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authorJaroslav Kysela <perex@suse.cz>2006-06-01 18:34:01 +0200
committerJaroslav Kysela <perex@suse.cz>2006-09-23 10:36:42 +0200
commit42750b04c5baa7c5ffdf0a8be2b9b320efdf069f (patch)
tree52aea8f1eeb44405b67bc5b381cce6bc20e2bff6 /sound/core
parent3eeab61aa3ddd3c0bedb7449ada1599de22fdb5a (diff)
[ALSA] Control API - TLV implementation for additional information like dB scale
This patch implements a TLV mechanism to transfer an additional information like dB scale to the user space. The types might be extended in future. Acked-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Jaroslav Kysela <perex@suse.cz>
Diffstat (limited to 'sound/core')
-rw-r--r--sound/core/control.c41
1 files changed, 39 insertions, 2 deletions
diff --git a/sound/core/control.c b/sound/core/control.c
index bb397eaa718..e9c8854d2f7 100644
--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -241,6 +241,7 @@ struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
kctl.info = ncontrol->info;
kctl.get = ncontrol->get;
kctl.put = ncontrol->put;
+ kctl.tlv = ncontrol->tlv;
kctl.private_value = ncontrol->private_value;
kctl.private_data = private_data;
return snd_ctl_new(&kctl, access);
@@ -1067,6 +1068,40 @@ static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
return 0;
}
+static int snd_ctl_tlv_read(struct snd_card *card,
+ struct snd_ctl_tlv __user *_tlv)
+{
+ struct snd_ctl_tlv tlv;
+ struct snd_kcontrol *kctl;
+ unsigned int len;
+ int err = 0;
+
+ if (copy_from_user(&tlv, _tlv, sizeof(tlv)))
+ return -EFAULT;
+ if (tlv.length < sizeof(unsigned int) * 3)
+ return -EINVAL;
+ down_read(&card->controls_rwsem);
+ kctl = snd_ctl_find_numid(card, tlv.numid);
+ if (kctl == NULL) {
+ err = -ENOENT;
+ goto __kctl_end;
+ }
+ if (kctl->tlv == NULL) {
+ err = -ENXIO;
+ goto __kctl_end;
+ }
+ len = kctl->tlv[1] + 2 * sizeof(unsigned int);
+ if (tlv.length < len) {
+ err = -ENOMEM;
+ goto __kctl_end;
+ }
+ if (copy_to_user(_tlv->tlv, kctl->tlv, len))
+ err = -EFAULT;
+ __kctl_end:
+ up_read(&card->controls_rwsem);
+ return err;
+}
+
static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct snd_ctl_file *ctl;
@@ -1086,11 +1121,11 @@ static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg
case SNDRV_CTL_IOCTL_CARD_INFO:
return snd_ctl_card_info(card, ctl, cmd, argp);
case SNDRV_CTL_IOCTL_ELEM_LIST:
- return snd_ctl_elem_list(ctl->card, argp);
+ return snd_ctl_elem_list(card, argp);
case SNDRV_CTL_IOCTL_ELEM_INFO:
return snd_ctl_elem_info_user(ctl, argp);
case SNDRV_CTL_IOCTL_ELEM_READ:
- return snd_ctl_elem_read_user(ctl->card, argp);
+ return snd_ctl_elem_read_user(card, argp);
case SNDRV_CTL_IOCTL_ELEM_WRITE:
return snd_ctl_elem_write_user(ctl, argp);
case SNDRV_CTL_IOCTL_ELEM_LOCK:
@@ -1105,6 +1140,8 @@ static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg
return snd_ctl_elem_remove(ctl, argp);
case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
return snd_ctl_subscribe_events(ctl, ip);
+ case SNDRV_CTL_IOCTL_TLV_READ:
+ return snd_ctl_tlv_read(card, argp);
case SNDRV_CTL_IOCTL_POWER:
return -ENOPROTOOPT;
case SNDRV_CTL_IOCTL_POWER_STATE: