[PATCH 6/7] ASoC: mchp-i2s-mcc: Add support to select TDM pins

[Codrin Ciubotariu]

SAMA7G5's I2S-MCC has 4 pairs of DIN/DOUT pins. Since TDM only uses a
single pair of pins for synchronous capture and playback, the controller
needs to be told which of the pair is connected. This can be mentioned
using the "microchip,tdm-data-pair" property from DT. The property is
optional, useful only if TDM is used. If it's missing, DIN/DOUT 0 pins
will be used by default.

Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@xxxxxxxxxxxxx>
---
 sound/soc/atmel/mchp-i2s-mcc.c | 52 +++++++++++++++++++++++++++++++---
 1 file changed, 48 insertions(+), 4 deletions(-)

diff --git a/sound/soc/atmel/mchp-i2s-mcc.c b/sound/soc/atmel/mchp-i2s-mcc.c
index 52d3f43148dc..3d13efb11444 100644
--- a/sound/soc/atmel/mchp-i2s-mcc.c
+++ b/sound/soc/atmel/mchp-i2s-mcc.c
@@ -100,6 +100,8 @@
 #define MCHP_I2SMCC_MRA_DATALENGTH_8_BITS_COMPACT	(7 << 1)
 
 #define MCHP_I2SMCC_MRA_WIRECFG_MASK		GENMASK(5, 4)
+#define MCHP_I2SMCC_MRA_WIRECFG_TDM(pin)	(((pin) << 4) & \
+						 MCHP_I2SMCC_MRA_WIRECFG_MASK)
 #define MCHP_I2SMCC_MRA_WIRECFG_I2S_1_TDM_0	(0 << 4)
 #define MCHP_I2SMCC_MRA_WIRECFG_I2S_2_TDM_1	(1 << 4)
 #define MCHP_I2SMCC_MRA_WIRECFG_I2S_4_TDM_2	(2 << 4)
@@ -245,6 +247,7 @@ struct mchp_i2s_mcc_dev {
 	unsigned int				frame_length;
 	int					tdm_slots;
 	int					channels;
+	u8					tdm_data_pair;
 	unsigned int				gclk_use:1;
 	unsigned int				gclk_running:1;
 	unsigned int				tx_rdy:1;
@@ -589,6 +592,8 @@ static int mchp_i2s_mcc_hw_params(struct snd_pcm_substream *substream,
 		if (!frame_length)
 			frame_length = 2 * params_physical_width(params);
 	} else if (dev->fmt & SND_SOC_DAIFMT_DSP_A) {
+		mra |= MCHP_I2SMCC_MRA_WIRECFG_TDM(dev->tdm_data_pair);
+
 		if (dev->tdm_slots) {
 			if (channels % 2 && channels * 2 <= dev->tdm_slots) {
 				/*
@@ -914,6 +919,45 @@ static const struct of_device_id mchp_i2s_mcc_dt_ids[] = {
 MODULE_DEVICE_TABLE(of, mchp_i2s_mcc_dt_ids);
 #endif
 
+static int mchp_i2s_mcc_soc_data_parse(struct platform_device *pdev,
+				       struct mchp_i2s_mcc_dev *dev)
+{
+	int err;
+
+	if (!dev->soc) {
+		dev_err(&pdev->dev, "failed to get soc data\n");
+		return -ENODEV;
+	}
+
+	if (dev->soc->data_pin_pair_num == 1)
+		return 0;
+
+	err = of_property_read_u8(pdev->dev.of_node, "microchip,tdm-data-pair",
+				  &dev->tdm_data_pair);
+	if (err < 0 && err != -EINVAL) {
+		dev_err(&pdev->dev,
+			"bad property data for 'microchip,tdm-data-pair': %d",
+			err);
+		return err;
+	}
+	if (err == -EINVAL) {
+		dev_info(&pdev->dev,
+			"'microchip,tdm-data-pair' not found; assuming DIN/DOUT 0 for TDM\n");
+		dev->tdm_data_pair = 0;
+	} else {
+		if (dev->tdm_data_pair > dev->soc->data_pin_pair_num - 1) {
+			dev_err(&pdev->dev,
+				"invalid value for 'microchip,tdm-data-pair': %d\n",
+				dev->tdm_data_pair);
+			return -EINVAL;
+		}
+		dev_dbg(&pdev->dev, "TMD format on DIN/DOUT %d pins\n",
+			dev->tdm_data_pair);
+	}
+
+	return 0;
+}
+
 static int mchp_i2s_mcc_probe(struct platform_device *pdev)
 {
 	struct mchp_i2s_mcc_dev *dev;
@@ -966,10 +1010,10 @@ static int mchp_i2s_mcc_probe(struct platform_device *pdev)
 	}
 
 	dev->soc = of_device_get_match_data(&pdev->dev);
-	if (!dev->soc) {
-		dev_err(&pdev->dev, "failed to get soc data\n");
-		return -ENODEV;
-	}
+	err = mchp_i2s_mcc_soc_data_parse(pdev, dev);
+	if (err < 0)
+		return err;
+
 	dev->dev = &pdev->dev;
 	dev->regmap = regmap;
 	platform_set_drvdata(pdev, dev);
-- 
2.27.0