)
+#define AIU_MEM_I2S_BUF_CNTL_INIT	BIT(0)
+#define AIU_RST_SOFT_I2S_FAST		BIT(0)
+
+#define AIU_FIFO_I2S_BLOCK		256
+
+static struct snd_pcm_hardware fifo_i2s_pcm = {
+	.info = (SNDRV_PCM_INFO_INTERLEAVED |
+		 SNDRV_PCM_INFO_MMAP |
+		 SNDRV_PCM_INFO_MMAP_VALID |
+		 SNDRV_PCM_INFO_PAUSE),
+	.formats = AIU_FORMATS,
+	.rate_min = 5512,
+	.rate_max = 192000,
+	.channels_min = 2,
+	.channels_max = 8,
+	.period_bytes_min = AIU_FIFO_I2S_BLOCK,
+	.period_bytes_max = AIU_FIFO_I2S_BLOCK * USHRT_MAX,
+	.periods_min = 2,
+	.periods_max = UINT_MAX,
+
+	/* No real justification for this */
+	.buffer_bytes_max = 1 * 1024 * 1024,
+};
+
+static int aiu_fifo_i2s_trigger(struct snd_pcm_substream *substream, int cmd,
+				struct snd_soc_dai *dai)
+{
+	struct snd_soc_component *component = dai->component;
+	unsigned int val;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		snd_soc_component_write(component, AIU_RST_SOFT,
+					AIU_RST_SOFT_I2S_FAST);
+		snd_soc_component_read(component, AIU_I2S_SYNC, &val);
+		break;
+	}
+
+	return aiu_fifo_trigger(substream, cmd, dai);
+}
+
+static int aiu_fifo_i2s_prepare(struct snd_pcm_substream *substream,
+				struct snd_soc_dai *dai)
+{
+	struct snd_soc_component *component = dai->component;
+	int ret;
+
+	ret = aiu_fifo_prepare(substream, dai);
+	if (ret)
+		return ret;
+
+	snd_soc_component_update_bits(component,
+				      AIU_MEM_I2S_BUF_CNTL,
+				      AIU_MEM_I2S_BUF_CNTL_INIT,
+				      AIU_MEM_I2S_BUF_CNTL_INIT);
+	snd_soc_component_update_bits(component,
+				      AIU_MEM_I2S_BUF_CNTL,
+				      AIU_MEM_I2S_BUF_CNTL_INIT, 0);
+
+	return 0;
+}
+
+static int aiu_fifo_i2s_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;
+	struct aiu_fifo *fifo = dai->playback_dma_data;
+	unsigned int val;
+	int ret;
+
+	ret = aiu_fifo_hw_params(substream, params, dai);
+	if (ret)
+		return ret;
+
+	switch (params_physical_width(params)) {
+	case 16:
+		val = AIU_MEM_I2S_CONTROL_MODE_16BIT;
+		break;
+	case 32:
+		val = 0;
+		break;
+	default:
+		dev_err(dai->dev, "Unsupported physical width %u\n",
+			params_physical_width(params));
+		return -EINVAL;
+	}
+
+	snd_soc_component_update_bits(component, AIU_MEM_I2S_CONTROL,
+				      AIU_MEM_I2S_CONTROL_MODE_16BIT,
+				      val);
+
+	/* Setup the irq periodicity */
+	val = params_period_bytes(params) / fifo->fifo_block;
+	val = FIELD_PREP(AIU_MEM_I2S_MASKS_IRQ_BLOCK, val);
+	snd_soc_component_update_bits(component, AIU_MEM_I2S_MASKS,
+				      AIU_MEM_I2S_MASKS_IRQ_BLOCK, val);
+
+	return 0;
+}
+
+const struct snd_soc_dai_ops aiu_fifo_i2s_dai_ops = {
+	.trigger	= aiu_fifo_i2s_trigger,
+	.prepare	= aiu_fifo_i2s_prepare,
+	.hw_params	= aiu_fifo_i2s_hw_params,
+	.hw_free	= aiu_fifo_hw_free,
+	.startup	= aiu_fifo_startup,
+	.shutdown	= aiu_fifo_shutdown,
+};
+
+int aiu_fifo_i2s_dai_probe(struct snd_soc_dai *dai)
+{
+	struct snd_soc_component *component = dai->component;
+	struct aiu *aiu = snd_soc_component_get_drvdata(component);
+	struct aiu_fifo *fifo;
+	int ret;
+
+	ret = aiu_fifo_dai_probe(dai);
+	if (ret)
+		return ret;
+
+	fifo = dai->playback_dma_data;
+
+	fifo->pcm = &fifo_i2s_pcm;
+	fifo->mem_offset = AIU_MEM_I2S_START;
+	fifo->fifo_block = AIU_FIFO_I2S_BLOCK;
+	fifo->pclk = aiu->i2s.clks[PCLK].clk;
+	fifo->irq = aiu->i2s.irq;
+
+	return 0;
+}

sound/soc/meson/aiu-fifo-spdif.c

···
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (c) 2020 BayLibre, SAS.
