Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1685 insertions, 0 deletions

diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c
new file mode 100644
index 000000000..a428bdb56
--- /dev/null
+++ b/drivers/iio/adc/stm32-dfsdm-adc.c
@@ -0,0 +1,1685 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file is the ADC part of the STM32 DFSDM driver
+ *
+ * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
+ * Author: Arnaud Pouliquen <arnaud.pouliquen@st.com>.
+ */
+
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/iio/adc/stm32-dfsdm-adc.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/hw-consumer.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/timer/stm32-lptim-trigger.h>
+#include <linux/iio/timer/stm32-timer-trigger.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/interrupt.h>
+#include <linux/module.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))
+
+/* Oversampling attribute default */
+#define DFSDM_DEFAULT_OVERSAMPLING  100
+
+/* Oversampling max values */
+#define DFSDM_MAX_INT_OVERSAMPLING 256
+#define DFSDM_MAX_FL_OVERSAMPLING 1024
+
+/* Limit filter output resolution to 31 bits. (i.e. sample range is +/-2^30) */
+#define DFSDM_DATA_MAX BIT(30)
+/*
+ * Data are output as two's complement data in a 24 bit field.
+ * Data from filters are in the range +/-2^(n-1)
+ * 2^(n-1) maximum positive value cannot be coded in 2's complement n bits
+ * An extra bit is required to avoid wrap-around of the binary code for 2^(n-1)
+ * So, the resolution of samples from filter is actually limited to 23 bits
+ */
+#define DFSDM_DATA_RES 24
+
+/* Filter configuration */
+#define DFSDM_CR1_CFG_MASK (DFSDM_CR1_RCH_MASK | DFSDM_CR1_RCONT_MASK | \
+			    DFSDM_CR1_RSYNC_MASK | DFSDM_CR1_JSYNC_MASK | \
+			    DFSDM_CR1_JSCAN_MASK)
+
+enum sd_converter_type {
+	DFSDM_AUDIO,
+	DFSDM_IIO,
+};
+
+struct stm32_dfsdm_dev_data {
+	int type;
+	int (*init)(struct device *dev, struct iio_dev *indio_dev);
+	unsigned int num_channels;
+	const struct regmap_config *regmap_cfg;
+};
+
+struct stm32_dfsdm_adc {
+	struct stm32_dfsdm *dfsdm;
+	const struct stm32_dfsdm_dev_data *dev_data;
+	unsigned int fl_id;
+	unsigned int nconv;
+	unsigned long smask;
+
+	/* ADC specific */
+	unsigned int oversamp;
+	struct iio_hw_consumer *hwc;
+	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 {
+	const char	*name;
+	unsigned int	val;
+};
+
+/* DFSDM channel serial interface type */
+static const struct stm32_dfsdm_str2field stm32_dfsdm_chan_type[] = {
+	{ "SPI_R", 0 }, /* SPI with data on rising edge */
+	{ "SPI_F", 1 }, /* SPI with data on falling edge */
+	{ "MANCH_R", 2 }, /* Manchester codec, rising edge = logic 0 */
+	{ "MANCH_F", 3 }, /* Manchester codec, falling edge = logic 1 */
+	{},
+};
+
+/* DFSDM channel clock source */
+static const struct stm32_dfsdm_str2field stm32_dfsdm_chan_src[] = {
+	/* External SPI clock (CLKIN x) */
+	{ "CLKIN", DFSDM_CHANNEL_SPI_CLOCK_EXTERNAL },
+	/* Internal SPI clock (CLKOUT) */
+	{ "CLKOUT", DFSDM_CHANNEL_SPI_CLOCK_INTERNAL },
+	/* Internal SPI clock divided by 2 (falling edge) */
+	{ "CLKOUT_F", DFSDM_CHANNEL_SPI_CLOCK_INTERNAL_DIV2_FALLING },
+	/* Internal SPI clock divided by 2 (falling edge) */
+	{ "CLKOUT_R", DFSDM_CHANNEL_SPI_CLOCK_INTERNAL_DIV2_RISING },
+	{},
+};
+
+static int stm32_dfsdm_str2val(const char *str,
+			       const struct stm32_dfsdm_str2field *list)
+{
+	const struct stm32_dfsdm_str2field *p = list;
+
+	for (p = list; p && p->name; p++)
+		if (!strcmp(p->name, str))
+			return p->val;
+
+	return -EINVAL;
+}
+
+/**
+ * struct stm32_dfsdm_trig_info - DFSDM trigger info
+ * @name:		name of the trigger, corresponding to its source
+ * @jextsel:		trigger signal selection
+ */
+struct stm32_dfsdm_trig_info {
+	const char *name;
+	unsigned int jextsel;
+};
+
+/* hardware injected trigger enable, edge selection */
+enum stm32_dfsdm_jexten {
+	STM32_DFSDM_JEXTEN_DISABLED,
+	STM32_DFSDM_JEXTEN_RISING_EDGE,
+	STM32_DFSDM_JEXTEN_FALLING_EDGE,
+	STM32_DFSDM_EXTEN_BOTH_EDGES,
+};
+
+static const struct stm32_dfsdm_trig_info stm32_dfsdm_trigs[] = {
+	{ TIM1_TRGO, 0 },
+	{ TIM1_TRGO2, 1 },
+	{ TIM8_TRGO, 2 },
+	{ TIM8_TRGO2, 3 },
+	{ TIM3_TRGO, 4 },
+	{ TIM4_TRGO, 5 },
+	{ TIM16_OC1, 6 },
+	{ TIM6_TRGO, 7 },
+	{ TIM7_TRGO, 8 },
+	{ LPTIM1_OUT, 26 },
+	{ LPTIM2_OUT, 27 },
+	{ LPTIM3_OUT, 28 },
+	{},
+};
+
+static int stm32_dfsdm_get_jextsel(struct iio_dev *indio_dev,
+				   struct iio_trigger *trig)
+{
+	int i;
+
+	/* lookup triggers registered by stm32 timer trigger driver */
+	for (i = 0; stm32_dfsdm_trigs[i].name; i++) {
+		/**
+		 * Checking both stm32 timer trigger type and trig name
+		 * should be safe against arbitrary trigger names.
