Re: [PATCH v4 09/12] IIO: ADC: add stm32 DFSDM support for PDM microphone

[Jonathan Cameron <jic23-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

On Thu, 9 Nov 2017 11:12:31 +0100
Arnaud Pouliquen <arnaud.pouliquen-qxv4g6HH51o@public.gmane.org> wrote:

> This code offers a way to handle PDM audio microphones in
> ASOC framework. Audio driver should use consumer API.
> A specific management is implemented for DMA, with a
> callback, to allows to handle audio buffers efficiently.
> 
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen-qxv4g6HH51o@public.gmane.org>

A few minor points inline.  I'm not sure I really 'like' the
solution we've ended up with currently but if it works it will
do just fine for now :)

Jonathan


> ---
> V3 -> V4 changes:
>  - Merge audio implementation in stm32-dfsdm-adc.c instead of creating separate file
>  - Add sysfs document for exported attributes
> 
>  .../ABI/testing/sysfs-bus-iio-dfsdm-adc-stm32      |  22 +
>  drivers/iio/adc/stm32-dfsdm-adc.c                  | 517 ++++++++++++++++++++-
>  include/linux/iio/adc/stm32-dfsdm-adc.h            |  27 ++
>  3 files changed, 562 insertions(+), 4 deletions(-)
>  create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-dfsdm-adc-stm32
>  create mode 100644 include/linux/iio/adc/stm32-dfsdm-adc.h
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-dfsdm-adc-stm32 b/Documentation/ABI/testing/sysfs-bus-iio-dfsdm-adc-stm32
> new file mode 100644
> index 0000000..0ce5508
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-iio-dfsdm-adc-stm32
> @@ -0,0 +1,22 @@
> +What:		/sys/bus/iio/devices/iio:deviceX/in_voltage_audio_sampling_rate
> +KernelVersion:	4.14
> +Contact:	arnaud.pouliquen-qxv4g6HH51o@public.gmane.org
> +Description:
> +		For audio purpose only.
> +		Used by audio driver to set/get the audio sampling rate.
> +		Reading returns current audio sample frequency.
> +		Writing value before starting conversions.

I would like to see a note here on why sampling_frequency can't be used for
this purpose.

> +
> +What:		/sys/bus/iio/devices/iio:deviceX/in_voltage_spi_clk_freq
> +KernelVersion:	4.14
> +Contact:	arnaud.pouliquen-qxv4g6HH51o@public.gmane.org
> +Description:
> +		For audio purpose only.
> +		Used by audio driver to set/get the spi input frequency
> +		when DFSDM SPI input channel is in slave mode.
> +		if DFSDM input is SPI master
> +			Reading  0,
> +			error on writing
> +		If DFSDM input is SPI Slave:
> +		Reading returns value previously set.
> +		Writing value before starting conversions.

I'd like a brief note here on why we might change this at runtime.

> diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c
> index f9419ab..f0952e26 100644
> --- a/drivers/iio/adc/stm32-dfsdm-adc.c
> +++ b/drivers/iio/adc/stm32-dfsdm-adc.c
> @@ -19,11 +19,15 @@
>   * this program. If not, see <http://www.gnu.org/licenses/>.
>   */
>  
> +#include <linux/dmaengine.h>
> +#include <linux/dma-mapping.h>
>  #include <linux/interrupt.h>
>  #include <linux/iio/buffer.h>
>  #include <linux/iio/hw-consumer.h>
>  #include <linux/iio/iio.h>
>  #include <linux/iio/sysfs.h>
> +#include <linux/iio/trigger_consumer.h>
> +#include <linux/iio/triggered_buffer.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/platform_device.h>
> @@ -32,6 +36,8 @@
>  
>  #include "stm32-dfsdm.h"
>  
> +#define DFSDM_DMA_BUFFER_SIZE (4 * PAGE_SIZE)
> +
>  /* Conversion timeout */
>  #define DFSDM_TIMEOUT_US 100000
>  #define DFSDM_TIMEOUT (msecs_to_jiffies(DFSDM_TIMEOUT_US / 1000))
> @@ -71,6 +77,18 @@ struct stm32_dfsdm_adc {
>  	struct completion completion;
>  	u32 *buffer;
>  
> +	/* Audio specific */
> +	unsigned int spi_freq;  /* SPI bus clock frequency */
> +	unsigned int sample_freq; /* Sample frequency after filter decimation */
> +	int (*cb)(const void *data, size_t size, void *cb_priv);
> +	void *cb_priv;
> +
> +	/* DMA */
> +	u8 *rx_buf;
> +	unsigned int bufi; /* Buffer current position */
> +	unsigned int buf_sz; /* Buffer size */
> +	struct dma_chan	*dma_chan;
> +	dma_addr_t dma_buf;
>  };
>  
>  struct stm32_dfsdm_str2field {
> @@ -364,10 +382,110 @@ int stm32_dfsdm_channel_parse_of(struct stm32_dfsdm *dfsdm,
>  	return 0;
>  }
>  
> +static ssize_t dfsdm_adc_audio_get_rate(struct iio_dev *indio_dev,
> +					uintptr_t priv,
> +					const struct iio_chan_spec *chan,
> +					char *buf)
> +{
> +	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
> +
> +	return snprintf(buf, PAGE_SIZE, "%d\n", adc->sample_freq);
> +}
> +
> +static ssize_t dfsdm_adc_audio_set_rate(struct iio_dev *indio_dev,
> +					uintptr_t priv,
> +					const struct iio_chan_spec *chan,
> +					const char *buf, size_t len)
> +{
> +	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
> +	struct stm32_dfsdm_filter *fl = &adc->dfsdm->fl_list[adc->fl_id];
> +	struct stm32_dfsdm_channel *ch = &adc->dfsdm->ch_list[adc->ch_id];
> +	unsigned int spi_freq = adc->spi_freq;
> +	unsigned int sample_freq;
> +	int ret;
> +
> +	ret = kstrtoint(buf, 0, &sample_freq);
> +	if (ret)
> +		return ret;
> +	dev_dbg(&indio_dev->dev, "Requested sample_freq :%d\n", sample_freq);
> +
> +	if (!sample_freq)
> +		return -EINVAL;
> +
> +	if (ch->src != DFSDM_CHANNEL_SPI_CLOCK_EXTERNAL)
> +		spi_freq = adc->dfsdm->spi_master_freq;
> +
> +	if (spi_freq % sample_freq)
> +		dev_warn(&indio_dev->dev, "Sampling rate not accurate (%d)\n",
> +			 spi_freq / (spi_freq / sample_freq));
> +
> +	ret = stm32_dfsdm_set_osrs(fl, 0, (spi_freq / sample_freq));
> +	if (ret < 0) {
> +		dev_err(&indio_dev->dev,
> +			"Not able to find filter parameter that match!\n");
> +		return ret;
> +	}
> +	adc->sample_freq = sample_freq;
> +
> +	return len;
> +}
> +
> +static ssize_t dfsdm_adc_audio_get_spiclk(struct iio_dev *indio_dev,
> +					  uintptr_t priv,
> +					  const struct iio_chan_spec *chan,
> +					  char *buf)
> +{
> +	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
> +
> +	return snprintf(buf, PAGE_SIZE, "%d\n", adc->spi_freq);
> +}
> +
> +static ssize_t dfsdm_adc_audio_set_spiclk(struct iio_dev *indio_dev,
> +					  uintptr_t priv,
> +					  const struct iio_chan_spec *chan,
> +					  const char *buf, size_t len)
> +{
> +	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
> +	struct stm32_dfsdm_filter *fl = &adc->dfsdm->fl_list[adc->fl_id];
> +	struct stm32_dfsdm_channel *ch = &adc->dfsdm->ch_list[adc->ch_id];
> +	unsigned int sample_freq = adc->sample_freq;
> +	unsigned int spi_freq;
> +	int ret;
> +
> +	dev_err(&indio_dev->dev, "enter %s\n", __func__);
> +	/* If DFSDM is master on SPI, SPI freq can not be updated */
> +	if (ch->src != DFSDM_CHANNEL_SPI_CLOCK_EXTERNAL)
> +		return -EPERM;
> +
> +	ret = kstrtoint(buf, 0, &spi_freq);
> +	if (ret)
> +		return ret;
> +
> +	if (!spi_freq)
> +		return -EINVAL;
> +
> +	if (sample_freq) {
> +		if (spi_freq % sample_freq)
> +			dev_warn(&indio_dev->dev,
> +				 "Sampling rate not accurate (%d)\n",
> +				 spi_freq / (spi_freq / sample_freq));
> +
> +		ret = stm32_dfsdm_set_osrs(fl, 0, (spi_freq / sample_freq));
> +		if (ret < 0) {
> +			dev_err(&indio_dev->dev,
> +				"No filter parameters that match!\n");
> +			return ret;
> +		}
> +	}
> +	adc->spi_freq = spi_freq;
> +
> +	return len;
> +}
blank line here please.