+// Author: Jerome Brunet <[e-mail]>
+
+#include <linux/clk.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+#include <sound/soc-dai.h>
+
+#include "aiu.h"
+#include "aiu-fifo.h"
+
+#define AIU_IEC958_DCU_FF_CTRL_EN		BIT(0)
+#define AIU_IEC958_DCU_FF_CTRL_AUTO_DISABLE	BIT(1)
+#define AIU_IEC958_DCU_FF_CTRL_IRQ_MODE		GENMASK(3, 2)
+#define AIU_IEC958_DCU_FF_CTRL_IRQ_OUT_THD	BIT(2)
+#define AIU_IEC958_DCU_FF_CTRL_IRQ_FRAME_READ	BIT(3)
+#define AIU_IEC958_DCU_FF_CTRL_SYNC_HEAD_EN	BIT(4)
+#define AIU_IEC958_DCU_FF_CTRL_BYTE_SEEK	BIT(5)
+#define AIU_IEC958_DCU_FF_CTRL_CONTINUE		BIT(6)
+#define AIU_MEM_IEC958_CONTROL_ENDIAN		GENMASK(5, 3)
+#define AIU_MEM_IEC958_CONTROL_RD_DDR		BIT(6)
+#define AIU_MEM_IEC958_CONTROL_MODE_16BIT	BIT(7)
+#define AIU_MEM_IEC958_CONTROL_MODE_LINEAR	BIT(8)
+#define AIU_MEM_IEC958_BUF_CNTL_INIT		BIT(0)
+
+#define AIU_FIFO_SPDIF_BLOCK			8
+
+static struct snd_pcm_hardware fifo_spdif_pcm = {
+	.info = (SNDRV_PCM_INFO_INTERLEAVED |
+		 SNDRV_PCM_INFO_MMAP |
+		 SNDRV_PCM_INFO_MMAP_VALID |
+		 SNDRV_PCM_INFO_PAUSE),
+	.formats = AIU_FORMATS,
+	.rate_min = 5512,
+	.rate_max = 192000,
+	.channels_min = 2,
+	.channels_max = 2,
+	.period_bytes_min = AIU_FIFO_SPDIF_BLOCK,
+	.period_bytes_max = AIU_FIFO_SPDIF_BLOCK * USHRT_MAX,
+	.periods_min = 2,
+	.periods_max = UINT_MAX,
+
+	/* No real justification for this */
+	.buffer_bytes_max = 1 * 1024 * 1024,
+};
+
+static void fifo_spdif_dcu_enable(struct snd_soc_component *component,
+				  bool enable)
+{
+	snd_soc_component_update_bits(component, AIU_IEC958_DCU_FF_CTRL,
+				      AIU_IEC958_DCU_FF_CTRL_EN,
+				      enable ? AIU_IEC958_DCU_FF_CTRL_EN : 0);
+}
+
+static int fifo_spdif_trigger(struct snd_pcm_substream *substream, int cmd,
+			      struct snd_soc_dai *dai)
+{
+	struct snd_soc_component *component = dai->component;
+	int ret;
+
+	ret = aiu_fifo_trigger(substream, cmd, dai);
+	if (ret)
+		return ret;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		fifo_spdif_dcu_enable(component, true);
+		break;
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+	case SNDRV_PCM_TRIGGER_STOP:
+		fifo_spdif_dcu_enable(component, false);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int fifo_spdif_prepare(struct snd_pcm_substream *substream,
+			      struct snd_soc_dai *dai)
+{
+	struct snd_soc_component *component = dai->component;
+	int ret;
+
+	ret = aiu_fifo_prepare(substream, dai);
+	if (ret)
+		return ret;
+
+	snd_soc_component_update_bits(component,
+				      AIU_MEM_IEC958_BUF_CNTL,
+				      AIU_MEM_IEC958_BUF_CNTL_INIT,
+				      AIU_MEM_IEC958_BUF_CNTL_INIT);
+	snd_soc_component_update_bits(component,
+				      AIU_MEM_IEC958_BUF_CNTL,
+				      AIU_MEM_IEC958_BUF_CNTL_INIT, 0);
+
+	return 0;
+}
+
+static int fifo_spdif_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;
+	unsigned int val;
+	int ret;
+
+	ret = aiu_fifo_hw_params(substream, params, dai);
+	if (ret)
+		return ret;
+
+	val = AIU_MEM_IEC958_CONTROL_RD_DDR |
+	      AIU_MEM_IEC958_CONTROL_MODE_LINEAR;
+
+	switch (params_physical_width(params)) {
+	case 16:
+		val |= AIU_MEM_IEC958_CONTROL_MODE_16BIT;
+		break;
+	case 32:
+		break;
+	default:
+		dev_err(dai->dev, "Unsupported physical width %u\n",
+			params_physical_width(params));
+		return -EINVAL;
+	}
+
+	snd_soc_component_update_bits(component, AIU_MEM_IEC958_CONTROL,
+				      AIU_MEM_IEC958_CONTROL_ENDIAN |
+				      AIU_MEM_IEC958_CONTROL_RD_DDR |
+				      AIU_MEM_IEC958_CONTROL_MODE_LINEAR |
+				      AIU_MEM_IEC958_CONTROL_MODE_16BIT,
+				      val);
+
+	/* Number bytes read by the FIFO between each IRQ */
