ASoC: spacemit: add i2s support for K1 SoC

Add ASoC platform driver for the SpacemiT K1 SoC full-duplex I2S
controller.

Co-developer: Jinmei Wei <[e-mail]>
Signed-off-by: Jinmei Wei <[e-mail]>
Signed-off-by: Troy Mitchell <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

sound/soc/Kconfig

···
 source "sound/soc/rockchip/Kconfig"
 source "sound/soc/samsung/Kconfig"
 source "sound/soc/sdca/Kconfig"
+source "sound/soc/spacemit/Kconfig"
 source "sound/soc/spear/Kconfig"
 source "sound/soc/sprd/Kconfig"
 source "sound/soc/starfive/Kconfig"

sound/soc/Makefile

···
 obj-$(CONFIG_SND_SOC)	+= samsung/
 obj-$(CONFIG_SND_SOC)	+= sdca/
 obj-$(CONFIG_SND_SOC)	+= sof/
+obj-$(CONFIG_SND_SOC)	+= spacemit/
 obj-$(CONFIG_SND_SOC)	+= spear/
 obj-$(CONFIG_SND_SOC)	+= sprd/
 obj-$(CONFIG_SND_SOC)	+= starfive/

sound/soc/spacemit/Kconfig

···
+# SPDX-License-Identifier: GPL-2.0-only
+menu "SpacemiT"
+	depends on COMPILE_TEST || ARCH_SPACEMIT
+	depends on HAVE_CLK
+
+config SND_SOC_K1_I2S
+	tristate "K1 I2S Device Driver"
+	select SND_SOC_GENERIC_DMAENGINE_PCM
+	select CMA
+	select DMA_CMA
+	help
+	  Say Y or M if you want to add support for I2S driver for
+	  K1 I2S controller. The device supports up to maximum of
+	  2 channels each for play and record.
+
+endmenu

sound/soc/spacemit/Makefile

···
+# SPDX-License-Identifier: GPL-2.0
+# K1 Platform Support
+snd-soc-k1-i2s-y := k1_i2s.o
+
+obj-$(CONFIG_SND_SOC_K1_I2S) += snd-soc-k1-i2s.o

