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>
diff --git a/sound/core/init.c b/sound/core/init.c
index b47ff8b..5ff297d 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -533,6 +533,64 @@
}
}
+#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 @@
#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;
@@ -576,6 +634,12 @@
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;
}