+		 */
+		if ((is_stm32_timer_trigger(trig) ||
+		     is_stm32_lptim_trigger(trig)) &&
+		    !strcmp(stm32_dfsdm_trigs[i].name, trig->name)) {
+			return stm32_dfsdm_trigs[i].jextsel;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static int stm32_dfsdm_compute_osrs(struct stm32_dfsdm_filter *fl,
+				    unsigned int fast, unsigned int oversamp)
+{
+	unsigned int i, d, fosr, iosr;
+	u64 res, max;
+	int bits, shift;
+	unsigned int m = 1;	/* multiplication factor */
+	unsigned int p = fl->ford;	/* filter order (ford) */
+	struct stm32_dfsdm_filter_osr *flo = &fl->flo[fast];
+
+	pr_debug("Requested oversampling: %d\n", oversamp);
+	/*
+	 * This function tries to compute filter oversampling and integrator
+	 * oversampling, base on oversampling ratio requested by user.
+	 *
+	 * Decimation d depends on the filter order and the oversampling ratios.
+	 * ford: filter order
+	 * fosr: filter over sampling ratio
+	 * iosr: integrator over sampling ratio
+	 */
+	if (fl->ford == DFSDM_FASTSINC_ORDER) {
+		m = 2;
+		p = 2;
+	}
+
+	/*
+	 * Look for filter and integrator oversampling ratios which allows
+	 * to maximize data output resolution.
+	 */
+	for (fosr = 1; fosr <= DFSDM_MAX_FL_OVERSAMPLING; fosr++) {
+		for (iosr = 1; iosr <= DFSDM_MAX_INT_OVERSAMPLING; iosr++) {
+			if (fast)
+				d = fosr * iosr;
+			else if (fl->ford == DFSDM_FASTSINC_ORDER)
+				d = fosr * (iosr + 3) + 2;
+			else
+				d = fosr * (iosr - 1 + p) + p;
+
+			if (d > oversamp)
+				break;
+			else if (d != oversamp)
+				continue;
+			/*
+			 * Check resolution (limited to signed 32 bits)
+			 *   res <= 2^31
+			 * Sincx filters:
+			 *   res = m * fosr^p x iosr (with m=1, p=ford)
+			 * FastSinc filter
+			 *   res = m * fosr^p x iosr (with m=2, p=2)
+			 */
+			res = fosr;
+			for (i = p - 1; i > 0; i--) {
+				res = res * (u64)fosr;
+				if (res > DFSDM_DATA_MAX)
+					break;
+			}
+			if (res > DFSDM_DATA_MAX)
+				continue;
+
+			res = res * (u64)m * (u64)iosr;
+			if (res > DFSDM_DATA_MAX)
+				continue;
+
+			if (res >= flo->res) {
+				flo->res = res;
+				flo->fosr = fosr;
+				flo->iosr = iosr;
+
+				bits = fls(flo->res);
+				/* 8 LBSs in data register contain chan info */
+				max = flo->res << 8;
+
+				/* if resolution is not a power of two */
+				if (flo->res > BIT(bits - 1))
+					bits++;
+				else
+					max--;
+
+				shift = DFSDM_DATA_RES - bits;
+				/*
+				 * Compute right/left shift
+				 * Right shift is performed by hardware
+				 * when transferring samples to data register.
+				 * Left shift is done by software on buffer
+				 */
+				if (shift > 0) {
+					/* Resolution is lower than 24 bits */
+					flo->rshift = 0;
+					flo->lshift = shift;
+				} else {
+					/*
+					 * If resolution is 24 bits or more,
+					 * max positive value may be ambiguous
+					 * (equal to max negative value as sign
+					 * bit is dropped).
+					 * Reduce resolution to 23 bits (rshift)
+					 * to keep the sign on bit 23 and treat
+					 * saturation before rescaling on 24
+					 * bits (lshift).
+					 */
+					flo->rshift = 1 - shift;
+					flo->lshift = 1;
+					max >>= flo->rshift;
+				}
+				flo->max = (s32)max;
+				flo->bits = bits;
+
+				pr_debug("fast %d, fosr %d, iosr %d, res 0x%llx/%d bits, rshift %d, lshift %d\n",
+					 fast, flo->fosr, flo->iosr,
+					 flo->res, bits, flo->rshift,
+					 flo->lshift);
+			}
+		}
+	}
+
+	if (!flo->res)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int stm32_dfsdm_compute_all_osrs(struct iio_dev *indio_dev,
+					unsigned int oversamp)
+{
+	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+	struct stm32_dfsdm_filter *fl = &adc->dfsdm->fl_list[adc->fl_id];
+	int ret0, ret1;
+
+	memset(&fl->flo[0], 0, sizeof(fl->flo[0]));
+	memset(&fl->flo[1], 0, sizeof(fl->flo[1]));
+
+	ret0 = stm32_dfsdm_compute_osrs(fl, 0, oversamp);
+	ret1 = stm32_dfsdm_compute_osrs(fl, 1, oversamp);
+	if (ret0 < 0 && ret1 < 0) {
+		dev_err(&indio_dev->dev,
+			"Filter parameters not found: errors %d/%d\n",
+			ret0, ret1);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int stm32_dfsdm_start_channel(struct iio_dev *indio_dev)
+{
+	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+	struct regmap *regmap = adc->dfsdm->regmap;
+	const struct iio_chan_spec *chan;
+	unsigned int bit;
+	int ret;
+
+	for_each_set_bit(bit, &adc->smask, sizeof(adc->smask) * BITS_PER_BYTE) {
+		chan = indio_dev->channels + bit;
+		ret = regmap_update_bits(regmap, DFSDM_CHCFGR1(chan->channel),
+					 DFSDM_CHCFGR1_CHEN_MASK,