sound/soc/spacemit/k1_i2s.c

···
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2025 Troy Mitchell <[e-mail]> */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/reset.h>
+#include <sound/dmaengine_pcm.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+
+#define SSCR			0x00	/* SPI/I2S top control register */
+#define SSFCR			0x04	/* SPI/I2S FIFO control register */
+#define SSINTEN			0x08	/* SPI/I2S interrupt enable register */
+#define SSDATR			0x10	/* SPI/I2S data register */
+#define SSPSP			0x18	/* SPI/I2S programmable serial protocol control register */
+#define SSRWT			0x24	/* SPI/I2S root control register */
+
+/* SPI/I2S Work data size, register bits value 0~31 indicated data size 1~32 bits */
+#define SSCR_FIELD_DSS		GENMASK(9, 5)
+#define SSCR_DW_8BYTE		FIELD_PREP(SSCR_FIELD_DSS, 0x7)
+#define SSCR_DW_16BYTE		FIELD_PREP(SSCR_FIELD_DSS, 0xf)
+#define SSCR_DW_18BYTE		FIELD_PREP(SSCR_FIELD_DSS, 0x11)
+#define SSCR_DW_32BYTE		FIELD_PREP(SSCR_FIELD_DSS, 0x1f)
+
+#define SSCR_SSE		BIT(0)		/* SPI/I2S Enable */
+#define SSCR_FRF_PSP		GENMASK(2, 1)	/* Frame Format*/
+#define SSCR_TRAIL		BIT(13)		/* Trailing Byte */
+
+#define SSFCR_FIELD_TFT		GENMASK(3, 0)   /* TXFIFO Trigger Threshold */
+#define SSFCR_FIELD_RFT		GENMASK(8, 5)   /* RXFIFO Trigger Threshold */
+#define SSFCR_TSRE		BIT(10)		/* Transmit Service Request Enable */
+#define SSFCR_RSRE		BIT(11)		/* Receive Service Request Enable */
+
+#define SSPSP_FSRT		BIT(3)		/* Frame Sync Relative Timing Bit */
+#define SSPSP_SFRMP		BIT(4)		/* Serial Frame Polarity */
+#define SSPSP_FIELD_SFRMWDTH	GENMASK(17, 12)	/* Serial Frame Width field  */
+
+#define SSRWT_RWOT		BIT(0)		/* Receive Without Transmit */
+
+#define SPACEMIT_PCM_RATES	(SNDRV_PCM_RATE_8000 | SNDRV_PCM_RATE_16000 | \
+				SNDRV_PCM_RATE_48000)
+#define SPACEMIT_PCM_FORMATS	(SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S32_LE)
+
+#define SPACEMIT_I2S_PERIOD_SIZE 1024
+
+struct spacemit_i2s_dev {
+	struct device *dev;
+
+	void __iomem *base;
+
+	struct reset_control *reset;
+
+	struct clk *sysclk;
+	struct clk *bclk;
+	struct clk *sspa_clk;
+
+	struct snd_dmaengine_dai_dma_data capture_dma_data;
+	struct snd_dmaengine_dai_dma_data playback_dma_data;
+
+	bool has_capture;
+	bool has_playback;
+
+	int dai_fmt;
+
+	int started_count;
+};
+
+static const struct snd_pcm_hardware spacemit_pcm_hardware = {
+	.info		  = SNDRV_PCM_INFO_INTERLEAVED |
+			    SNDRV_PCM_INFO_BATCH,
+	.formats          = SPACEMIT_PCM_FORMATS,
+	.rates		  = SPACEMIT_PCM_RATES,
+	.rate_min         = SNDRV_PCM_RATE_8000,
+	.rate_max         = SNDRV_PCM_RATE_192000,
+	.channels_min     = 1,
+	.channels_max     = 2,
+	.buffer_bytes_max = SPACEMIT_I2S_PERIOD_SIZE * 4 * 4,
+	.period_bytes_min = SPACEMIT_I2S_PERIOD_SIZE * 2,
+	.period_bytes_max = SPACEMIT_I2S_PERIOD_SIZE * 4,
+	.periods_min	  = 2,
+	.periods_max	  = 4,
+};
+
+static const struct snd_dmaengine_pcm_config spacemit_dmaengine_pcm_config = {
+	.pcm_hardware = &spacemit_pcm_hardware,
+	.prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config,
+	.chan_names = {"tx", "rx"},
+	.prealloc_buffer_size = 32 * 1024,
+};
+
+static void spacemit_i2s_init(struct spacemit_i2s_dev *i2s)
+{
+	u32 sscr_val, sspsp_val, ssfcr_val, ssrwt_val;
+
