ASoC: core: Add API for configuration of DAI BCLK ratio

Some codec drivers when running in slave mode require that BCLK to sample rate ratio
is explicitly set by the machine driver as it may not be exactly rate * frame size.

Extend the DAI API by adding :-

int snd_soc_dai_set_bclk_ratio(struct snd_soc_dai *dai, unsigned int ratio);
Signed-off-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

include/sound/soc-dai.h

@@ -105,6 +105,8 @@ int snd_soc_dai_set_clkdiv(struct snd_soc_dai *dai,
 int snd_soc_dai_set_pll(struct snd_soc_dai *dai,
 	int pll_id, int source, unsigned int freq_in, unsigned int freq_out);
 
+int snd_soc_dai_set_bclk_ratio(struct snd_soc_dai *dai, unsigned int ratio);
+
 /* Digital Audio interface formatting */
 int snd_soc_dai_set_fmt(struct snd_soc_dai *dai, unsigned int fmt);
 
@@ -131,6 +133,7 @@ struct snd_soc_dai_ops {
 	int (*set_pll)(struct snd_soc_dai *dai, int pll_id, int source,
 		unsigned int freq_in, unsigned int freq_out);
 	int (*set_clkdiv)(struct snd_soc_dai *dai, int div_id, int div);
+	int (*set_bclk_ratio)(struct snd_soc_dai *dai, unsigned int ratio);
 
 	/*
 	 * DAI format configuration

sound/soc/soc-core.c

@@ -3576,6 +3576,22 @@ int snd_soc_codec_set_pll(struct snd_soc_codec *codec, int pll_id, int source,
 }
 EXPORT_SYMBOL_GPL(snd_soc_codec_set_pll);
 
+/**
+ * snd_soc_dai_set_bclk_ratio - configure BCLK to sample rate ratio.
+ * @dai: DAI
+ * @ratio Ratio of BCLK to Sample rate.
+ *
+ * Configures the DAI for a preset BCLK to sample rate ratio.
+ */
+int snd_soc_dai_set_bclk_ratio(struct snd_soc_dai *dai, unsigned int ratio)
+{
+	if (dai->driver && dai->driver->ops->set_bclk_ratio)
+		return dai->driver->ops->set_bclk_ratio(dai, ratio);
+	else
+		return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(snd_soc_dai_set_bclk_ratio);
+
 /**
  * snd_soc_dai_set_fmt - configure DAI hardware audio format.
  * @dai: DAI