+					 DFSDM_CHCFGR1_CHEN(1));
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static void stm32_dfsdm_stop_channel(struct iio_dev *indio_dev)
+{
+	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+	struct regmap *regmap = adc->dfsdm->regmap;
+	const struct iio_chan_spec *chan;
+	unsigned int bit;
+
+	for_each_set_bit(bit, &adc->smask, sizeof(adc->smask) * BITS_PER_BYTE) {
+		chan = indio_dev->channels + bit;
+		regmap_update_bits(regmap, DFSDM_CHCFGR1(chan->channel),
+				   DFSDM_CHCFGR1_CHEN_MASK,
+				   DFSDM_CHCFGR1_CHEN(0));
+	}
+}
+
+static int stm32_dfsdm_chan_configure(struct stm32_dfsdm *dfsdm,
+				      struct stm32_dfsdm_channel *ch)
+{
+	unsigned int id = ch->id;
+	struct regmap *regmap = dfsdm->regmap;
+	int ret;
+
+	ret = regmap_update_bits(regmap, DFSDM_CHCFGR1(id),
+				 DFSDM_CHCFGR1_SITP_MASK,
+				 DFSDM_CHCFGR1_SITP(ch->type));
+	if (ret < 0)
+		return ret;
+	ret = regmap_update_bits(regmap, DFSDM_CHCFGR1(id),
+				 DFSDM_CHCFGR1_SPICKSEL_MASK,
+				 DFSDM_CHCFGR1_SPICKSEL(ch->src));
+	if (ret < 0)
+		return ret;
+	return regmap_update_bits(regmap, DFSDM_CHCFGR1(id),
+				  DFSDM_CHCFGR1_CHINSEL_MASK,
+				  DFSDM_CHCFGR1_CHINSEL(ch->alt_si));
+}
+
+static int stm32_dfsdm_start_filter(struct stm32_dfsdm_adc *adc,
+				    unsigned int fl_id,
+				    struct iio_trigger *trig)
+{
+	struct stm32_dfsdm *dfsdm = adc->dfsdm;
+	int ret;
+
+	/* Enable filter */
+	ret = regmap_update_bits(dfsdm->regmap, DFSDM_CR1(fl_id),
+				 DFSDM_CR1_DFEN_MASK, DFSDM_CR1_DFEN(1));
+	if (ret < 0)
+		return ret;
+
+	/* Nothing more to do for injected (scan mode/triggered) conversions */
+	if (adc->nconv > 1 || trig)
+		return 0;
+
+	/* Software start (single or continuous) regular conversion */
+	return regmap_update_bits(dfsdm->regmap, DFSDM_CR1(fl_id),
+				  DFSDM_CR1_RSWSTART_MASK,
+				  DFSDM_CR1_RSWSTART(1));
+}
+
+static void stm32_dfsdm_stop_filter(struct stm32_dfsdm *dfsdm,
+				    unsigned int fl_id)
+{
+	/* Disable conversion */
+	regmap_update_bits(dfsdm->regmap, DFSDM_CR1(fl_id),
+			   DFSDM_CR1_DFEN_MASK, DFSDM_CR1_DFEN(0));
+}
+
+static int stm32_dfsdm_filter_set_trig(struct iio_dev *indio_dev,
+				       unsigned int fl_id,
+				       struct iio_trigger *trig)
+{
+	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+	struct regmap *regmap = adc->dfsdm->regmap;
+	u32 jextsel = 0, jexten = STM32_DFSDM_JEXTEN_DISABLED;
+	int ret;
+
+	if (trig) {
+		ret = stm32_dfsdm_get_jextsel(indio_dev, trig);
+		if (ret < 0)
+			return ret;
+
+		/* set trigger source and polarity (default to rising edge) */
+		jextsel = ret;
+		jexten = STM32_DFSDM_JEXTEN_RISING_EDGE;
+	}
+
+	ret = regmap_update_bits(regmap, DFSDM_CR1(fl_id),
+				 DFSDM_CR1_JEXTSEL_MASK | DFSDM_CR1_JEXTEN_MASK,
+				 DFSDM_CR1_JEXTSEL(jextsel) |
+				 DFSDM_CR1_JEXTEN(jexten));
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int stm32_dfsdm_channels_configure(struct iio_dev *indio_dev,
+					  unsigned int fl_id,
+					  struct iio_trigger *trig)
+{
+	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+	struct regmap *regmap = adc->dfsdm->regmap;
+	struct stm32_dfsdm_filter *fl = &adc->dfsdm->fl_list[fl_id];
+	struct stm32_dfsdm_filter_osr *flo = &fl->flo[0];
+	const struct iio_chan_spec *chan;
+	unsigned int bit;
+	int ret;
+
+	fl->fast = 0;
+
+	/*
+	 * In continuous mode, use fast mode configuration,
+	 * if it provides a better resolution.
+	 */
+	if (adc->nconv == 1 && !trig && iio_buffer_enabled(indio_dev)) {
+		if (fl->flo[1].res >= fl->flo[0].res) {
+			fl->fast = 1;
+			flo = &fl->flo[1];
+		}
+	}
+
+	if (!flo->res)
+		return -EINVAL;
+
+	dev_dbg(&indio_dev->dev, "Samples actual resolution: %d bits",
+		min(flo->bits, (u32)DFSDM_DATA_RES - 1));
+
+	for_each_set_bit(bit, &adc->smask,
+			 sizeof(adc->smask) * BITS_PER_BYTE) {
+		chan = indio_dev->channels + bit;
+
+		ret = regmap_update_bits(regmap,
+					 DFSDM_CHCFGR2(chan->channel),
+					 DFSDM_CHCFGR2_DTRBS_MASK,
+					 DFSDM_CHCFGR2_DTRBS(flo->rshift));
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int stm32_dfsdm_filter_configure(struct iio_dev *indio_dev,
+					unsigned int fl_id,
+					struct iio_trigger *trig)
+{
+	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+	struct regmap *regmap = adc->dfsdm->regmap;
+	struct stm32_dfsdm_filter *fl = &adc->dfsdm->fl_list[fl_id];
+	struct stm32_dfsdm_filter_osr *flo = &fl->flo[fl->fast];
+	u32 cr1;
+	const struct iio_chan_spec *chan;
+	unsigned int bit, jchg = 0;
+	int ret;
+
