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// 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)
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