ALSA: hda/i915: Associate audio component with devres

The HD-audio i915 binding code contains a single pointer, hdac_acomp,
for allowing the access to audio component from the master bind/unbind
callbacks.  This was needed because the callbacks pass only the device
pointer and we can't guarantee the object type assigned to the drvdata
(which is free for each controller driver implementation).
And this implementation will be a problem if we support multiple
components for different DRM drivers, not only i915.

As a solution, allocate the audio component object via devres and
associate it with the given device, so that the component callbacks
can refer to it via devres_find().

The removal of the object is still done half-manually via
devres_destroy() to make the code consistent (although it may work
without the explicit call).

Also, the snd_hda_i915_register_notifier() had the reference to
hdac_acomp as well.  In this patch, the corresponding code is removed
by passing hdac_bus object to the function, too.
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/hda_i915.h

@@ -17,7 +17,8 @@ int snd_hdac_acomp_get_eld(struct hdac_device *codec, hda_nid_t nid, int dev_id,
 			   bool *audio_enabled, char *buffer, int max_bytes);
 int snd_hdac_i915_init(struct hdac_bus *bus);
 int snd_hdac_i915_exit(struct hdac_bus *bus);
-int snd_hdac_i915_register_notifier(const struct drm_audio_component_audio_ops *);
+int snd_hdac_i915_register_notifier(struct hdac_bus *bus,
+				    const struct drm_audio_component_audio_ops *ops);
 #else
 static inline int snd_hdac_set_codec_wakeup(struct hdac_bus *bus, bool enable)
 {
@@ -49,7 +50,8 @@ static inline int snd_hdac_i915_exit(struct hdac_bus *bus)
 {
 	return 0;
 }
-static inline int snd_hdac_i915_register_notifier(const struct drm_audio_component_audio_ops *ops)
+static inline int snd_hdac_i915_register_notifier(struct hdac_bus *bus,
+						  const struct drm_audio_component_audio_ops *ops)
 {
 	return -ENODEV;
 }

sound/hda/hdac_i915.c

@@ -22,7 +22,14 @@
 #include <sound/hda_i915.h>
 #include <sound/hda_register.h>
 
-static struct drm_audio_component *hdac_acomp;
+static void hdac_acomp_release(struct device *dev, void *res)
+{
+}
+
+static struct drm_audio_component *hdac_get_acomp(struct device *dev)
+{
+	return devres_find(dev, hdac_acomp_release, NULL, NULL);
+}
 
 /**
  * snd_hdac_set_codec_wakeup - Enable / disable HDMI/DP codec wakeup
@@ -262,7 +269,7 @@ EXPORT_SYMBOL_GPL(snd_hdac_acomp_get_eld);
 
 static int hdac_component_master_bind(struct device *dev)
 {
-	struct drm_audio_component *acomp = hdac_acomp;
+	struct drm_audio_component *acomp = hdac_get_acomp(dev);
 	int ret;
 
 	ret = component_bind_all(dev, acomp);
@@ -294,7 +301,7 @@ static int hdac_component_master_bind(struct device *dev)
 
 static void hdac_component_master_unbind(struct device *dev)
 {
-	struct drm_audio_component *acomp = hdac_acomp;
+	struct drm_audio_component *acomp = hdac_get_acomp(dev);
 
 	module_put(acomp->ops->owner);
 	component_unbind_all(dev, acomp);
@@ -314,6 +321,7 @@ static int hdac_component_master_match(struct device *dev, void *data)
 
 /**
  * snd_hdac_i915_register_notifier - Register i915 audio component ops
+ * @bus: HDA core bus
  * @aops: i915 audio component ops
  *
  * This function is supposed to be used only by a HD-audio controller
@@ -323,12 +331,13 @@ static int hdac_component_master_match(struct device *dev, void *data)
  *
  * Returns zero for success or a negative error code.
  */
-int snd_hdac_i915_register_notifier(const struct drm_audio_component_audio_ops *aops)
+int snd_hdac_i915_register_notifier(struct hdac_bus *bus,
+				    const struct drm_audio_component_audio_ops *aops)
 {
-	if (!hdac_acomp)
+	if (!bus->audio_component)
 		return -ENODEV;
 