+	/* Average integrator oversampling */
+	ret = regmap_update_bits(regmap, DFSDM_FCR(fl_id), DFSDM_FCR_IOSR_MASK,
+				 DFSDM_FCR_IOSR(flo->iosr - 1));
+	if (ret)
+		return ret;
+
+	/* Filter order and Oversampling */
+	ret = regmap_update_bits(regmap, DFSDM_FCR(fl_id), DFSDM_FCR_FOSR_MASK,
+				 DFSDM_FCR_FOSR(flo->fosr - 1));
+	if (ret)
+		return ret;
+
+	ret = regmap_update_bits(regmap, DFSDM_FCR(fl_id), DFSDM_FCR_FORD_MASK,
+				 DFSDM_FCR_FORD(fl->ford));
+	if (ret)
+		return ret;
+
+	ret = stm32_dfsdm_filter_set_trig(indio_dev, fl_id, trig);
+	if (ret)
+		return ret;
+
+	ret = regmap_update_bits(regmap, DFSDM_CR1(fl_id),
+				 DFSDM_CR1_FAST_MASK,
+				 DFSDM_CR1_FAST(fl->fast));
+	if (ret)
+		return ret;
+
+	/*
+	 * DFSDM modes configuration W.R.T audio/iio type modes
+	 * ----------------------------------------------------------------
+	 * Modes         | regular |  regular     | injected | injected   |
+	 *               |         |  continuous  |          | + scan     |
+	 * --------------|---------|--------------|----------|------------|
+	 * single conv   |    x    |              |          |            |
+	 * (1 chan)      |         |              |          |            |
+	 * --------------|---------|--------------|----------|------------|
+	 * 1 Audio chan	 |         | sample freq  |          |            |
+	 *               |         | or sync_mode |          |            |
+	 * --------------|---------|--------------|----------|------------|
+	 * 1 IIO chan	 |         | sample freq  | trigger  |            |
+	 *               |         | or sync_mode |          |            |
+	 * --------------|---------|--------------|----------|------------|
+	 * 2+ IIO chans  |         |              |          | trigger or |
+	 *               |         |              |          | sync_mode  |
+	 * ----------------------------------------------------------------
+	 */
+	if (adc->nconv == 1 && !trig) {
+		bit = __ffs(adc->smask);
+		chan = indio_dev->channels + bit;
+
+		/* Use regular conversion for single channel without trigger */
+		cr1 = DFSDM_CR1_RCH(chan->channel);
+
+		/* Continuous conversions triggered by SPI clk in buffer mode */
+		if (iio_buffer_enabled(indio_dev))
+			cr1 |= DFSDM_CR1_RCONT(1);
+
+		cr1 |= DFSDM_CR1_RSYNC(fl->sync_mode);
+	} else {
+		/* Use injected conversion for multiple channels */
+		for_each_set_bit(bit, &adc->smask,
+				 sizeof(adc->smask) * BITS_PER_BYTE) {
+			chan = indio_dev->channels + bit;
+			jchg |= BIT(chan->channel);
+		}
+		ret = regmap_write(regmap, DFSDM_JCHGR(fl_id), jchg);
+		if (ret < 0)
+			return ret;
+
+		/* Use scan mode for multiple channels */
+		cr1 = DFSDM_CR1_JSCAN((adc->nconv > 1) ? 1 : 0);
+
+		/*
+		 * Continuous conversions not supported in injected mode,
+		 * either use:
+		 * - conversions in sync with filter 0
+		 * - triggered conversions
+		 */
+		if (!fl->sync_mode && !trig)
+			return -EINVAL;
+		cr1 |= DFSDM_CR1_JSYNC(fl->sync_mode);
+	}
+
+	return regmap_update_bits(regmap, DFSDM_CR1(fl_id), DFSDM_CR1_CFG_MASK,
+				  cr1);
+}
+
+static int stm32_dfsdm_channel_parse_of(struct stm32_dfsdm *dfsdm,
+					struct iio_dev *indio_dev,
+					struct iio_chan_spec *ch)
+{
+	struct stm32_dfsdm_channel *df_ch;
+	const char *of_str;
+	int chan_idx = ch->scan_index;
+	int ret, val;
+
+	ret = of_property_read_u32_index(indio_dev->dev.of_node,
+					 "st,adc-channels", chan_idx,
+					 &ch->channel);
+	if (ret < 0) {
+		dev_err(&indio_dev->dev,
+			" Error parsing 'st,adc-channels' for idx %d\n",
+			chan_idx);
+		return ret;
+	}
+	if (ch->channel >= dfsdm->num_chs) {
+		dev_err(&indio_dev->dev,
+			" Error bad channel number %d (max = %d)\n",
+			ch->channel, dfsdm->num_chs);
+		return -EINVAL;
+	}
+
+	ret = of_property_read_string_index(indio_dev->dev.of_node,
+					    "st,adc-channel-names", chan_idx,
+					    &ch->datasheet_name);
+	if (ret < 0) {
+		dev_err(&indio_dev->dev,
+			" Error parsing 'st,adc-channel-names' for idx %d\n",
+			chan_idx);
+		return ret;
+	}
+
+	df_ch =  &dfsdm->ch_list[ch->channel];
+	df_ch->id = ch->channel;
+
+	ret = of_property_read_string_index(indio_dev->dev.of_node,
+					    "st,adc-channel-types", chan_idx,
+					    &of_str);
+	if (!ret) {
+		val = stm32_dfsdm_str2val(of_str, stm32_dfsdm_chan_type);
+		if (val < 0)
+			return val;
+	} else {
+		val = 0;
+	}
+	df_ch->type = val;
+
+	ret = of_property_read_string_index(indio_dev->dev.of_node,
+					    "st,adc-channel-clk-src", chan_idx,
+					    &of_str);
