[PATCH 0/5] Fix several issues in the DesignWare I2S driver

[PATCH 0/5] Fix several issues in the DesignWare I2S driver

[phucduc.bui]

From: bui duc phuc <phucduc.bui@gmail.com>

Hi all,

I've continued reviewing the DesignWare I2S driver and referred to
the DesignWare APB I2S databook when looking into its clock
configuration, channel limits, and FIFO handling.

I couldn't access the document through the manufacturer's website
due to regional restrictions, so I've found an externally hosted
copy for convenience. The Synopsys product page is also included
for reference.

Databook: 
https://www.scribd.com/document/891940768/Designware-apb-i2s
Manufacturer's website: 
https://www.synopsys.com/dw/ipdir.php?c=DW_apb_i2s

Compile-tested only.

Best regards,
Phuc

bui duc phuc (5):
  ASoC: dwc: Fix bit clock rate in TDM mode
  ASoC: dwc: Fix error handling in dw_i2s_set_fmt()
  ASoC: dwc: Fix channels_max derived from COMP_PARAM_1
  ASoC: dwc: Fix DMA fifo_size calculation
  ASoC: dwc: Remove redundant error messages

 sound/soc/dwc/dwc-i2s.c | 53 ++++++++++++++++-------------------------
 1 file changed, 21 insertions(+), 32 deletions(-)

-- 
2.43.0

[PATCH 1/5] ASoC: dwc: Fix bit clock rate in TDM mode

[phucduc.bui]

From: bui duc phuc <phucduc.bui@gmail.com>

The bit clock is computed as rate * data_width * 2, which only fits
a two-slot I2S frame. Use rate * data_width * tdm_slots in TDM mode.

Fixes: 221acc16aee1 ("ASoC: dwc: Add TDM mode support")
Signed-off-by: bui duc phuc <phucduc.bui@gmail.com>
---
 sound/soc/dwc/dwc-i2s.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/sound/soc/dwc/dwc-i2s.c b/sound/soc/dwc/dwc-i2s.c
index dbda943cfaf3..9007ba1157ac 100644
--- a/sound/soc/dwc/dwc-i2s.c
+++ b/sound/soc/dwc/dwc-i2s.c
@@ -331,7 +331,10 @@ static int dw_i2s_hw_params(struct snd_pcm_substream *substream,
 			}
 		} else {
 			u32 bitclk = config->sample_rate *
-					config->data_width * 2;
+				     config->data_width * 2;
+			if (dev->tdm_slots)
+				bitclk = config->sample_rate *
+					 config->data_width * dev->tdm_slots;
 
 			ret = clk_set_rate(dev->clk, bitclk);
 			if (ret) {
-- 
2.43.0

[PATCH 2/5] ASoC: dwc: Fix error handling in dw_i2s_set_fmt()

[phucduc.bui]

From: bui duc phuc <phucduc.bui@gmail.com>

Return early when an unsupported clock provider format is
encountered, preventing the function from updating frame_offset
before returning an error.

Fixes: 221acc16aee1 ("ASoC: dwc: Add TDM mode support")
Signed-off-by: bui duc phuc <phucduc.bui@gmail.com>
---
 sound/soc/dwc/dwc-i2s.c | 24 +++++++-----------------
 1 file changed, 7 insertions(+), 17 deletions(-)

diff --git a/sound/soc/dwc/dwc-i2s.c b/sound/soc/dwc/dwc-i2s.c
index 9007ba1157ac..6dc84c55db0f 100644
--- a/sound/soc/dwc/dwc-i2s.c
+++ b/sound/soc/dwc/dwc-i2s.c
@@ -390,29 +390,19 @@ static int dw_i2s_trigger(struct snd_pcm_substream *substream,
 static int dw_i2s_set_fmt(struct snd_soc_dai *cpu_dai, unsigned int fmt)
 {
 	struct dw_i2s_dev *dev = snd_soc_dai_get_drvdata(cpu_dai);
-	int ret = 0;
 