+	snd_soc_component_write(component, AIU_IEC958_BPF,
+				params_period_bytes(params));
+
+	/*
+	 * AUTO_DISABLE and SYNC_HEAD are enabled by default but
+	 * this should be disabled in PCM (uncompressed) mode
+	 */
+	snd_soc_component_update_bits(component, AIU_IEC958_DCU_FF_CTRL,
+				      AIU_IEC958_DCU_FF_CTRL_AUTO_DISABLE |
+				      AIU_IEC958_DCU_FF_CTRL_IRQ_MODE |
+				      AIU_IEC958_DCU_FF_CTRL_SYNC_HEAD_EN,
+				      AIU_IEC958_DCU_FF_CTRL_IRQ_FRAME_READ);
+
+	return 0;
+}
+
+const struct snd_soc_dai_ops aiu_fifo_spdif_dai_ops = {
+	.trigger	= fifo_spdif_trigger,
+	.prepare	= fifo_spdif_prepare,
+	.hw_params	= fifo_spdif_hw_params,
+	.hw_free	= aiu_fifo_hw_free,
+	.startup	= aiu_fifo_startup,
+	.shutdown	= aiu_fifo_shutdown,
+};
+
+int aiu_fifo_spdif_dai_probe(struct snd_soc_dai *dai)
+{
+	struct snd_soc_component *component = dai->component;
+	struct aiu *aiu = snd_soc_component_get_drvdata(component);
+	struct aiu_fifo *fifo;
+	int ret;
+
+	ret = aiu_fifo_dai_probe(dai);
+	if (ret)
+		return ret;
+
+	fifo = dai->playback_dma_data;
+
+	fifo->pcm = &fifo_spdif_pcm;
+	fifo->mem_offset = AIU_MEM_IEC958_START;
+	fifo->fifo_block = 1;
+	fifo->pclk = aiu->spdif.clks[PCLK].clk;
+	fifo->irq = aiu->spdif.irq;
+
+	return 0;
+}

sound/soc/meson/aiu-fifo.c

···
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (c) 2020 BayLibre, SAS.
+// Author: Jerome Brunet <[e-mail]>
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+#include <sound/soc-dai.h>
+
+#include "aiu-fifo.h"
+
+#define AIU_MEM_START	0x00
+#define AIU_MEM_RD	0x04
+#define AIU_MEM_END	0x08
+#define AIU_MEM_MASKS	0x0c
+#define  AIU_MEM_MASK_CH_RD GENMASK(7, 0)
+#define  AIU_MEM_MASK_CH_MEM GENMASK(15, 8)
+#define AIU_MEM_CONTROL	0x10
+#define  AIU_MEM_CONTROL_INIT BIT(0)
+#define  AIU_MEM_CONTROL_FILL_EN BIT(1)
+#define  AIU_MEM_CONTROL_EMPTY_EN BIT(2)
+
+static struct snd_soc_dai *aiu_fifo_dai(struct snd_pcm_substream *ss)
+{
+	struct snd_soc_pcm_runtime *rtd = ss->private_data;
+
+	return rtd->cpu_dai;
+}
+
+snd_pcm_uframes_t aiu_fifo_pointer(struct snd_soc_component *component,
+				   struct snd_pcm_substream *substream)
+{
+	struct snd_soc_dai *dai = aiu_fifo_dai(substream);
+	struct aiu_fifo *fifo = dai->playback_dma_data;
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	unsigned int addr;
+
+	snd_soc_component_read(component, fifo->mem_offset + AIU_MEM_RD,
+			       &addr);
+
+	return bytes_to_frames(runtime, addr - (unsigned int)runtime->dma_addr);
+}
+
+static void aiu_fifo_enable(struct snd_soc_dai *dai, bool enable)
+{
+	struct snd_soc_component *component = dai->component;
+	struct aiu_fifo *fifo = dai->playback_dma_data;
+	unsigned int en_mask = (AIU_MEM_CONTROL_FILL_EN |
+				AIU_MEM_CONTROL_EMPTY_EN);
+
+	snd_soc_component_update_bits(component,
+				      fifo->mem_offset + AIU_MEM_CONTROL,
+				      en_mask, enable ? en_mask : 0);
+}
+
+int aiu_fifo_trigger(struct snd_pcm_substream *substream, int cmd,
+		     struct snd_soc_dai *dai)
+{
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		aiu_fifo_enable(dai, true);
+		break;
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+	case SNDRV_PCM_TRIGGER_STOP:
+		aiu_fifo_enable(dai, false);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+int aiu_fifo_prepare(struct snd_pcm_substream *substream,
+		     struct snd_soc_dai *dai)
+{
+	struct snd_soc_component *component = dai->component;
+	struct aiu_fifo *fifo = dai->playback_dma_data;
+
+	snd_soc_component_update_bits(component,
+				      fifo->mem_offset + AIU_MEM_CONTROL,
+				      AIU_MEM_CONTROL_INIT,
