ASoC: Make rtd->codec optional

There are some place in the ASoC core that expect rtd->codec to be non NULL
(mainly CODEC specific sysfs files). With componentization going forward
rtd->codec might be NULL in some cases. This patch prepares the core for this by
not registering CODEC specific sysfs files if rtd->codec is NULL. sysfs file
removal does not need to be conditionalized as it handles the removal of
non-existing files just fine.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>

sound/soc/soc-core.c

@@ -1261,17 +1261,21 @@ static int soc_post_component_init(struct snd_soc_pcm_runtime *rtd,
 	}
 	rtd->dev_registered = 1;
 
-	/* add DAPM sysfs entries for this codec */
-	ret = snd_soc_dapm_sys_add(rtd->dev);
-	if (ret < 0)
-		dev_err(rtd->dev,
-			"ASoC: failed to add codec dapm sysfs entries: %d\n", ret);
+	if (rtd->codec) {
+		/* add DAPM sysfs entries for this codec */
+		ret = snd_soc_dapm_sys_add(rtd->dev);
+		if (ret < 0)
+			dev_err(rtd->dev,
+				"ASoC: failed to add codec dapm sysfs entries: %d\n",
+				ret);
 
-	/* add codec sysfs entries */
-	ret = device_create_file(rtd->dev, &dev_attr_codec_reg);
-	if (ret < 0)
-		dev_err(rtd->dev,
-			"ASoC: failed to add codec sysfs files: %d\n", ret);
+		/* add codec sysfs entries */
+		ret = device_create_file(rtd->dev, &dev_attr_codec_reg);
+		if (ret < 0)
+			dev_err(rtd->dev,
+				"ASoC: failed to add codec sysfs files: %d\n",
+				ret);
+	}
 
 	return 0;
 }