-	hdac_acomp->audio_ops = aops;
+	bus->audio_component->audio_ops = aops;
 	return 0;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_i915_register_notifier);
@@ -365,18 +374,19 @@ int snd_hdac_i915_init(struct hdac_bus *bus)
 	struct drm_audio_component *acomp;
 	int ret;
 
-	if (WARN_ON(hdac_acomp))
+	if (WARN_ON(hdac_get_acomp(dev)))
 		return -EBUSY;
 
 	if (!i915_gfx_present())
 		return -ENODEV;
 
-	i915_acomp = kzalloc(sizeof(*i915_acomp), GFP_KERNEL);
+	i915_acomp = devres_alloc(hdac_acomp_release, sizeof(*i915_acomp),
+				  GFP_KERNEL);
 	if (!i915_acomp)
 		return -ENOMEM;
 	acomp = &i915_acomp->base;
 	bus->audio_component = acomp;
-	hdac_acomp = acomp;
+	devres_add(dev, acomp);
 
 	component_match_add(dev, &match, hdac_component_master_match, bus);
 	ret = component_master_add_with_match(dev, &hdac_component_master_ops,
@@ -400,9 +410,8 @@ int snd_hdac_i915_init(struct hdac_bus *bus)
 out_master_del:
 	component_master_del(dev, &hdac_component_master_ops);
 out_err:
-	kfree(acomp);
 	bus->audio_component = NULL;
-	hdac_acomp = NULL;
+	devres_destroy(dev, hdac_acomp_release, NULL, NULL);
 	dev_info(dev, "failed to add i915 component master (%d)\n", ret);
 
 	return ret;
@@ -434,9 +443,8 @@ int snd_hdac_i915_exit(struct hdac_bus *bus)
 
 	component_master_del(dev, &hdac_component_master_ops);
 
-	kfree(acomp);
 	bus->audio_component = NULL;
-	hdac_acomp = NULL;
+	devres_destroy(dev, hdac_acomp_release, NULL, NULL);
 
 	return 0;
 }

sound/pci/hda/patch_hdmi.c

@@ -2288,7 +2288,7 @@ static void generic_hdmi_free(struct hda_codec *codec)
 	int pin_idx, pcm_idx;
 
 	if (codec_has_acomp(codec))
-		snd_hdac_i915_register_notifier(NULL);
+		snd_hdac_i915_register_notifier(&codec->bus->core, NULL);
 
 	for (pin_idx = 0; pin_idx < spec->num_pins; pin_idx++) {
 		struct hdmi_spec_per_pin *per_pin = get_pin(spec, pin_idx);
@@ -2518,7 +2518,8 @@ static void register_i915_notifier(struct hda_codec *codec)
 	 */
 	wmb();
 	spec->drm_audio_ops.pin_eld_notify = intel_pin_eld_notify;
-	snd_hdac_i915_register_notifier(&spec->drm_audio_ops);
+	snd_hdac_i915_register_notifier(&codec->bus->core,
+					&spec->drm_audio_ops);
 }
 
 /* setup_stream ops override for HSW+ */

sound/soc/codecs/hdac_hdmi.c

@@ -1812,7 +1812,7 @@ static int hdmi_codec_probe(struct snd_soc_component *component)
 		return ret;
 
 	aops.audio_ptr = hdev;
-	ret = snd_hdac_i915_register_notifier(&aops);
+	ret = snd_hdac_i915_register_notifier(hdev->bus, &aops);
 	if (ret < 0) {
 		dev_err(&hdev->dev, "notifier register failed: err: %d\n", ret);
 		return ret;