+				      AIU_MEM_CONTROL_INIT);
+	snd_soc_component_update_bits(component,
+				      fifo->mem_offset + AIU_MEM_CONTROL,
+				      AIU_MEM_CONTROL_INIT, 0);
+	return 0;
+}
+
+int aiu_fifo_hw_params(struct snd_pcm_substream *substream,
+		       struct snd_pcm_hw_params *params,
+		       struct snd_soc_dai *dai)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_soc_component *component = dai->component;
+	struct aiu_fifo *fifo = dai->playback_dma_data;
+	dma_addr_t end;
+	int ret;
+
+	ret = snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
+	if (ret < 0)
+		return ret;
+
+	/* Setup the fifo boundaries */
+	end = runtime->dma_addr + runtime->dma_bytes - fifo->fifo_block;
+	snd_soc_component_write(component, fifo->mem_offset + AIU_MEM_START,
+				runtime->dma_addr);
+	snd_soc_component_write(component, fifo->mem_offset + AIU_MEM_RD,
+				runtime->dma_addr);
+	snd_soc_component_write(component, fifo->mem_offset + AIU_MEM_END,
+				end);
+
+	/* Setup the fifo to read all the memory - no skip */
+	snd_soc_component_update_bits(component,
+				      fifo->mem_offset + AIU_MEM_MASKS,
+				      AIU_MEM_MASK_CH_RD | AIU_MEM_MASK_CH_MEM,
+				      FIELD_PREP(AIU_MEM_MASK_CH_RD, 0xff) |
+				      FIELD_PREP(AIU_MEM_MASK_CH_MEM, 0xff));
+
+	return 0;
+}
+
+int aiu_fifo_hw_free(struct snd_pcm_substream *substream,
+		     struct snd_soc_dai *dai)
+{
+	return snd_pcm_lib_free_pages(substream);
+}
+
+static irqreturn_t aiu_fifo_isr(int irq, void *dev_id)
+{
+	struct snd_pcm_substream *playback = dev_id;
+
+	snd_pcm_period_elapsed(playback);
+
+	return IRQ_HANDLED;
+}
+
+int aiu_fifo_startup(struct snd_pcm_substream *substream,
+		     struct snd_soc_dai *dai)
+{
+	struct aiu_fifo *fifo = dai->playback_dma_data;
+	int ret;
+
+	snd_soc_set_runtime_hwparams(substream, fifo->pcm);
+
+	/*
+	 * Make sure the buffer and period size are multiple of the fifo burst
+	 * size
+	 */
+	ret = snd_pcm_hw_constraint_step(substream->runtime, 0,
+					 SNDRV_PCM_HW_PARAM_BUFFER_BYTES,
+					 fifo->fifo_block);
+	if (ret)
+		return ret;
+
+	ret = snd_pcm_hw_constraint_step(substream->runtime, 0,
+					 SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
+					 fifo->fifo_block);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(fifo->pclk);
+	if (ret)
+		return ret;
+
+	ret = request_irq(fifo->irq, aiu_fifo_isr, 0, dev_name(dai->dev),
+			  substream);
+	if (ret)
+		clk_disable_unprepare(fifo->pclk);
+
+	return ret;
+}
+
+void aiu_fifo_shutdown(struct snd_pcm_substream *substream,
+		       struct snd_soc_dai *dai)
+{
+	struct aiu_fifo *fifo = dai->playback_dma_data;
+
+	free_irq(fifo->irq, substream);
+	clk_disable_unprepare(fifo->pclk);
+}
+
+int aiu_fifo_pcm_new(struct snd_soc_pcm_runtime *rtd,
+		     struct snd_soc_dai *dai)
+{
+	struct snd_pcm_substream *substream =
+		rtd->pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream;
+	struct snd_card *card = rtd->card->snd_card;
+	struct aiu_fifo *fifo = dai->playback_dma_data;
+	size_t size = fifo->pcm->buffer_bytes_max;
+
+	snd_pcm_lib_preallocate_pages(substream,
+				      SNDRV_DMA_TYPE_DEV,
+				      card->dev, size, size);
+
+	return 0;
+}
+
+int aiu_fifo_dai_probe(struct snd_soc_dai *dai)
+{
+	struct aiu_fifo *fifo;
+
+	fifo = kzalloc(sizeof(*fifo), GFP_KERNEL);
+	if (!fifo)
+		return -ENOMEM;
+
+	dai->playback_dma_data = fifo;
+
+	return 0;
+}
+
+int aiu_fifo_dai_remove(struct snd_soc_dai *dai)
+{
+	kfree(dai->playback_dma_data);
+
+	return 0;
+}
+

sound/soc/meson/aiu-fifo.h

···
+/* SPDX-License-Identifier: (GPL-2.0 OR MIT) */
+/*
+ * Copyright (c) 2020 BayLibre, SAS.
+ * Author: Jerome Brunet <[e-mail]>
+ */
+
+#ifndef _MESON_AIU_FIFO_H
+#define _MESON_AIU_FIFO_H
+
+struct snd_pcm_hardware;
+struct snd_soc_component_driver;
+struct snd_soc_dai_driver;
+struct clk;
+struct snd_pcm_ops;
+struct snd_pcm_substream;
+struct snd_soc_dai;
+struct snd_pcm_hw_params;
+struct platform_device;
+
+struct aiu_fifo {
+	struct snd_pcm_hardware *pcm;
+	unsigned int mem_offset;
+	unsigned int fifo_block;
+	struct clk *pclk;
+	int irq;
+};
+
+int aiu_fifo_dai_probe(struct snd_soc_dai *dai);
+int aiu_fifo_dai_remove(struct snd_soc_dai *dai);
+
+snd_pcm_uframes_t aiu_fifo_pointer(struct snd_soc_component *component,
+				   struct snd_pcm_substream *substream);
+
+int aiu_fifo_trigger(struct snd_pcm_substream *substream, int cmd,
+		     struct snd_soc_dai *dai);
+int aiu_fifo_prepare(struct snd_pcm_substream *substream,
+		     struct snd_soc_dai *dai);
+int aiu_fifo_hw_params(struct snd_pcm_substream *substream,
+		       struct snd_pcm_hw_params *params,
+		       struct snd_soc_dai *dai);
+int aiu_fifo_hw_free(struct snd_pcm_substream *substream,
+		     struct snd_soc_dai *dai);
+int aiu_fifo_startup(struct snd_pcm_substream *substream,
+		     struct snd_soc_dai *dai);
+void aiu_fifo_shutdown(struct snd_pcm_substream *substream,
+		       struct snd_soc_dai *dai);
+int aiu_fifo_pcm_new(struct snd_soc_pcm_runtime *rtd,
+		     struct snd_soc_dai *dai);
+
+#endif /* _MESON_AIU_FIFO_H */

sound/soc/meson/aiu.c

···
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (c) 2020 BayLibre, SAS.
+// Author: Jerome Brunet <[e-mail]>
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+#include <sound/soc.h>
+#include <sound/soc-dai.h>
+
+#include <dt-bindings/sound/meson-aiu.h>
+#include "aiu.h"
+#include "aiu-fifo.h"
+
+#define AIU_I2S_MISC_958_SRC_SHIFT 3
+
+static const char * const aiu_spdif_encode_sel_texts[] = {
+	"SPDIF", "I2S",
+};
+
+static SOC_ENUM_SINGLE_DECL(aiu_spdif_encode_sel_enum, AIU_I2S_MISC,
+			    AIU_I2S_MISC_958_SRC_SHIFT,
+			    aiu_spdif_encode_sel_texts);
+
+static const struct snd_kcontrol_new aiu_spdif_encode_mux =
+	SOC_DAPM_ENUM("SPDIF Buffer Src", aiu_spdif_encode_sel_enum);
+
+static const struct snd_soc_dapm_widget aiu_cpu_dapm_widgets[] = {
+	SND_SOC_DAPM_MUX("SPDIF SRC SEL", SND_SOC_NOPM, 0, 0,
+			 &aiu_spdif_encode_mux),
+};
+
+static const struct snd_soc_dapm_route aiu_cpu_dapm_routes[] = {
+	{ "I2S Encoder Playback", NULL, "I2S FIFO Playback" },
+	{ "SPDIF SRC SEL", "SPDIF", "SPDIF FIFO Playback" },
+	{ "SPDIF SRC SEL", "I2S", "I2S FIFO Playback" },
+	{ "SPDIF Encoder Playback", NULL, "SPDIF SRC SEL" },
+};
+
+int aiu_of_xlate_dai_name(struct snd_soc_component *component,
+			  struct of_phandle_args *args,
+			  const char **dai_name,
+			  unsigned int component_id)
+{
+	struct snd_soc_dai *dai;
+	int id;
+
+	if (args->args_count != 2)
+		return -EINVAL;
+
+	if (args->args[0] != component_id)
+		return -EINVAL;
+
+	id = args->args[1];
+
+	if (id < 0 || id >= component->num_dai)
+		return -EINVAL;
+
+	for_each_component_dais(component, dai) {
+		if (id == 0)
+			break;
+		id--;
+	}
+
+	*dai_name = dai->driver->name;
+
+	return 0;
+}
+
+static int aiu_cpu_of_xlate_dai_name(struct snd_soc_component *component,
+				     struct of_phandle_args *args,
+				     const char **dai_name)
+{
+	return aiu_of_xlate_dai_name(component, args, dai_name, AIU_CPU);
+}
+
