[PATCH v4 6/6] ALSA: led control - add sysfs kcontrol LED marking layer
Jaroslav Kysela
perex at perex.cz
Wed Mar 17 18:29:45 CET 2021
We need to manage the kcontrol entries association for the LED trigger
from the user space. This patch adds a layer to the sysfs tree like:
/sys/devices/virtual/sound/ctl-led/mic
+ card0
| + attach
| + detach
| ...
+ card1
+ attach
...
Operations:
attach and detach
- amixer style ID is accepted and easy strings for numid and
simple names
reset
- reset all associated kcontrol entries
list
- list associated kcontrol entries (numid values only)
Additional symlinks:
/sys/devices/virtual/sound/ctl-led/mic/card0/card ->
/sys/class/sound/card0
/sys/class/sound/card0/controlC0/led-mic ->
/sys/devices/virtual/sound/ctl-led/mic/card0
Signed-off-by: Jaroslav Kysela <perex at perex.cz>
---
sound/core/control_led.c | 366 ++++++++++++++++++++++++++++++++++++++-
1 file changed, 362 insertions(+), 4 deletions(-)
diff --git a/sound/core/control_led.c b/sound/core/control_led.c
index dfa51d8461e1..d4fb8b873f34 100644
--- a/sound/core/control_led.c
+++ b/sound/core/control_led.c
@@ -24,6 +24,12 @@ enum snd_ctl_led_mode {
MODE_ON,
};
+struct snd_ctl_led_card {
+ struct device dev;
+ int number;
+ struct snd_ctl_led *led;
+};
+
struct snd_ctl_led {
struct device dev;
struct list_head controls;
@@ -31,6 +37,7 @@ struct snd_ctl_led {
unsigned int group;
enum led_audio trigger_type;
enum snd_ctl_led_mode mode;
+ struct snd_ctl_led_card *cards[SNDRV_CARDS];
};
struct snd_ctl_led_ctl {
@@ -58,6 +65,9 @@ static struct snd_ctl_led snd_ctl_leds[MAX_LED] = {
},
};
+static void snd_ctl_led_sysfs_add(struct snd_card *card);
+static void snd_ctl_led_sysfs_remove(struct snd_card *card);
+
#define UPDATE_ROUTE(route, cb) \
do { \
int route2 = (cb); \
@@ -222,6 +232,46 @@ static void snd_ctl_led_notify(struct snd_card *card, unsigned int mask,
}
}
+static int snd_ctl_led_set_id(int card_number, struct snd_ctl_elem_id *id,
+ unsigned int group, bool set)
+{
+ struct snd_card *card;
+ struct snd_kcontrol *kctl;
+ struct snd_kcontrol_volatile *vd;
+ unsigned int ioff, access, new_access;
+ int err = 0;
+
+ card = snd_card_ref(card_number);
+ if (card) {
+ down_write(&card->controls_rwsem);
+ kctl = snd_ctl_find_id(card, id);
+ if (kctl) {
+ ioff = snd_ctl_get_ioff(kctl, id);
+ vd = &kctl->vd[ioff];
+ access = vd->access & SNDRV_CTL_ELEM_ACCESS_LED_MASK;
+ if (access != 0 && access != group_to_access(group)) {
+ err = -EXDEV;
+ goto unlock;
+ }
+ new_access = vd->access & ~SNDRV_CTL_ELEM_ACCESS_LED_MASK;
+ if (set)
+ new_access |= group_to_access(group);
+ if (new_access != vd->access) {
+ vd->access = new_access;
+ snd_ctl_led_notify(card, SNDRV_CTL_EVENT_MASK_INFO, kctl, ioff);
+ }
+ } else {
+ err = -ENOENT;
+ }
+unlock:
+ up_write(&card->controls_rwsem);
+ snd_card_unref(card);
+ } else {
+ err = -ENXIO;
+ }
+ return err;
+}
+
static void snd_ctl_led_refresh(void)
{
unsigned int group;
@@ -230,6 +280,12 @@ static void snd_ctl_led_refresh(void)
snd_ctl_led_set_state(NULL, group_to_access(group), NULL, 0);
}