+	sscr_val = SSCR_TRAIL | SSCR_FRF_PSP;
+	ssfcr_val = FIELD_PREP(SSFCR_FIELD_TFT, 5) |
+		    FIELD_PREP(SSFCR_FIELD_RFT, 5) |
+		    SSFCR_RSRE | SSFCR_TSRE;
+	ssrwt_val = SSRWT_RWOT;
+	sspsp_val = SSPSP_SFRMP;
+
+	writel(sscr_val, i2s->base + SSCR);
+	writel(ssfcr_val, i2s->base + SSFCR);
+	writel(sspsp_val, i2s->base + SSPSP);
+	writel(ssrwt_val, i2s->base + SSRWT);
+	writel(0, i2s->base + SSINTEN);
+}
+
+static int spacemit_i2s_hw_params(struct snd_pcm_substream *substream,
+				  struct snd_pcm_hw_params *params,
+				  struct snd_soc_dai *dai)
+{
+	struct spacemit_i2s_dev *i2s = snd_soc_dai_get_drvdata(dai);
+	struct snd_dmaengine_dai_dma_data *dma_data;
+	u32 data_width, data_bits;
+	unsigned long bclk_rate;
+	u32 val;
+	int ret;
+
+	val = readl(i2s->base + SSCR);
+	if (val & SSCR_SSE)
+		return 0;
+
+	dma_data = &i2s->playback_dma_data;
+
+	if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
+		dma_data = &i2s->capture_dma_data;
+
+	switch (params_format(params)) {
+	case SNDRV_PCM_FORMAT_S8:
+		data_bits = 8;
+		data_width = SSCR_DW_8BYTE;
+		dma_data->maxburst = 8;
+		dma_data->addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+		break;
+	case SNDRV_PCM_FORMAT_S16_LE:
+		data_bits = 16;
+		data_width = SSCR_DW_16BYTE;
+		dma_data->maxburst = 16;
+		dma_data->addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
+		break;
+	case SNDRV_PCM_FORMAT_S32_LE:
+		data_bits = 32;
+		data_width = SSCR_DW_32BYTE;
+		dma_data->maxburst = 32;
+		dma_data->addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+		break;
+	default:
+		dev_dbg(i2s->dev, "unexpected data width type");
+		return -EINVAL;
+	}
+
+	switch (i2s->dai_fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
+	case SND_SOC_DAIFMT_I2S:
+		if (data_bits == 16) {
+			data_width = SSCR_DW_32BYTE;
+			dma_data->maxburst = 32;
+			dma_data->addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+		}
+
+		snd_pcm_hw_constraint_minmax(substream->runtime,
+					     SNDRV_PCM_HW_PARAM_CHANNELS,
+					     1, 2);
+		snd_pcm_hw_constraint_mask64(substream->runtime,
+					     SNDRV_PCM_HW_PARAM_FORMAT,
+					     SNDRV_PCM_FMTBIT_S16_LE);
+		break;
+	case SND_SOC_DAIFMT_DSP_A:
+	case SND_SOC_DAIFMT_DSP_B:
+		snd_pcm_hw_constraint_minmax(substream->runtime,
+					     SNDRV_PCM_HW_PARAM_CHANNELS,
+					     1, 1);
+		snd_pcm_hw_constraint_mask64(substream->runtime,
+					     SNDRV_PCM_HW_PARAM_FORMAT,
+					     SNDRV_PCM_FMTBIT_S32_LE);
+		break;
+	default:
+		dev_dbg(i2s->dev, "unexpected format type");
+		return -EINVAL;
+
+	}
+
+	val = readl(i2s->base + SSCR);
+	val &= ~SSCR_DW_32BYTE;
+	val |= data_width;
+	writel(val, i2s->base + SSCR);
+
+	bclk_rate = params_channels(params) *
+		    params_rate(params) *
+		    data_bits;
+
+	ret = clk_set_rate(i2s->bclk, bclk_rate);
+	if (ret)
+		return ret;
+
+	return clk_set_rate(i2s->sspa_clk, bclk_rate);
+}
+
+static int spacemit_i2s_set_sysclk(struct snd_soc_dai *cpu_dai, int clk_id,
+				   unsigned int freq, int dir)
+{
+	struct spacemit_i2s_dev *i2s = dev_get_drvdata(cpu_dai->dev);
+
+	if (freq == 0)
+		return 0;
+
+	return clk_set_rate(i2s->sysclk, freq);
+}
+
+static int spacemit_i2s_set_fmt(struct snd_soc_dai *cpu_dai,
+				unsigned int fmt)
+{
+	struct spacemit_i2s_dev *i2s = dev_get_drvdata(cpu_dai->dev);
