ASoC: wm8994: Enabling VMID should take a runtime PM reference

commit db966f8a upstream.

We can enable VMID independently of the bias in some use cases so we need
to ensure that the core device is powered up.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

sound/soc/codecs/wm8994.c

@@ -729,6 +729,8 @@ static void vmid_reference(struct snd_soc_codec *codec)
 {
 	struct wm8994_priv *wm8994 = snd_soc_codec_get_drvdata(codec);
 
+	pm_runtime_get_sync(codec->dev);
+
 	wm8994->vmid_refcount++;
 
 	dev_dbg(codec->dev, "Referencing VMID, refcount is now %d\n",
@@ -796,6 +798,8 @@ static void vmid_dereference(struct snd_soc_codec *codec)
 				    WM8994_VMID_BUF_ENA |
 				    WM8994_VMID_RAMP_MASK, 0);
 	}
+
+	pm_runtime_put(codec->dev);
 }
 
 static int vmid_event(struct snd_soc_dapm_widget *w,