 	switch (fmt & SND_SOC_DAIFMT_CLOCK_PROVIDER_MASK) {
 	case SND_SOC_DAIFMT_BC_FC:
-		if (dev->capability & DW_I2S_SLAVE)
-			ret = 0;
-		else
-			ret = -EINVAL;
+		if (!(dev->capability & DW_I2S_SLAVE))
+			return -EINVAL;
 		break;
 	case SND_SOC_DAIFMT_BP_FP:
-		if (dev->capability & DW_I2S_MASTER)
-			ret = 0;
-		else
-			ret = -EINVAL;
-		break;
-	case SND_SOC_DAIFMT_BC_FP:
-	case SND_SOC_DAIFMT_BP_FC:
-		ret = -EINVAL;
+		if (!(dev->capability & DW_I2S_MASTER))
+			return -EINVAL;
 		break;
 	default:
 		dev_dbg(dev->dev, "dwc : Invalid clock provider format\n");
-		ret = -EINVAL;
-		break;
+		return -EINVAL;
 	}
 
 	switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
@@ -427,11 +417,11 @@ static int dw_i2s_set_fmt(struct snd_soc_dai *cpu_dai, unsigned int fmt)
 		dev->frame_offset = 0;
 		break;
 	default:
-		dev_err(dev->dev, "DAI format unsupported");
+		dev_err(dev->dev, "DAI format unsupported\n");
 		return -EINVAL;
 	}
 
-	return ret;
+	return 0;
 }
 
 static int dw_i2s_set_tdm_slot(struct snd_soc_dai *cpu_dai,	unsigned int tx_mask,
-- 
2.43.0

[PATCH 3/5] ASoC: dwc: Fix channels_max derived from COMP_PARAM_1

[phucduc.bui]

From: bui duc phuc <phucduc.bui@gmail.com>

The I2S_TX_CHANNELS (bits 10:9) and I2S_RX_CHANNELS (bits 8:7) fields
of I2S_COMP_PARAM_1 encode the number of hardware channels minus one,
i.e. values 0..3 mean 1..4 channels. In I2S mode each hardware channel
is one serial data line carrying a left/right pair, so the maximum
number of audio channels is 2 * (N + 1).

The current code uses 1 << (N + 1), which only produces the correct
result for N < 2. For N >= 2, it overestimates the maximum number of
audio channels.

Use 2 * (N + 1) for both playback and capture.

Fixes: b226efe5818b ("ASoC: dwc: Read I2S block configuration from registers")
Signed-off-by: bui duc phuc <phucduc.bui@gmail.com>
---
 sound/soc/dwc/dwc-i2s.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/soc/dwc/dwc-i2s.c b/sound/soc/dwc/dwc-i2s.c
index 6dc84c55db0f..0de7bcb2d0c5 100644
--- a/sound/soc/dwc/dwc-i2s.c
+++ b/sound/soc/dwc/dwc-i2s.c
@@ -605,7 +605,7 @@ static int dw_configure_dai(struct dw_i2s_dev *dev,
 			idx = 1;
 		dw_i2s_dai->playback.channels_min = MIN_CHANNEL_NUM;
 		dw_i2s_dai->playback.channels_max =
-				1 << (COMP1_TX_CHANNELS(comp1) + 1);
+				2 * (COMP1_TX_CHANNELS(comp1) + 1);
 		dw_i2s_dai->playback.formats = formats[idx];
 		dw_i2s_dai->playback.rates = rates;
 	}
@@ -619,7 +619,7 @@ static int dw_configure_dai(struct dw_i2s_dev *dev,
 			idx = 1;
 		dw_i2s_dai->capture.channels_min = MIN_CHANNEL_NUM;
 		dw_i2s_dai->capture.channels_max =
-				1 << (COMP1_RX_CHANNELS(comp1) + 1);
+				2 * (COMP1_RX_CHANNELS(comp1) + 1);
 		dw_i2s_dai->capture.formats = formats[idx];
 		dw_i2s_dai->capture.rates = rates;
 	}
-- 
2.43.0

[PATCH 4/5] ASoC: dwc: Fix DMA fifo_size calculation

[phucduc.bui]

From: bui duc phuc <phucduc.bui@gmail.com>

fifo_size should be the FIFO size in bytes (depth * width / 8), but
the code shifts by 8 instead of 3. For capture the parentheses also
make it always 0.

