sound/soc/stm/stm32_adfsdm.c - kernel/common - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * This file is part of STM32 DFSDM ASoC DAI driver
  *
  * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
  * Authors: Arnaud Pouliquen <[email protected]>
  *          Olivier Moysan <[email protected]>
  */

 #include <linux/clk.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>

 #include <linux/iio/iio.h>
 #include <linux/iio/consumer.h>
 #include <linux/iio/adc/stm32-dfsdm-adc.h>

 #include <sound/pcm.h>
 #include <sound/soc.h>

 #define STM32_ADFSDM_DRV_NAME "stm32-adfsdm"

 #define DFSDM_MAX_PERIOD_SIZE	(PAGE_SIZE / 2)
 #define DFSDM_MAX_PERIODS	6

 struct stm32_adfsdm_priv {
 	struct snd_soc_dai_driver dai_drv;
 	struct snd_pcm_substream *substream;
 	struct device *dev;

 	/* IIO */
 	struct iio_channel *iio_ch;
 	struct iio_cb_buffer *iio_cb;
 	bool iio_active;

 	/* PCM buffer */
 	unsigned char *pcm_buff;
 	unsigned int pos;

 	struct mutex lock; /* protect against race condition on iio state */
 };

 static const struct snd_pcm_hardware stm32_adfsdm_pcm_hw = {
 	.info = SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER |
 		SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_PAUSE,
 	.formats = SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S32_LE,

 	.rate_min = 8000,
 	.rate_max = 32000,

 	.channels_min = 1,
 	.channels_max = 1,

 	.periods_min = 2,
 	.periods_max = DFSDM_MAX_PERIODS,

 	.period_bytes_max = DFSDM_MAX_PERIOD_SIZE,
 	.buffer_bytes_max = DFSDM_MAX_PERIODS * DFSDM_MAX_PERIOD_SIZE
 };

 static void stm32_adfsdm_shutdown(struct snd_pcm_substream *substream,
 				  struct snd_soc_dai *dai)
 {
 	struct stm32_adfsdm_priv *priv = snd_soc_dai_get_drvdata(dai);

 	mutex_lock(&priv->lock);
 	if (priv->iio_active) {
 		iio_channel_stop_all_cb(priv->iio_cb);
 		priv->iio_active = false;
 	}
 	mutex_unlock(&priv->lock);
 }

 static int stm32_adfsdm_dai_prepare(struct snd_pcm_substream *substream,
 				    struct snd_soc_dai *dai)
 {
 	struct stm32_adfsdm_priv *priv = snd_soc_dai_get_drvdata(dai);
 	int ret;

 	mutex_lock(&priv->lock);
 	if (priv->iio_active) {
 		iio_channel_stop_all_cb(priv->iio_cb);
 		priv->iio_active = false;
 	}

 	ret = iio_write_channel_attribute(priv->iio_ch,
 					  substream->runtime->rate, 0,
 					  IIO_CHAN_INFO_SAMP_FREQ);
 	if (ret < 0) {
 		dev_err(dai->dev, "%s: Failed to set %d sampling rate\n",
 			__func__, substream->runtime->rate);
 		goto out;
 	}

 	if (!priv->iio_active) {
 		ret = iio_channel_start_all_cb(priv->iio_cb);
 		if (!ret)
 			priv->iio_active = true;
 		else
 			dev_err(dai->dev, "%s: IIO channel start failed (%d)\n",
 				__func__, ret);
 	}

 out:
 	mutex_unlock(&priv->lock);

 	return ret;
 }

 static int stm32_adfsdm_set_sysclk(struct snd_soc_dai *dai, int clk_id,
 				   unsigned int freq, int dir)
 {
 	struct stm32_adfsdm_priv *priv = snd_soc_dai_get_drvdata(dai);
 	ssize_t size;
 	char str_freq[10];

 	dev_dbg(dai->dev, "%s: Enter for freq %d\n", __func__, freq);

