ASoC: cs42l42: Implement 'set_bclk_ratio'

The driver wants to know the bit rate on the serial bus and takes that
to be the value set by 'set_sysclk'. The 'set_bclk_ratio' op is a better
fit for figuring out the clocking parameters of the serial bus, so
implement that and give it precedence over the prior methods.
Signed-off-by: Martin Povišer <povik+lin@cutebit.org>
Link: https://lore.kernel.org/r/20220915094444.11434-11-povik+lin@cutebit.orgSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/cs42l42.c

@@ -898,7 +898,10 @@ static int cs42l42_pcm_hw_params(struct snd_pcm_substream *substream,
 
 	cs42l42->srate = params_rate(params);
 
-	if (cs42l42->sclk) {
+	if (cs42l42->bclk_ratio) {
+		/* machine driver has set the BCLK/samp-rate ratio */
+		bclk = cs42l42->bclk_ratio * params_rate(params);
+	} else if (cs42l42->sclk) {
 		/* machine driver has set the SCLK */
 		bclk = cs42l42->sclk;
 	} else {
@@ -984,6 +987,17 @@ static int cs42l42_set_sysclk(struct snd_soc_dai *dai,
 	return -EINVAL;
 }
 
+static int cs42l42_set_bclk_ratio(struct snd_soc_dai *dai,
+				unsigned int bclk_ratio)
+{
+	struct snd_soc_component *component = dai->component;
+	struct cs42l42_private *cs42l42 = snd_soc_component_get_drvdata(component);
+
+	cs42l42->bclk_ratio = bclk_ratio;
+
+	return 0;
+}
+
 static int cs42l42_mute_stream(struct snd_soc_dai *dai, int mute, int stream)
 {
 	struct snd_soc_component *component = dai->component;
@@ -1087,6 +1101,7 @@ static const struct snd_soc_dai_ops cs42l42_ops = {
 	.hw_params	= cs42l42_pcm_hw_params,
 	.set_fmt	= cs42l42_set_dai_fmt,
 	.set_sysclk	= cs42l42_set_sysclk,
+	.set_bclk_ratio	= cs42l42_set_bclk_ratio,
 	.mute_stream	= cs42l42_mute_stream,
 };
 

sound/soc/codecs/cs42l42.h

@@ -35,6 +35,7 @@ struct  cs42l42_private {
 	int irq;
 	int pll_config;
 	u32 sclk;
+	u32 bclk_ratio;
 	u32 srate;
 	u8 plug_state;
 	u8 hs_type;