+	u32 sspsp_val;
+
+	sspsp_val = readl(i2s->base + SSPSP);
+	sspsp_val &= ~SSPSP_FIELD_SFRMWDTH;
+	sspsp_val |= SSPSP_FSRT;
+
+	i2s->dai_fmt = fmt;
+
+	switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
+	case SND_SOC_DAIFMT_I2S:
+		sspsp_val |= FIELD_PREP(SSPSP_FIELD_SFRMWDTH, 0x10);
+		break;
+	case SND_SOC_DAIFMT_DSP_B:
+		/* DSP_B: next frame asserted after previous frame end, so clear FSRT */
+		sspsp_val &= ~SSPSP_FSRT;
+		fallthrough;
+	case SND_SOC_DAIFMT_DSP_A:
+		sspsp_val |= FIELD_PREP(SSPSP_FIELD_SFRMWDTH, 0x1);
+		break;
+	default:
+		dev_dbg(i2s->dev, "unexpected format type");
+		return -EINVAL;
+	}
+
+	writel(sspsp_val, i2s->base + SSPSP);
+
+	return 0;
+}
+
+static int spacemit_i2s_trigger(struct snd_pcm_substream *substream,
+				int cmd, struct snd_soc_dai *dai)
+{
+	struct spacemit_i2s_dev *i2s = snd_soc_dai_get_drvdata(dai);
+	u32 val;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		if (!i2s->started_count) {
+			val = readl(i2s->base + SSCR);
+			val |= SSCR_SSE;
+			writel(val, i2s->base + SSCR);
+		}
+		i2s->started_count++;
+		break;
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		if (i2s->started_count)
+			i2s->started_count--;
+
+		if (!i2s->started_count) {
+			val = readl(i2s->base + SSCR);
+			val &= ~SSCR_SSE;
+			writel(val, i2s->base + SSCR);
+		}
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int spacemit_i2s_dai_probe(struct snd_soc_dai *dai)
+{
+	struct spacemit_i2s_dev *i2s = snd_soc_dai_get_drvdata(dai);
+
+	snd_soc_dai_init_dma_data(dai,
+				  i2s->has_playback ? &i2s->playback_dma_data : NULL,
+				  i2s->has_capture ? &i2s->capture_dma_data : NULL);
+
+	reset_control_deassert(i2s->reset);
+
+	spacemit_i2s_init(i2s);
+
+	return 0;
+}
+
+static int spacemit_i2s_dai_remove(struct snd_soc_dai *dai)
+{
+	struct spacemit_i2s_dev *i2s = snd_soc_dai_get_drvdata(dai);
+
+	reset_control_assert(i2s->reset);
+
+	return 0;
+}
+
+static const struct snd_soc_dai_ops spacemit_i2s_dai_ops = {
+	.probe = spacemit_i2s_dai_probe,
+	.remove = spacemit_i2s_dai_remove,
+	.hw_params = spacemit_i2s_hw_params,
+	.set_sysclk = spacemit_i2s_set_sysclk,
+	.set_fmt = spacemit_i2s_set_fmt,
+	.trigger = spacemit_i2s_trigger,
+};
+
+static struct snd_soc_dai_driver spacemit_i2s_dai = {
+	.ops = &spacemit_i2s_dai_ops,
+	.playback = {
+		.channels_min = 1,
+		.channels_max = 2,
+		.rates = SPACEMIT_PCM_RATES,
+		.rate_min = SNDRV_PCM_RATE_8000,
+		.rate_max = SNDRV_PCM_RATE_48000,
+		.formats = SPACEMIT_PCM_FORMATS,
+	},
+	.capture = {
+		.channels_min = 1,
+		.channels_max = 2,
+		.rates = SPACEMIT_PCM_RATES,
+		.rate_min = SNDRV_PCM_RATE_8000,
+		.rate_max = SNDRV_PCM_RATE_48000,
+		.formats = SPACEMIT_PCM_FORMATS,
+	},
+	.symmetric_rate = 1,
+};
+
+static int spacemit_i2s_init_dai(struct spacemit_i2s_dev *i2s,
+				 struct snd_soc_dai_driver **dp,
+				 dma_addr_t addr)
+{
+	struct device_node *node = i2s->dev->of_node;
+	struct snd_soc_dai_driver *dai;
+	struct property *dma_names;
+	const char *dma_name;
+
+	of_property_for_each_string(node, "dma-names", dma_names, dma_name) {
+		if (!strcmp(dma_name, "tx"))
+			i2s->has_playback = true;
+		if (!strcmp(dma_name, "rx"))
+			i2s->has_capture = true;
+	}
+
+	dai = devm_kmemdup(i2s->dev, &spacemit_i2s_dai,