+static void snd_ctl_led_ctl_destroy(struct snd_ctl_led_ctl *lctl)
+{
+ list_del(&lctl->list);
+ kfree(lctl);
+}
+
static void snd_ctl_led_clean(struct snd_card *card)
{
unsigned int group;
@@ -241,13 +297,47 @@ static void snd_ctl_led_clean(struct snd_card *card)
repeat:
list_for_each_entry(lctl, &led->controls, list)
if (!card || lctl->card == card) {
- list_del(&lctl->list);
- kfree(lctl);
+ snd_ctl_led_ctl_destroy(lctl);
goto repeat;
}
}
}
+static int snd_ctl_led_reset(int card_number, unsigned int group)
+{
+ struct snd_card *card;
+ struct snd_ctl_led *led;
+ struct snd_ctl_led_ctl *lctl;
+ struct snd_kcontrol_volatile *vd;
+ bool change = false;
+
+ card = snd_card_ref(card_number);
+ if (!card)
+ return -ENXIO;
+
+ mutex_lock(&snd_ctl_led_mutex);
+ if (!snd_ctl_led_card_valid[card_number]) {
+ mutex_unlock(&snd_ctl_led_mutex);
+ snd_card_unref(card);
+ return -ENXIO;
+ }
+ led = &snd_ctl_leds[group];
+repeat:
+ list_for_each_entry(lctl, &led->controls, list)
+ if (lctl->card == card) {
+ vd = &lctl->kctl->vd[lctl->index_offset];
+ vd->access &= ~group_to_access(group);
+ snd_ctl_led_ctl_destroy(lctl);
+ change = true;
+ goto repeat;
+ }
+ mutex_unlock(&snd_ctl_led_mutex);
+ if (change)
+ snd_ctl_led_set_state(NULL, group_to_access(group), NULL, 0);
+ snd_card_unref(card);
+ return 0;
+}
+
static void snd_ctl_led_register(struct snd_card *card)
{
struct snd_kcontrol *kctl;
@@ -264,10 +354,12 @@ static void snd_ctl_led_register(struct snd_card *card)
for (ioff = 0; ioff < kctl->count; ioff++)
snd_ctl_led_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, kctl, ioff);
snd_ctl_led_refresh();
+ snd_ctl_led_sysfs_add(card);
}
static void snd_ctl_led_disconnect(struct snd_card *card)
{
+ snd_ctl_led_sysfs_remove(card);
mutex_lock(&snd_ctl_led_mutex);
snd_ctl_led_card_valid[card->number] = false;
snd_ctl_led_clean(card);
@@ -349,8 +441,264 @@ static const struct attribute_group *snd_ctl_led_dev_attr_groups[] = {
NULL,
};
+static char *find_eos(char *s)
+{
+ while (*s && *s != ',')
+ s++;
+ if (*s)
+ s++;
+ return s;
+}
+
+static char *parse_uint(char *s, unsigned int *val)
+{
+ unsigned long long res;
+ if (kstrtoull(s, 10, &res))
+ res = 0;
+ *val = res;
+ return find_eos(s);
+}
+
+static char *parse_string(char *s, char *val, size_t val_size)
+{
+ if (*s == '"' || *s == '\'') {
+ char c = *s;
+ s++;
+ while (*s && *s != c) {
+ if (val_size > 1) {
+ *val++ = *s;
+ val_size--;
+ }
+ s++;
+ }
+ } else {
+ while (*s && *s != ',') {
+ if (val_size > 1) {
+ *val++ = *s;
+ val_size--;
+ }
+ s++;
+ }
+ }
+ *val = '\0';
+ if (*s)
+ s++;
+ return s;
+}
+
+static char *parse_iface(char *s, unsigned int *val)
+{
+ if (!strncasecmp(s, "card", 4))
+ *val = SNDRV_CTL_ELEM_IFACE_CARD;
+ else if (!strncasecmp(s, "mixer", 5))
+ *val = SNDRV_CTL_ELEM_IFACE_MIXER;
+ return find_eos(s);
+}
+
+/*
+ * These types of input strings are accepted:
+ *
+ * unsigned integer - numid (equivaled to numid=UINT)
+ * string - basic mixer name (equivalent to iface=MIXER,name=STR)
+ * numid=UINT
+ * [iface=MIXER,][device=UINT,][subdevice=UINT,]name=STR[,index=UINT]
