1 files changed, 278 insertions, 0 deletions
diff --git a/sound/core/control_led.c b/sound/core/control_led.c
new file mode 100644
index 000000000000..3e2c3c485c5c
--- /dev/null
+++ b/sound/core/control_led.c
@@ -0,0 +1,278 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  LED state routines for driver control interface
+ *  Copyright (c) 2021 by Jaroslav Kysela <perex@perex.cz>
+ */
+
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/leds.h>
+#include <sound/core.h>
+#include <sound/control.h>
+
+MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
+MODULE_DESCRIPTION("ALSA control interface to LED trigger code.");
+MODULE_LICENSE("GPL");
+
+#define MAX_LED (((SNDRV_CTL_ELEM_ACCESS_MIC_LED - SNDRV_CTL_ELEM_ACCESS_SPK_LED) \
+			>> SNDRV_CTL_ELEM_ACCESS_LED_SHIFT) + 1)
+
+struct snd_ctl_led {
+	struct list_head list;
+	struct snd_card *card;
+	unsigned int access;
+	struct snd_kcontrol *kctl;
+	unsigned int index_offset;
+};
+
+static DEFINE_MUTEX(snd_ctl_led_mutex);
+static struct list_head snd_ctl_led_controls[MAX_LED];
+static bool snd_ctl_led_card_valid[SNDRV_CARDS];
+
+#define UPDATE_ROUTE(route, cb) \
+	do { \
+		int route2 = (cb); \
+		if (route2 >= 0) \
+			route = route < 0 ? route2 : (route | route2); \
+	} while (0)
+
+static inline unsigned int access_to_group(unsigned int access)
+{
+	return ((access & SNDRV_CTL_ELEM_ACCESS_LED_MASK) >>
+				SNDRV_CTL_ELEM_ACCESS_LED_SHIFT) - 1;
+}
+
+static inline unsigned int group_to_access(unsigned int group)
+{
+	return (group + 1) << SNDRV_CTL_ELEM_ACCESS_LED_SHIFT;
+}
+
+static struct list_head *snd_ctl_led_controls_by_access(unsigned int access)
+{
+	unsigned int group = access_to_group(access);
+	if (group >= MAX_LED)
+		return NULL;
+	return &snd_ctl_led_controls[group];
+}
+
+static int snd_ctl_led_get(struct snd_ctl_led *lctl)
+{
+	struct snd_kcontrol *kctl = lctl->kctl;
+	struct snd_ctl_elem_info info;
+	struct snd_ctl_elem_value value;
+	unsigned int i;
+	int result;
+
+	memset(&info, 0, sizeof(info));
+	info.id = kctl->id;
+	info.id.index += lctl->index_offset;
+	info.id.numid += lctl->index_offset;
+	result = kctl->info(kctl, &info);
+	if (result < 0)
+		return -1;
+	memset(&value, 0, sizeof(value));
+	value.id = info.id;
+	result = kctl->get(kctl, &value);
+	if (result < 0)
+		return -1;
+	if (info.type == SNDRV_CTL_ELEM_TYPE_BOOLEAN ||
+	    info.type == SNDRV_CTL_ELEM_TYPE_INTEGER) {
+		for (i = 0; i < info.count; i++)
+			if (value.value.integer.value[i] != info.value.integer.min)
+				return 1;
+	} else if (info.type == SNDRV_CTL_ELEM_TYPE_INTEGER64) {
+		for (i = 0; i < info.count; i++)
+			if (value.value.integer64.value[i] != info.value.integer64.min)
+				return 1;
+	}
+	return 0;
+}
+
+static void snd_ctl_led_set_state(struct snd_card *card, unsigned int access,
+				  struct snd_kcontrol *kctl, unsigned int ioff)
+{
+	struct list_head *controls;
+	struct snd_ctl_led *lctl;
+	enum led_audio led_trigger_type;
+	int route;
+	bool found;
+
+	controls = snd_ctl_led_controls_by_access(access);
+	if (!controls)
+		return;
+	if (access == SNDRV_CTL_ELEM_ACCESS_SPK_LED) {
+		led_trigger_type = LED_AUDIO_MUTE;
+	} else if (access == SNDRV_CTL_ELEM_ACCESS_MIC_LED) {
+		led_trigger_type = LED_AUDIO_MICMUTE;
+	} else {
+		return;
+	}
+	route = -1;
+	found = false;
+	mutex_lock(&snd_ctl_led_mutex);
+	/* the card may not be registered (active) at this point */
+	if (card && !snd_ctl_led_card_valid[card->number]) {
+		mutex_unlock(&snd_ctl_led_mutex);
+		return;
+	}
+	list_for_each_entry(lctl, controls, list) {
+		if (lctl->kctl == kctl && lctl->index_offset == ioff)
+			found = true;
+		UPDATE_ROUTE(route, snd_ctl_led_get(lctl));
+	}
+	if (!found && kctl && card) {
+		lctl = kzalloc(sizeof(*lctl), GFP_KERNEL);
+		if (lctl) {
+			lctl->card = card;
+			lctl->access = access;
+			lctl->kctl = kctl;
+			lctl->index_offset = ioff;
+			list_add(&lctl->list, controls);
+			UPDATE_ROUTE(route, snd_ctl_led_get(lctl));
+		}
+	}
+	mutex_unlock(&snd_ctl_led_mutex);