Use depth * width / 8 for both directions.

Fixes: 52ea7c0543f8 ("ASoC: dwc: i2s: Add StarFive JH7110 SoC support")
Signed-off-by: bui duc phuc <phucduc.bui@gmail.com>
---
 sound/soc/dwc/dwc-i2s.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/sound/soc/dwc/dwc-i2s.c b/sound/soc/dwc/dwc-i2s.c
index 0de7bcb2d0c5..1ff5b6f8864d 100644
--- a/sound/soc/dwc/dwc-i2s.c
+++ b/sound/soc/dwc/dwc-i2s.c
@@ -664,14 +664,14 @@ static int dw_configure_dai_by_pd(struct dw_i2s_dev *dev,
 			idx2 = COMP1_TX_WORDSIZE_0(comp1);
 			dev->play_dma_data.dt.addr = res->start + I2S_TXDMA;
 			dev->play_dma_data.dt.fifo_size = dev->fifo_th * 2 *
-				(fifo_width[idx2]) >> 8;
+							  fifo_width[idx2] / 8;
 			dev->play_dma_data.dt.maxburst = 16;
 		}
 		if (COMP1_RX_ENABLED(comp1)) {
 			idx2 = COMP2_RX_WORDSIZE_0(comp2);
 			dev->capture_dma_data.dt.addr = res->start + I2S_RXDMA;
 			dev->capture_dma_data.dt.fifo_size = dev->fifo_th * 2 *
-				(fifo_width[idx2] >> 8);
+							     fifo_width[idx2] / 8;
 			dev->capture_dma_data.dt.maxburst = 16;
 		}
 	} else {
@@ -711,7 +711,7 @@ static int dw_configure_dai_by_dt(struct dw_i2s_dev *dev,
 		dev->capability |= DWC_I2S_PLAY;
 		dev->play_dma_data.dt.addr = res->start + I2S_TXDMA;
 		dev->play_dma_data.dt.fifo_size = fifo_depth *
-			(fifo_width[idx2]) >> 8;
+						  fifo_width[idx2] / 8;
 		dev->play_dma_data.dt.maxburst = 16;
 	}
 	if (COMP1_RX_ENABLED(comp1)) {
@@ -720,7 +720,7 @@ static int dw_configure_dai_by_dt(struct dw_i2s_dev *dev,
 		dev->capability |= DWC_I2S_RECORD;
 		dev->capture_dma_data.dt.addr = res->start + I2S_RXDMA;
 		dev->capture_dma_data.dt.fifo_size = fifo_depth *
-			(fifo_width[idx2] >> 8);
+						     fifo_width[idx2] / 8;
 		dev->capture_dma_data.dt.maxburst = 16;
 	}
 
-- 
2.43.0

[PATCH 5/5] ASoC: dwc: Remove redundant error messages

[phucduc.bui]

From: bui duc phuc <phucduc.bui@gmail.com>

The underlying functions already report these errors deeper in
the call chain, making the additional dev_err_probe() and
dev_err() calls unnecessary.

