ASoC: stm32: add SAI driver

This patch implements SAI ASoC driver for STM32.

Signed-off-by: olivier moysan <olivier.moysan@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 884 insertions, 0 deletions

diff --git a/sound/soc/stm/stm32_sai_sub.c b/sound/soc/stm/stm32_sai_sub.c
new file mode 100644
index 000000000000..ae4706ca265b
--- /dev/null
+++ b/sound/soc/stm/stm32_sai_sub.c
@@ -0,0 +1,884 @@
+/*
+ * STM32 ALSA SoC Digital Audio Interface (SAI) driver.
+ *
+ * Copyright (C) 2016, STMicroelectronics - All Rights Reserved
+ * Author(s): Olivier Moysan <olivier.moysan@st.com> for STMicroelectronics.
+ *
+ * License terms: GPL V2.0.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+ * details.
+ */
+
+#include <linux/clk.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/regmap.h>
+
+#include <sound/core.h>
+#include <sound/dmaengine_pcm.h>
+#include <sound/pcm_params.h>
+
+#include "stm32_sai.h"
+
+#define SAI_FREE_PROTOCOL	0x0
+
+#define SAI_SLOT_SIZE_AUTO	0x0
+#define SAI_SLOT_SIZE_16	0x1
+#define SAI_SLOT_SIZE_32	0x2
+
+#define SAI_DATASIZE_8		0x2
+#define SAI_DATASIZE_10		0x3
+#define SAI_DATASIZE_16		0x4
+#define SAI_DATASIZE_20		0x5
+#define SAI_DATASIZE_24		0x6
+#define SAI_DATASIZE_32		0x7
+
+#define STM_SAI_FIFO_SIZE	8
+#define STM_SAI_DAI_NAME_SIZE	15
+
+#define STM_SAI_IS_PLAYBACK(ip)	((ip)->dir == SNDRV_PCM_STREAM_PLAYBACK)
+#define STM_SAI_IS_CAPTURE(ip)	((ip)->dir == SNDRV_PCM_STREAM_CAPTURE)
+
+#define STM_SAI_A_ID		0x0
+#define STM_SAI_B_ID		0x1
+
+#define STM_SAI_BLOCK_NAME(x)	(((x)->id == STM_SAI_A_ID) ? "A" : "B")
+
+/**
+ * struct stm32_sai_sub_data - private data of SAI sub block (block A or B)
+ * @pdev: device data pointer
+ * @regmap: SAI register map pointer
+ * @dma_params: dma configuration data for rx or tx channel
+ * @cpu_dai_drv: DAI driver data pointer
+ * @cpu_dai: DAI runtime data pointer
+ * @substream: PCM substream data pointer
+ * @pdata: SAI block parent data pointer
+ * @sai_ck: kernel clock feeding the SAI clock generator
+ * @phys_addr: SAI registers physical base address
+ * @mclk_rate: SAI block master clock frequency (Hz). set at init
+ * @id: SAI sub block id corresponding to sub-block A or B
+ * @dir: SAI block direction (playback or capture). set at init
+ * @master: SAI block mode flag. (true=master, false=slave) set at init
+ * @fmt: SAI block format. relevant only for custom protocols. set at init
+ * @sync: SAI block synchronization mode. (none, internal or external)
+ * @fs_length: frame synchronization length. depends on protocol settings
+ * @slots: rx or tx slot number
+ * @slot_width: rx or tx slot width in bits
+ * @slot_mask: rx or tx active slots mask. set at init or at runtime
+ * @data_size: PCM data width. corresponds to PCM substream width.
