ASoC: fsl_sai: Implement set_bclk_ratio

This is to allow machine drivers to set a certain bitclk rate
which might not be exactly rate * frame size.

Cc: NXP Linux Team <linux-imx@nxp.com>
Signed-off-by: Viorel Suman <viorel.suman@nxp.com>
Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>
Acked-by: Nicolin Chen <nicoleotsuka@gmail.com>
Link: https://lore.kernel.org/r/20190830215910.31590-1-daniel.baluta@nxp.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/fsl/fsl_sai.c

@@ -137,6 +137,16 @@ static int fsl_sai_set_dai_tdm_slot(struct snd_soc_dai *cpu_dai, u32 tx_mask,
 	return 0;
 }
 
+static int fsl_sai_set_dai_bclk_ratio(struct snd_soc_dai *dai,
+				      unsigned int ratio)
+{
+	struct fsl_sai *sai = snd_soc_dai_get_drvdata(dai);
+
+	sai->bclk_ratio = ratio;
+
+	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)
 {
@@ -423,8 +433,14 @@ static int fsl_sai_hw_params(struct snd_pcm_substream *substream,
 		slot_width = sai->slot_width;
 
 	if (!sai->is_slave_mode) {
-		ret = fsl_sai_set_bclk(cpu_dai, tx,
-				slots * slot_width * params_rate(params));
+		if (sai->bclk_ratio)
+			ret = fsl_sai_set_bclk(cpu_dai, tx,
+					       sai->bclk_ratio *
+					       params_rate(params));
+		else
+			ret = fsl_sai_set_bclk(cpu_dai, tx,
+					       slots * slot_width *
+					       params_rate(params));
 		if (ret)
 			return ret;
 
@@ -630,6 +646,7 @@ static void fsl_sai_shutdown(struct snd_pcm_substream *substream,
 }
 
 static const struct snd_soc_dai_ops fsl_sai_pcm_dai_ops = {
+	.set_bclk_ratio	= fsl_sai_set_dai_bclk_ratio,
 	.set_sysclk	= fsl_sai_set_dai_sysclk,
 	.set_fmt	= fsl_sai_set_dai_fmt,
 	.set_tdm_slot	= fsl_sai_set_dai_tdm_slot,

sound/soc/fsl/fsl_sai.h

@@ -176,6 +176,7 @@ struct fsl_sai {
 	unsigned int mclk_streams;
 	unsigned int slots;
 	unsigned int slot_width;
+	unsigned int bclk_ratio;
 
 	const struct fsl_sai_soc_data *soc_data;
 	struct snd_dmaengine_dai_dma_data dma_params_rx;