>  static int stm32_dfsdm_start_conv(struct stm32_dfsdm_adc *adc, bool dma)
>  {
>  	struct regmap *regmap = adc->dfsdm->regmap;
>  	int ret;
> +	unsigned int dma_en = 0, cont_en = 0;
>  
>  	ret = stm32_dfsdm_start_channel(adc->dfsdm, adc->ch_id);
>  	if (ret < 0)
> @@ -378,6 +496,24 @@ static int stm32_dfsdm_start_conv(struct stm32_dfsdm_adc *adc, bool dma)
>  	if (ret < 0)
>  		goto stop_channels;
>  
> +	if (dma) {
> +		/* Enable DMA transfer*/
> +		dma_en =  DFSDM_CR1_RDMAEN(1);
> +		/* Enable conversion triggered by SPI clock*/
> +		cont_en = DFSDM_CR1_RCONT(1);
> +	}
> +	/* Enable DMA transfer*/
> +	ret = regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
> +				 DFSDM_CR1_RDMAEN_MASK, dma_en);
> +	if (ret < 0)
> +		goto stop_channels;
> +
> +	/* Enable conversion triggered by SPI clock*/
> +	ret = regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
> +				 DFSDM_CR1_RCONT_MASK, cont_en);
> +	if (ret < 0)
> +		goto stop_channels;
> +
>  	ret = stm32_dfsdm_start_filter(adc->dfsdm, adc->fl_id);
>  	if (ret < 0)
>  		goto stop_channels;
> @@ -411,6 +547,241 @@ static void stm32_dfsdm_stop_conv(struct stm32_dfsdm_adc *adc)
>  	stm32_dfsdm_stop_channel(adc->dfsdm, adc->ch_id);
>  }
>  
> +static int stm32_dfsdm_set_watermark(struct iio_dev *indio_dev,
> +				     unsigned int val)
> +{
> +	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
> +	unsigned int watermark = DFSDM_DMA_BUFFER_SIZE / 2;
> +
> +	/*
> +	 * DMA cyclic transfers are used, buffer is split into two periods.
> +	 * There should be :
> +	 * - always one buffer (period) DMA is working on
> +	 * - one buffer (period) driver pushed to ASoC side.
> +	 */
> +	watermark = min(watermark, val * (unsigned int)(sizeof(u32)));
> +	adc->buf_sz = watermark * 2;
> +
> +	return 0;
> +}
> +
> +static const struct iio_info stm32_dfsdm_info_audio = {
> +	.hwfifo_set_watermark = stm32_dfsdm_set_watermark,
> +	.driver_module = THIS_MODULE,

This has gone - now handled by macro magic...