+ */
+static ssize_t set_led_id(struct snd_ctl_led_card *led_card, const char *buf, size_t count,
+ bool attach)
+{
+ char buf2[256], *s;
+ size_t len = max(sizeof(s) - 1, count);
+ struct snd_ctl_elem_id id;
+ int err;
+
+ strncpy(buf2, buf, len);
+ buf2[len] = '\0';
+ memset(&id, 0, sizeof(id));
+ id.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
+ s = buf2;
+ while (*s) {
+ if (!strncasecmp(s, "numid=", 6)) {
+ s = parse_uint(s + 6, &id.numid);
+ } else if (!strncasecmp(s, "iface=", 6)) {
+ s = parse_iface(s + 6, &id.iface);
+ } else if (!strncasecmp(s, "device=", 7)) {
+ s = parse_uint(s + 7, &id.device);
+ } else if (!strncasecmp(s, "subdevice=", 10)) {
+ s = parse_uint(s + 10, &id.subdevice);
+ } else if (!strncasecmp(s, "name=", 5)) {
+ s = parse_string(s + 5, id.name, sizeof(id.name));
+ } else if (!strncasecmp(s, "index=", 6)) {
+ s = parse_uint(s + 6, &id.index);
+ } else if (s == buf2) {
+ while (*s) {
+ if (*s < '0' || *s > '9')
+ break;
+ s++;
+ }
+ if (*s == '\0')
+ parse_uint(buf2, &id.numid);
+ else {
+ for (; *s >= ' '; s++);
+ *s = '\0';
+ strlcpy(id.name, buf2, sizeof(id.name));
+ }
+ break;
+ }
+ if (*s == ',')
+ s++;
+ }
+
+ err = snd_ctl_led_set_id(led_card->number, &id, led_card->led->group, attach);
+ if (err < 0)
+ return err;
+
+ return count;
+}
+
+static ssize_t parse_attach(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct snd_ctl_led_card *led_card = container_of(dev, struct snd_ctl_led_card, dev);
+ return set_led_id(led_card, buf, count, true);
+}
+
+static ssize_t parse_detach(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct snd_ctl_led_card *led_card = container_of(dev, struct snd_ctl_led_card, dev);
+ return set_led_id(led_card, buf, count, false);
+}
+
+static ssize_t ctl_reset(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct snd_ctl_led_card *led_card = container_of(dev, struct snd_ctl_led_card, dev);
+ int err;
+
+ if (count > 0 && buf[0] == '1') {
+ err = snd_ctl_led_reset(led_card->number, led_card->led->group);
+ if (err < 0)
+ return err;
+ }
+ return count;
+}
+
+static ssize_t ctl_list(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct snd_ctl_led_card *led_card = container_of(dev, struct snd_ctl_led_card, dev);
+ struct snd_card *card;
+ struct snd_ctl_led_ctl *lctl;
+ char *buf2 = buf;
+ size_t l;
+
+ card = snd_card_ref(led_card->number);
+ if (!card)
+ return -ENXIO;
+ down_read(&card->controls_rwsem);
+ mutex_lock(&snd_ctl_led_mutex);
+ if (snd_ctl_led_card_valid[led_card->number]) {
+ list_for_each_entry(lctl, &led_card->led->controls, list)
+ if (lctl->card == card) {
+ if (buf2 - buf > PAGE_SIZE - 16)
+ break;
+ if (buf2 != buf)
+ *buf2++ = ' ';
+ l = scnprintf(buf2, 15, "%u",
+ lctl->kctl->id.numid +
+ lctl->index_offset);
+ buf2[l] = '\0';
+ buf2 += l + 1;
+ }
+ }
+ mutex_unlock(&snd_ctl_led_mutex);
+ up_read(&card->controls_rwsem);
+ snd_card_unref(card);
+ return buf2 - buf;
+}
+
+static DEVICE_ATTR(attach, 0200, NULL, parse_attach);
+static DEVICE_ATTR(detach, 0200, NULL, parse_detach);
