* [PATCH v2 2/2] ASoC: fsl_sai: Add RX/TX BCLK swap support
2026-04-04 18:35 [PATCH v2 1/2] ASoC: dt-bindings: fsl-sai: Document RX/TX BCLK swap support Marek Vasut
@ 2026-04-04 18:35 ` Marek Vasut
0 siblings, 0 replies; 2+ messages in thread
From: Marek Vasut @ 2026-04-04 18:35 UTC (permalink / raw)
To: linux-sound
Cc: Marek Vasut, Conor Dooley, Fabio Estevam, Jaroslav Kysela,
Krzysztof Kozlowski, Liam Girdwood, Mark Brown, Nicolin Chen,
Rob Herring, Shengjiu Wang, Takashi Iwai, Xiubo Li, devicetree,
linux-kernel, linuxppc-dev
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
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