 	/* Set IIO frequency if CODEC is master as clock comes from SPI_IN */

 	snprintf(str_freq, sizeof(str_freq), "%d\n", freq);
 	size = iio_write_channel_ext_info(priv->iio_ch, "spi_clk_freq",
 					  str_freq, sizeof(str_freq));
 	if (size != sizeof(str_freq)) {
 		dev_err(dai->dev, "%s: Failed to set SPI clock\n",
 			__func__);
 		return -EINVAL;
 	}
 	return 0;
 }

 static const struct snd_soc_dai_ops stm32_adfsdm_dai_ops = {
 	.shutdown = stm32_adfsdm_shutdown,
 	.prepare = stm32_adfsdm_dai_prepare,
 	.set_sysclk = stm32_adfsdm_set_sysclk,
 };

 static const struct snd_soc_dai_driver stm32_adfsdm_dai = {
 	.capture = {
 		    .channels_min = 1,
 		    .channels_max = 1,
 		    .formats = SNDRV_PCM_FMTBIT_S16_LE |
 			       SNDRV_PCM_FMTBIT_S32_LE,
 		    .rates = (SNDRV_PCM_RATE_8000 | SNDRV_PCM_RATE_16000 |
 			      SNDRV_PCM_RATE_32000),
 		    },
 	.ops = &stm32_adfsdm_dai_ops,
 };

 static const struct snd_soc_component_driver stm32_adfsdm_dai_component = {
 	.name = "stm32_dfsdm_audio",
 };

 static void memcpy_32to16(void *dest, const void *src, size_t n)
 {
 	unsigned int i = 0;
 	u16 *d = (u16 *)dest, *s = (u16 *)src;

 	s++;
 	for (i = n; i > 0; i--) {
 		*d++ = *s++;
 		s++;
 	}
 }

 static int stm32_afsdm_pcm_cb(const void *data, size_t size, void *private)
 {
 	struct stm32_adfsdm_priv *priv = private;
 	struct snd_soc_pcm_runtime *rtd = priv->substream->private_data;
 	u8 *pcm_buff = priv->pcm_buff;
 	u8 *src_buff = (u8 *)data;
 	unsigned int old_pos = priv->pos;
 	size_t buff_size = snd_pcm_lib_buffer_bytes(priv->substream);
 	size_t period_size = snd_pcm_lib_period_bytes(priv->substream);
 	size_t cur_size, src_size = size;
 	snd_pcm_format_t format = priv->substream->runtime->format;

 	if (format == SNDRV_PCM_FORMAT_S16_LE)
 		src_size >>= 1;
 	cur_size = src_size;

 	dev_dbg(rtd->dev, "%s: buff_add :%pK, pos = %d, size = %zu\n",
 		__func__, &pcm_buff[priv->pos], priv->pos, src_size);

 	if ((priv->pos + src_size) > buff_size) {
 		if (format == SNDRV_PCM_FORMAT_S16_LE)
 			memcpy_32to16(&pcm_buff[priv->pos], src_buff,
 				      buff_size - priv->pos);
 		else
 			memcpy(&pcm_buff[priv->pos], src_buff,
 			       buff_size - priv->pos);
 		cur_size -= buff_size - priv->pos;
 		priv->pos = 0;
 	}

 	if (format == SNDRV_PCM_FORMAT_S16_LE)
 		memcpy_32to16(&pcm_buff[priv->pos],
 			      &src_buff[src_size - cur_size], cur_size);
 	else
 		memcpy(&pcm_buff[priv->pos], &src_buff[src_size - cur_size],
 		       cur_size);

 	priv->pos = (priv->pos + cur_size) % buff_size;

 	if (cur_size != src_size || (old_pos && (old_pos % period_size < size)))
 		snd_pcm_period_elapsed(priv->substream);

 	return 0;
 }

 static int stm32_adfsdm_trigger(struct snd_pcm_substream *substream, int cmd)
 {
 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
 	struct stm32_adfsdm_priv *priv =
 		snd_soc_dai_get_drvdata(rtd->cpu_dai);