> +};
> +
> +static unsigned int stm32_dfsdm_adc_dma_residue(struct stm32_dfsdm_adc *adc)
> +{
> +	struct dma_tx_state state;
> +	enum dma_status status;
> +
> +	status = dmaengine_tx_status(adc->dma_chan,
> +				     adc->dma_chan->cookie,
> +				     &state);
> +	if (status == DMA_IN_PROGRESS) {
> +		/* Residue is size in bytes from end of buffer */
> +		unsigned int i = adc->buf_sz - state.residue;
> +		unsigned int size;
> +
> +		/* Return available bytes */
> +		if (i >= adc->bufi)
> +			size = i - adc->bufi;
> +		else
> +			size = adc->buf_sz + i - adc->bufi;
> +
> +		return size;
> +	}
> +
> +	return 0;
> +}
> +
> +static void stm32_dfsdm_audio_dma_buffer_done(void *data)
> +{
> +	struct iio_dev *indio_dev = data;
> +	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
> +	int available = stm32_dfsdm_adc_dma_residue(adc);
> +	size_t old_pos;
> +
> +	/*
> +	 * FIXME: Buffer interface does not support cyclic DMA buffer,and offers
> +	 * only an interface to push data samples per samples.
> +	 * For this reason IIO buffer interface is not used and interface is
> +	 * bypassed using a private callback registered by ASoC.
> +	 * This should be a temporary solution waiting a cyclic DMA engine
> +	 * support in IIO.
More specifically the in kernel interfaces don't support dma cyclic
buffers.  We can already do them to userspace.  Doesn't really matter
though!

> +	 */
> +
> +	dev_dbg(&indio_dev->dev, "%s: pos = %d, available = %d\n", __func__,
> +		adc->bufi, available);
> +	old_pos = adc->bufi;
> +
> +	while (available >= indio_dev->scan_bytes) {
> +		u32 *buffer = (u32 *)&adc->rx_buf[adc->bufi];
> +
> +		/* Mask 8 LSB that contains the channel ID */
> +		*buffer = (*buffer & 0xFFFFFF00) << 8;
> +		available -= indio_dev->scan_bytes;
> +		adc->bufi += indio_dev->scan_bytes;
> +		if (adc->bufi >= adc->buf_sz) {
> +			if (adc->cb)
> +				adc->cb(&adc->rx_buf[old_pos],
> +					 adc->buf_sz - old_pos, adc->cb_priv);
> +			adc->bufi = 0;
> +			old_pos = 0;
> +		}
> +	}
> +	if (adc->cb)
> +		adc->cb(&adc->rx_buf[old_pos], adc->bufi - old_pos,
> +				adc->cb_priv);
> +}
> +
> +static int stm32_dfsdm_adc_dma_start(struct iio_dev *indio_dev)
> +{
> +	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
> +	struct dma_async_tx_descriptor *desc;
> +	dma_cookie_t cookie;
> +	int ret;
> +
> +	if (!adc->dma_chan)
> +		return -EINVAL;
> +
> +	dev_dbg(&indio_dev->dev, "%s size=%d watermark=%d\n", __func__,
> +		adc->buf_sz, adc->buf_sz / 2);
> +
> +	/* Prepare a DMA cyclic transaction */
> +	desc = dmaengine_prep_dma_cyclic(adc->dma_chan,
> +					 adc->dma_buf,
> +					 adc->buf_sz, adc->buf_sz / 2,
> +					 DMA_DEV_TO_MEM,
> +					 DMA_PREP_INTERRUPT);
> +	if (!desc)
> +		return -EBUSY;
> +
> +	desc->callback = stm32_dfsdm_audio_dma_buffer_done;
> +	desc->callback_param = indio_dev;
> +
> +	cookie = dmaengine_submit(desc);
> +	ret = dma_submit_error(cookie);
> +	if (ret) {
> +		dmaengine_terminate_all(adc->dma_chan);
> +		return ret;
> +	}
> +
> +	/* Issue pending DMA requests */
> +	dma_async_issue_pending(adc->dma_chan);
> +
> +	return 0;
> +}
> +
> +static int stm32_dfsdm_postenable(struct iio_dev *indio_dev)
> +{
> +	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
> +	int ret;
> +
> +	/* Reset adc buffer index */
> +	adc->bufi = 0;
> +
> +	ret = stm32_dfsdm_start_dfsdm(adc->dfsdm);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = stm32_dfsdm_start_conv(adc, true);
> +	if (ret) {
> +		dev_err(&indio_dev->dev, "Can't start conversion\n");
> +		goto stop_dfsdm;
> +	}
> +
> +	if (adc->dma_chan) {
> +		ret = stm32_dfsdm_adc_dma_start(indio_dev);
> +		if (ret) {
> +			dev_err(&indio_dev->dev, "Can't start DMA\n");
> +			goto err_stop_conv;
> +		}
> +	}
> +
> +	return 0;
> +
> +err_stop_conv:
> +	stm32_dfsdm_stop_conv(adc);
> +stop_dfsdm:
> +	stm32_dfsdm_stop_dfsdm(adc->dfsdm);
> +
> +	return ret;
> +}
> +
> +static int stm32_dfsdm_predisable(struct iio_dev *indio_dev)
> +{
> +	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
> +
> +	if (adc->dma_chan)
> +		dmaengine_terminate_all(adc->dma_chan);
> +
> +	stm32_dfsdm_stop_conv(adc);
> +
> +	stm32_dfsdm_stop_dfsdm(adc->dfsdm);
> +
> +	return 0;
> +}
> +
> +static const struct iio_buffer_setup_ops stm32_dfsdm_buffer_setup_ops = {
> +	.postenable = &stm32_dfsdm_postenable,
> +	.predisable = &stm32_dfsdm_predisable,
> +};
> +
> +/**
> + * stm32_dfsdm_get_buff_cb - register a callback
> + *	that will be called when DMA transfer period is achieved.
Please run kernel-doc over this file. I'm fairly sure this isn't
quite meeting the spec...