+ */
+struct stm32_sai_sub_data {
+	struct platform_device *pdev;
+	struct regmap *regmap;
+	struct snd_dmaengine_dai_dma_data dma_params;
+	struct snd_soc_dai_driver *cpu_dai_drv;
+	struct snd_soc_dai *cpu_dai;
+	struct snd_pcm_substream *substream;
+	struct stm32_sai_data *pdata;
+	struct clk *sai_ck;
+	dma_addr_t phys_addr;
+	unsigned int mclk_rate;
+	unsigned int id;
+	int dir;
+	bool master;
+	int fmt;
+	int sync;
+	int fs_length;
+	int slots;
+	int slot_width;
+	int slot_mask;
+	int data_size;
+};
+
+enum stm32_sai_fifo_th {
+	STM_SAI_FIFO_TH_EMPTY,
+	STM_SAI_FIFO_TH_QUARTER,
+	STM_SAI_FIFO_TH_HALF,
+	STM_SAI_FIFO_TH_3_QUARTER,
+	STM_SAI_FIFO_TH_FULL,
+};
+
+static bool stm32_sai_sub_readable_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case STM_SAI_CR1_REGX:
+	case STM_SAI_CR2_REGX:
+	case STM_SAI_FRCR_REGX:
+	case STM_SAI_SLOTR_REGX:
+	case STM_SAI_IMR_REGX:
+	case STM_SAI_SR_REGX:
+	case STM_SAI_CLRFR_REGX:
+	case STM_SAI_DR_REGX:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool stm32_sai_sub_volatile_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case STM_SAI_DR_REGX:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool stm32_sai_sub_writeable_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case STM_SAI_CR1_REGX:
+	case STM_SAI_CR2_REGX:
+	case STM_SAI_FRCR_REGX:
+	case STM_SAI_SLOTR_REGX:
+	case STM_SAI_IMR_REGX:
+	case STM_SAI_SR_REGX:
+	case STM_SAI_CLRFR_REGX:
+	case STM_SAI_DR_REGX:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static const struct regmap_config stm32_sai_sub_regmap_config = {
+	.reg_bits = 32,
+	.reg_stride = 4,
+	.val_bits = 32,
+	.max_register = STM_SAI_DR_REGX,
+	.readable_reg = stm32_sai_sub_readable_reg,
+	.volatile_reg = stm32_sai_sub_volatile_reg,
+	.writeable_reg = stm32_sai_sub_writeable_reg,
+	.fast_io = true,
+};
+
+static irqreturn_t stm32_sai_isr(int irq, void *devid)
+{
+	struct stm32_sai_sub_data *sai = (struct stm32_sai_sub_data *)devid;
+	struct snd_pcm_substream *substream = sai->substream;
+	struct platform_device *pdev = sai->pdev;
+	unsigned int sr, imr, flags;
+	snd_pcm_state_t status = SNDRV_PCM_STATE_RUNNING;
+
+	regmap_read(sai->regmap, STM_SAI_IMR_REGX, &imr);
+	regmap_read(sai->regmap, STM_SAI_SR_REGX, &sr);
+
+	flags = sr & imr;
+	if (!flags)
+		return IRQ_NONE;
+
+	regmap_update_bits(sai->regmap, STM_SAI_CLRFR_REGX, SAI_XCLRFR_MASK,
+			   SAI_XCLRFR_MASK);
+
+	if (flags & SAI_XIMR_OVRUDRIE) {
+		dev_err(&pdev->dev, "IT %s\n",
+			STM_SAI_IS_PLAYBACK(sai) ? "underrun" : "overrun");
+		status = SNDRV_PCM_STATE_XRUN;
+	}
+
+	if (flags & SAI_XIMR_MUTEDETIE)
+		dev_dbg(&pdev->dev, "IT mute detected\n");
+
+	if (flags & SAI_XIMR_WCKCFGIE) {
+		dev_err(&pdev->dev, "IT wrong clock configuration\n");
+		status = SNDRV_PCM_STATE_DISCONNECTED;
+	}
+
+	if (flags & SAI_XIMR_CNRDYIE)
+		dev_warn(&pdev->dev, "IT Codec not ready\n");
+
+	if (flags & SAI_XIMR_AFSDETIE) {
+		dev_warn(&pdev->dev, "IT Anticipated frame synchro\n");
+		status = SNDRV_PCM_STATE_XRUN;
+	}
+
+	if (flags & SAI_XIMR_LFSDETIE) {
