diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c
index 588907cc3b6b..cb596f104919 100644
--- a/drivers/iio/adc/stm32-dfsdm-adc.c
+++ b/drivers/iio/adc/stm32-dfsdm-adc.c
@@ -39,9 +39,16 @@
 #define DFSDM_MAX_INT_OVERSAMPLING 256
 #define DFSDM_MAX_FL_OVERSAMPLING 1024
 
-/* Max sample resolutions */
-#define DFSDM_MAX_RES BIT(31)
-#define DFSDM_DATA_RES BIT(23)
+/* 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 | \
@@ -181,14 +188,15 @@ static int stm32_dfsdm_get_jextsel(struct iio_dev *indio_dev,
 	return -EINVAL;
 }
 
-static int stm32_dfsdm_set_osrs(struct stm32_dfsdm_filter *fl,
-				unsigned int fast, unsigned int oversamp)
+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;
-	s64 delta;
+	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;
 
 	pr_debug("%s: Requested oversampling: %d\n",  __func__, oversamp);
 	/*
@@ -207,11 +215,9 @@ static int stm32_dfsdm_set_osrs(struct stm32_dfsdm_filter *fl,
 
 	/*
 	 * Look for filter and integrator oversampling ratios which allows
-	 * to reach 24 bits data output resolution.
-	 * Leave as soon as if exact resolution if reached.
-	 * Otherwise the higher resolution below 32 bits is kept.
+	 * to maximize data output resolution.
 	 */
-	fl->res = 0;
+	flo->res = 0;
 	for (fosr = 1; fosr <= DFSDM_MAX_FL_OVERSAMPLING; fosr++) {
 		for (iosr = 1; iosr <= DFSDM_MAX_INT_OVERSAMPLING; iosr++) {
 			if (fast)
@@ -236,32 +242,68 @@ static int stm32_dfsdm_set_osrs(struct stm32_dfsdm_filter *fl,
 			res = fosr;
 			for (i = p - 1; i > 0; i--) {
 				res = res * (u64)fosr;
-				if (res > DFSDM_MAX_RES)
+				if (res > DFSDM_DATA_MAX)
 					break;
 			}
-			if (res > DFSDM_MAX_RES)
+			if (res > DFSDM_DATA_MAX)
 				continue;
+
 			res = res * (u64)m * (u64)iosr;
-			if (res > DFSDM_MAX_RES)
+			if (res > DFSDM_DATA_MAX)
 				continue;
 
-			delta = res - DFSDM_DATA_RES;
-
-			if (res >= fl->res) {
-				fl->res = res;
-				fl->fosr = fosr;
-				fl->iosr = iosr;
-				fl->fast = fast;
-				pr_debug("%s: fosr = %d, iosr = %d\n",
-					 __func__, fl->fosr, fl->iosr);
+			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;
+
+				pr_debug("%s: fast %d, fosr %d, iosr %d, res 0x%llx/%d bits, rshift %d, lshift %d\n",
+					 __func__, fast, flo->fosr, flo->iosr,
+					 flo->res, bits, flo->rshift,
+					 flo->lshift);
 			}
-
-			if (!delta)
-				return 0;
 		}
 	}
 
-	if (!fl->res)
+	if (!flo->res)
 		return -EINVAL;
 
 	return 0;
@@ -384,6 +426,36 @@ static int stm32_dfsdm_filter_set_trig(struct stm32_dfsdm_adc *adc,
 	return 0;
 }
 
+static int stm32_dfsdm_channels_configure(struct stm32_dfsdm_adc *adc,
+					  unsigned int fl_id,
+					  struct iio_trigger *trig)
+{
+	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
+	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;
+	const struct iio_chan_spec *chan;
+	unsigned int bit;
+	int ret;
+
+	if (!flo->res)
+		return -EINVAL;
+
+	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 stm32_dfsdm_adc *adc,
 					unsigned int fl_id,
 					struct iio_trigger *trig)
@@ -391,6 +463,7 @@ static int stm32_dfsdm_filter_configure(struct stm32_dfsdm_adc *adc,
 	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
 	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;
 	u32 cr1;
 	const struct iio_chan_spec *chan;
 	unsigned int bit, jchg = 0;
@@ -398,13 +471,13 @@ static int stm32_dfsdm_filter_configure(struct stm32_dfsdm_adc *adc,
 
 	/* Average integrator oversampling */
 	ret = regmap_update_bits(regmap, DFSDM_FCR(fl_id), DFSDM_FCR_IOSR_MASK,
-				 DFSDM_FCR_IOSR(fl->iosr - 1));
+				 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(fl->fosr - 1));
+				 DFSDM_FCR_FOSR(flo->fosr - 1));
 	if (ret)
 		return ret;
 
@@ -573,7 +646,7 @@ static int dfsdm_adc_set_samp_freq(struct iio_dev *indio_dev,
 			"Rate not accurate. requested (%u), actual (%u)\n",
 			sample_freq, spi_freq / oversamp);
 