> + *
> + * @iio_dev: Handle to IIO device.
> + * @cb: pointer to callback function.
> + *	@data: pointer to data buffer
> + *	@size: size in byte of the data buffer
> + *	@private: pointer to consumer private structure
> + * @private: pointer to consumer private structure
> + */
> +int stm32_dfsdm_get_buff_cb(struct iio_dev *iio_dev,
> +			    int (*cb)(const void *data, size_t size,
> +				      void *private),
> +			    void *private)
> +{
> +	struct stm32_dfsdm_adc *adc;
> +
> +	if (!iio_dev)
> +		return -EINVAL;
> +	adc = iio_priv(iio_dev);
> +
> +	if (iio_dev !=  iio_priv_to_dev(adc))
> +		return -EINVAL;
Same as for the case below..

> +
> +	adc->cb = cb;
> +	adc->cb_priv = private;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(stm32_dfsdm_get_buff_cb);
> +
> +/**
> + * stm32_dfsdm_release_buff_cb - unregister buffer callback
> + *
> + * @iio_dev: Handle to IIO device.
> + */
> +int stm32_dfsdm_release_buff_cb(struct iio_dev *iio_dev)
> +{
> +	struct stm32_dfsdm_adc *adc;
> +
> +	if (!iio_dev)
> +		return -EINVAL;
> +	adc = iio_priv(iio_dev);
> +
> +	if (iio_dev !=  iio_priv_to_dev(adc))
> +		return -EINVAL;
I can't immediately spot why this could ever fail so we definitely
need a comment here saying what it is protecting against!

