ASoC: fsl_sai: add tdm slots operation support

Add tdm slots operation support. If tdm slots and slot width have
been configured in machine driver, we should use these values.
Otherwise, using relevant channels and word length to set slots
and slot width.

SAI will generate BCLK depends on sample rate, slots and slot width.
And there may be unused BCLK cycles before each LRCLK transition.
Signed-off-by: Zidan Wang <zidan.wang@freescale.com>
Acked-by: Nicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/fsl/fsl_sai.c

@@ -126,6 +126,17 @@ static irqreturn_t fsl_sai_isr(int irq, void *devid)
 		return IRQ_HANDLED;
 }
 
+static int fsl_sai_set_dai_tdm_slot(struct snd_soc_dai *cpu_dai, u32 tx_mask,
+				u32 rx_mask, int slots, int slot_width)
+{
+	struct fsl_sai *sai = snd_soc_dai_get_drvdata(cpu_dai);
+
+	sai->slots = slots;
+	sai->slot_width = slot_width;
+
+	return 0;
+}
+
 static int fsl_sai_set_dai_sysclk_tr(struct snd_soc_dai *cpu_dai,
 		int clk_id, unsigned int freq, int fsl_dir)
 {
@@ -395,11 +406,19 @@ static int fsl_sai_hw_params(struct snd_pcm_substream *substream,
 	unsigned int channels = params_channels(params);
 	u32 word_width = snd_pcm_format_width(params_format(params));
 	u32 val_cr4 = 0, val_cr5 = 0;
+	u32 slots = (channels == 1) ? 2 : channels;
+	u32 slot_width = word_width;
 	int ret;
 
+	if (sai->slots)
+		slots = sai->slots;
+
+	if (sai->slot_width)
+		slot_width = sai->slot_width;
+
 	if (!sai->is_slave_mode) {
 		ret = fsl_sai_set_bclk(cpu_dai, tx,
-			2 * word_width * params_rate(params));
+				slots * slot_width * params_rate(params));
 		if (ret)
 			return ret;
 
@@ -411,21 +430,20 @@ static int fsl_sai_hw_params(struct snd_pcm_substream *substream,
 
 			sai->mclk_streams |= BIT(substream->stream);
 		}
-
 	}
 
 	if (!sai->is_dsp_mode)
-		val_cr4 |= FSL_SAI_CR4_SYWD(word_width);
+		val_cr4 |= FSL_SAI_CR4_SYWD(slot_width);
 
-	val_cr5 |= FSL_SAI_CR5_WNW(word_width);
-	val_cr5 |= FSL_SAI_CR5_W0W(word_width);
+	val_cr5 |= FSL_SAI_CR5_WNW(slot_width);
+	val_cr5 |= FSL_SAI_CR5_W0W(slot_width);
 
 	if (sai->is_lsb_first)
 		val_cr5 |= FSL_SAI_CR5_FBT(0);
 	else
 		val_cr5 |= FSL_SAI_CR5_FBT(word_width - 1);
 
-	val_cr4 |= FSL_SAI_CR4_FRSZ(channels);
+	val_cr4 |= FSL_SAI_CR4_FRSZ(slots);
 
 	/*
 	 * For SAI master mode, when Tx(Rx) sync with Rx(Tx) clock, Rx(Tx) will
@@ -591,6 +609,7 @@ static void fsl_sai_shutdown(struct snd_pcm_substream *substream,
 static const struct snd_soc_dai_ops fsl_sai_pcm_dai_ops = {
 	.set_sysclk	= fsl_sai_set_dai_sysclk,
 	.set_fmt	= fsl_sai_set_dai_fmt,
+	.set_tdm_slot	= fsl_sai_set_dai_tdm_slot,
 	.hw_params	= fsl_sai_hw_params,
 	.hw_free	= fsl_sai_hw_free,
 	.trigger	= fsl_sai_trigger,

sound/soc/fsl/fsl_sai.h

@@ -143,6 +143,9 @@ struct fsl_sai {
 
 	unsigned int mclk_id[2];
 	unsigned int mclk_streams;
+	unsigned int slots;
+	unsigned int slot_width;
+
 	struct snd_dmaengine_dai_dma_data dma_params_rx;
 	struct snd_dmaengine_dai_dma_data dma_params_tx;
 };