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Commit 9fb6198e authored by Jaroslav Kysela's avatar Jaroslav Kysela Committed by Takashi Iwai
Browse files

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: default avatarJaroslav Kysela <perex@perex.cz>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent f21f237c

sound/core/init.c

+65 −1
Original line number Diff line number Diff line
@@ -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;

}