+		dev_warn(&pdev->dev, "IT Late frame synchro\n");
+		status = SNDRV_PCM_STATE_XRUN;
+	}
+
+	if (status != SNDRV_PCM_STATE_RUNNING) {
+		snd_pcm_stream_lock(substream);
+		snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
+		snd_pcm_stream_unlock(substream);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int stm32_sai_set_sysclk(struct snd_soc_dai *cpu_dai,
+				int clk_id, unsigned int freq, int dir)
+{
+	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
+
+	if ((dir == SND_SOC_CLOCK_OUT) && sai->master) {
+		sai->mclk_rate = freq;
+		dev_dbg(cpu_dai->dev, "SAI MCLK frequency is %uHz\n", freq);
+	}
+
+	return 0;
+}
+
+static int stm32_sai_set_dai_tdm_slot(struct snd_soc_dai *cpu_dai, u32 tx_mask,
+				      u32 rx_mask, int slots, int slot_width)
+{
+	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
+	int slotr, slotr_mask, slot_size;
+
+	dev_dbg(cpu_dai->dev, "masks tx/rx:%#x/%#x, slots:%d, width:%d\n",
+		tx_mask, rx_mask, slots, slot_width);
+
+	switch (slot_width) {
+	case 16:
+		slot_size = SAI_SLOT_SIZE_16;
+		break;
+	case 32:
+		slot_size = SAI_SLOT_SIZE_32;
+		break;
+	default:
+		slot_size = SAI_SLOT_SIZE_AUTO;
+		break;
+	}
+
+	slotr = SAI_XSLOTR_SLOTSZ_SET(slot_size) |
+		SAI_XSLOTR_NBSLOT_SET(slots - 1);
+	slotr_mask = SAI_XSLOTR_SLOTSZ_MASK | SAI_XSLOTR_NBSLOT_MASK;
+
+	/* tx/rx mask set in machine init, if slot number defined in DT */
+	if (STM_SAI_IS_PLAYBACK(sai)) {
+		sai->slot_mask = tx_mask;
+		slotr |= SAI_XSLOTR_SLOTEN_SET(tx_mask);
+	}
+
+	if (STM_SAI_IS_CAPTURE(sai)) {
+		sai->slot_mask = rx_mask;
+		slotr |= SAI_XSLOTR_SLOTEN_SET(rx_mask);
+	}
+
+	slotr_mask |= SAI_XSLOTR_SLOTEN_MASK;
+
+	regmap_update_bits(sai->regmap, STM_SAI_SLOTR_REGX, slotr_mask, slotr);
+
+	sai->slot_width = slot_width;
+	sai->slots = slots;
+
+	return 0;
+}
+
+static int stm32_sai_set_dai_fmt(struct snd_soc_dai *cpu_dai, unsigned int fmt)
+{
+	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
+	int cr1 = 0, frcr = 0;
+	int cr1_mask = 0, frcr_mask = 0;
+	int ret;
+
+	dev_dbg(cpu_dai->dev, "fmt %x\n", fmt);
+
+	switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
+	/* SCK active high for all protocols */
+	case SND_SOC_DAIFMT_I2S:
+		cr1 |= SAI_XCR1_CKSTR;
+		frcr |= SAI_XFRCR_FSOFF | SAI_XFRCR_FSDEF;
+		break;
+	/* Left justified */
+	case SND_SOC_DAIFMT_MSB:
+		frcr |= SAI_XFRCR_FSPOL | SAI_XFRCR_FSDEF;
+		break;
+	/* Right justified */
+	case SND_SOC_DAIFMT_LSB:
+		frcr |= SAI_XFRCR_FSPOL | SAI_XFRCR_FSDEF;
+		break;
+	case SND_SOC_DAIFMT_DSP_A:
+		frcr |= SAI_XFRCR_FSPOL | SAI_XFRCR_FSOFF;
+		break;
+	case SND_SOC_DAIFMT_DSP_B:
+		frcr |= SAI_XFRCR_FSPOL;
+		break;
+	default:
+		dev_err(cpu_dai->dev, "Unsupported protocol %#x\n",
+			fmt & SND_SOC_DAIFMT_FORMAT_MASK);
+		return -EINVAL;
+	}
+
+	cr1_mask |= SAI_XCR1_PRTCFG_MASK | SAI_XCR1_CKSTR;
+	frcr_mask |= SAI_XFRCR_FSPOL | SAI_XFRCR_FSOFF |
+		     SAI_XFRCR_FSDEF;
+
+	/* DAI clock strobing. Invert setting previously set */
+	switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
+	case SND_SOC_DAIFMT_NB_NF:
+		break;