+static int aiu_cpu_component_probe(struct snd_soc_component *component)
+{
+	struct aiu *aiu = snd_soc_component_get_drvdata(component);
+
+	/* Required for the SPDIF Source control operation */
+	return clk_prepare_enable(aiu->i2s.clks[PCLK].clk);
+}
+
+static void aiu_cpu_component_remove(struct snd_soc_component *component)
+{
+	struct aiu *aiu = snd_soc_component_get_drvdata(component);
+
+	clk_disable_unprepare(aiu->i2s.clks[PCLK].clk);
+}
+
+static const struct snd_soc_component_driver aiu_cpu_component = {
+	.name			= "AIU CPU",
+	.dapm_widgets		= aiu_cpu_dapm_widgets,
+	.num_dapm_widgets	= ARRAY_SIZE(aiu_cpu_dapm_widgets),
+	.dapm_routes		= aiu_cpu_dapm_routes,
+	.num_dapm_routes	= ARRAY_SIZE(aiu_cpu_dapm_routes),
+	.of_xlate_dai_name	= aiu_cpu_of_xlate_dai_name,
+	.pointer		= aiu_fifo_pointer,
+	.probe			= aiu_cpu_component_probe,
+	.remove			= aiu_cpu_component_remove,
+};
+
+static struct snd_soc_dai_driver aiu_cpu_dai_drv[] = {
+	[CPU_I2S_FIFO] = {
+		.name = "I2S FIFO",
+		.playback = {
+			.stream_name	= "I2S FIFO Playback",
+			.channels_min	= 2,
+			.channels_max	= 8,
+			.rates		= SNDRV_PCM_RATE_CONTINUOUS,
+			.rate_min	= 5512,
+			.rate_max	= 192000,
+			.formats	= AIU_FORMATS,
+		},
+		.ops		= &aiu_fifo_i2s_dai_ops,
+		.pcm_new	= aiu_fifo_pcm_new,
+		.probe		= aiu_fifo_i2s_dai_probe,
+		.remove		= aiu_fifo_dai_remove,
+	},
+	[CPU_SPDIF_FIFO] = {
+		.name = "SPDIF FIFO",
+		.playback = {
+			.stream_name	= "SPDIF FIFO Playback",
+			.channels_min	= 2,
+			.channels_max	= 2,
+			.rates		= SNDRV_PCM_RATE_CONTINUOUS,
+			.rate_min	= 5512,
+			.rate_max	= 192000,
+			.formats	= AIU_FORMATS,
+		},
+		.ops		= &aiu_fifo_spdif_dai_ops,
+		.pcm_new	= aiu_fifo_pcm_new,
+		.probe		= aiu_fifo_spdif_dai_probe,
+		.remove		= aiu_fifo_dai_remove,
+	},
+	[CPU_I2S_ENCODER] = {
+		.name = "I2S Encoder",
+		.playback = {
+			.stream_name = "I2S Encoder Playback",
+			.channels_min = 2,
+			.channels_max = 8,
+			.rates = SNDRV_PCM_RATE_8000_192000,
+			.formats = AIU_FORMATS,
+		},
+		.ops = &aiu_encoder_i2s_dai_ops,
+	},
+	[CPU_SPDIF_ENCODER] = {
+		.name = "SPDIF Encoder",
+		.playback = {
+			.stream_name = "SPDIF Encoder Playback",
+			.channels_min = 2,
+			.channels_max = 2,
+			.rates = (SNDRV_PCM_RATE_32000  |
+				  SNDRV_PCM_RATE_44100  |
+				  SNDRV_PCM_RATE_48000  |
+				  SNDRV_PCM_RATE_88200  |
+				  SNDRV_PCM_RATE_96000  |
+				  SNDRV_PCM_RATE_176400 |
+				  SNDRV_PCM_RATE_192000),
+			.formats = AIU_FORMATS,
+		},
+		.ops = &aiu_encoder_spdif_dai_ops,
+	}
+};
+
+static const struct regmap_config aiu_regmap_cfg = {
+	.reg_bits	= 32,
+	.val_bits	= 32,
+	.reg_stride	= 4,
+	.max_register	= 0x2ac,
+};
+
+static int aiu_clk_bulk_get(struct device *dev,
+			    const char * const *ids,
+			    unsigned int num,
+			    struct aiu_interface *interface)
+{
+	struct clk_bulk_data *clks;
+	int i, ret;
+
+	clks = devm_kcalloc(dev, num, sizeof(clks), GFP_KERNEL);
+	if (!clks)
+		return -ENOMEM;
+
+	for (i = 0; i < num; i++)
+		clks[i].id = ids[i];
+
+	ret = devm_clk_bulk_get(dev, num, clks);
+	if (ret < 0)
+		return ret;
+
+	interface->clks = clks;
+	interface->clk_num = num;
+	return 0;
+}
+
+static const char * const aiu_i2s_ids[] = {
+	[PCLK]	= "i2s_pclk",
+	[AOCLK]	= "i2s_aoclk",
+	[MCLK]	= "i2s_mclk",
+	[MIXER]	= "i2s_mixer",
+};
+
+static const char * const aiu_spdif_ids[] = {
+	[PCLK]	= "spdif_pclk",
+	[AOCLK]	= "spdif_aoclk",
