[PATCH v2 1/2] ASoC: dt-bindings: fsl-sai: Document RX/TX BCLK swap support

[PATCH v2 1/2] ASoC: dt-bindings: fsl-sai: Document RX/TX BCLK swap support

[Marek Vasut]

Document support for setting the Bit Clock Swap bit in CR2 register
via new "fsl,sai-bit-clock-swap" DT property. This bit swaps the
bit clock used by the transmitter or receiver in asynchronous mode,
i.e. makes transmitter use RX_BCLK and TX_SYNC, and vice versa,
makes receiver use TX_BCLK and RX_SYNC.

Signed-off-by: Marek Vasut <marex@nabladev.com>
---
Cc: Conor Dooley <conor+dt@kernel.org>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Nicolin Chen <nicoleotsuka@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Shengjiu Wang <shengjiu.wang@gmail.com>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Xiubo Li <Xiubo.Lee@gmail.com>
Cc: devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-sound@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
---
V2: - Drop | from description
    - Update email, rebase on next
---
 Documentation/devicetree/bindings/sound/fsl,sai.yaml | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Documentation/devicetree/bindings/sound/fsl,sai.yaml b/Documentation/devicetree/bindings/sound/fsl,sai.yaml
index 83b5ea5f3d70e..ba65b3f3d0662 100644
--- a/Documentation/devicetree/bindings/sound/fsl,sai.yaml
+++ b/Documentation/devicetree/bindings/sound/fsl,sai.yaml
@@ -162,6 +162,13 @@ properties:
       of transmitter.
     type: boolean
 
+  fsl,sai-bit-clock-swap:
+    description:
+      Enable Bit Clock Swap, which swaps the bit clock used by the transmitter
+      or receiver in asynchronous mode, i.e. makes transmitter use RX_BCLK and
+      TX_SYNC, and vice versa, makes receiver use TX_BCLK and RX_SYNC.
+    type: boolean
+
   fsl,shared-interrupt:
     description: Interrupt is shared with other modules.
     type: boolean
-- 
2.53.0

[PATCH v2 2/2] ASoC: fsl_sai: Add RX/TX BCLK swap support

[Marek Vasut]

Add support for setting the Bit Clock Swap bit in CR2 register
via new "fsl,sai-bit-clock-swap" DT property. This bit swaps the
bit clock used by the transmitter or receiver in asynchronous mode,
i.e. makes transmitter use RX_BCLK and TX_SYNC, and vice versa,
makes receiver use TX_BCLK and RX_SYNC.

Signed-off-by: Marek Vasut <marex@nabladev.com>
---
Cc: Conor Dooley <conor+dt@kernel.org>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Nicolin Chen <nicoleotsuka@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Shengjiu Wang <shengjiu.wang@gmail.com>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Xiubo Li <Xiubo.Lee@gmail.com>
Cc: devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-sound@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
---
V2: Update email, rebase on next
---
 sound/soc/fsl/fsl_sai.c | 7 ++++++-
 sound/soc/fsl/fsl_sai.h | 2 ++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c
index bd336d2e4cb38..87a40e2b9fdf7 100644
--- a/sound/soc/fsl/fsl_sai.c
+++ b/sound/soc/fsl/fsl_sai.c
@@ -355,6 +355,9 @@ static int fsl_sai_set_dai_fmt_tr(struct snd_soc_dai *cpu_dai,
 	unsigned int ofs = sai->soc_data->reg_offset;
 	u32 val_cr2 = 0, val_cr4 = 0;
 
+	if (sai->is_bit_clock_swap)
+		val_cr2 |= FSL_SAI_CR2_BCS;
+
 	if (!sai->is_lsb_first)
 		val_cr4 |= FSL_SAI_CR4_MF;
 
@@ -453,7 +456,8 @@ static int fsl_sai_set_dai_fmt_tr(struct snd_soc_dai *cpu_dai,
 	}
 
 	regmap_update_bits(sai->regmap, FSL_SAI_xCR2(tx, ofs),
-			   FSL_SAI_CR2_BCP | FSL_SAI_CR2_BCD_MSTR, val_cr2);
+			   FSL_SAI_CR2_BCS | FSL_SAI_CR2_BCP | FSL_SAI_CR2_BCD_MSTR,
+			   val_cr2);
 	regmap_update_bits(sai->regmap, FSL_SAI_xCR4(tx, ofs),
 			   FSL_SAI_CR4_MF | FSL_SAI_CR4_FSE |
 			   FSL_SAI_CR4_FSP | FSL_SAI_CR4_FSD_MSTR, val_cr4);
@@ -1507,6 +1511,7 @@ static int fsl_sai_probe(struct platform_device *pdev)
 	sai->soc_data = of_device_get_match_data(dev);
 