+	case SND_SOC_DAIFMT_IB_NF:
+		cr1 ^= SAI_XCR1_CKSTR;
+		break;
+	case SND_SOC_DAIFMT_NB_IF:
+		frcr ^= SAI_XFRCR_FSPOL;
+		break;
+	case SND_SOC_DAIFMT_IB_IF:
+		/* Invert fs & sck */
+		cr1 ^= SAI_XCR1_CKSTR;
+		frcr ^= SAI_XFRCR_FSPOL;
+		break;
+	default:
+		dev_err(cpu_dai->dev, "Unsupported strobing %#x\n",
+			fmt & SND_SOC_DAIFMT_INV_MASK);
+		return -EINVAL;
+	}
+	cr1_mask |= SAI_XCR1_CKSTR;
+	frcr_mask |= SAI_XFRCR_FSPOL;
+
+	regmap_update_bits(sai->regmap, STM_SAI_FRCR_REGX, frcr_mask, frcr);
+
+	/* DAI clock master masks */
+	switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
+	case SND_SOC_DAIFMT_CBM_CFM:
+		/* codec is master */
+		cr1 |= SAI_XCR1_SLAVE;
+		sai->master = false;
+		break;
+	case SND_SOC_DAIFMT_CBS_CFS:
+		sai->master = true;
+		break;
+	default:
+		dev_err(cpu_dai->dev, "Unsupported mode %#x\n",
+			fmt & SND_SOC_DAIFMT_MASTER_MASK);
+		return -EINVAL;
+	}
+	cr1_mask |= SAI_XCR1_SLAVE;
+
+	ret = regmap_update_bits(sai->regmap, STM_SAI_CR1_REGX, cr1_mask, cr1);
+	if (ret < 0) {
+		dev_err(cpu_dai->dev, "Failed to update CR1 register\n");
+		return ret;
+	}
+
+	sai->fmt = fmt;
+
+	return 0;
+}
+
+static int stm32_sai_startup(struct snd_pcm_substream *substream,
+			     struct snd_soc_dai *cpu_dai)
+{
+	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
+	int imr, cr2, ret;
+
+	sai->substream = substream;
+
+	ret = clk_prepare_enable(sai->sai_ck);
+	if (ret < 0) {
+		dev_err(cpu_dai->dev, "failed to enable clock: %d\n", ret);
+		return ret;
+	}
+
+	/* Enable ITs */
+	regmap_update_bits(sai->regmap, STM_SAI_SR_REGX,
+			   SAI_XSR_MASK, (unsigned int)~SAI_XSR_MASK);
+
+	regmap_update_bits(sai->regmap, STM_SAI_CLRFR_REGX,
+			   SAI_XCLRFR_MASK, SAI_XCLRFR_MASK);
+
+	imr = SAI_XIMR_OVRUDRIE;
+	if (STM_SAI_IS_CAPTURE(sai)) {
+		regmap_read(sai->regmap, STM_SAI_CR2_REGX, &cr2);
+		if (cr2 & SAI_XCR2_MUTECNT_MASK)
+			imr |= SAI_XIMR_MUTEDETIE;
+	}
+
+	if (sai->master)
+		imr |= SAI_XIMR_WCKCFGIE;
+	else
+		imr |= SAI_XIMR_AFSDETIE | SAI_XIMR_LFSDETIE;
+
+	regmap_update_bits(sai->regmap, STM_SAI_IMR_REGX,
+			   SAI_XIMR_MASK, imr);
+
+	return 0;
+}
+
+static int stm32_sai_set_config(struct snd_soc_dai *cpu_dai,
+				struct snd_pcm_substream *substream,
+				struct snd_pcm_hw_params *params)
+{
+	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
+	int cr1, cr1_mask, ret;
+	int fth = STM_SAI_FIFO_TH_HALF;
+
+	/* FIFO config */
+	regmap_update_bits(sai->regmap, STM_SAI_CR2_REGX,
+			   SAI_XCR2_FFLUSH | SAI_XCR2_FTH_MASK,
+			   SAI_XCR2_FFLUSH | SAI_XCR2_FTH_SET(fth));
+
+	/* Mode, data format and channel config */
+	cr1 = SAI_XCR1_PRTCFG_SET(SAI_FREE_PROTOCOL);
+	switch (params_format(params)) {
+	case SNDRV_PCM_FORMAT_S8:
+		cr1 |= SAI_XCR1_DS_SET(SAI_DATASIZE_8);
+		break;
+	case SNDRV_PCM_FORMAT_S16_LE:
+		cr1 |= SAI_XCR1_DS_SET(SAI_DATASIZE_16);
+		break;
+	case SNDRV_PCM_FORMAT_S32_LE:
+		cr1 |= SAI_XCR1_DS_SET(SAI_DATASIZE_32);
+		break;
+	default:
+		dev_err(cpu_dai->dev, "Data format not supported");
+		return -EINVAL;
+	}
+	cr1_mask = SAI_XCR1_DS_MASK | SAI_XCR1_PRTCFG_MASK;