+	if (!ret) {
+		val = stm32_dfsdm_str2val(of_str, stm32_dfsdm_chan_src);
+		if (val < 0)
+			return val;
+	} else {
+		val = 0;
+	}
+	df_ch->src = val;
+
+	ret = of_property_read_u32_index(indio_dev->dev.of_node,
+					 "st,adc-alt-channel", chan_idx,
+					 &df_ch->alt_si);
+	if (ret < 0)
+		df_ch->alt_si = 0;
+
+	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 int dfsdm_adc_set_samp_freq(struct iio_dev *indio_dev,
+				   unsigned int sample_freq,
+				   unsigned int spi_freq)
+{
+	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+	unsigned int oversamp;
+	int ret;
+
+	oversamp = DIV_ROUND_CLOSEST(spi_freq, sample_freq);
+	if (spi_freq % sample_freq)
+		dev_dbg(&indio_dev->dev,
+			"Rate not accurate. requested (%u), actual (%u)\n",
+			sample_freq, spi_freq / oversamp);
+
+	ret = stm32_dfsdm_compute_all_osrs(indio_dev, oversamp);
+	if (ret < 0)
+		return ret;
+
+	adc->sample_freq = spi_freq / oversamp;
+	adc->oversamp = oversamp;
+
+	return 0;
+}
+
+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_channel *ch = &adc->dfsdm->ch_list[chan->channel];
+	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) {
+		ret = dfsdm_adc_set_samp_freq(indio_dev, sample_freq, spi_freq);
+		if (ret < 0)
+			return ret;
+	}
+	adc->spi_freq = spi_freq;
+
+	return len;
+}
+
+static int stm32_dfsdm_start_conv(struct iio_dev *indio_dev,
+				  struct iio_trigger *trig)
+{
+	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+	struct regmap *regmap = adc->dfsdm->regmap;
+	int ret;
+
+	ret = stm32_dfsdm_channels_configure(indio_dev, adc->fl_id, trig);
+	if (ret < 0)
+		return ret;
+
+	ret = stm32_dfsdm_start_channel(indio_dev);
+	if (ret < 0)
+		return ret;
+
+	ret = stm32_dfsdm_filter_configure(indio_dev, adc->fl_id, trig);
+	if (ret < 0)
+		goto stop_channels;
+
+	ret = stm32_dfsdm_start_filter(adc, adc->fl_id, trig);
+	if (ret < 0)
+		goto filter_unconfigure;
+
+	return 0;
+
+filter_unconfigure:
+	regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
+			   DFSDM_CR1_CFG_MASK, 0);
+stop_channels:
+	stm32_dfsdm_stop_channel(indio_dev);
+
+	return ret;
+}
+
+static void stm32_dfsdm_stop_conv(struct iio_dev *indio_dev)
+{
+	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+	struct regmap *regmap = adc->dfsdm->regmap;
+
+	stm32_dfsdm_stop_filter(adc->dfsdm, adc->fl_id);
+
+	regmap_update_bits(regmap, DFSDM_CR1(adc->fl_id),
+			   DFSDM_CR1_CFG_MASK, 0);
+
+	stm32_dfsdm_stop_channel(indio_dev);
+}
+
+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;
+	unsigned int rx_buf_sz = DFSDM_DMA_BUFFER_SIZE;
+
+	/*
+	 * 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 = min(rx_buf_sz, watermark * 2 * adc->nconv);
+
+	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 inline void stm32_dfsdm_process_data(struct stm32_dfsdm_adc *adc,
+					    s32 *buffer)
+{
+	struct stm32_dfsdm_filter *fl = &adc->dfsdm->fl_list[adc->fl_id];
+	struct stm32_dfsdm_filter_osr *flo = &fl->flo[fl->fast];
+	unsigned int i = adc->nconv;
+	s32 *ptr = buffer;
+
+	while (i--) {
+		/* Mask 8 LSB that contains the channel ID */
+		*ptr &= 0xFFFFFF00;
+		/* Convert 2^(n-1) sample to 2^(n-1)-1 to avoid wrap-around */
+		if (*ptr > flo->max)
+			*ptr -= 1;
+		/*
+		 * Samples from filter are retrieved with 23 bits resolution
+		 * or less. Shift left to align MSB on 24 bits.
+		 */
+		*ptr <<= flo->lshift;
+
+		ptr++;
+	}
+}
+
+static void stm32_dfsdm_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, "pos = %d, available = %d\n",
+		adc->bufi, available);
+	old_pos = adc->bufi;
+
+	while (available >= indio_dev->scan_bytes) {
+		s32 *buffer = (s32 *)&adc->rx_buf[adc->bufi];
+
+		stm32_dfsdm_process_data(adc, buffer);
+
+		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;
+		}
+		/*
+		 * In DMA mode the trigger services of IIO are not used
+		 * (e.g. no call to iio_trigger_poll).
+		 * Calling irq handler associated to the hardware trigger is not
+		 * relevant as the conversions have already been done. Data
+		 * transfers are performed directly in DMA callback instead.
+		 * This implementation avoids to call trigger irq handler that
+		 * may sleep, in an atomic context (DMA irq handler context).
+		 */
+		if (adc->dev_data->type == DFSDM_IIO)
+			iio_push_to_buffers(indio_dev, buffer);
+	}
+	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);
+	/*
+	 * The DFSDM supports half-word transfers. However, for 16 bits record,
+	 * 4 bytes buswidth is kept, to avoid losing samples LSBs when left
+	 * shift is required.
