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

[Marek Vasut <marex@nabladev.com>]

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