+
+	cr1_mask |= SAI_XCR1_RX_TX;
+	if (STM_SAI_IS_CAPTURE(sai))
+		cr1 |= SAI_XCR1_RX_TX;
+
+	cr1_mask |= SAI_XCR1_MONO;
+	if ((sai->slots == 2) && (params_channels(params) == 1))
+		cr1 |= SAI_XCR1_MONO;
+
+	ret = regmap_update_bits(sai->regmap, STM_SAI_CR1_REGX, cr1_mask, cr1);
+	if (ret < 0) {
+		dev_err(cpu_dai->dev, "Failed to update CR1 register\n");
+		return ret;
+	}
+
+	/* DMA config */
+	sai->dma_params.maxburst = STM_SAI_FIFO_SIZE * fth / sizeof(u32);
+	snd_soc_dai_set_dma_data(cpu_dai, substream, (void *)&sai->dma_params);
+
+	return 0;
+}
+
+static int stm32_sai_set_slots(struct snd_soc_dai *cpu_dai)
+{
+	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
+	int slotr, slot_sz;
+
+	regmap_read(sai->regmap, STM_SAI_SLOTR_REGX, &slotr);
+
+	/*
+	 * If SLOTSZ is set to auto in SLOTR, align slot width on data size
+	 * By default slot width = data size, if not forced from DT
+	 */
+	slot_sz = slotr & SAI_XSLOTR_SLOTSZ_MASK;
+	if (slot_sz == SAI_XSLOTR_SLOTSZ_SET(SAI_SLOT_SIZE_AUTO))
+		sai->slot_width = sai->data_size;
+
+	if (sai->slot_width < sai->data_size) {
+		dev_err(cpu_dai->dev,
+			"Data size %d larger than slot width\n",
+			sai->data_size);
+		return -EINVAL;
+	}
+
+	/* Slot number is set to 2, if not specified in DT */
+	if (!sai->slots)
+		sai->slots = 2;
+
+	/* The number of slots in the audio frame is equal to NBSLOT[3:0] + 1*/
+	regmap_update_bits(sai->regmap, STM_SAI_SLOTR_REGX,
+			   SAI_XSLOTR_NBSLOT_MASK,
+			   SAI_XSLOTR_NBSLOT_SET((sai->slots - 1)));
+
+	/* Set default slots mask if not already set from DT */
+	if (!(slotr & SAI_XSLOTR_SLOTEN_MASK)) {
+		sai->slot_mask = (1 << sai->slots) - 1;
+		regmap_update_bits(sai->regmap,
+				   STM_SAI_SLOTR_REGX, SAI_XSLOTR_SLOTEN_MASK,
+				   SAI_XSLOTR_SLOTEN_SET(sai->slot_mask));
+	}
+
+	dev_dbg(cpu_dai->dev, "slots %d, slot width %d\n",
+		sai->slots, sai->slot_width);
+
+	return 0;
+}
+
+static void stm32_sai_set_frame(struct snd_soc_dai *cpu_dai)
+{
+	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
+	int fs_active, offset, format;
+	int frcr, frcr_mask;
+
+	format = sai->fmt & SND_SOC_DAIFMT_FORMAT_MASK;
+	sai->fs_length = sai->slot_width * sai->slots;
+
+	fs_active = sai->fs_length / 2;
+	if ((format == SND_SOC_DAIFMT_DSP_A) ||
+	    (format == SND_SOC_DAIFMT_DSP_B))
+		fs_active = 1;
+
+	frcr = SAI_XFRCR_FRL_SET((sai->fs_length - 1));
+	frcr |= SAI_XFRCR_FSALL_SET((fs_active - 1));
+	frcr_mask = SAI_XFRCR_FRL_MASK | SAI_XFRCR_FSALL_MASK;
+
+	dev_dbg(cpu_dai->dev, "frame length %d, frame active %d\n",
+		sai->fs_length, fs_active);
+
+	regmap_update_bits(sai->regmap, STM_SAI_FRCR_REGX, frcr_mask, frcr);
+
+	if ((sai->fmt & SND_SOC_DAIFMT_FORMAT_MASK) == SND_SOC_DAIFMT_LSB) {
+		offset = sai->slot_width - sai->data_size;
+
+		regmap_update_bits(sai->regmap, STM_SAI_SLOTR_REGX,
+				   SAI_XSLOTR_FBOFF_MASK,
+				   SAI_XSLOTR_FBOFF_SET(offset));
+	}
+}
+
+static int stm32_sai_configure_clock(struct snd_soc_dai *cpu_dai,
+				     struct snd_pcm_hw_params *params)
+{
+	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