+	if (route >= 0)
+		ledtrig_audio_set(led_trigger_type, route ? LED_OFF : LED_ON);
+}
+
+static struct snd_ctl_led *snd_ctl_led_find(struct snd_kcontrol *kctl, unsigned int ioff)
+{
+	struct list_head *controls;
+	struct snd_ctl_led *lctl;
+	unsigned int group;
+
+	for (group = 0; group < MAX_LED; group++) {
+		controls = &snd_ctl_led_controls[group];
+		list_for_each_entry(lctl, controls, list)
+			if (lctl->kctl == kctl && lctl->index_offset == ioff)
+				return lctl;
+	}
+	return NULL;
+}
+
+static unsigned int snd_ctl_led_remove(struct snd_kcontrol *kctl, unsigned int ioff,
+				       unsigned int access)
+{
+	struct snd_ctl_led *lctl;
+	unsigned int ret = 0;
+
+	mutex_lock(&snd_ctl_led_mutex);
+	lctl = snd_ctl_led_find(kctl, ioff);
+	if (lctl && (access == 0 || access != lctl->access)) {
+		ret = lctl->access;
+		list_del(&lctl->list);
+		kfree(lctl);
+	}
+	mutex_unlock(&snd_ctl_led_mutex);
+	return ret;
+}
+
+static void snd_ctl_led_notify(struct snd_card *card, unsigned int mask,
+			       struct snd_kcontrol *kctl, unsigned int ioff)
+{
+	struct snd_kcontrol_volatile *vd;
+	unsigned int access, access2;
+
+	if (mask == SNDRV_CTL_EVENT_MASK_REMOVE) {
+		access = snd_ctl_led_remove(kctl, ioff, 0);
+		if (access)
+			snd_ctl_led_set_state(card, access, NULL, 0);
+	} else if (mask & SNDRV_CTL_EVENT_MASK_INFO) {
+		vd = &kctl->vd[ioff];
+		access = vd->access & SNDRV_CTL_ELEM_ACCESS_LED_MASK;
+		access2 = snd_ctl_led_remove(kctl, ioff, access);
+		if (access2)
+			snd_ctl_led_set_state(card, access2, NULL, 0);
+		if (access)
+			snd_ctl_led_set_state(card, access, kctl, ioff);
+	} else if ((mask & (SNDRV_CTL_EVENT_MASK_ADD |
+			    SNDRV_CTL_EVENT_MASK_VALUE)) != 0) {
+		vd = &kctl->vd[ioff];
+		access = vd->access & SNDRV_CTL_ELEM_ACCESS_LED_MASK;
+		if (access)
+			snd_ctl_led_set_state(card, access, kctl, ioff);
+	}
+}
+
+static void snd_ctl_led_refresh(void)
+{
+	unsigned int group;
+
+	for (group = 0; group < MAX_LED; group++)
+		snd_ctl_led_set_state(NULL, group_to_access(group), NULL, 0);
+}
+
+static void snd_ctl_led_clean(struct snd_card *card)
+{
+	unsigned int group;
+	struct list_head *controls;
+	struct snd_ctl_led *lctl;
+
+	for (group = 0; group < MAX_LED; group++) {
+		controls = &snd_ctl_led_controls[group];
+repeat:
+		list_for_each_entry(lctl, controls, list)
+			if (!card || lctl->card == card) {
+				list_del(&lctl->list);
+				kfree(lctl);
+				goto repeat;
+			}
+	}
+}
+
+static void snd_ctl_led_register(struct snd_card *card)
+{
+	struct snd_kcontrol *kctl;
+	unsigned int ioff;
+
+	if (snd_BUG_ON(card->number < 0 ||
+		       card->number >= ARRAY_SIZE(snd_ctl_led_card_valid)))
+		return;
+	mutex_lock(&snd_ctl_led_mutex);
+	snd_ctl_led_card_valid[card->number] = true;
+	mutex_unlock(&snd_ctl_led_mutex);
+	/* the register callback is already called with held card->controls_rwsem */
+	list_for_each_entry(kctl, &card->controls, list)
+		for (ioff = 0; ioff < kctl->count; ioff++)
+			snd_ctl_led_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, kctl, ioff);
+	snd_ctl_led_refresh();
+}
+
+static void snd_ctl_led_disconnect(struct snd_card *card)
+{
+	mutex_lock(&snd_ctl_led_mutex);
+	snd_ctl_led_card_valid[card->number] = false;
+	snd_ctl_led_clean(card);
+	mutex_unlock(&snd_ctl_led_mutex);
+	snd_ctl_led_refresh();
+}
+
+/*
+ * Control layer registration
+ */
+static struct snd_ctl_layer_ops snd_ctl_led_lops = {
+	.module_name = SND_CTL_LAYER_MODULE_LED,
+	.lregister = snd_ctl_led_register,
+	.ldisconnect = snd_ctl_led_disconnect,
+	.lnotify = snd_ctl_led_notify,
+};
+
+static int __init snd_ctl_led_init(void)
+{
+	unsigned int group;
+
+	for (group = 0; group < MAX_LED; group++)
+		INIT_LIST_HEAD(&snd_ctl_led_controls[group]);
+	snd_ctl_register_layer(&snd_ctl_led_lops);
+	return 0;
+}
+
+static void __exit snd_ctl_led_exit(void)
+{
+	snd_ctl_disconnect_layer(&snd_ctl_led_lops);
+	snd_ctl_led_clean(NULL);
+}
+
+module_init(snd_ctl_led_init)
+module_exit(snd_ctl_led_exit)