 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
 	case SNDRV_PCM_TRIGGER_RESUME:
 		priv->pos = 0;
 		return stm32_dfsdm_get_buff_cb(priv->iio_ch->indio_dev,
 					       stm32_afsdm_pcm_cb, priv);
 	case SNDRV_PCM_TRIGGER_SUSPEND:
 	case SNDRV_PCM_TRIGGER_STOP:
 		return stm32_dfsdm_release_buff_cb(priv->iio_ch->indio_dev);
 	}

 	return -EINVAL;
 }

 static int stm32_adfsdm_pcm_open(struct snd_pcm_substream *substream)
 {
 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
 	struct stm32_adfsdm_priv *priv = snd_soc_dai_get_drvdata(rtd->cpu_dai);
 	int ret;

 	ret =  snd_soc_set_runtime_hwparams(substream, &stm32_adfsdm_pcm_hw);
 	if (!ret)
 		priv->substream = substream;

 	return ret;
 }

 static int stm32_adfsdm_pcm_close(struct snd_pcm_substream *substream)
 {
 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
 	struct stm32_adfsdm_priv *priv =
 		snd_soc_dai_get_drvdata(rtd->cpu_dai);

 	snd_pcm_lib_free_pages(substream);
 	priv->substream = NULL;

 	return 0;
 }

 static snd_pcm_uframes_t stm32_adfsdm_pcm_pointer(
 					    struct snd_pcm_substream *substream)
 {
 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
 	struct stm32_adfsdm_priv *priv =
 		snd_soc_dai_get_drvdata(rtd->cpu_dai);

 	return bytes_to_frames(substream->runtime, priv->pos);
 }

 static int stm32_adfsdm_pcm_hw_params(struct snd_pcm_substream *substream,
 				      struct snd_pcm_hw_params *params)
 {
 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
 	struct stm32_adfsdm_priv *priv =
 		snd_soc_dai_get_drvdata(rtd->cpu_dai);
 	int ret;

 	ret =  snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
 	if (ret < 0)
 		return ret;
 	priv->pcm_buff = substream->runtime->dma_area;

 	return iio_channel_cb_set_buffer_watermark(priv->iio_cb,
 						   params_period_size(params));
 }

 static int stm32_adfsdm_pcm_hw_free(struct snd_pcm_substream *substream)
 {
 	snd_pcm_lib_free_pages(substream);

 	return 0;
 }

 static struct snd_pcm_ops stm32_adfsdm_pcm_ops = {
 	.open		= stm32_adfsdm_pcm_open,
 	.close		= stm32_adfsdm_pcm_close,
 	.hw_params	= stm32_adfsdm_pcm_hw_params,
 	.hw_free	= stm32_adfsdm_pcm_hw_free,
 	.trigger	= stm32_adfsdm_trigger,
 	.pointer	= stm32_adfsdm_pcm_pointer,
 };

 static int stm32_adfsdm_pcm_new(struct snd_soc_pcm_runtime *rtd)
 {
 	struct snd_pcm *pcm = rtd->pcm;
 	struct stm32_adfsdm_priv *priv =
 		snd_soc_dai_get_drvdata(rtd->cpu_dai);
 	unsigned int size = DFSDM_MAX_PERIODS * DFSDM_MAX_PERIOD_SIZE;

 	snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV,
 					      priv->dev, size, size);
 	return 0;
 }

 static void stm32_adfsdm_pcm_free(struct snd_pcm *pcm)
 {
 	struct snd_pcm_substream *substream;

 	substream = pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream;
 	if (substream)
 		snd_pcm_lib_preallocate_free_for_all(pcm);
 }

 static struct snd_soc_component_driver stm32_adfsdm_soc_platform = {
 	.ops		= &stm32_adfsdm_pcm_ops,
 	.pcm_new	= stm32_adfsdm_pcm_new,
 	.pcm_free	= stm32_adfsdm_pcm_free,
 };

 static const struct of_device_id stm32_adfsdm_of_match[] = {
 	{.compatible = "st,stm32h7-dfsdm-dai"},
 	{}
 };
 MODULE_DEVICE_TABLE(of, stm32_adfsdm_of_match);

 static int stm32_adfsdm_probe(struct platform_device *pdev)
 {
 	struct stm32_adfsdm_priv *priv;
 	struct snd_soc_component *component;
 	int ret;