+	int cr1, mask, div = 0;
+	int sai_clk_rate, ret;
+
+	if (!sai->mclk_rate) {
+		dev_err(cpu_dai->dev, "Mclk rate is null\n");
+		return -EINVAL;
+	}
+
+	if (!(params_rate(params) % 11025))
+		clk_set_parent(sai->sai_ck, sai->pdata->clk_x11k);
+	else
+		clk_set_parent(sai->sai_ck, sai->pdata->clk_x8k);
+	sai_clk_rate = clk_get_rate(sai->sai_ck);
+
+	/*
+	 * mclk_rate = 256 * fs
+	 * MCKDIV = 0 if sai_ck < 3/2 * mclk_rate
+	 * MCKDIV = sai_ck / (2 * mclk_rate) otherwise
+	 */
+	if (2 * sai_clk_rate >= 3 * sai->mclk_rate)
+		div = DIV_ROUND_CLOSEST(sai_clk_rate, 2 * sai->mclk_rate);
+
+	if (div > SAI_XCR1_MCKDIV_MAX) {
+		dev_err(cpu_dai->dev, "Divider %d out of range\n", div);
+		return -EINVAL;
+	}
+	dev_dbg(cpu_dai->dev, "SAI clock %d, divider %d\n", sai_clk_rate, div);
+
+	mask = SAI_XCR1_MCKDIV_MASK;
+	cr1 = SAI_XCR1_MCKDIV_SET(div);
+	ret = regmap_update_bits(sai->regmap, STM_SAI_CR1_REGX, mask, cr1);
+	if (ret < 0) {
+		dev_err(cpu_dai->dev, "Failed to update CR1 register\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int stm32_sai_hw_params(struct snd_pcm_substream *substream,
+			       struct snd_pcm_hw_params *params,
+			       struct snd_soc_dai *cpu_dai)
+{
+	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
+	int ret;
+
+	sai->data_size = params_width(params);
+
+	ret = stm32_sai_set_slots(cpu_dai);
+	if (ret < 0)
+		return ret;
+	stm32_sai_set_frame(cpu_dai);
+
+	ret = stm32_sai_set_config(cpu_dai, substream, params);
+	if (ret)
+		return ret;
+
+	if (sai->master)
+		ret = stm32_sai_configure_clock(cpu_dai, params);
+
+	return ret;
+}
+
+static int stm32_sai_trigger(struct snd_pcm_substream *substream, int cmd,
+			     struct snd_soc_dai *cpu_dai)
+{
+	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
+	int ret;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		dev_dbg(cpu_dai->dev, "Enable DMA and SAI\n");
+
+		regmap_update_bits(sai->regmap, STM_SAI_CR1_REGX,
+				   SAI_XCR1_DMAEN, SAI_XCR1_DMAEN);
+
+		/* Enable SAI */
+		ret = regmap_update_bits(sai->regmap, STM_SAI_CR1_REGX,
+					 SAI_XCR1_SAIEN, SAI_XCR1_SAIEN);
+		if (ret < 0)
+			dev_err(cpu_dai->dev, "Failed to update CR1 register\n");
+		break;
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+	case SNDRV_PCM_TRIGGER_STOP:
+		dev_dbg(cpu_dai->dev, "Disable DMA and SAI\n");
+
+		regmap_update_bits(sai->regmap, STM_SAI_CR1_REGX,
+				   SAI_XCR1_DMAEN,
+				   (unsigned int)~SAI_XCR1_DMAEN);
+
+		ret = regmap_update_bits(sai->regmap, STM_SAI_CR1_REGX,
+					 SAI_XCR1_SAIEN,
+					 (unsigned int)~SAI_XCR1_SAIEN);
+		if (ret < 0)
+			dev_err(cpu_dai->dev, "Failed to update CR1 register\n");
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+static void stm32_sai_shutdown(struct snd_pcm_substream *substream,
+			       struct snd_soc_dai *cpu_dai)
+{
+	struct stm32_sai_sub_data *sai = snd_soc_dai_get_drvdata(cpu_dai);
+
+	regmap_update_bits(sai->regmap, STM_SAI_IMR_REGX, SAI_XIMR_MASK, 0);
+
+	clk_disable_unprepare(sai->sai_ck);
+	sai->substream = NULL;
+}
+
