[PATCH] ASoC: cs42xx8: add error checks for constraints in TDM mode

[Shengjiu Wang]

In the TDM format the ADC and DAC serial ports will only operate as a
slave, the sysclk should not be less than 256FS and Quad-Speed Mode (100
to 200 kHz sample rates) is not supported by ADC. So add error checks
for these constraints.

Signed-off-by: Shengjiu Wang <shengjiu.wang@xxxxxxx>
---
 sound/soc/codecs/cs42xx8.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/sound/soc/codecs/cs42xx8.c b/sound/soc/codecs/cs42xx8.c
index d14538c49b97..378995561ab2 100644
--- a/sound/soc/codecs/cs42xx8.c
+++ b/sound/soc/codecs/cs42xx8.c
@@ -43,6 +43,7 @@ struct cs42xx8_priv {
 	struct clk *clk;
 
 	bool slave_mode;
+	bool is_tdm_mode;
 	unsigned long sysclk;
 	u32 tx_channels;
 	struct gpio_desc *gpiod_reset;
@@ -217,6 +218,8 @@ static int cs42xx8_set_dai_fmt(struct snd_soc_dai *codec_dai,
 	struct cs42xx8_priv *cs42xx8 = snd_soc_component_get_drvdata(component);
 	u32 val;
 
+	cs42xx8->is_tdm_mode = false;
+
 	/* Set DAI format */
 	switch (format & SND_SOC_DAIFMT_FORMAT_MASK) {
 	case SND_SOC_DAIFMT_LEFT_J:
@@ -230,6 +233,7 @@ static int cs42xx8_set_dai_fmt(struct snd_soc_dai *codec_dai,
 		break;
 	case SND_SOC_DAIFMT_DSP_A:
 		val = CS42XX8_INTF_DAC_DIF_TDM | CS42XX8_INTF_ADC_DIF_TDM;
+		cs42xx8->is_tdm_mode = true;
 		break;
 	default:
 		dev_err(component->dev, "unsupported dai format\n");
@@ -253,6 +257,11 @@ static int cs42xx8_set_dai_fmt(struct snd_soc_dai *codec_dai,
 		return -EINVAL;
 	}
 
+	if (cs42xx8->is_tdm_mode && !cs42xx8->slave_mode) {
+		dev_err(component->dev, "TDM mode is supported only in slave mode\n");
+		return -EINVAL;
+	}
+
 	return 0;
 }
 
@@ -335,6 +344,19 @@ static int cs42xx8_hw_params(struct snd_pcm_substream *substream,
 
 	cs42xx8->rate[tx] = params_rate(params);
 
+	if (cs42xx8->is_tdm_mode) {
+		if (cs42xx8->sysclk < 256 * cs42xx8->rate[tx]) {
+			dev_err(component->dev, "Unsupported sysclk in TDM mode\n");
+			return -EINVAL;
+		}
+
+		if (!tx && cs42xx8->rate[tx] > 100000) {
+			dev_err(component->dev,
+				"ADC does not support Quad-Speed Mode in TDM mode\n");
+			return -EINVAL;
+		}
+	}
+
 	mask = CS42XX8_FUNCMOD_MFREQ_MASK;
 	val = cs42xx8_ratios[i].mfreq;
 
-- 
2.34.1