> +	adc->cb = NULL;
> +	adc->cb_priv = NULL;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(stm32_dfsdm_release_buff_cb);
> +
>  static int stm32_dfsdm_single_conv(struct iio_dev *indio_dev,
>  				   const struct iio_chan_spec *chan, int *res)
>  {
> @@ -544,6 +915,67 @@ static irqreturn_t stm32_dfsdm_irq(int irq, void *arg)
>  	return IRQ_HANDLED;
>  }
>  
> +/*
> + * Define external info for SPI Frequency and audio sampling rate that can be
> + * configured by ASoC driver through consumer.h API
> + */
> +static const struct iio_chan_spec_ext_info dfsdm_adc_audio_ext_info[] = {
> +	/* filter oversampling: Post filter oversampling ratio */
> +	{
> +		.name = "audio_sampling_rate",
> +		.shared = IIO_SHARED_BY_TYPE,
> +		.read = dfsdm_adc_audio_get_rate,
> +		.write = dfsdm_adc_audio_set_rate,
> +	},
> +	/* data_right_bit_shift : Filter output data shifting */
> +	{
> +		.name = "spi_clk_freq",
> +		.shared = IIO_SHARED_BY_TYPE,
> +		.read = dfsdm_adc_audio_get_spiclk,
> +		.write = dfsdm_adc_audio_set_spiclk,
> +	},
> +	{},
> +};
> +
> +static int stm32_dfsdm_dma_request(struct iio_dev *indio_dev)
> +{
> +	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
> +	struct dma_slave_config config;
> +	int ret;
> +
> +	adc->dma_chan = dma_request_slave_channel(&indio_dev->dev, "rx");
> +	if (!adc->dma_chan)
> +		return -EINVAL;
> +
> +	adc->rx_buf = dma_alloc_coherent(adc->dma_chan->device->dev,
> +					 DFSDM_DMA_BUFFER_SIZE,
> +					 &adc->dma_buf, GFP_KERNEL);
> +	if (!adc->rx_buf) {
> +		ret = -ENOMEM;
> +		goto err_release;
> +	}
> +
> +	/* Configure DMA channel to read data register */
> +	memset(&config, 0, sizeof(config));
> +	config.src_addr = (dma_addr_t)adc->dfsdm->phys_base;
> +	config.src_addr += DFSDM_RDATAR(adc->fl_id);
> +	config.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> +
> +	ret = dmaengine_slave_config(adc->dma_chan, &config);
> +	if (ret)
> +		goto err_free;
> +
> +	return 0;
> +
> +err_free:
> +	dma_free_coherent(adc->dma_chan->device->dev, DFSDM_DMA_BUFFER_SIZE,
> +			  adc->rx_buf, adc->dma_buf);
> +err_release:
> +	dma_release_channel(adc->dma_chan);
> +
> +	return ret;
> +}
> +
>  static int stm32_dfsdm_adc_chan_init_one(struct iio_dev *indio_dev,
>  					 struct iio_chan_spec *ch)
>  {
> @@ -564,7 +996,12 @@ static int stm32_dfsdm_adc_chan_init_one(struct iio_dev *indio_dev,
>  	ch->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
>  	ch->info_mask_shared_by_all = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO);
>  
> -	ch->scan_type.sign = 'u';
> +	if (adc->dev_data->type == DFSDM_AUDIO) {
> +		ch->scan_type.sign = 's';
> +		ch->ext_info = dfsdm_adc_audio_ext_info;
> +	} else {
> +		ch->scan_type.sign = 'u';
> +	}
>  	ch->scan_type.realbits = 24;
>  	ch->scan_type.storagebits = 32;
>  	adc->ch_id = ch->channel;
> @@ -573,6 +1010,58 @@ static int stm32_dfsdm_adc_chan_init_one(struct iio_dev *indio_dev,
>  					  &adc->dfsdm->ch_list[ch->channel]);
>  }
>  
> +static int stm32_dfsdm_audio_init(struct iio_dev *indio_dev)
> +{
> +	struct iio_chan_spec *ch;
> +	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
> +	int ret;
> +
> +	ret = stm32_dfsdm_dma_request(indio_dev);
> +	if (ret) {
> +		dev_err(&indio_dev->dev, "DMA request failed\n");
> +		return ret;
> +	}
> +
> +	indio_dev->modes |= INDIO_BUFFER_SOFTWARE;
> +
> +	ret = iio_triggered_buffer_setup(indio_dev,
> +					 &iio_pollfunc_store_time,
> +					 NULL,