-	ret = stm32_dfsdm_set_osrs(fl, 0, oversamp);
+	ret = stm32_dfsdm_compute_osrs(fl, 0, oversamp);
 	if (ret < 0) {
 		dev_err(&indio_dev->dev, "No filter parameters that match!\n");
 		return ret;
@@ -623,6 +696,10 @@ static int stm32_dfsdm_start_conv(struct stm32_dfsdm_adc *adc,
 	struct regmap *regmap = adc->dfsdm->regmap;
 	int ret;
 
+	ret = stm32_dfsdm_channels_configure(adc, adc->fl_id, trig);
+	if (ret < 0)
+		return ret;
+
 	ret = stm32_dfsdm_start_channel(adc);
 	if (ret < 0)
 		return ret;
@@ -729,6 +806,8 @@ static void stm32_dfsdm_dma_buffer_done(void *data)
 {
 	struct iio_dev *indio_dev = data;
 	struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
+	struct stm32_dfsdm_filter *fl = &adc->dfsdm->fl_list[adc->fl_id];
+	struct stm32_dfsdm_filter_osr *flo = &fl->flo;
 	int available = stm32_dfsdm_adc_dma_residue(adc);
 	size_t old_pos;
 
@@ -751,10 +830,19 @@ static void stm32_dfsdm_dma_buffer_done(void *data)
 	old_pos = adc->bufi;
 
 	while (available >= indio_dev->scan_bytes) {
-		u32 *buffer = (u32 *)&adc->rx_buf[adc->bufi];
+		s32 *buffer = (s32 *)&adc->rx_buf[adc->bufi];
 
 		/* Mask 8 LSB that contains the channel ID */
-		*buffer = (*buffer & 0xFFFFFF00) << 8;
+		*buffer &= 0xFFFFFF00;
+		/* Convert 2^(n-1) sample to 2^(n-1)-1 to avoid wrap-around */
+		if (*buffer > flo->max)
+			*buffer -= 1;
+		/*
+		 * Samples from filter are retrieved with 23 bits resolution
+		 * or less. Shift left to align MSB on 24 bits.
+		 */
+		*buffer <<= flo->lshift;
+
 		available -= indio_dev->scan_bytes;
 		adc->bufi += indio_dev->scan_bytes;
 		if (adc->bufi >= adc->buf_sz) {
@@ -1078,7 +1166,7 @@ static int stm32_dfsdm_write_raw(struct iio_dev *indio_dev,
 		ret = iio_device_claim_direct_mode(indio_dev);
 		if (ret)
 			return ret;
-		ret = stm32_dfsdm_set_osrs(fl, 0, val);
+		ret = stm32_dfsdm_compute_osrs(fl, 0, val);
 		if (!ret)
 			adc->oversamp = val;
 		iio_device_release_direct_mode(indio_dev);
@@ -1327,8 +1415,8 @@ static int stm32_dfsdm_adc_init(struct iio_dev *indio_dev)
 	int ret, chan_idx;
 
 	adc->oversamp = DFSDM_DEFAULT_OVERSAMPLING;
-	ret = stm32_dfsdm_set_osrs(&adc->dfsdm->fl_list[adc->fl_id], 0,
-				   adc->oversamp);
+	ret = stm32_dfsdm_compute_osrs(&adc->dfsdm->fl_list[adc->fl_id], 0,
+				       adc->oversamp);
 	if (ret < 0)
 		return ret;
 
diff --git a/drivers/iio/adc/stm32-dfsdm.h b/drivers/iio/adc/stm32-dfsdm.h
index 8708394b0725..18b06ee6ed7b 100644
--- a/drivers/iio/adc/stm32-dfsdm.h
+++ b/drivers/iio/adc/stm32-dfsdm.h
@@ -243,19 +243,33 @@ enum stm32_dfsdm_sinc_order {
 };
 
 /**
- * struct stm32_dfsdm_filter - structure relative to stm32 FDSDM filter
+ * struct stm32_dfsdm_filter_osr - DFSDM filter settings linked to oversampling
  * @iosr: integrator oversampling
  * @fosr: filter oversampling
- * @ford: filter order
+ * @rshift: output sample right shift (hardware shift)
+ * @lshift: output sample left shift (software shift)
  * @res: output sample resolution
+ * @max: output sample maximum positive value
+ */
+struct stm32_dfsdm_filter_osr {
+	unsigned int iosr;
+	unsigned int fosr;
+	unsigned int rshift;
+	unsigned int lshift;
+	u64 res;
+	s32 max;
+};
+
+/**
+ * struct stm32_dfsdm_filter - structure relative to stm32 FDSDM filter
+ * @ford: filter order
+ * @flo: filter oversampling structure
  * @sync_mode: filter synchronized with filter 0
  * @fast: filter fast mode
  */
 struct stm32_dfsdm_filter {
-	unsigned int iosr;
-	unsigned int fosr;
 	enum stm32_dfsdm_sinc_order ford;
-	u64 res;
+	struct stm32_dfsdm_filter_osr flo;
 	unsigned int sync_mode;
 	unsigned int fast;
 };