+static DEVICE_ATTR(reset, 0200, NULL, ctl_reset);
+static DEVICE_ATTR(list, 0444, ctl_list, NULL);
+
+static struct attribute *snd_ctl_led_card_attrs[] = {
+ &dev_attr_attach.attr,
+ &dev_attr_detach.attr,
+ &dev_attr_reset.attr,
+ &dev_attr_list.attr,
+ NULL,
+};
+
+static const struct attribute_group snd_ctl_led_card_attr_group = {
+ .attrs = snd_ctl_led_card_attrs,
+};
+
+static const struct attribute_group *snd_ctl_led_card_attr_groups[] = {
+ &snd_ctl_led_card_attr_group,
+ NULL,
+};
+
static struct device snd_ctl_led_dev;
+static void snd_ctl_led_sysfs_add(struct snd_card *card)
+{
+ unsigned int group;
+ struct snd_ctl_led_card *led_card;
+ struct snd_ctl_led *led;
+ char link_name[32];
+
+ for (group = 0; group < MAX_LED; group++) {
+ led = &snd_ctl_leds[group];
+ led_card = kzalloc(sizeof(*led_card), GFP_KERNEL);
+ if (!led_card)
+ goto cerr2;
+ led_card->number = card->number;
+ led_card->led = led;
+ device_initialize(&led_card->dev);
+ if (dev_set_name(&led_card->dev, "card%d", card->number) < 0)
+ goto cerr;
+ led_card->dev.parent = &led->dev;
+ led_card->dev.groups = snd_ctl_led_card_attr_groups;
+ if (device_add(&led_card->dev))
+ goto cerr;
+ led->cards[card->number] = led_card;
+ snprintf(link_name, sizeof(link_name), "led-%s", led->name);
+ WARN(sysfs_create_link(&card->ctl_dev.kobj, &led_card->dev.kobj, link_name),
+ "can't create symlink to controlC%i device\n", card->number);
+ WARN(sysfs_create_link(&led_card->dev.kobj, &card->card_dev.kobj, "card"),
+ "can't create symlink to card%i\n", card->number);
+
+ continue;
+cerr:
+ put_device(&led_card->dev);
+cerr2:
+ printk(KERN_ERR "snd_ctl_led: unable to add card%d", card->number);
+ kfree(led_card);
+ }
+}
+
+static void snd_ctl_led_sysfs_remove(struct snd_card *card)
+{
+ unsigned int group;
+ struct snd_ctl_led_card *led_card;
+ struct snd_ctl_led *led;
+ char link_name[32];
+
+ for (group = 0; group < MAX_LED; group++) {
+ led = &snd_ctl_leds[group];
+ led_card = led->cards[card->number];
+ if (!led_card)
+ continue;
+ snprintf(link_name, sizeof(link_name), "led-%s", led->name);
+ sysfs_remove_link(&card->ctl_dev.kobj, link_name);
+ sysfs_remove_link(&led_card->dev.kobj, "card");
+ device_del(&led_card->dev);
+ kfree(led_card);
+ led->cards[card->number] = NULL;
+ }
+}
+
/*
* Control layer registration
*/
@@ -397,14 +745,24 @@ static int __init snd_ctl_led_init(void)
static void __exit snd_ctl_led_exit(void)
{
struct snd_ctl_led *led;
- unsigned int group;
+ struct snd_card *card;
+ unsigned int group, card_number;
+ snd_ctl_disconnect_layer(&snd_ctl_led_lops);
+ for (card_number = 0; card_number < SNDRV_CARDS; card_number++) {
+ if (!snd_ctl_led_card_valid[card_number])
+ continue;
+ card = snd_card_ref(card_number);
+ if (card) {
+ snd_ctl_led_sysfs_remove(card);
+ snd_card_unref(card);
+ }
+ }
for (group = 0; group < MAX_LED; group++) {
led = &snd_ctl_leds[group];
device_del(&led->dev);
}
device_del(&snd_ctl_led_dev);
- snd_ctl_disconnect_layer(&snd_ctl_led_lops);
snd_ctl_led_clean(NULL);
}
--
2.29.2
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