ASoC: fsl_sai: Add RX/TX BCLK swap support

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>
Link: https://patch.msgid.link/20260404183547.46509-2-marex@nabladev.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c
index bd336d2e4cb383b9f99604745a174b2c1e85f5fd..87a40e2b9fdf7797d31539f0b7c19312bf68d77f 100644 (file)
--- 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 af967833b6eda3d3e91b5e4f2dd6e073b692d01a..6d84e5ff2258ef0a009e75ad4d92ab09e61a94f5 100644 (file)
--- 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;