 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;

 	priv->dev = &pdev->dev;
 	priv->dai_drv = stm32_adfsdm_dai;
 	mutex_init(&priv->lock);

 	dev_set_drvdata(&pdev->dev, priv);

 	ret = devm_snd_soc_register_component(&pdev->dev,
 					      &stm32_adfsdm_dai_component,
 					      &priv->dai_drv, 1);
 	if (ret < 0)
 		return ret;

 	/* Associate iio channel */
 	priv->iio_ch  = devm_iio_channel_get_all(&pdev->dev);
 	if (IS_ERR(priv->iio_ch))
 		return PTR_ERR(priv->iio_ch);

 	priv->iio_cb = iio_channel_get_all_cb(&pdev->dev, NULL, NULL);
 	if (IS_ERR(priv->iio_cb))
 		return PTR_ERR(priv->iio_cb);

 	component = devm_kzalloc(&pdev->dev, sizeof(*component), GFP_KERNEL);
 	if (!component)
 		return -ENOMEM;
 #ifdef CONFIG_DEBUG_FS
 	component->debugfs_prefix = "pcm";
 #endif

 	ret = snd_soc_add_component(&pdev->dev, component,
 				    &stm32_adfsdm_soc_platform, NULL, 0);
 	if (ret < 0)
 		dev_err(&pdev->dev, "%s: Failed to register PCM platform\n",
 			__func__);

 	return ret;
 }

 static int stm32_adfsdm_remove(struct platform_device *pdev)
 {
 	snd_soc_unregister_component(&pdev->dev);

 	return 0;
 }

 static struct platform_driver stm32_adfsdm_driver = {
 	.driver = {
 		   .name = STM32_ADFSDM_DRV_NAME,
 		   .of_match_table = stm32_adfsdm_of_match,
 		   },
 	.probe = stm32_adfsdm_probe,
 	.remove = stm32_adfsdm_remove,
 };

 module_platform_driver(stm32_adfsdm_driver);

 MODULE_DESCRIPTION("stm32 DFSDM DAI driver");
 MODULE_AUTHOR("Arnaud Pouliquen <[email protected]>");
 MODULE_LICENSE("GPL v2");
 MODULE_ALIAS("platform:" STM32_ADFSDM_DRV_NAME);
	// SPDX-License-Identifier: GPL-2.0
	/*
	* This file is part of STM32 DFSDM ASoC DAI driver
	*
	* Copyright (C) 2017, STMicroelectronics - All Rights Reserved
	* Authors: Arnaud Pouliquen <[email protected]>
	* Olivier Moysan <[email protected]>
	*/

	#include <linux/clk.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/platform_device.h>
	#include <linux/slab.h>

	#include <linux/iio/iio.h>
	#include <linux/iio/consumer.h>
	#include <linux/iio/adc/stm32-dfsdm-adc.h>

	#include <sound/pcm.h>
	#include <sound/soc.h>

	#define STM32_ADFSDM_DRV_NAME "stm32-adfsdm"

	#define DFSDM_MAX_PERIOD_SIZE (PAGE_SIZE / 2)
	#define DFSDM_MAX_PERIODS 6

	struct stm32_adfsdm_priv {
	struct snd_soc_dai_driver dai_drv;
	struct snd_pcm_substream *substream;
	struct device *dev;

	/* IIO */
	struct iio_channel *iio_ch;
	struct iio_cb_buffer *iio_cb;
	bool iio_active;

	/* PCM buffer */
	unsigned char *pcm_buff;
	unsigned int pos;

	struct mutex lock; /* protect against race condition on iio state */
	};

	static const struct snd_pcm_hardware stm32_adfsdm_pcm_hw = {
	.info = SNDRV_PCM_INFO_INTERLEAVED \| SNDRV_PCM_INFO_BLOCK_TRANSFER \|
	SNDRV_PCM_INFO_MMAP \| SNDRV_PCM_INFO_PAUSE,
	.formats = SNDRV_PCM_FMTBIT_S16_LE \| SNDRV_PCM_FMTBIT_S32_LE,

