[PATCH v6 10/13] IIO: ADC: add stm32 DFSDM support for PDM microphone

Arnaud Pouliquen
2017-12-01T17:40:17Z

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@st.com>
---
.../ABI/testing/sysfs-bus-iio-dfsdm-adc-stm32 | 16 +
drivers/iio/adc/stm32-dfsdm-adc.c | 507 ++++++++++++++++++++-
include/linux/iio/adc/stm32-dfsdm-adc.h | 28 ++
3 files changed, 543 insertions(+), 8 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..da98223
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-iio-dfsdm-adc-stm32
@@ -0,0 +1,16 @@
+What: /sys/bus/iio/devices/iio:deviceX/in_voltage_spi_clk_freq
+KernelVersion: 4.14
+Contact: arnaud.pouliquen@st.com
+Description:
+ For audio purpose only.
+ Used by audio driver to set/get the spi input frequency.
+ This is mandatory if DFSDM is slave on SPI bus, to
+ provide information on the SPI clock frequency during runtime
+ Notice that the SPI frequency should be a multiple of sample
+ frequency to ensure the precision.
+ if DFSDM input is SPI master
+ Reading SPI clkout frequency,
+ error on writing
+ If DFSDM input is SPI Slave:
+ Reading returns value previously set.
+ Writing value before starting conversions.
\ No newline at end of file
diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c
index f9419ab..80b0ca7 100644
--- a/drivers/iio/adc/stm32-dfsdm-adc.c
+++ b/drivers/iio/adc/stm32-dfsdm-adc.c
@@ -19,19 +19,25 @@
* 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/of_device.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/slab.h>

#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 +382,63 @@ int stm32_dfsdm_channel_parse_of(struct stm32_dfsdm *dfsdm,
return 0;
}

+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;
+}
+
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 +449,24 @@ 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 +500,231 @@ 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 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: In Kernel 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.
+ */
+
+ 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.
+ *
+ * @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);
+
+ 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);
+
+ 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)
{
@@ -466,15 +780,41 @@ static int stm32_dfsdm_write_raw(struct iio_dev *indio_dev,
{
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;
int ret = -EINVAL;

- if (mask == IIO_CHAN_INFO_OVERSAMPLING_RATIO) {
+ switch (mask) {
+ case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
ret = stm32_dfsdm_set_osrs(fl, 0, val);
if (!ret)
adc->oversamp = val;
+
+ return ret;
+
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ if (!val)
+ return -EINVAL;
+ if (ch->src != DFSDM_CHANNEL_SPI_CLOCK_EXTERNAL)
+ spi_freq = adc->dfsdm->spi_master_freq;
+
+ if (spi_freq % val)
+ dev_warn(&indio_dev->dev,
+ "Sampling rate not accurate (%d)\n",
+ spi_freq / (spi_freq / val));
+
+ ret = stm32_dfsdm_set_osrs(fl, 0, (spi_freq / val));
+ if (ret < 0) {
+ dev_err(&indio_dev->dev,
+ "Not able to find parameter that match!\n");
+ return ret;
+ }
+ adc->sample_freq = val;
+
+ return 0;
}

- return ret;
+ return -EINVAL;
}

static int stm32_dfsdm_read_raw(struct iio_dev *indio_dev,
@@ -507,11 +847,22 @@ static int stm32_dfsdm_read_raw(struct iio_dev *indio_dev,
*val = adc->oversamp;

return IIO_VAL_INT;
+
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ *val = adc->sample_freq;
+
+ return IIO_VAL_INT;
}

return -EINVAL;
}

+static const struct iio_info stm32_dfsdm_info_audio = {
+ .hwfifo_set_watermark = stm32_dfsdm_set_watermark,
+ .read_raw = stm32_dfsdm_read_raw,
+ .write_raw = stm32_dfsdm_write_raw,
+};
+
static const struct iio_info stm32_dfsdm_info_adc = {
.read_raw = stm32_dfsdm_read_raw,
.write_raw = stm32_dfsdm_write_raw,
@@ -544,6 +895,60 @@ 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[] = {
+ /* spi_clk_freq : clock freq on SPI/manchester bus used by channel */
+ {
+ .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 +969,12 @@ 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 +983,64 @@ 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);
+ struct stm32_dfsdm_channel *d_ch;
+ 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;
+ }
+ ch->info_mask_separate = BIT(IIO_CHAN_INFO_SAMP_FREQ);
+
+ d_ch = &adc->dfsdm->ch_list[adc->ch_id];
+ if (d_ch->src != DFSDM_CHANNEL_SPI_CLOCK_EXTERNAL)
+ adc->spi_freq = adc->dfsdm->spi_master_freq;
+
+ 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 +1093,18 @@ 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 +1155,13 @@ 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;

/*
@@ -712,7 +1193,10 @@ static int stm32_dfsdm_adc_probe(struct platform_device *pdev)
if (ret < 0)
return ret;

- return iio_device_register(iio);
+ iio_device_register(iio);
+ if (dev_data->type == DFSDM_AUDIO)
+ return devm_of_platform_populate(&pdev->dev);
+ return 0;
}

static int stm32_dfsdm_adc_remove(struct platform_device *pdev)
@@ -721,7 +1205,14 @@ 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..cad7963
--- /dev/null
+++ b/include/linux/iio/adc/stm32-dfsdm-adc.h
@@ -0,0 +1,28 @@
+/*
+ * 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@st.com>.
+ *
+ * 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
--
2.7.4