ALSA: core: Expose sound card online/offline state

Expose sound card online/offline state to procfs so userspace application
can poll and read sound card's state.

Change-Id: Ie605ad57f4ce5abf62a216e790407029658ac3c9
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
Signed-off-by: Banajit Goswami <bgoswami@codeaurora.org>
Signed-off-by: Sudheer Papothi <spapothi@codeaurora.org>
Signed-off-by: Meng Wang <mengw@codeaurora.org>

include/sound/core.h

@@ -118,6 +118,11 @@ struct snd_card {
 	const struct attribute_group *dev_groups[4]; /* assigned sysfs attr */
 	bool registered;		/* card_dev is registered? */
 	wait_queue_head_t remove_sleep;
+#ifdef CONFIG_AUDIO_QGKI
+	int offline;			/* if this sound card is offline */
+	unsigned long offline_change;
+	wait_queue_head_t offline_poll_wait;
+#endif
 
 #ifdef CONFIG_PM
 	unsigned int power_state;	/* power state */
@@ -250,6 +255,11 @@ static inline void snd_card_unref(struct snd_card *card)
 	put_device(&card->card_dev);
 }
 
+#ifdef CONFIG_AUDIO_QGKI
+void snd_card_change_online_state(struct snd_card *card, int online);
+bool snd_card_is_online_state(struct snd_card *card);
+#endif
+
 #define snd_card_set_dev(card, devptr) ((card)->dev = (devptr))
 
 /* device.c */

include/sound/soc.h

@@ -534,6 +534,11 @@ static inline void snd_soc_jack_free_gpios(struct snd_soc_jack *jack, int count,
 }
 #endif
 
+#ifdef CONFIG_AUDIO_QGKI
+void snd_soc_card_change_online_state(struct snd_soc_card *soc_card,
+				int online);
+#endif
+
 struct snd_ac97 *snd_soc_alloc_ac97_component(struct snd_soc_component *component);
 struct snd_ac97 *snd_soc_new_ac97_component(struct snd_soc_component *component,
 	unsigned int id, unsigned int id_mask);

sound/core/info.c

@@ -71,6 +71,43 @@ EXPORT_SYMBOL(snd_seq_root);
 struct snd_info_entry *snd_oss_root;
 #endif
 
+#ifdef CONFIG_AUDIO_QGKI
+#define SND_CARD_STATE_MAX_LEN 16
+
+static ssize_t snd_info_card_state_read(struct snd_info_entry *entry,
+			void *file_private_data, struct file *file,
+			char __user *buf, size_t count, loff_t pos)
+{
+	struct snd_card *card = entry->private_data;
+	int len;
+	char buffer[SND_CARD_STATE_MAX_LEN];
+
+	/* make sure offline is updated prior to wake up */
+	rmb();
+	len = snprintf(buffer, sizeof(buffer), "%s\n",
+			card->offline ? "OFFLINE" : "ONLINE");
+	return simple_read_from_buffer(buf, count, &pos, buffer, len);
+}
+
+static unsigned int snd_info_card_state_poll(struct snd_info_entry *entry,
+				void *private_data, struct file *file,
+				poll_table *wait)
+{
+	struct snd_card *card = entry->private_data;
+
+	poll_wait(file, &card->offline_poll_wait, wait);
+	if (xchg(&card->offline_change, 0))
+		return POLLIN | POLLPRI | POLLRDNORM;
+	else
+		return 0;
+}
+
+static struct snd_info_entry_ops snd_info_card_state_proc_ops = {
+	.read = snd_info_card_state_read,
+	.poll = snd_info_card_state_poll,
+};
+#endif
+
 static int alloc_info_private(struct snd_info_entry *entry,
 			      struct snd_info_private_data **ret)
 {
@@ -505,6 +542,10 @@ int snd_info_card_create(struct snd_card *card)
 {
 	char str[8];
 	struct snd_info_entry *entry;
+#ifdef CONFIG_AUDIO_QGKI
+	struct snd_info_entry *entry_state;
+#endif
+	int ret;
 
 	if (snd_BUG_ON(!card))
 		return -ENXIO;
@@ -515,7 +556,23 @@ int snd_info_card_create(struct snd_card *card)
 		return -ENOMEM;
 	card->proc_root = entry;
 
-	return snd_card_ro_proc_new(card, "id", card, snd_card_id_read);
+	ret = snd_card_ro_proc_new(card, "id", card, snd_card_id_read);
+	if (ret)
+		return ret;
+
+#ifdef CONFIG_AUDIO_QGKI
+	entry_state = snd_info_create_card_entry(card, "state",
+						card->proc_root);
+	if (!entry_state) {
+		dev_dbg(card->dev, "unable to create card entry state\n");
+		card->proc_root = NULL;
+		return -ENOMEM;
+	}
+	entry_state->size = SND_CARD_STATE_MAX_LEN;
+	entry_state->content = SNDRV_INFO_CONTENT_DATA;
+	entry_state->c.ops = &snd_info_card_state_proc_ops;
+#endif
+	return 0;
 }
 
 /*

sound/core/init.c

@@ -215,7 +215,9 @@ int snd_card_new(struct device *parent, int idx, const char *xid,
 	init_waitqueue_head(&card->power_sleep);
 #endif
 	init_waitqueue_head(&card->remove_sleep);
-
+#ifdef CONFIG_AUDIO_QGKI
+	init_waitqueue_head(&card->offline_poll_wait);
+#endif
 	device_initialize(&card->card_dev);
 	card->card_dev.parent = parent;
 	card->card_dev.class = sound_class;
@@ -981,6 +983,37 @@ int snd_card_file_remove(struct snd_card *card, struct file *file)
 }
 EXPORT_SYMBOL(snd_card_file_remove);
 
+#ifdef CONFIG_AUDIO_QGKI
+/**
+ * snd_card_change_online_state - mark card's online/offline state
+ * @card: Card to mark
+ * @online: whether online of offline
+ *
+ * Mutes the DAI DAC.
+ */
+void snd_card_change_online_state(struct snd_card *card, int online)
+{
+	snd_printd("snd card %s state change %d -> %d\n",
+		card->shortname, !card->offline, online);
+	card->offline = !online;
+	/* make sure offline is updated prior to wake up */
+	wmb();
+	xchg(&card->offline_change, 1);
+	wake_up_interruptible(&card->offline_poll_wait);
+}
+EXPORT_SYMBOL(snd_card_change_online_state);
+
+/**
+ * snd_card_is_online_state - return true if card is online state
+ * @card: Card to query
+ */
+bool snd_card_is_online_state(struct snd_card *card)
+{
+	return !card->offline;
+}
+EXPORT_SYMBOL(snd_card_is_online_state);
+#endif
+
 #ifdef CONFIG_PM
 /**
  *  snd_power_wait - wait until the power-state is changed.

sound/soc/soc-core.c

@@ -2921,6 +2921,19 @@ struct snd_soc_component *snd_soc_lookup_component(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(snd_soc_lookup_component);
 
+#ifdef CONFIG_AUDIO_QGKI
+/**
+ * snd_soc_card_change_online_state - Mark if soc card is online/offline
+ *
+ * @soc_card: soc_card to mark
+ */
+void snd_soc_card_change_online_state(struct snd_soc_card *soc_card, int online)
+{
+	snd_card_change_online_state(soc_card->snd_card, online);
+}
+EXPORT_SYMBOL(snd_soc_card_change_online_state);
+#endif
+
 /* Retrieve a card's name from device tree */
 int snd_soc_of_parse_card_name(struct snd_soc_card *card,
 			       const char *propname)