+	[MCLK]	= "spdif_mclk_sel"
+};
+
+static int aiu_clk_get(struct device *dev)
+{
+	struct aiu *aiu = dev_get_drvdata(dev);
+	int ret;
+
+	aiu->pclk = devm_clk_get(dev, "pclk");
+	if (IS_ERR(aiu->pclk)) {
+		if (PTR_ERR(aiu->pclk) != -EPROBE_DEFER)
+			dev_err(dev, "Can't get the aiu pclk\n");
+		return PTR_ERR(aiu->pclk);
+	}
+
+	aiu->spdif_mclk = devm_clk_get(dev, "spdif_mclk");
+	if (IS_ERR(aiu->spdif_mclk)) {
+		if (PTR_ERR(aiu->spdif_mclk) != -EPROBE_DEFER)
+			dev_err(dev, "Can't get the aiu spdif master clock\n");
+		return PTR_ERR(aiu->spdif_mclk);
+	}
+
+	ret = aiu_clk_bulk_get(dev, aiu_i2s_ids, ARRAY_SIZE(aiu_i2s_ids),
+			       &aiu->i2s);
+	if (ret) {
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "Can't get the i2s clocks\n");
+		return ret;
+	}
+
+	ret = aiu_clk_bulk_get(dev, aiu_spdif_ids, ARRAY_SIZE(aiu_spdif_ids),
+			       &aiu->spdif);
+	if (ret) {
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "Can't get the spdif clocks\n");
+		return ret;
+	}
+
+	ret = clk_prepare_enable(aiu->pclk);
+	if (ret) {
+		dev_err(dev, "peripheral clock enable failed\n");
+		return ret;
+	}
+
+	ret = devm_add_action_or_reset(dev,
+				       (void(*)(void *))clk_disable_unprepare,
+				       aiu->pclk);
+	if (ret)
+		dev_err(dev, "failed to add reset action on pclk");
+
+	return ret;
+}
+
+static int aiu_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	void __iomem *regs;
+	struct regmap *map;
+	struct aiu *aiu;
+	int ret;
+
+	aiu = devm_kzalloc(dev, sizeof(*aiu), GFP_KERNEL);
+	if (!aiu)
+		return -ENOMEM;
+	platform_set_drvdata(pdev, aiu);
+
+	ret = device_reset(dev);
+	if (ret) {
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "Failed to reset device\n");
+		return ret;
+	}
+
+	regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(regs))
+		return PTR_ERR(regs);
+
+	map = devm_regmap_init_mmio(dev, regs, &aiu_regmap_cfg);
+	if (IS_ERR(map)) {
+		dev_err(dev, "failed to init regmap: %ld\n",
+			PTR_ERR(map));
+		return PTR_ERR(map);
+	}
+
+	aiu->i2s.irq = platform_get_irq_byname(pdev, "i2s");
+	if (aiu->i2s.irq < 0) {
+		dev_err(dev, "Can't get i2s irq\n");
+		return aiu->i2s.irq;
+	}
+
+	aiu->spdif.irq = platform_get_irq_byname(pdev, "spdif");
+	if (aiu->spdif.irq < 0) {
+		dev_err(dev, "Can't get spdif irq\n");
+		return aiu->spdif.irq;
+	}
+
+	ret = aiu_clk_get(dev);
+	if (ret)
+		return ret;
+
+	/* Register the cpu component of the aiu */
+	ret = snd_soc_register_component(dev, &aiu_cpu_component,
+					 aiu_cpu_dai_drv,
+					 ARRAY_SIZE(aiu_cpu_dai_drv));
+	if (ret)
+		dev_err(dev, "Failed to register cpu component\n");
+
+	return ret;
+}
+
+static int aiu_remove(struct platform_device *pdev)
+{
+	snd_soc_unregister_component(&pdev->dev);
+
+	return 0;
+}
+
+static const struct of_device_id aiu_of_match[] = {
+	{ .compatible = "amlogic,aiu-gxbb", },
+	{ .compatible = "amlogic,aiu-gxl", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, aiu_of_match);
+
+static struct platform_driver aiu_pdrv = {
+	.probe = aiu_probe,
+	.remove = aiu_remove,
+	.driver = {
+		.name = "meson-aiu",
+		.of_match_table = aiu_of_match,
+	},
+};
+module_platform_driver(aiu_pdrv);
+
+MODULE_DESCRIPTION("Meson AIU Driver");
+MODULE_AUTHOR("Jerome Brunet <[e-mail]>");
+MODULE_LICENSE("GPL v2");

sound/soc/meson/aiu.h

···
+/* SPDX-License-Identifier: (GPL-2.0 OR MIT) */
+/*
+ * Copyright (c) 2018 BayLibre, SAS.
