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ALSA: add /sys/class/sound/card#/id (r/w) and card#/number (r/o) files 

For udev, we need a way to rename soundcard names. The soundcard numbers
(indexes) are hardwired but we have a text identification which can be
changed at run-time. The ALSA user space tools already allow using of
this text identification.

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Jaroslav Kysela 2008-11-11 16:51:02 +01:00 committed by Takashi Iwai
parent f21f237cf5
commit 9fb6198e8c
1 changed files with 65 additions and 1 deletions
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66
sound/core/init.c
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@ -533,6 +533,64 @@ static void choose_default_id(struct snd_card *card)
}
}
#ifndef CONFIG_SYSFS_DEPRECATED
static ssize_t
card_id_show_attr(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct snd_card *card = dev_get_drvdata(dev);
return snprintf(buf, PAGE_SIZE, "%s\n", card ? card->id : "(null)");
}
static ssize_t
card_id_store_attr(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct snd_card *card = dev_get_drvdata(dev);
char buf1[sizeof(card->id)];
size_t copy = count > sizeof(card->id) - 1 ?
sizeof(card->id) - 1 : count;
size_t idx;
int c;
for (idx = 0; idx < copy; idx++) {
c = buf[idx];
if (!isalnum(c) && c != '_' && c != '-')
return -EINVAL;
}
memcpy(buf1, buf, copy);
buf1[copy] = '\0';
mutex_lock(&snd_card_mutex);
if (!snd_info_check_reserved_words(buf1)) {
__exist:
mutex_unlock(&snd_card_mutex);
return -EEXIST;
}
for (idx = 0; idx < snd_ecards_limit; idx++) {
if (snd_cards[idx] && !strcmp(snd_cards[idx]->id, buf1))
goto __exist;
}
strcpy(card->id, buf1);
mutex_unlock(&snd_card_mutex);
return count;
}
static struct device_attribute card_id_attrs =
__ATTR(id, S_IRUGO | S_IWUSR, card_id_show_attr, card_id_store_attr);
static ssize_t
card_number_show_attr(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct snd_card *card = dev_get_drvdata(dev);
return snprintf(buf, PAGE_SIZE, "%i\n", card ? card->number : -1);
}
static struct device_attribute card_number_attrs =
__ATTR(number, S_IRUGO, card_number_show_attr, NULL);
#endif /* CONFIG_SYSFS_DEPRECATED */
/**
* snd_card_register - register the soundcard
* @card: soundcard structure
@ -553,7 +611,7 @@ int snd_card_register(struct snd_card *card)
#ifndef CONFIG_SYSFS_DEPRECATED
if (!card->card_dev) {
card->card_dev = device_create(sound_class, card->dev,
MKDEV(0, 0), NULL,
MKDEV(0, 0), card,
"card%i", card->number);
if (IS_ERR(card->card_dev))
card->card_dev = NULL;
@ -575,6 +633,12 @@ int snd_card_register(struct snd_card *card)
#if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
if (snd_mixer_oss_notify_callback)
snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_REGISTER);
#endif
#ifndef CONFIG_SYSFS_DEPRECATED
if (card->card_dev) {
device_create_file(card->card_dev, &card_id_attrs);
device_create_file(card->card_dev, &card_number_attrs);
}
#endif
return 0;
}