+	 */
+	struct dma_slave_config config = {
+		.src_addr = (dma_addr_t)adc->dfsdm->phys_base,
+		.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES,
+	};
+	struct dma_async_tx_descriptor *desc;
+	dma_cookie_t cookie;
+	int ret;
+
+	if (!adc->dma_chan)
+		return -EINVAL;
+
+	dev_dbg(&indio_dev->dev, "size=%d watermark=%d\n",
+		adc->buf_sz, adc->buf_sz / 2);
+
+	if (adc->nconv == 1 && !indio_dev->trig)
+		config.src_addr += DFSDM_RDATAR(adc->fl_id);
+	else
+		config.src_addr += DFSDM_JDATAR(adc->fl_id);
+	ret = dmaengine_slave_config(adc->dma_chan, &config);
+	if (ret)
+		return ret;
+
+	/* 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_dma_buffer_done;
+	desc->callback_param = indio_dev;
+
+	cookie = dmaengine_submit(desc);
+	ret = dma_submit_error(cookie);
+	if (ret)
+		goto err_stop_dma;
+
+	/* Issue pending DMA requests */
+	dma_async_issue_pending(adc->dma_chan);
+
+	if (adc->nconv == 1 && !indio_dev->trig) {
+		/* Enable regular DMA transfer*/
+		ret = regmap_update_bits(adc->dfsdm->regmap,
+					 DFSDM_CR1(adc->fl_id),
+					 DFSDM_CR1_RDMAEN_MASK,
+					 DFSDM_CR1_RDMAEN_MASK);
+	} else {
+		/* Enable injected DMA transfer*/
+		ret = regmap_update_bits(adc->dfsdm->regmap,
+					 DFSDM_CR1(adc->fl_id),
+					 DFSDM_CR1_JDMAEN_MASK,
+					 DFSDM_CR1_JDMAEN_MASK);
+	}
+
+	if (ret < 0)
+		goto err_stop_dma;
+
+	return 0;
+
+err_stop_dma:
+	dmaengine_terminate_all(adc->dma_chan);
+
+	return ret;
+}
+
+static void stm32_dfsdm_adc_dma_stop(struct iio_dev *indio_dev)
+{
+	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+
+	if (!adc->dma_chan)
+		return;
+
+	regmap_update_bits(adc->dfsdm->regmap, DFSDM_CR1(adc->fl_id),
+			   DFSDM_CR1_RDMAEN_MASK | DFSDM_CR1_JDMAEN_MASK, 0);
+	dmaengine_terminate_all(adc->dma_chan);
+}
+
+static int stm32_dfsdm_update_scan_mode(struct iio_dev *indio_dev,
+					const unsigned long *scan_mask)
+{
+	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+
+	adc->nconv = bitmap_weight(scan_mask, indio_dev->masklength);
+	adc->smask = *scan_mask;
+
+	dev_dbg(&indio_dev->dev, "nconv=%d mask=%lx\n", adc->nconv, *scan_mask);
+
+	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;
+
+	if (adc->hwc) {
+		ret = iio_hw_consumer_enable(adc->hwc);
+		if (ret < 0)
+			return ret;
+	}
+
+	ret = stm32_dfsdm_start_dfsdm(adc->dfsdm);
+	if (ret < 0)
+		goto err_stop_hwc;
+
+	ret = stm32_dfsdm_adc_dma_start(indio_dev);
+	if (ret) {
+		dev_err(&indio_dev->dev, "Can't start DMA\n");
+		goto stop_dfsdm;
+	}
+
+	ret = stm32_dfsdm_start_conv(indio_dev, indio_dev->trig);
+	if (ret) {
+		dev_err(&indio_dev->dev, "Can't start conversion\n");
+		goto err_stop_dma;
+	}
+
+	return 0;
+
+err_stop_dma:
+	stm32_dfsdm_adc_dma_stop(indio_dev);
+stop_dfsdm:
+	stm32_dfsdm_stop_dfsdm(adc->dfsdm);
+err_stop_hwc:
+	if (adc->hwc)
+		iio_hw_consumer_disable(adc->hwc);
+
+	return ret;
+}
+
+static int stm32_dfsdm_predisable(struct iio_dev *indio_dev)
+{
+	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+
+	stm32_dfsdm_stop_conv(indio_dev);
+
+	stm32_dfsdm_adc_dma_stop(indio_dev);
+
+	stm32_dfsdm_stop_dfsdm(adc->dfsdm);
+
+	if (adc->hwc)
+		iio_hw_consumer_disable(adc->hwc);
+
+	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)
+{
+	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+	long timeout;
+	int ret;
+
+	reinit_completion(&adc->completion);
+
+	adc->buffer = res;
+
+	ret = stm32_dfsdm_start_dfsdm(adc->dfsdm);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_update_bits(adc->dfsdm->regmap, DFSDM_CR2(adc->fl_id),
+				 DFSDM_CR2_REOCIE_MASK, DFSDM_CR2_REOCIE(1));
+	if (ret < 0)
+		goto stop_dfsdm;
+
+	adc->nconv = 1;
+	adc->smask = BIT(chan->scan_index);
+	ret = stm32_dfsdm_start_conv(indio_dev, NULL);
+	if (ret < 0) {
+		regmap_update_bits(adc->dfsdm->regmap, DFSDM_CR2(adc->fl_id),
+				   DFSDM_CR2_REOCIE_MASK, DFSDM_CR2_REOCIE(0));
+		goto stop_dfsdm;
+	}
+
+	timeout = wait_for_completion_interruptible_timeout(&adc->completion,
+							    DFSDM_TIMEOUT);
+
+	/* Mask IRQ for regular conversion achievement*/
+	regmap_update_bits(adc->dfsdm->regmap, DFSDM_CR2(adc->fl_id),
+			   DFSDM_CR2_REOCIE_MASK, DFSDM_CR2_REOCIE(0));
+
+	if (timeout == 0)
+		ret = -ETIMEDOUT;
+	else if (timeout < 0)
+		ret = timeout;
+	else
+		ret = IIO_VAL_INT;
+
+	stm32_dfsdm_stop_conv(indio_dev);
+
+	stm32_dfsdm_process_data(adc, res);
+
+stop_dfsdm:
+	stm32_dfsdm_stop_dfsdm(adc->dfsdm);
+
+	return ret;
+}
+
+static int stm32_dfsdm_write_raw(struct iio_dev *indio_dev,
+				 struct iio_chan_spec const *chan,
+				 int val, int val2, long mask)
+{
+	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+	struct stm32_dfsdm_channel *ch = &adc->dfsdm->ch_list[chan->channel];
+	unsigned int spi_freq;
+	int ret = -EINVAL;
+
+	switch (ch->src) {
+	case DFSDM_CHANNEL_SPI_CLOCK_INTERNAL:
+		spi_freq = adc->dfsdm->spi_master_freq;
+		break;
+	case DFSDM_CHANNEL_SPI_CLOCK_INTERNAL_DIV2_FALLING:
+	case DFSDM_CHANNEL_SPI_CLOCK_INTERNAL_DIV2_RISING:
+		spi_freq = adc->dfsdm->spi_master_freq / 2;
+		break;
+	default:
+		spi_freq = adc->spi_freq;
+	}
+
+	switch (mask) {