 	sai->is_lsb_first = of_property_read_bool(np, "lsb-first");
+	sai->is_bit_clock_swap = of_property_read_bool(np, "fsl,sai-bit-clock-swap");
 
 	base = devm_platform_get_and_ioremap_resource(pdev, 0, &sai->res);
 	if (IS_ERR(base))
diff --git a/sound/soc/fsl/fsl_sai.h b/sound/soc/fsl/fsl_sai.h
index af967833b6eda..6d84e5ff2258e 100644
--- a/sound/soc/fsl/fsl_sai.h
+++ b/sound/soc/fsl/fsl_sai.h
@@ -118,6 +118,7 @@
 
 /* SAI Transmit and Receive Configuration 2 Register */
 #define FSL_SAI_CR2_SYNC	BIT(30)
+#define FSL_SAI_CR2_BCS		BIT(29)
 #define FSL_SAI_CR2_BCI		BIT(28)
 #define FSL_SAI_CR2_MSEL_MASK	(0x3 << 26)
 #define FSL_SAI_CR2_MSEL_BUS	0
@@ -301,6 +302,7 @@ struct fsl_sai {
 	struct fsl_sai_dl_cfg *dl_cfg;
 	unsigned int dl_cfg_cnt;
 	bool mclk_direction_output;
+	bool is_bit_clock_swap;
 
 	unsigned int mclk_id[2];
 	unsigned int mclk_streams;
-- 
2.53.0

Re: [PATCH v2 1/2] ASoC: dt-bindings: fsl-sai: Document RX/TX BCLK swap support

[Rob Herring (Arm)]

On Sat, 04 Apr 2026 20:35:00 +0200, Marek Vasut wrote:
> Document support for setting the Bit Clock Swap bit in CR2 register
> via new "fsl,sai-bit-clock-swap" DT property. This bit swaps the
> bit clock used by the transmitter or receiver in asynchronous mode,
> i.e. makes transmitter use RX_BCLK and TX_SYNC, and vice versa,
> makes receiver use TX_BCLK and RX_SYNC.
> 
> Signed-off-by: Marek Vasut <marex@nabladev.com>
> ---
> Cc: Conor Dooley <conor+dt@kernel.org>
> Cc: Fabio Estevam <festevam@gmail.com>
> Cc: Jaroslav Kysela <perex@perex.cz>
> Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
> Cc: Liam Girdwood <lgirdwood@gmail.com>
> Cc: Mark Brown <broonie@kernel.org>
> Cc: Nicolin Chen <nicoleotsuka@gmail.com>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Shengjiu Wang <shengjiu.wang@gmail.com>
> Cc: Takashi Iwai <tiwai@suse.com>
> Cc: Xiubo Li <Xiubo.Lee@gmail.com>
> Cc: devicetree@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Cc: linux-sound@vger.kernel.org
> Cc: linuxppc-dev@lists.ozlabs.org
> ---
> V2: - Drop | from description
>     - Update email, rebase on next
> ---
>  Documentation/devicetree/bindings/sound/fsl,sai.yaml | 7 +++++++
>  1 file changed, 7 insertions(+)
> 

Acked-by: Rob Herring (Arm) <robh@kernel.org>

Re: [PATCH v2 2/2] ASoC: fsl_sai: Add RX/TX BCLK swap support

[Marek Vasut]

On 4/4/26 8:35 PM, Marek Vasut wrote:
> Add support for setting the Bit Clock Swap bit in CR2 register
> via new "fsl,sai-bit-clock-swap" DT property. This bit swaps the
> bit clock used by the transmitter or receiver in asynchronous mode,
> i.e. makes transmitter use RX_BCLK and TX_SYNC, and vice versa,
> makes receiver use TX_BCLK and RX_SYNC.
Is there anything left over to do with this patch ?

Re: [PATCH v2 1/2] ASoC: dt-bindings: fsl-sai: Document RX/TX BCLK swap support

[Mark Brown]

On Sat, 04 Apr 2026 20:35:00 +0200, Marek Vasut wrote:
> ASoC: dt-bindings: fsl-sai: Document RX/TX BCLK swap support

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-7.2

Thanks!

[1/2] ASoC: dt-bindings: fsl-sai: Document RX/TX BCLK swap support
      https://git.kernel.org/broonie/sound/c/9897a9776681
[2/2] ASoC: fsl_sai: Add RX/TX BCLK swap support
      https://git.kernel.org/broonie/sound/c/dc06cf4268a4

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark