[PATCH v7 10/13] IIO: ADC: add stm32 DFSDM support for PDM microphone
Jonathan Cameron
jic23 at kernel.org
Sun Dec 10 10:14:11 PST 2017
On Fri, 8 Dec 2017 15:49:23 +0100
Arnaud Pouliquen <arnaud.pouliquen at st.com> 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 at st.com>
Hi Arnaud,
I'm afraid I missed a few things on the earlier versions.
Around the use of the iio_triggered_buffer_setup
(which does some stuff we don't need here)
Also ordering isn't quite consistent between probe and
remove.
Jonathan
> ---
> V6 to V7 updates:
> - SPDX-Licensing.
> - Minor typo fixes.
>
> .../ABI/testing/sysfs-bus-iio-dfsdm-adc-stm32 | 16 +
> drivers/iio/adc/stm32-dfsdm-adc.c | 508 ++++++++++++++++++++-
> include/linux/iio/adc/stm32-dfsdm-adc.h | 18 +
> 3 files changed, 534 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 at 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 68b5920..2d6aed5 100644
> --- a/drivers/iio/adc/stm32-dfsdm-adc.c
> +++ b/drivers/iio/adc/stm32-dfsdm-adc.c
> @@ -6,19 +6,25 @@
> * Author: Arnaud Pouliquen <arnaud.pouliquen at st.com>.
> */
>
> +#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))
> @@ -58,6 +64,18 @@ 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 {
> @@ -351,10 +369,63 @@ 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)
> @@ -365,6 +436,24 @@ 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;
> @@ -398,6 +487,231 @@ 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)
> {
> @@ -453,15 +767,41 @@ 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,
> @@ -494,11 +834,22 @@ 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,
> @@ -531,6 +882,60 @@ 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;
Superficially looks like this could be more elegantly done
using C99 structure init above.
struct dma_slave_config config = {
.src_addr = (dma_addr_t)adc-dfsdm->phys_base +
DFSDM_RDATAR(adc->fl_ix),
.src_addr_width = DMA_SLAVE_BUS_WIDTH_4_BYTES
};
All the rest will be zeroed by the compiler..
> +
> + 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)
> {
> @@ -551,7 +956,12 @@ 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;
> @@ -560,6 +970,64 @@ 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,
Why? What reads the time?
I'm not terribly keen on this being used here given we don't actually
have a triggered_buffer... This is going to allocate an IIO kfifo
that we don't use as well (not huge, but not elegant to allocate
one we don't use).
> + 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;
> @@ -612,11 +1080,20 @@ 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,
> + },
> {}
> };
>
> @@ -667,8 +1144,13 @@ 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;
>
> /*
> @@ -700,7 +1182,10 @@ 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);
Hmm. This is a little ugly in that the devm call will get
unwound after the IIO device is unregistered and all if it's
interfaces have gone away.
I don't think it 'matters' as such here but it would be
nicer if the remove order was the precise reverse of the probe order
and to do that you can't use a managed function here.
> + return 0;
> }
>
> static int stm32_dfsdm_adc_remove(struct platform_device *pdev)
> @@ -709,7 +1194,14 @@ 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);
This is not in the reverse order of the probe as these are (I think)
set up in the audio init as a result of the platform populate?
So these should be before the iio_device_unregister.
This whole chunk is really an unwind of the audio init. I would
make that explicit by having an audio exit function called here.
> + }
> 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..e7dc7a5
> --- /dev/null
> +++ b/include/linux/iio/adc/stm32-dfsdm-adc.h
> @@ -0,0 +1,18 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * 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 at st.com>.
> + */
> +
> +#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
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