+			   sizeof(*dai), GFP_KERNEL);
+	if (!dai)
+		return -ENOMEM;
+
+	if (i2s->has_playback) {
+		dai->playback.stream_name = "Playback";
+		dai->playback.channels_min = 1;
+		dai->playback.channels_max = 2;
+		dai->playback.rates = SPACEMIT_PCM_RATES;
+		dai->playback.formats = SPACEMIT_PCM_FORMATS;
+
+		i2s->playback_dma_data.addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
+		i2s->playback_dma_data.maxburst = 32;
+		i2s->playback_dma_data.addr = addr;
+	}
+
+	if (i2s->has_capture) {
+		dai->capture.stream_name = "Capture";
+		dai->capture.channels_min = 1;
+		dai->capture.channels_max = 2;
+		dai->capture.rates = SPACEMIT_PCM_RATES;
+		dai->capture.formats = SPACEMIT_PCM_FORMATS;
+
+		i2s->capture_dma_data.addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
+		i2s->capture_dma_data.maxburst = 32;
+		i2s->capture_dma_data.addr = addr;
+	}
+
+	if (dp)
+		*dp = dai;
+
+	return 0;
+}
+
+static const struct snd_soc_component_driver spacemit_i2s_component = {
+	.name = "i2s-k1",
+	.legacy_dai_naming = 1,
+};
+
+static int spacemit_i2s_probe(struct platform_device *pdev)
+{
+	struct snd_soc_dai_driver *dai;
+	struct spacemit_i2s_dev *i2s;
+	struct resource *res;
+	struct clk *clk;
+	int ret;
+
+	i2s = devm_kzalloc(&pdev->dev, sizeof(*i2s), GFP_KERNEL);
+	if (!i2s)
+		return -ENOMEM;
+
+	i2s->dev = &pdev->dev;
+
+	i2s->sysclk = devm_clk_get_enabled(i2s->dev, "sysclk");
+	if (IS_ERR(i2s->sysclk))
+		return dev_err_probe(i2s->dev, PTR_ERR(i2s->sysclk),
+				     "failed to enable sysbase clock\n");
+
+	i2s->bclk = devm_clk_get_enabled(i2s->dev, "bclk");
+	if (IS_ERR(i2s->bclk))
+		return dev_err_probe(i2s->dev, PTR_ERR(i2s->bclk), "failed to enable bit clock\n");
+
+	clk = devm_clk_get_enabled(i2s->dev, "sspa_bus");
+	if (IS_ERR(clk))
+		return dev_err_probe(i2s->dev, PTR_ERR(clk), "failed to enable sspa_bus clock\n");
+
+	i2s->sspa_clk = devm_clk_get_enabled(i2s->dev, "sspa");
+	if (IS_ERR(clk))
+		return dev_err_probe(i2s->dev, PTR_ERR(clk), "failed to enable sspa clock\n");
+
+	i2s->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
+	if (IS_ERR(i2s->base))
+		return dev_err_probe(i2s->dev, PTR_ERR(i2s->base), "failed to map registers\n");
+
+	i2s->reset = devm_reset_control_get_exclusive(&pdev->dev, NULL);
+	if (IS_ERR(i2s->reset))
+		return dev_err_probe(i2s->dev, PTR_ERR(i2s->reset),
+				     "failed to get reset control");
+
+	dev_set_drvdata(i2s->dev, i2s);
+
+	spacemit_i2s_init_dai(i2s, &dai, res->start + SSDATR);
+
+	ret = devm_snd_soc_register_component(i2s->dev,
+					      &spacemit_i2s_component,
+					      dai, 1);
+	if (ret)
+		return dev_err_probe(i2s->dev, ret, "failed to register component");
+
+	return devm_snd_dmaengine_pcm_register(&pdev->dev, &spacemit_dmaengine_pcm_config, 0);
+}
+
+static const struct of_device_id spacemit_i2s_of_match[] = {
+	{ .compatible = "spacemit,k1-i2s", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, spacemit_i2s_of_match);
+
+static struct platform_driver spacemit_i2s_driver = {
+	.probe = spacemit_i2s_probe,
+	.driver = {
+		.name = "i2s-k1",
+		.of_match_table = spacemit_i2s_of_match,
+	},
+};
+module_platform_driver(spacemit_i2s_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("I2S bus driver for SpacemiT K1 SoC");