+	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+		ret = iio_device_claim_direct_mode(indio_dev);
+		if (ret)
+			return ret;
+
+		ret = stm32_dfsdm_compute_all_osrs(indio_dev, val);
+		if (!ret) {
+			dev_dbg(&indio_dev->dev,
+				"Sampling rate changed from (%u) to (%u)\n",
+				adc->sample_freq, spi_freq / val);
+			adc->oversamp = val;
+			adc->sample_freq = spi_freq / val;
+		}
+		iio_device_release_direct_mode(indio_dev);
+		return ret;
+
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		if (!val)
+			return -EINVAL;
+
+		ret = iio_device_claim_direct_mode(indio_dev);
+		if (ret)
+			return ret;
+
+		ret = dfsdm_adc_set_samp_freq(indio_dev, val, spi_freq);
+		iio_device_release_direct_mode(indio_dev);
+		return ret;
+	}
+
+	return -EINVAL;
+}
+
+static int stm32_dfsdm_read_raw(struct iio_dev *indio_dev,
+				struct iio_chan_spec const *chan, int *val,
+				int *val2, long mask)
+{
+	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = iio_device_claim_direct_mode(indio_dev);
+		if (ret)
+			return ret;
+		ret = iio_hw_consumer_enable(adc->hwc);
+		if (ret < 0) {
+			dev_err(&indio_dev->dev,
+				"%s: IIO enable failed (channel %d)\n",
+				__func__, chan->channel);
+			iio_device_release_direct_mode(indio_dev);
+			return ret;
+		}
+		ret = stm32_dfsdm_single_conv(indio_dev, chan, val);
+		iio_hw_consumer_disable(adc->hwc);
+		if (ret < 0) {
+			dev_err(&indio_dev->dev,
+				"%s: Conversion failed (channel %d)\n",
+				__func__, chan->channel);
+			iio_device_release_direct_mode(indio_dev);
+			return ret;
+		}
+		iio_device_release_direct_mode(indio_dev);
+		return IIO_VAL_INT;
+
+	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 int stm32_dfsdm_validate_trigger(struct iio_dev *indio_dev,
+					struct iio_trigger *trig)
+{
+	return stm32_dfsdm_get_jextsel(indio_dev, trig) < 0 ? -EINVAL : 0;
+}
+
+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,
+	.update_scan_mode = stm32_dfsdm_update_scan_mode,
+};
+
+static const struct iio_info stm32_dfsdm_info_adc = {
+	.hwfifo_set_watermark = stm32_dfsdm_set_watermark,
+	.read_raw = stm32_dfsdm_read_raw,
+	.write_raw = stm32_dfsdm_write_raw,
+	.update_scan_mode = stm32_dfsdm_update_scan_mode,
+	.validate_trigger = stm32_dfsdm_validate_trigger,
+};
+
+static irqreturn_t stm32_dfsdm_irq(int irq, void *arg)
+{
+	struct iio_dev *indio_dev = arg;
+	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+	struct regmap *regmap = adc->dfsdm->regmap;
+	unsigned int status, int_en;
+
+	regmap_read(regmap, DFSDM_ISR(adc->fl_id), &status);
+	regmap_read(regmap, DFSDM_CR2(adc->fl_id), &int_en);
+
+	if (status & DFSDM_ISR_REOCF_MASK) {
+		/* Read the data register clean the IRQ status */
+		regmap_read(regmap, DFSDM_RDATAR(adc->fl_id), adc->buffer);
+		complete(&adc->completion);
+	}
+
+	if (status & DFSDM_ISR_ROVRF_MASK) {
+		if (int_en & DFSDM_CR2_ROVRIE_MASK)
+			dev_warn(&indio_dev->dev, "Overrun detected\n");
+		regmap_update_bits(regmap, DFSDM_ICR(adc->fl_id),
+				   DFSDM_ICR_CLRROVRF_MASK,
+				   DFSDM_ICR_CLRROVRF_MASK);
+	}
+
+	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 device *dev,
+				   struct iio_dev *indio_dev)
+{
+	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+
+	adc->dma_chan = dma_request_chan(dev, "rx");
+	if (IS_ERR(adc->dma_chan)) {
+		int ret = PTR_ERR(adc->dma_chan);
+
+		adc->dma_chan = NULL;
+		return ret;
+	}
+
+	adc->rx_buf = dma_alloc_coherent(adc->dma_chan->device->dev,
+					 DFSDM_DMA_BUFFER_SIZE,
+					 &adc->dma_buf, GFP_KERNEL);
+	if (!adc->rx_buf) {
+		dma_release_channel(adc->dma_chan);
+		return -ENOMEM;
+	}
+
+	indio_dev->modes |= INDIO_BUFFER_SOFTWARE;
+	indio_dev->setup_ops = &stm32_dfsdm_buffer_setup_ops;
+
+	return 0;
+}
+
+static int stm32_dfsdm_adc_chan_init_one(struct iio_dev *indio_dev,
+					 struct iio_chan_spec *ch)
+{
+	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+	int ret;
+
+	ret = stm32_dfsdm_channel_parse_of(adc->dfsdm, indio_dev, ch);
+	if (ret < 0)
+		return ret;
+
+	ch->type = IIO_VOLTAGE;
+	ch->indexed = 1;
+
+	/*
+	 * IIO_CHAN_INFO_RAW: used to compute regular conversion
+	 * IIO_CHAN_INFO_OVERSAMPLING_RATIO: used to set oversampling
+	 */
+	ch->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
+	ch->info_mask_shared_by_all = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) |
+					BIT(IIO_CHAN_INFO_SAMP_FREQ);
+
+	if (adc->dev_data->type == DFSDM_AUDIO) {
+		ch->ext_info = dfsdm_adc_audio_ext_info;
+	} else {
+		ch->scan_type.shift = 8;
+	}
+	ch->scan_type.sign = 's';
+	ch->scan_type.realbits = 24;
+	ch->scan_type.storagebits = 32;
+
+	return stm32_dfsdm_chan_configure(adc->dfsdm,
+					  &adc->dfsdm->ch_list[ch->channel]);
+}
+
+static int stm32_dfsdm_audio_init(struct device *dev, 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;
+
+	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[ch->channel];
+	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(dev, indio_dev);
+}
+
+static int stm32_dfsdm_adc_init(struct device *dev, struct iio_dev *indio_dev)
+{
+	struct iio_chan_spec *ch;
+	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+	int num_ch;