	.rate_min = 8000,
	.rate_max = 32000,

	.channels_min = 1,
	.channels_max = 1,

	.periods_min = 2,
	.periods_max = DFSDM_MAX_PERIODS,

	.period_bytes_max = DFSDM_MAX_PERIOD_SIZE,
	.buffer_bytes_max = DFSDM_MAX_PERIODS * DFSDM_MAX_PERIOD_SIZE
	};

	static void stm32_adfsdm_shutdown(struct snd_pcm_substream *substream,
	struct snd_soc_dai *dai)
	{
	struct stm32_adfsdm_priv *priv = snd_soc_dai_get_drvdata(dai);

	mutex_lock(&priv->lock);
	if (priv->iio_active) {
	iio_channel_stop_all_cb(priv->iio_cb);
	priv->iio_active = false;
	}
	mutex_unlock(&priv->lock);
	}

	static int stm32_adfsdm_dai_prepare(struct snd_pcm_substream *substream,
	struct snd_soc_dai *dai)
	{
	struct stm32_adfsdm_priv *priv = snd_soc_dai_get_drvdata(dai);
	int ret;

	mutex_lock(&priv->lock);
	if (priv->iio_active) {
	iio_channel_stop_all_cb(priv->iio_cb);
	priv->iio_active = false;
	}

	ret = iio_write_channel_attribute(priv->iio_ch,
	substream->runtime->rate, 0,
	IIO_CHAN_INFO_SAMP_FREQ);
	if (ret < 0) {
	dev_err(dai->dev, "%s: Failed to set %d sampling rate\n",
	__func__, substream->runtime->rate);
	goto out;
	}

	if (!priv->iio_active) {
	ret = iio_channel_start_all_cb(priv->iio_cb);
	if (!ret)
	priv->iio_active = true;
	else
	dev_err(dai->dev, "%s: IIO channel start failed (%d)\n",
	__func__, ret);
	}

	out:
	mutex_unlock(&priv->lock);

	return ret;
	}

	static int stm32_adfsdm_set_sysclk(struct snd_soc_dai *dai, int clk_id,
	unsigned int freq, int dir)
	{
	struct stm32_adfsdm_priv *priv = snd_soc_dai_get_drvdata(dai);
	ssize_t size;
	char str_freq[10];

	dev_dbg(dai->dev, "%s: Enter for freq %d\n", __func__, freq);

	/* Set IIO frequency if CODEC is master as clock comes from SPI_IN */

	snprintf(str_freq, sizeof(str_freq), "%d\n", freq);
	size = iio_write_channel_ext_info(priv->iio_ch, "spi_clk_freq",
	str_freq, sizeof(str_freq));
	if (size != sizeof(str_freq)) {
	dev_err(dai->dev, "%s: Failed to set SPI clock\n",
	__func__);
	return -EINVAL;
	}
	return 0;
	}

	static const struct snd_soc_dai_ops stm32_adfsdm_dai_ops = {
	.shutdown = stm32_adfsdm_shutdown,
	.prepare = stm32_adfsdm_dai_prepare,
	.set_sysclk = stm32_adfsdm_set_sysclk,
	};

	static const struct snd_soc_dai_driver stm32_adfsdm_dai = {
	.capture = {
	.channels_min = 1,
	.channels_max = 1,
	.formats = SNDRV_PCM_FMTBIT_S16_LE \|
	SNDRV_PCM_FMTBIT_S32_LE,
	.rates = (SNDRV_PCM_RATE_8000 \| SNDRV_PCM_RATE_16000 \|
	SNDRV_PCM_RATE_32000),
	},
	.ops = &stm32_adfsdm_dai_ops,
	};

	static const struct snd_soc_component_driver stm32_adfsdm_dai_component = {
	.name = "stm32_dfsdm_audio",
	};

	static void memcpy_32to16(void dest, const void src, size_t n)
	{
	unsigned int i = 0;
	u16 d = (u16 )dest, s = (u16 )src;