Signed-off-by: bui duc phuc <phucduc.bui@gmail.com>
---
 sound/soc/dwc/dwc-i2s.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/sound/soc/dwc/dwc-i2s.c b/sound/soc/dwc/dwc-i2s.c
index 1ff5b6f8864d..87b47661e469 100644
--- a/sound/soc/dwc/dwc-i2s.c
+++ b/sound/soc/dwc/dwc-i2s.c
@@ -752,7 +752,7 @@ static int jh7110_i2s_crg_master_init(struct dw_i2s_dev *dev)
 
 	ret = clk_bulk_get(dev->dev, ARRAY_SIZE(clks), clks);
 	if (ret)
-		return dev_err_probe(dev->dev, ret, "failed to get i2s clocks\n");
+		return ret;
 
 	mclk = clks[0].clk;
 	mclk_ext = clks[1].clk;
@@ -830,7 +830,7 @@ static int jh7110_i2s_crg_slave_init(struct dw_i2s_dev *dev)
 
 	ret = clk_bulk_get(dev->dev, ARRAY_SIZE(clks), clks);
 	if (ret)
-		return dev_err_probe(dev->dev, ret, "failed to get i2s clocks\n");
+		return ret;
 
 	mclk = clks[0].clk;
 	mclk_ext = clks[1].clk;
@@ -966,10 +966,8 @@ static int dw_i2s_probe(struct platform_device *pdev)
 	if (irq > 0) {
 		ret = devm_request_irq(&pdev->dev, irq, i2s_irq_handler, 0,
 				pdev->name, dev);
-		if (ret < 0) {
-			dev_err(&pdev->dev, "failed to request irq\n");
+		if (ret < 0)
 			goto err_assert_reset;
-		}
 	}
 
 	dev->i2s_reg_comp1 = I2S_COMP_PARAM_1;
@@ -1010,10 +1008,8 @@ static int dw_i2s_probe(struct platform_device *pdev)
 	dev_set_drvdata(&pdev->dev, dev);
 	ret = devm_snd_soc_register_component(&pdev->dev, &dw_i2s_component,
 					 dw_i2s_dai, 1);
-	if (ret != 0) {
-		dev_err(&pdev->dev, "not able to register dai\n");
+	if (ret)
 		goto err_assert_reset;
-	}
 
 	if (!pdata || dev->is_jh7110) {
 		if (irq >= 0) {
-- 
2.43.0

Re: [PATCH 5/5] ASoC: dwc: Remove redundant error messages

[Mark Brown]

> The underlying functions already report these errors deeper in
> the call chain, making the additional dev_err_probe() and
> dev_err() calls unnecessary.

>  		ret = devm_request_irq(&pdev->dev, irq, i2s_irq_handler, 0,
>  				pdev->name, dev);
> -		if (ret < 0) {
> -			dev_err(&pdev->dev, "failed to request irq\n");
> +		if (ret < 0)
>  			goto err_assert_reset;

request_irq() logs some failures, but not those where the interrupt is
just missing.

-- 
Mark Brown <broonie@kernel.org>

Re: [PATCH 5/5] ASoC: dwc: Remove redundant error messages

[Bui Duc Phuc]

Hi Mark,

Thank you for your review.

>
> > The underlying functions already report these errors deeper in
> > the call chain, making the additional dev_err_probe() and
> > dev_err() calls unnecessary.
>
> >               ret = devm_request_irq(&pdev->dev, irq, i2s_irq_handler, 0,
> >                               pdev->name, dev);
> > -             if (ret < 0) {
> > -                     dev_err(&pdev->dev, "failed to request irq\n");
> > +             if (ret < 0)
> >                       goto err_assert_reset;
>
> request_irq() logs some failures, but not those where the interrupt is
> just missing.


I understand.
With platform_get_irq_optional(), a missing IRQ is not considered an error,
so no error message is expected in that case.