+static int stm32_sai_dai_probe(struct snd_soc_dai *cpu_dai)
+{
+	struct stm32_sai_sub_data *sai = dev_get_drvdata(cpu_dai->dev);
+
+	sai->dma_params.addr = (dma_addr_t)(sai->phys_addr + STM_SAI_DR_REGX);
+	sai->dma_params.maxburst = 1;
+	/* Buswidth will be set by framework at runtime */
+	sai->dma_params.addr_width = DMA_SLAVE_BUSWIDTH_UNDEFINED;
+
+	if (STM_SAI_IS_PLAYBACK(sai))
+		snd_soc_dai_init_dma_data(cpu_dai, &sai->dma_params, NULL);
+	else
+		snd_soc_dai_init_dma_data(cpu_dai, NULL, &sai->dma_params);
+
+	return 0;
+}
+
+static const struct snd_soc_dai_ops stm32_sai_pcm_dai_ops = {
+	.set_sysclk	= stm32_sai_set_sysclk,
+	.set_fmt	= stm32_sai_set_dai_fmt,
+	.set_tdm_slot	= stm32_sai_set_dai_tdm_slot,
+	.startup	= stm32_sai_startup,
+	.hw_params	= stm32_sai_hw_params,
+	.trigger	= stm32_sai_trigger,
+	.shutdown	= stm32_sai_shutdown,
+};
+
+static const struct snd_pcm_hardware stm32_sai_pcm_hw = {
+	.info = SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP,
+	.buffer_bytes_max = 8 * PAGE_SIZE,
+	.period_bytes_min = 1024, /* 5ms at 48kHz */
+	.period_bytes_max = PAGE_SIZE,
+	.periods_min = 2,
+	.periods_max = 8,
+};
+
+static struct snd_soc_dai_driver stm32_sai_playback_dai[] = {
+{
+		.probe = stm32_sai_dai_probe,
+		.id = 1, /* avoid call to fmt_single_name() */
+		.playback = {
+			.channels_min = 1,
+			.channels_max = 2,
+			.rate_min = 8000,
+			.rate_max = 192000,
+			.rates = SNDRV_PCM_RATE_CONTINUOUS,
+			/* DMA does not support 24 bits transfers */
+			.formats =
+				SNDRV_PCM_FMTBIT_S8 |
+				SNDRV_PCM_FMTBIT_S16_LE |
+				SNDRV_PCM_FMTBIT_S32_LE,
+		},
+		.ops = &stm32_sai_pcm_dai_ops,
+	}
+};
+
+static struct snd_soc_dai_driver stm32_sai_capture_dai[] = {
+{
+		.probe = stm32_sai_dai_probe,
+		.id = 1, /* avoid call to fmt_single_name() */
+		.capture = {
+			.channels_min = 1,
+			.channels_max = 2,
+			.rate_min = 8000,
+			.rate_max = 192000,
+			.rates = SNDRV_PCM_RATE_CONTINUOUS,
+			/* DMA does not support 24 bits transfers */
+			.formats =
+				SNDRV_PCM_FMTBIT_S8 |
+				SNDRV_PCM_FMTBIT_S16_LE |
+				SNDRV_PCM_FMTBIT_S32_LE,
+		},
+		.ops = &stm32_sai_pcm_dai_ops,
+	}
+};
+
+static const struct snd_dmaengine_pcm_config stm32_sai_pcm_config = {
+	.pcm_hardware	= &stm32_sai_pcm_hw,
+	.prepare_slave_config	= snd_dmaengine_pcm_prepare_slave_config,
+};
+
+static const struct snd_soc_component_driver stm32_component = {
+	.name = "stm32-sai",
+};
+
+static const struct of_device_id stm32_sai_sub_ids[] = {
+	{ .compatible = "st,stm32-sai-sub-a",
+	  .data = (void *)STM_SAI_A_ID},
+	{ .compatible = "st,stm32-sai-sub-b",
+	  .data = (void *)STM_SAI_B_ID},
+	{}
+};
+MODULE_DEVICE_TABLE(of, stm32_sai_sub_ids);
+
+static int stm32_sai_sub_parse_of(struct platform_device *pdev,
+				  struct stm32_sai_sub_data *sai)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct resource *res;
+	void __iomem *base;
+
+	if (!np)
+		return -ENODEV;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+	dev_err(&pdev->dev, "res %pr\n", res);
+
+	base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	sai->phys_addr = res->start;
