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| author | Jaroslav Kysela <perex@suse.cz> | 2006-06-01 18:34:01 +0200 |
|---|---|---|
| committer | Jaroslav Kysela <perex@suse.cz> | 2006-09-23 10:36:42 +0200 |
| commit | 42750b04c5baa7c5ffdf0a8be2b9b320efdf069f (patch) | |
| tree | 52aea8f1eeb44405b67bc5b381cce6bc20e2bff6 /sound/core/control.c | |
| parent | 3eeab61aa3ddd3c0bedb7449ada1599de22fdb5a (diff) | |
| download | linux-42750b04c5baa7c5ffdf0a8be2b9b320efdf069f.tar.gz linux-42750b04c5baa7c5ffdf0a8be2b9b320efdf069f.tar.bz2 linux-42750b04c5baa7c5ffdf0a8be2b9b320efdf069f.zip | |
[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/control.c')
| -rw-r--r-- | sound/core/control.c | 41 |
1 files changed, 39 insertions, 2 deletions
diff --git a/sound/core/control.c b/sound/core/control.c index bb397eaa7187..e9c8854d2f7b 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: |