[PATCH 3/3] ASoC: stm32: add mdf dai support

[Olivier Moysan]

Add driver to handle DAI interface for PDM microphones connected
to MDF STM32 IP.

Signed-off-by: Olivier Moysan <olivier.moysan@xxxxxxxxxxx>
---
 sound/soc/stm/Kconfig      |  15 ++
 sound/soc/stm/Makefile     |   3 +
 sound/soc/stm/stm32_amdf.c | 376 +++++++++++++++++++++++++++++++++++++
 3 files changed, 394 insertions(+)
 create mode 100644 sound/soc/stm/stm32_amdf.c

diff --git a/sound/soc/stm/Kconfig b/sound/soc/stm/Kconfig
index 2753d6c2a826..6661b3a8e4f8 100644
--- a/sound/soc/stm/Kconfig
+++ b/sound/soc/stm/Kconfig
@@ -44,4 +44,19 @@ config SND_SOC_STM32_DFSDM
 	  Select this option to enable the STM32 Digital Filter
 	  for Sigma Delta Modulators (DFSDM) driver used
 	  in various STM32 series for digital microphone capture.
+
+config SND_SOC_STM32_MDF
+	tristate "SoC Audio support for STM32 MDF"
+	depends on ARCH_STM32 || COMPILE_TEST
+	depends on SND_SOC
+	depends on STM32_MDF_ADC
+	select SND_SOC_GENERIC_DMAENGINE_PCM
+	select SND_SOC_DMIC
+	select IIO_BUFFER_CB
+	help
+	  Select this option to enable the STM32 Multi-function
+	  Digital Filter (MDF) driver used in STM32MP2 series for
+	  digital microphone capture.
+
+	  Module name is stm32_amdf when the driver is built as a module.
 endmenu
diff --git a/sound/soc/stm/Makefile b/sound/soc/stm/Makefile
index 3372432faa09..4e1b3f943a44 100644
--- a/sound/soc/stm/Makefile
+++ b/sound/soc/stm/Makefile
@@ -16,3 +16,6 @@ obj-$(CONFIG_SND_SOC_STM32_SPDIFRX) += snd-soc-stm32-spdifrx.o
 