+	int ret, chan_idx;
+
+	adc->oversamp = DFSDM_DEFAULT_OVERSAMPLING;
+	ret = stm32_dfsdm_compute_all_osrs(indio_dev, adc->oversamp);
+	if (ret < 0)
+		return ret;
+
+	num_ch = of_property_count_u32_elems(indio_dev->dev.of_node,
+					     "st,adc-channels");
+	if (num_ch < 0 || num_ch > adc->dfsdm->num_chs) {
+		dev_err(&indio_dev->dev, "Bad st,adc-channels\n");
+		return num_ch < 0 ? num_ch : -EINVAL;
+	}
+
+	/* Bind to SD modulator IIO device */
+	adc->hwc = devm_iio_hw_consumer_alloc(&indio_dev->dev);
+	if (IS_ERR(adc->hwc))
+		return -EPROBE_DEFER;
+
+	ch = devm_kcalloc(&indio_dev->dev, num_ch, sizeof(*ch),
+			  GFP_KERNEL);
+	if (!ch)
+		return -ENOMEM;
+
+	for (chan_idx = 0; chan_idx < num_ch; chan_idx++) {
+		ch[chan_idx].scan_index = chan_idx;
+		ret = stm32_dfsdm_adc_chan_init_one(indio_dev, &ch[chan_idx]);
+		if (ret < 0) {
+			dev_err(&indio_dev->dev, "Channels init failed\n");
+			return ret;
+		}
+	}
+
+	indio_dev->num_channels = num_ch;
+	indio_dev->channels = ch;
+
+	init_completion(&adc->completion);
+
+	/* Optionally request DMA */
+	ret = stm32_dfsdm_dma_request(dev, indio_dev);
+	if (ret) {
+		if (ret != -ENODEV)
+			return dev_err_probe(dev, ret,
+					     "DMA channel request failed with\n");
+
+		dev_dbg(dev, "No DMA support\n");
+		return 0;
+	}
+
+	ret = iio_triggered_buffer_setup(indio_dev,
+					 &iio_pollfunc_store_time, NULL,
+					 &stm32_dfsdm_buffer_setup_ops);
+	if (ret) {
+		stm32_dfsdm_dma_release(indio_dev);
+		dev_err(&indio_dev->dev, "buffer setup failed\n");
+		return ret;
+	}
+
+	/* lptimer/timer hardware triggers */
+	indio_dev->modes |= INDIO_HARDWARE_TRIGGERED;
+
+	return 0;
+}
+
+static const struct stm32_dfsdm_dev_data stm32h7_dfsdm_adc_data = {
+	.type = DFSDM_IIO,
+	.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,
+	},
+	{}
+};
+MODULE_DEVICE_TABLE(of, stm32_dfsdm_adc_match);
+
+static int stm32_dfsdm_adc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct stm32_dfsdm_adc *adc;
+	struct device_node *np = dev->of_node;
+	const struct stm32_dfsdm_dev_data *dev_data;
+	struct iio_dev *iio;
+	char *name;
+	int ret, irq, val;
+
+	dev_data = of_device_get_match_data(dev);
+	iio = devm_iio_device_alloc(dev, sizeof(*adc));
+	if (!iio) {
+		dev_err(dev, "%s: Failed to allocate IIO\n", __func__);
+		return -ENOMEM;
+	}
+
+	adc = iio_priv(iio);
+	adc->dfsdm = dev_get_drvdata(dev->parent);
+
+	iio->dev.of_node = np;
+	iio->modes = INDIO_DIRECT_MODE;
+
+	platform_set_drvdata(pdev, iio);
+
+	ret = of_property_read_u32(dev->of_node, "reg", &adc->fl_id);
+	if (ret != 0 || adc->fl_id >= adc->dfsdm->num_fls) {
+		dev_err(dev, "Missing or bad reg property\n");
+		return -EINVAL;
+	}
+
+	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;
+
+	/*
+	 * In a first step IRQs generated for channels are not treated.
+	 * So IRQ associated to filter instance 0 is dedicated to the Filter 0.
+	 */
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	ret = devm_request_irq(dev, irq, stm32_dfsdm_irq,
+			       0, pdev->name, iio);
+	if (ret < 0) {
+		dev_err(dev, "Failed to request IRQ\n");
+		return ret;
+	}
+
+	ret = of_property_read_u32(dev->of_node, "st,filter-order", &val);
+	if (ret < 0) {
+		dev_err(dev, "Failed to set filter order\n");
+		return ret;
+	}
+
+	adc->dfsdm->fl_list[adc->fl_id].ford = val;
+
+	ret = of_property_read_u32(dev->of_node, "st,filter0-sync", &val);
+	if (!ret)
+		adc->dfsdm->fl_list[adc->fl_id].sync_mode = val;
+
+	adc->dev_data = dev_data;
+	ret = dev_data->init(dev, iio);
+	if (ret < 0)
+		return ret;
+
+	ret = iio_device_register(iio);
+	if (ret < 0)
+		goto err_cleanup;
+
+	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)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+
+	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;
+}
+
+static int stm32_dfsdm_adc_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+
+	if (iio_buffer_enabled(indio_dev))
+		stm32_dfsdm_predisable(indio_dev);
+
+	return 0;
+}
+
+static int stm32_dfsdm_adc_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+	const struct iio_chan_spec *chan;
+	struct stm32_dfsdm_channel *ch;
+	int i, ret;
+
+	/* restore channels configuration */
+	for (i = 0; i < indio_dev->num_channels; i++) {
+		chan = indio_dev->channels + i;
+		ch = &adc->dfsdm->ch_list[chan->channel];
+		ret = stm32_dfsdm_chan_configure(adc->dfsdm, ch);
+		if (ret)
+			return ret;
+	}
+
+	if (iio_buffer_enabled(indio_dev))
+		stm32_dfsdm_postenable(indio_dev);
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(stm32_dfsdm_adc_pm_ops,
+				stm32_dfsdm_adc_suspend,
+				stm32_dfsdm_adc_resume);
+
+static struct platform_driver stm32_dfsdm_adc_driver = {
+	.driver = {
+		.name = "stm32-dfsdm-adc",
+		.of_match_table = stm32_dfsdm_adc_match,
+		.pm = pm_sleep_ptr(&stm32_dfsdm_adc_pm_ops),
+	},
+	.probe = stm32_dfsdm_adc_probe,
+	.remove = stm32_dfsdm_adc_remove,
+};
+module_platform_driver(stm32_dfsdm_adc_driver);
+
+MODULE_DESCRIPTION("STM32 sigma delta ADC");
+MODULE_AUTHOR("Arnaud Pouliquen <arnaud.pouliquen@st.com>");
+MODULE_LICENSE("GPL v2");