+	sai->regmap = devm_regmap_init_mmio(&pdev->dev, base,
+					    &stm32_sai_sub_regmap_config);
+
+	/* Get direction property */
+	if (of_property_match_string(np, "dma-names", "tx") >= 0) {
+		sai->dir = SNDRV_PCM_STREAM_PLAYBACK;
+	} else if (of_property_match_string(np, "dma-names", "rx") >= 0) {
+		sai->dir = SNDRV_PCM_STREAM_CAPTURE;
+	} else {
+		dev_err(&pdev->dev, "Unsupported direction\n");
+		return -EINVAL;
+	}
+
+	sai->sai_ck = devm_clk_get(&pdev->dev, "sai_ck");
+	if (IS_ERR(sai->sai_ck)) {
+		dev_err(&pdev->dev, "missing kernel clock sai_ck\n");
+		return PTR_ERR(sai->sai_ck);
+	}
+
+	return 0;
+}
+
+static int stm32_sai_sub_dais_init(struct platform_device *pdev,
+				   struct stm32_sai_sub_data *sai)
+{
+	sai->cpu_dai_drv = devm_kzalloc(&pdev->dev,
+					sizeof(struct snd_soc_dai_driver),
+					GFP_KERNEL);
+	if (!sai->cpu_dai_drv)
+		return -ENOMEM;
+
+	sai->cpu_dai_drv->name = dev_name(&pdev->dev);
+	if (STM_SAI_IS_PLAYBACK(sai)) {
+		memcpy(sai->cpu_dai_drv, &stm32_sai_playback_dai,
+		       sizeof(stm32_sai_playback_dai));
+		sai->cpu_dai_drv->playback.stream_name = sai->cpu_dai_drv->name;
+	} else {
+		memcpy(sai->cpu_dai_drv, &stm32_sai_capture_dai,
+		       sizeof(stm32_sai_capture_dai));
+		sai->cpu_dai_drv->capture.stream_name = sai->cpu_dai_drv->name;
+	}
+
+	return 0;
+}
+
+static int stm32_sai_sub_probe(struct platform_device *pdev)
+{
+	struct stm32_sai_sub_data *sai;
+	const struct of_device_id *of_id;
+	int ret;
+
+	sai = devm_kzalloc(&pdev->dev, sizeof(*sai), GFP_KERNEL);
+	if (!sai)
+		return -ENOMEM;
+
+	of_id = of_match_device(stm32_sai_sub_ids, &pdev->dev);
+	if (!of_id)
+		return -EINVAL;
+	sai->id = (uintptr_t)of_id->data;
+
+	sai->pdev = pdev;
+	platform_set_drvdata(pdev, sai);
+
+	sai->pdata = dev_get_drvdata(pdev->dev.parent);
+	if (!sai->pdata) {
+		dev_err(&pdev->dev, "Parent device data not available\n");
+		return -EINVAL;
+	}
+
+	ret = stm32_sai_sub_parse_of(pdev, sai);
+	if (ret)
+		return ret;
+
+	ret = stm32_sai_sub_dais_init(pdev, sai);
+	if (ret)
+		return ret;
+
+	ret = devm_request_irq(&pdev->dev, sai->pdata->irq, stm32_sai_isr,
+			       IRQF_SHARED, dev_name(&pdev->dev), sai);
+	if (ret) {
+		dev_err(&pdev->dev, "irq request returned %d\n", ret);
+		return ret;
+	}
+
+	ret = devm_snd_soc_register_component(&pdev->dev, &stm32_component,
+					      sai->cpu_dai_drv, 1);
+	if (ret)
+		return ret;
+
+	ret = devm_snd_dmaengine_pcm_register(&pdev->dev,
+					      &stm32_sai_pcm_config, 0);
+	if (ret) {
+		dev_err(&pdev->dev, "could not register pcm dma\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static struct platform_driver stm32_sai_sub_driver = {
+	.driver = {
+		.name = "st,stm32-sai-sub",
+		.of_match_table = stm32_sai_sub_ids,
+	},
+	.probe = stm32_sai_sub_probe,
+};
+
+module_platform_driver(stm32_sai_sub_driver);
+
+MODULE_DESCRIPTION("STM32 Soc SAI sub-block Interface");
+MODULE_AUTHOR("Olivier Moysan, <olivier.moysan@st.com>");
+MODULE_ALIAS("platform:st,stm32-sai-sub");
+MODULE_LICENSE("GPL v2");