> +					 &stm32_dfsdm_buffer_setup_ops);
> +	if (ret) {
> +		dev_err(&indio_dev->dev, "Buffer setup failed\n");
> +		goto err_dma_disable;
> +	}
> +
> +	ch = devm_kzalloc(&indio_dev->dev, sizeof(*ch), GFP_KERNEL);
> +	if (!ch)
> +		return -ENOMEM;
> +
> +	ch->scan_index = 0;
> +	ret = stm32_dfsdm_adc_chan_init_one(indio_dev, ch);
> +	if (ret < 0) {
> +		dev_err(&indio_dev->dev, "channels init failed\n");
> +		goto err_buffer_cleanup;
> +	}
> +
> +	indio_dev->num_channels = 1;
> +	indio_dev->channels = ch;
> +
> +	return 0;
> +
> +err_buffer_cleanup:
> +	iio_triggered_buffer_cleanup(indio_dev);
> +
> +err_dma_disable:
> +	if (adc->dma_chan) {
> +		dma_free_coherent(adc->dma_chan->device->dev,
> +				  DFSDM_DMA_BUFFER_SIZE,
> +				  adc->rx_buf, adc->dma_buf);
> +		dma_release_channel(adc->dma_chan);
> +	}
> +	return ret;
> +}
> +
>  static int stm32_dfsdm_adc_init(struct iio_dev *indio_dev)
>  {
>  	struct iio_chan_spec *ch;
> @@ -625,10 +1114,18 @@ static const struct stm32_dfsdm_dev_data stm32h7_dfsdm_adc_data = {
>  	.init = stm32_dfsdm_adc_init,
>  };
>  
> +static const struct stm32_dfsdm_dev_data stm32h7_dfsdm_audio_data = {
> +	.type = DFSDM_AUDIO,
> +	.init = stm32_dfsdm_audio_init,
> +};
> +
>  static const struct of_device_id stm32_dfsdm_adc_match[] = {
>  	{ .compatible = "st,stm32-dfsdm-adc",
>  		.data = &stm32h7_dfsdm_adc_data,
>  	},
> +	{ .compatible = "st,stm32-dfsdm-dmic",
> +		.data = &stm32h7_dfsdm_audio_data,
> +	},
>  	{}
>  };
>  
> @@ -679,8 +1176,13 @@ static int stm32_dfsdm_adc_probe(struct platform_device *pdev)
>  	name = devm_kzalloc(dev, sizeof("dfsdm-adc0"), GFP_KERNEL);
>  	if (!name)
>  		return -ENOMEM;
> -	iio->info = &stm32_dfsdm_info_adc;
> -	snprintf(name, sizeof("dfsdm-adc0"), "dfsdm-adc%d", adc->fl_id);
> +	if (dev_data->type == DFSDM_AUDIO) {
> +		iio->info = &stm32_dfsdm_info_audio;
> +		snprintf(name, sizeof("dfsdm-pdm0"), "dfsdm-pdm%d", adc->fl_id);
> +	} else {
> +		iio->info = &stm32_dfsdm_info_adc;
> +		snprintf(name, sizeof("dfsdm-adc0"), "dfsdm-adc%d", adc->fl_id);
> +	}
>  	iio->name = name;
>  
>  	/*
> @@ -721,7 +1223,14 @@ static int stm32_dfsdm_adc_remove(struct platform_device *pdev)
>  	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
>  
>  	iio_device_unregister(indio_dev);
> -
> +	if (indio_dev->pollfunc)
> +		iio_triggered_buffer_cleanup(indio_dev);
> +	if (adc->dma_chan) {
> +		dma_free_coherent(adc->dma_chan->device->dev,
> +				  DFSDM_DMA_BUFFER_SIZE,
> +				  adc->rx_buf, adc->dma_buf);
> +		dma_release_channel(adc->dma_chan);
> +	}
>  	return 0;
>  }
>  
> diff --git a/include/linux/iio/adc/stm32-dfsdm-adc.h b/include/linux/iio/adc/stm32-dfsdm-adc.h
> new file mode 100644
> index 0000000..6885645
> --- /dev/null
> +++ b/include/linux/iio/adc/stm32-dfsdm-adc.h
> @@ -0,0 +1,27 @@
> +/*
> + * This file discribe the STM32 DFSDM IIO driver API for audio part
> + *
> + * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
> + * Author(s): Arnaud Pouliquen <arnaud.pouliquen-qxv4g6HH51o@public.gmane.org>.
> + *
> + * 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.
> + */
> +#ifndef STM32_DFSDM_ADC_H
> +#define STM32_DFSDM_ADC_H
> +
> +int stm32_dfsdm_get_buff_cb(struct iio_dev *iio_dev,
> +			    int (*cb)(const void *data, size_t size,
> +				      void *private),
> +			    void *private);
> +int stm32_dfsdm_release_buff_cb(struct iio_dev *iio_dev);
> +
> +#endif

--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html