	s++;
	for (i = n; i > 0; i--) {
	d++ = s++;
	s++;
	}
	}

	static int stm32_afsdm_pcm_cb(const void data, size_t size, void private)
	{
	struct stm32_adfsdm_priv *priv = private;
	struct snd_soc_pcm_runtime *rtd = priv->substream->private_data;
	u8 *pcm_buff = priv->pcm_buff;
	u8 src_buff = (u8 )data;
	unsigned int old_pos = priv->pos;
	size_t buff_size = snd_pcm_lib_buffer_bytes(priv->substream);
	size_t period_size = snd_pcm_lib_period_bytes(priv->substream);
	size_t cur_size, src_size = size;
	snd_pcm_format_t format = priv->substream->runtime->format;

	if (format == SNDRV_PCM_FORMAT_S16_LE)
	src_size >>= 1;
	cur_size = src_size;

	dev_dbg(rtd->dev, "%s: buff_add :%pK, pos = %d, size = %zu\n",
	__func__, &pcm_buff[priv->pos], priv->pos, src_size);

	if ((priv->pos + src_size) > buff_size) {
	if (format == SNDRV_PCM_FORMAT_S16_LE)
	memcpy_32to16(&pcm_buff[priv->pos], src_buff,
	buff_size - priv->pos);
	else
	memcpy(&pcm_buff[priv->pos], src_buff,
	buff_size - priv->pos);
	cur_size -= buff_size - priv->pos;
	priv->pos = 0;
	}

	if (format == SNDRV_PCM_FORMAT_S16_LE)
	memcpy_32to16(&pcm_buff[priv->pos],
	&src_buff[src_size - cur_size], cur_size);
	else
	memcpy(&pcm_buff[priv->pos], &src_buff[src_size - cur_size],
	cur_size);

	priv->pos = (priv->pos + cur_size) % buff_size;

	if (cur_size != src_size \|\| (old_pos && (old_pos % period_size < size)))
	snd_pcm_period_elapsed(priv->substream);

	return 0;
	}

	static int stm32_adfsdm_trigger(struct snd_pcm_substream *substream, int cmd)
	{
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct stm32_adfsdm_priv *priv =
	snd_soc_dai_get_drvdata(rtd->cpu_dai);

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
	case SNDRV_PCM_TRIGGER_RESUME:
	priv->pos = 0;
	return stm32_dfsdm_get_buff_cb(priv->iio_ch->indio_dev,
	stm32_afsdm_pcm_cb, priv);
	case SNDRV_PCM_TRIGGER_SUSPEND:
	case SNDRV_PCM_TRIGGER_STOP:
	return stm32_dfsdm_release_buff_cb(priv->iio_ch->indio_dev);
	}

	return -EINVAL;
	}

	static int stm32_adfsdm_pcm_open(struct snd_pcm_substream *substream)
	{
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct stm32_adfsdm_priv *priv = snd_soc_dai_get_drvdata(rtd->cpu_dai);
	int ret;

	ret = snd_soc_set_runtime_hwparams(substream, &stm32_adfsdm_pcm_hw);
	if (!ret)
	priv->substream = substream;

	return ret;
	}

	static int stm32_adfsdm_pcm_close(struct snd_pcm_substream *substream)
	{
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct stm32_adfsdm_priv *priv =
	snd_soc_dai_get_drvdata(rtd->cpu_dai);

	snd_pcm_lib_free_pages(substream);
	priv->substream = NULL;

	return 0;
	}

	static snd_pcm_uframes_t stm32_adfsdm_pcm_pointer(
	struct snd_pcm_substream *substream)
	{
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct stm32_adfsdm_priv *priv =
	snd_soc_dai_get_drvdata(rtd->cpu_dai);

	return bytes_to_frames(substream->runtime, priv->pos);
	}

	static int stm32_adfsdm_pcm_hw_params(struct snd_pcm_substream *substream,
	struct snd_pcm_hw_params *params)
	{
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct stm32_adfsdm_priv *priv =
	snd_soc_dai_get_drvdata(rtd->cpu_dai);
	int ret;

	ret = snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
	if (ret < 0)
	return ret;
	priv->pcm_buff = substream->runtime->dma_area;

	return iio_channel_cb_set_buffer_watermark(priv->iio_cb,
	params_period_size(params));
	}

	static int stm32_adfsdm_pcm_hw_free(struct snd_pcm_substream *substream)
	{
	snd_pcm_lib_free_pages(substream);