+ * Author: Jerome Brunet <[e-mail]>
+ */
+
+#ifndef _MESON_AIU_H
+#define _MESON_AIU_H
+
+struct clk;
+struct clk_bulk_data;
+struct device;
+struct of_phandle_args;
+struct snd_soc_component_driver;
+struct snd_soc_dai;
+struct snd_soc_dai_driver;
+struct snd_soc_dai_ops;
+
+enum aiu_clk_ids {
+	PCLK = 0,
+	AOCLK,
+	MCLK,
+	MIXER
+};
+
+struct aiu_interface {
+	struct clk_bulk_data *clks;
+	unsigned int clk_num;
+	unsigned int irq;
+};
+
+struct aiu {
+	struct clk *pclk;
+	struct clk *spdif_mclk;
+	struct aiu_interface i2s;
+	struct aiu_interface spdif;
+};
+
+#define AIU_FORMATS (SNDRV_PCM_FMTBIT_S16_LE |	\
+		     SNDRV_PCM_FMTBIT_S20_LE |	\
+		     SNDRV_PCM_FMTBIT_S24_LE)
+
+int aiu_of_xlate_dai_name(struct snd_soc_component *component,
+			  struct of_phandle_args *args,
+			  const char **dai_name,
+			  unsigned int component_id);
+
+int aiu_fifo_i2s_dai_probe(struct snd_soc_dai *dai);
+int aiu_fifo_spdif_dai_probe(struct snd_soc_dai *dai);
+
+extern const struct snd_soc_dai_ops aiu_fifo_i2s_dai_ops;
+extern const struct snd_soc_dai_ops aiu_fifo_spdif_dai_ops;
+extern const struct snd_soc_dai_ops aiu_encoder_i2s_dai_ops;
+extern const struct snd_soc_dai_ops aiu_encoder_spdif_dai_ops;
+
+#define AIU_IEC958_BPF			0x000
+#define AIU_958_MISC			0x010
+#define AIU_IEC958_DCU_FF_CTRL		0x01c
+#define AIU_958_CHSTAT_L0		0x020
+#define AIU_958_CHSTAT_L1		0x024
+#define AIU_958_CTRL			0x028
+#define AIU_I2S_SOURCE_DESC		0x034
+#define AIU_I2S_DAC_CFG			0x040
+#define AIU_I2S_SYNC			0x044
+#define AIU_I2S_MISC			0x048
+#define AIU_RST_SOFT			0x054
+#define AIU_CLK_CTRL			0x058
+#define AIU_CLK_CTRL_MORE		0x064
+#define AIU_CODEC_DAC_LRCLK_CTRL	0x0a0
+#define AIU_HDMI_CLK_DATA_CTRL		0x0a8
+#define AIU_ACODEC_CTRL			0x0b0
+#define AIU_958_CHSTAT_R0		0x0c0
+#define AIU_958_CHSTAT_R1		0x0c4
+#define AIU_MEM_I2S_START		0x180
+#define AIU_MEM_I2S_MASKS		0x18c
+#define AIU_MEM_I2S_CONTROL		0x190
+#define AIU_MEM_IEC958_START		0x194
+#define AIU_MEM_IEC958_CONTROL		0x1a4
+#define AIU_MEM_I2S_BUF_CNTL		0x1d8
+#define AIU_MEM_IEC958_BUF_CNTL		0x1fc
+
+#endif /* _MESON_AIU_H */