 #DFSDM
 obj-$(CONFIG_SND_SOC_STM32_DFSDM) += stm32_adfsdm.o
+
+#MDF
+obj-$(CONFIG_SND_SOC_STM32_MDF) += stm32_amdf.o
diff --git a/sound/soc/stm/stm32_amdf.c b/sound/soc/stm/stm32_amdf.c
new file mode 100644
index 000000000000..c946edbc2343
--- /dev/null
+++ b/sound/soc/stm/stm32_amdf.c
@@ -0,0 +1,376 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * This file is part of STM32 MDF ASoC DAI driver
+ *
+ * Copyright (C) 2023, STMicroelectronics.
+ * Author: Olivier Moysan <olivier.moysan@xxxxxxxxxxx>.
+ */
+
+#include <linux/clk.h>
+#include <linux/iio/adc/stm32-mdf-adc.h>
+#include <linux/iio/consumer.h>
+#include <linux/iio/iio.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+
+#include <sound/pcm.h>
+#include <sound/soc.h>
+
+#define STM32_AMDF_DRV_NAME "stm32-amdf"
+
+#define MDF_MAX_PERIOD_SIZE	(PAGE_SIZE / 2)
+#define MDF_MAX_PERIODS	6
+
+struct stm32_amdf_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_amdf_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,
+
+	.channels_min = 1,
+	.channels_max = 1,
+
+	.periods_min = 2,
+	.periods_max = MDF_MAX_PERIODS,
+
+	.period_bytes_max = MDF_MAX_PERIOD_SIZE,
+	.buffer_bytes_max = MDF_MAX_PERIODS * MDF_MAX_PERIOD_SIZE
+};
+
+static void stm32_amdf_shutdown(struct snd_pcm_substream *substream,
+				struct snd_soc_dai *dai)
+{
+	struct stm32_amdf_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_amdf_dai_prepare(struct snd_pcm_substream *substream,
+				  struct snd_soc_dai *dai)
+{
+	struct stm32_amdf_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 const struct snd_soc_dai_ops stm32_amdf_dai_ops = {
+	.shutdown = stm32_amdf_shutdown,
+	.prepare = stm32_amdf_dai_prepare,
+};
+
+static const struct snd_soc_dai_driver stm32_amdf_dai = {
+	.capture = {
+		    .channels_min = 1,
+		    .channels_max = 1,
+		    .formats = SNDRV_PCM_FMTBIT_S16_LE |
+			       SNDRV_PCM_FMTBIT_S32_LE,
+		    .rates = SNDRV_PCM_RATE_CONTINUOUS,
+		    .rate_min = 8000,
+		    .rate_max = 48000,
+		    },
+	.ops = &stm32_amdf_dai_ops,
+};
+
+static const struct snd_soc_component_driver stm32_amdf_dai_component = {
+	.name = "stm32_mdf_audio",
+};
+
+static void stm32_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 >> 1; i > 0; i--) {
+		*d++ = *s++;
+		s++;
+	}
+}
+
+static int stm32_afsdm_pcm_cb(const void *data, size_t size, void *private)
+{
+	struct stm32_amdf_priv *priv = private;
+	struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(priv->substream);
+	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)
+			stm32_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)
+		stm32_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_amdf_trigger(struct snd_soc_component *component,
+			      struct snd_pcm_substream *substream, int cmd)
+{
+	struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
+	struct stm32_amdf_priv *priv =
+		snd_soc_dai_get_drvdata(snd_soc_rtd_to_cpu(rtd, 0));
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+		priv->pos = 0;
+		return stm32_mdf_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_mdf_release_buff_cb(priv->iio_ch->indio_dev);
+	}
+
+	return -EINVAL;
+}
+
+static int stm32_amdf_pcm_open(struct snd_soc_component *component,
+			       struct snd_pcm_substream *substream)
+{
+	struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
+	struct stm32_amdf_priv *priv = snd_soc_dai_get_drvdata(snd_soc_rtd_to_cpu(rtd, 0));
+	int ret;
+
+	ret =  snd_soc_set_runtime_hwparams(substream, &stm32_amdf_pcm_hw);
+	if (!ret)
+		priv->substream = substream;
+
+	return ret;
+}
+
+static int stm32_amdf_pcm_close(struct snd_soc_component *component,
+				struct snd_pcm_substream *substream)
+{
+	struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
+	struct stm32_amdf_priv *priv =
+		snd_soc_dai_get_drvdata(snd_soc_rtd_to_cpu(rtd, 0));
+
+	priv->substream = NULL;
+
+	return 0;
+}
+
+static snd_pcm_uframes_t stm32_amdf_pcm_pointer(struct snd_soc_component *component,
+						struct snd_pcm_substream *substream)
+{
+	struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
+	struct stm32_amdf_priv *priv =