To handle other IRQ retrieval errors explicitly, I'll update the code
as follows:

------------------------------------------------------------------------------------------
irq = platform_get_irq_optional(pdev, 0);
if (irq < 0 && irq != -ENXIO)
        return dev_err_probe(&pdev->dev, irq, "failed to get IRQ\n");

if (irq > 0) {
        ret = devm_request_irq(&pdev->dev, irq, i2s_irq_handler, 0,
                                               pdev->name, dev);
        if (ret)
                goto err_assert_reset;
}
-------------------------------------------------------------------------------------------

Best regards,
Phuc

Re: [PATCH 1/5] ASoC: dwc: Fix bit clock rate in TDM mode

[Maxim Kochetkov]

06.11.2026 14:29, phucduc.bui@gmail.com wrote:
> From: bui duc phuc <phucduc.bui@gmail.com>
> 
> The bit clock is computed as rate * data_width * 2, which only fits
> a two-slot I2S frame. Use rate * data_width * tdm_slots in TDM mode.
> 
> Fixes: 221acc16aee1 ("ASoC: dwc: Add TDM mode support")
> Signed-off-by: bui duc phuc <phucduc.bui@gmail.com>
> ---
>   sound/soc/dwc/dwc-i2s.c | 5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/sound/soc/dwc/dwc-i2s.c b/sound/soc/dwc/dwc-i2s.c
> index dbda943cfaf3..9007ba1157ac 100644
> --- a/sound/soc/dwc/dwc-i2s.c
> +++ b/sound/soc/dwc/dwc-i2s.c
> @@ -331,7 +331,10 @@ static int dw_i2s_hw_params(struct snd_pcm_substream *substream,
>   			}
>   		} else {
>   			u32 bitclk = config->sample_rate *
> -					config->data_width * 2;
> +				     config->data_width * 2;

Should the identation be fixed in a separate commit? It is not related 
to TDM clock rate.

> +			if (dev->tdm_slots)
> +				bitclk = config->sample_rate *
> +					 config->data_width * dev->tdm_slots;

Reviewed-by: Maxim Kochetkov <fido_max@inbox.ru>

Re: [PATCH 2/5] ASoC: dwc: Fix error handling in dw_i2s_set_fmt()

[Maxim Kochetkov]

06.11.2026 14:29, phucduc.bui@gmail.com wrote:
> From: bui duc phuc <phucduc.bui@gmail.com>
> 
> Return early when an unsupported clock provider format is
> encountered, preventing the function from updating frame_offset
> before returning an error.
> 
> Fixes: 221acc16aee1 ("ASoC: dwc: Add TDM mode support")
> Signed-off-by: bui duc phuc <phucduc.bui@gmail.com>


Reviewed-by: Maxim Kochetkov <fido_max@inbox.ru>


>   	switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
> @@ -427,11 +417,11 @@ static int dw_i2s_set_fmt(struct snd_soc_dai *cpu_dai, unsigned int fmt)
>   		dev->frame_offset = 0;
>   		break;
>   	default:
> -		dev_err(dev->dev, "DAI format unsupported");
> +		dev_err(dev->dev, "DAI format unsupported\n");


Should the typo be fixed in a separate commit?

Re: [PATCH 3/5] ASoC: dwc: Fix channels_max derived from COMP_PARAM_1

[Maxim Kochetkov]

06.11.2026 14:29, phucduc.bui@gmail.com wrote:
> From: bui duc phuc <phucduc.bui@gmail.com>
> 
> The I2S_TX_CHANNELS (bits 10:9) and I2S_RX_CHANNELS (bits 8:7) fields
> of I2S_COMP_PARAM_1 encode the number of hardware channels minus one,
> i.e. values 0..3 mean 1..4 channels. In I2S mode each hardware channel
> is one serial data line carrying a left/right pair, so the maximum
> number of audio channels is 2 * (N + 1).
> 
> The current code uses 1 << (N + 1), which only produces the correct
> result for N < 2. For N >= 2, it overestimates the maximum number of
> audio channels.
> 
> Use 2 * (N + 1) for both playback and capture.
> 
> Fixes: b226efe5818b ("ASoC: dwc: Read I2S block configuration from registers")
> Signed-off-by: bui duc phuc <phucduc.bui@gmail.com>

Reviewed-by: Maxim Kochetkov <fido_max@inbox.ru>