	return 0;
	}

	static struct snd_pcm_ops stm32_adfsdm_pcm_ops = {
	.open = stm32_adfsdm_pcm_open,
	.close = stm32_adfsdm_pcm_close,
	.hw_params = stm32_adfsdm_pcm_hw_params,
	.hw_free = stm32_adfsdm_pcm_hw_free,
	.trigger = stm32_adfsdm_trigger,
	.pointer = stm32_adfsdm_pcm_pointer,
	};

	static int stm32_adfsdm_pcm_new(struct snd_soc_pcm_runtime *rtd)
	{
	struct snd_pcm *pcm = rtd->pcm;
	struct stm32_adfsdm_priv *priv =
	snd_soc_dai_get_drvdata(rtd->cpu_dai);
	unsigned int size = DFSDM_MAX_PERIODS * DFSDM_MAX_PERIOD_SIZE;

	snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV,
	priv->dev, size, size);
	return 0;
	}

	static void stm32_adfsdm_pcm_free(struct snd_pcm *pcm)
	{
	struct snd_pcm_substream *substream;

	substream = pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream;
	if (substream)
	snd_pcm_lib_preallocate_free_for_all(pcm);
	}

	static struct snd_soc_component_driver stm32_adfsdm_soc_platform = {
	.ops = &stm32_adfsdm_pcm_ops,
	.pcm_new = stm32_adfsdm_pcm_new,
	.pcm_free = stm32_adfsdm_pcm_free,
	};

	static const struct of_device_id stm32_adfsdm_of_match[] = {
	{.compatible = "st,stm32h7-dfsdm-dai"},
	{}
	};
	MODULE_DEVICE_TABLE(of, stm32_adfsdm_of_match);

	static int stm32_adfsdm_probe(struct platform_device *pdev)
	{
	struct stm32_adfsdm_priv *priv;
	struct snd_soc_component *component;
	int ret;

	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
	return -ENOMEM;

	priv->dev = &pdev->dev;
	priv->dai_drv = stm32_adfsdm_dai;
	mutex_init(&priv->lock);

	dev_set_drvdata(&pdev->dev, priv);

	ret = devm_snd_soc_register_component(&pdev->dev,
	&stm32_adfsdm_dai_component,
	&priv->dai_drv, 1);
	if (ret < 0)
	return ret;

	/* Associate iio channel */
	priv->iio_ch = devm_iio_channel_get_all(&pdev->dev);
	if (IS_ERR(priv->iio_ch))
	return PTR_ERR(priv->iio_ch);

	priv->iio_cb = iio_channel_get_all_cb(&pdev->dev, NULL, NULL);
	if (IS_ERR(priv->iio_cb))
	return PTR_ERR(priv->iio_cb);

	component = devm_kzalloc(&pdev->dev, sizeof(*component), GFP_KERNEL);
	if (!component)
	return -ENOMEM;
	#ifdef CONFIG_DEBUG_FS
	component->debugfs_prefix = "pcm";
	#endif

	ret = snd_soc_add_component(&pdev->dev, component,
	&stm32_adfsdm_soc_platform, NULL, 0);
	if (ret < 0)
	dev_err(&pdev->dev, "%s: Failed to register PCM platform\n",
	__func__);

	return ret;
	}

	static int stm32_adfsdm_remove(struct platform_device *pdev)
	{
	snd_soc_unregister_component(&pdev->dev);

	return 0;
	}

	static struct platform_driver stm32_adfsdm_driver = {
	.driver = {
	.name = STM32_ADFSDM_DRV_NAME,
	.of_match_table = stm32_adfsdm_of_match,
	},
	.probe = stm32_adfsdm_probe,
	.remove = stm32_adfsdm_remove,
	};

	module_platform_driver(stm32_adfsdm_driver);

	MODULE_DESCRIPTION("stm32 DFSDM DAI driver");
	MODULE_AUTHOR("Arnaud Pouliquen <[email protected]>");
	MODULE_LICENSE("GPL v2");
	MODULE_ALIAS("platform:" STM32_ADFSDM_DRV_NAME);