+		snd_soc_dai_get_drvdata(snd_soc_rtd_to_cpu(rtd, 0));
+
+	return bytes_to_frames(substream->runtime, priv->pos);
+}
+
+static int stm32_amdf_pcm_hw_params(struct snd_soc_component *component,
+				    struct snd_pcm_substream *substream,
+				    struct snd_pcm_hw_params *params)
+{
+	struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
+	struct stm32_amdf_priv *priv =
+		snd_soc_dai_get_drvdata(snd_soc_rtd_to_cpu(rtd, 0));
+
+	priv->pcm_buff = substream->runtime->dma_area;
+
+	return iio_channel_cb_set_buffer_watermark(priv->iio_cb,
+						   params_period_size(params));
+}
+
+static int stm32_amdf_pcm_new(struct snd_soc_component *component,
+			      struct snd_soc_pcm_runtime *rtd)
+{
+	struct snd_pcm *pcm = rtd->pcm;
+	struct stm32_amdf_priv *priv =
+		snd_soc_dai_get_drvdata(snd_soc_rtd_to_cpu(rtd, 0));
+	unsigned int size = MDF_MAX_PERIODS * MDF_MAX_PERIOD_SIZE;
+
+	snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_DEV,
+				       priv->dev, size, size);
+
+	return 0;
+}
+
+static int stm32_amdf_dummy_cb(const void *data, void *private)
+{
+	/*
+	 * This dummy callback is requested by iio_channel_get_all_cb() API,
+	 * but the stm32_mdf_get_buff_cb() API is used instead, to optimize
+	 * DMA transfers.
+	 */
+	return 0;
+}
+
+static void stm32_amdf_cleanup(void *data)
+{
+	iio_channel_release_all_cb(data);
+}
+
+static const struct snd_soc_component_driver stm32_amdf_soc_platform = {
+	.open		= stm32_amdf_pcm_open,
+	.close		= stm32_amdf_pcm_close,
+	.hw_params	= stm32_amdf_pcm_hw_params,
+	.trigger	= stm32_amdf_trigger,
+	.pointer	= stm32_amdf_pcm_pointer,
+	.pcm_new	= stm32_amdf_pcm_new,
+	.debugfs_prefix	= "pcm",
+};
+
+static const struct of_device_id stm32_amdf_of_match[] = {
+	{.compatible = "st,stm32mp25-mdf-dai"},
+	{}
+};
+MODULE_DEVICE_TABLE(of, stm32_amdf_of_match);
+
+static int stm32_amdf_probe(struct platform_device *pdev)
+{
+	struct stm32_amdf_priv *priv;
+	unsigned int channels_max;
+	int ret;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->dev = &pdev->dev;
+	priv->dai_drv = stm32_amdf_dai;
+	priv->dai_drv.name = dev_name(&pdev->dev);
+	mutex_init(&priv->lock);
+
+	dev_set_drvdata(&pdev->dev, priv);
+
+	/* Associate iio channel */
+	priv->iio_ch  = devm_iio_channel_get_all(&pdev->dev);
+	if (IS_ERR(priv->iio_ch)) {
+		dev_err(&pdev->dev, "Failed to get IIO channels %ld\n", PTR_ERR(priv->iio_ch));
+		return PTR_ERR(priv->iio_ch);
+	}
+
+	priv->iio_cb = iio_channel_get_all_cb(&pdev->dev, &stm32_amdf_dummy_cb, NULL);
+	if (IS_ERR(priv->iio_cb)) {
+		dev_err(&pdev->dev, "Failed to get IIO callbacks %ld\n", PTR_ERR(priv->iio_cb));
+		return PTR_ERR(priv->iio_cb);
+	}
+
+	ret = devm_add_action_or_reset(&pdev->dev, stm32_amdf_cleanup, priv->iio_cb);
+	if (ret < 0)  {
+		dev_err(&pdev->dev, "Unable to add action\n");
+		return ret;
+	}
+
+	channels_max = stm32_mdf_get_sub_channels_nb(priv->iio_ch->indio_dev);
+	priv->dai_drv.capture.channels_max = channels_max;
+
+	ret = devm_snd_soc_register_component(&pdev->dev, &stm32_amdf_dai_component,
+					      &priv->dai_drv, 1);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to register %s\n", stm32_amdf_dai_component.name);
+		return ret;
+	}
+
+	ret = devm_snd_soc_register_component(&pdev->dev, &stm32_amdf_soc_platform,
+					      NULL, 0);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to register PCM platform\n");
+		return ret;
+	}
+
+	pm_runtime_enable(&pdev->dev);
+
+	return ret;
+}
+
+static void stm32_amdf_remove(struct platform_device *pdev)
+{
+	pm_runtime_disable(&pdev->dev);
+}
+
+static struct platform_driver stm32_amdf_driver = {
+	.driver = {
+		   .name = STM32_AMDF_DRV_NAME,
+		   .of_match_table = stm32_amdf_of_match,
+		   },
+	.probe = stm32_amdf_probe,
+	.remove = stm32_amdf_remove,
+};
+
+module_platform_driver(stm32_amdf_driver);
+
+MODULE_DESCRIPTION("stm32 MDF DAI driver");
+MODULE_AUTHOR("Olivier Moysan <olivier.moysan@xxxxxxxxxxx>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" STM32_AMDF_DRV_NAME);
+MODULE_IMPORT_NS("IIO_CONSUMER");
-- 
2.43.0