ASoC: wm8904: configure sysclk/FLL automatically

This adds a new mode WM8904_CLK_AUTO which automatically enables the FLL
if a frequency different than the MCLK is set.

These additions make the codec work with the simple-card driver in
general and especially in systems where the MCLK doesn't match the
required clock.

Signed-off-by: Michael Walle <[e-mail]>
Acked-by: Charles Keepax <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

sound/soc/codecs/wm8904.c

···
 	return 0;
 }
 
-
-static int wm8904_set_sysclk(struct snd_soc_dai *dai, int clk_id,
-			     unsigned int freq, int dir)
-{
-	struct snd_soc_component *component = dai->component;
-	struct wm8904_priv *priv = snd_soc_component_get_drvdata(component);
-
-	switch (clk_id) {
-	case WM8904_CLK_MCLK:
-		priv->sysclk_src = clk_id;
-		priv->mclk_rate = freq;
-		break;
-
-	case WM8904_CLK_FLL:
-		priv->sysclk_src = clk_id;
-		break;
-
-	default:
-		return -EINVAL;
-	}
-
-	dev_dbg(dai->dev, "Clock source is %d at %uHz\n", clk_id, freq);
-
-	wm8904_configure_clocking(component);
-
-	return 0;
-}
-
 static int wm8904_set_fmt(struct snd_soc_dai *dai, unsigned int fmt)
 {
 	struct snd_soc_component *component = dai->component;
···
 	/* Reenable SYSCLK if it was previously active */
 	snd_soc_component_update_bits(component, WM8904_CLOCK_RATES_2,
 			    WM8904_CLK_SYS_ENA, clock2);
+
+	return 0;
+}
+
+static int wm8904_set_sysclk(struct snd_soc_dai *dai, int clk_id,
+			     unsigned int freq, int dir)
+{
+	struct snd_soc_component *component = dai->component;
+	struct wm8904_priv *priv = snd_soc_component_get_drvdata(component);
+	unsigned long mclk_freq;
+	int ret;
+
+	switch (clk_id) {
+	case WM8904_CLK_AUTO:
+		mclk_freq = clk_get_rate(priv->mclk);
+		/* enable FLL if a different sysclk is desired */
+		if (mclk_freq != freq) {
+			priv->sysclk_src = WM8904_CLK_FLL;
+			ret = wm8904_set_fll(dai, WM8904_FLL_MCLK,
+					     WM8904_FLL_MCLK,
+					     mclk_freq, freq);
+			if (ret)
+				return ret;
+			break;
+		}
+		clk_id = WM8904_CLK_MCLK;
+		/* fallthrough */
+
+	case WM8904_CLK_MCLK:
+		priv->sysclk_src = clk_id;
+		priv->mclk_rate = freq;
+		break;
+
+	case WM8904_CLK_FLL:
+		priv->sysclk_src = clk_id;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	dev_dbg(dai->dev, "Clock source is %d at %uHz\n", clk_id, freq);
+
+	wm8904_configure_clocking(component);
 
 	return 0;
 }

sound/soc/codecs/wm8904.h

···
 #ifndef _WM8904_H
 #define _WM8904_H
 
+#define WM8904_CLK_AUTO 0
 #define WM8904_CLK_MCLK 1
 #define WM8904_CLK_FLL  2