Add master clock handling for nau8824

Merge series from Maxim Kochetkov <fido_max@inbox.ru>:

nau8824 has external MCLK pin. So add enable/disable external clock
management.

Documentation/devicetree/bindings/sound/nuvoton,nau8824.yaml

@@ -23,6 +23,14 @@ properties:
   '#sound-dai-cells':
     const: 0
 
+  clocks:
+    items:
+      - description: The phandle of the master clock to the CODEC
+
+  clock-names:
+    items:
+      - const: mclk
+
   interrupts:
     maxItems: 1
 

sound/soc/codecs/nau8824.c

@@ -506,6 +506,7 @@ static int system_clock_control(struct snd_soc_dapm_widget *w,
 	struct regmap *regmap = nau8824->regmap;
 	unsigned int value;
 	bool clk_fll, error;
+	int ret;
 
 	if (SND_SOC_DAPM_EVENT_OFF(event)) {
 		dev_dbg(nau8824->dev, "system clock control : POWER OFF\n");
@@ -520,8 +521,15 @@ static int system_clock_control(struct snd_soc_dapm_widget *w,
 		} else {
 			nau8824_config_sysclk(nau8824, NAU8824_CLK_DIS, 0);
 		}
+
+		clk_disable_unprepare(nau8824->mclk);
 	} else {
 		dev_dbg(nau8824->dev, "system clock control : POWER ON\n");
+
+		ret = clk_prepare_enable(nau8824->mclk);
+		if (ret)
+			return ret;
+
 		/* Check the clock source setting is proper or not
 		 * no matter the source is from FLL or MCLK.
 		 */
@@ -563,16 +571,21 @@ static int dmic_clock_control(struct snd_soc_dapm_widget *w,
 	struct snd_soc_component *component = snd_soc_dapm_to_component(w->dapm);
 	struct nau8824 *nau8824 = snd_soc_component_get_drvdata(component);
 	int src;
+	unsigned int freq;
+
+	freq = clk_get_rate(nau8824->mclk);
+	if (!freq)
+		freq = nau8824->fs * 256;
 
 	/* The DMIC clock is gotten from system clock (256fs) divided by
 	 * DMIC_SRC (1, 2, 4, 8, 16, 32). The clock has to be equal or
 	 * less than 3.072 MHz.
 	 */
 	for (src = 0; src < 5; src++) {
-		if ((0x1 << (8 - src)) * nau8824->fs <= DMIC_CLK)
+		if (freq / (0x1 << src) <= DMIC_CLK)
 			break;
 	}
-	dev_dbg(nau8824->dev, "dmic src %d for mclk %d\n", src, nau8824->fs * 256);
+	dev_dbg(nau8824->dev, "dmic src %d for mclk %d\n", src, freq);
 	regmap_update_bits(nau8824->regmap, NAU8824_REG_CLK_DIVIDER,
 		NAU8824_CLK_DMIC_SRC_MASK, (src << NAU8824_CLK_DMIC_SRC_SFT));
 
@@ -1871,6 +1884,10 @@ static int nau8824_read_device_properties(struct device *dev,
 	if (ret)
 		nau8824->jack_eject_debounce = 1;
 
+	nau8824->mclk = devm_clk_get_optional(dev, "mclk");
+	if (IS_ERR(nau8824->mclk))
+		return PTR_ERR(nau8824->mclk);
+
 	return 0;
 }
 

sound/soc/codecs/nau8824.h

@@ -434,6 +434,7 @@ struct nau8824 {
 	struct snd_soc_jack *jack;
 	struct work_struct jdet_work;
 	struct semaphore jd_sem;
+	struct clk *mclk;
 	int fs;
 	int irq;
 	int resume_lock;