ASoC: cs42l51: fix mclk support

The MCLK clock is made optional for cs42l51 codec.
However, ASoC DAPM clock supply widget, expects the clock to be defined
unconditionally.
Register MCLK DAPM conditionally in codec driver,
depending on clock presence in DT.

Fixes: 5e8d63a7 ("ASoC: cs42l51: add mclk support")
Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/cs42l51.c

@@ -21,6 +21,7 @@
  *  - master mode *NOT* supported
  */
 
+#include <linux/clk.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <sound/core.h>
@@ -41,6 +42,7 @@ enum master_slave_mode {
 
 struct cs42l51_private {
 	unsigned int mclk;
+	struct clk *mclk_handle;
 	unsigned int audio_mode;	/* The mode (I2S or left-justified) */
 	enum master_slave_mode func;
 };
@@ -492,8 +494,12 @@ static int cs42l51_component_probe(struct snd_soc_component *component)
 {
 	int ret, reg;
 	struct snd_soc_dapm_context *dapm;
+	struct cs42l51_private *cs42l51;
 
+	cs42l51 = snd_soc_component_get_drvdata(component);
 	dapm = snd_soc_component_get_dapm(component);
+
+	if (cs42l51->mclk_handle)
 		snd_soc_dapm_new_controls(dapm, cs42l51_dapm_mclk_widgets, 1);
 
 	/*
@@ -548,6 +554,13 @@ int cs42l51_probe(struct device *dev, struct regmap *regmap)
 
 	dev_set_drvdata(dev, cs42l51);
 
+	cs42l51->mclk_handle = devm_clk_get(dev, "MCLK");
+	if (IS_ERR(cs42l51->mclk_handle)) {
+		if (PTR_ERR(cs42l51->mclk_handle) != -ENOENT)
+			return PTR_ERR(cs42l51->mclk_handle);
+		cs42l51->mclk_handle = NULL;
+	}
+
 	/* Verify that we have a CS42L51 */
 	ret = regmap_read(regmap, CS42L51_CHIP_REV_ID, &val);
 	if (ret < 0) {