ALSA: led control - add sysfs kcontrol LED marking layer

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@perex.cz>
Link: https://lore.kernel.org/r/20210317172945.842280-7-perex@perex.cz
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Jaroslav Kysela 2021-03-17 18:29:45 +01:00 committed by Takashi Iwai
parent cb17fe0045
commit a135dfb5de

View file

@ -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);
}