Unverified Commit eca94980 authored by Arnaud Pouliquen's avatar Arnaud Pouliquen Committed by Mark Brown
Browse files

IIO: ADC: add stm32 DFSDM support for PDM microphone 



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: default avatarArnaud Pouliquen <arnaud.pouliquen@st.com>
Reviewed-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent e2e6771c

Documentation/ABI/testing/sysfs-bus-iio-dfsdm-adc-stm32

0 → 100644
+16 −0
Original line number Diff line number Diff line 
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

drivers/iio/adc/stm32-dfsdm-adc.c

+495 −7
Original line number Diff line number Diff line
@@ -6,19 +6,23 @@ 
 * Author: Arnaud Pouliquen <arnaud.pouliquen@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/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 +62,18 @@ 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 +367,63 @@ 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 +434,24 @@ 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 +485,231 @@ 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 +765,41 @@ 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 -EINVAL;

}



static int stm32_dfsdm_read_raw(struct iio_dev *indio_dev,
@@ -493,12 +831,23 @@ static int stm32_dfsdm_read_raw(struct iio_dev *indio_dev, 
	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:

		*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 +880,70 @@ 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 void stm32_dfsdm_dma_release(struct iio_dev *indio_dev)

{

	struct stm32_dfsdm_adc *adc = iio_priv(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);

	}

}



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 = {

		.src_addr = (dma_addr_t)adc->dfsdm->phys_base +

			DFSDM_RDATAR(adc->fl_id),

		.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES,

	};

	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;

	}



	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 +964,12 @@ 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);



	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 +978,39 @@ 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;



	indio_dev->modes |= INDIO_BUFFER_SOFTWARE;

	indio_dev->setup_ops = &stm32_dfsdm_buffer_setup_ops;



	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");

		return ret;

	}

	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 stm32_dfsdm_dma_request(indio_dev);

}



static int stm32_dfsdm_adc_init(struct iio_dev *indio_dev)

{

	struct iio_chan_spec *ch;
@@ -612,11 +1063,20 @@ 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 +1127,13 @@ static int stm32_dfsdm_adc_probe(struct platform_device *pdev) 
	name = devm_kzalloc(dev, sizeof("dfsdm-adc0"), GFP_KERNEL);

	if (!name)

		return -ENOMEM;

	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 +1165,27 @@ static int stm32_dfsdm_adc_probe(struct platform_device *pdev) 
	if (ret < 0)

		return ret;



	return iio_device_register(iio);

	ret = iio_device_register(iio);

	if (ret < 0)

		goto err_cleanup;



	dev_err(dev, "of_platform_populate\n");

	if (dev_data->type == DFSDM_AUDIO) {

		ret = of_platform_populate(np, NULL, NULL, dev);

		if (ret < 0) {

			dev_err(dev, "Failed to find an audio DAI\n");

			goto err_unregister;

		}

	}



	return 0;



err_unregister:

	iio_device_unregister(iio);

err_cleanup:

	stm32_dfsdm_dma_release(iio);



	return ret;

}



static int stm32_dfsdm_adc_remove(struct platform_device *pdev)
@@ -708,7 +1193,10 @@ static int stm32_dfsdm_adc_remove(struct platform_device *pdev) 
	struct stm32_dfsdm_adc *adc = platform_get_drvdata(pdev);

	struct iio_dev *indio_dev = iio_priv_to_dev(adc);



	if (adc->dev_data->type == DFSDM_AUDIO)

		of_platform_depopulate(&pdev->dev);

	iio_device_unregister(indio_dev);

	stm32_dfsdm_dma_release(indio_dev);



	return 0;

}

include/linux/iio/adc/stm32-dfsdm-adc.h

0 → 100644
+18 −0
Original line number Diff line number Diff line 
/* 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@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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