[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>
diff --git a/include/sound/asound.h b/include/sound/asound.h
index 41885f4..76a2040 100644
--- a/include/sound/asound.h
+++ b/include/sound/asound.h
@@ -688,7 +688,7 @@
* *
****************************************************************************/
-#define SNDRV_CTL_VERSION SNDRV_PROTOCOL_VERSION(2, 0, 3)
+#define SNDRV_CTL_VERSION SNDRV_PROTOCOL_VERSION(2, 0, 4)
struct snd_ctl_card_info {
int card; /* card number */
@@ -818,6 +818,12 @@
unsigned char reserved[128-sizeof(struct timespec)];
};
+struct snd_ctl_tlv {
+ unsigned int numid; /* control element numeric identification */
+ unsigned int length; /* in bytes aligned to 4 */
+ unsigned int tlv[0]; /* first TLV */
+};
+
enum {
SNDRV_CTL_IOCTL_PVERSION = _IOR('U', 0x00, int),
SNDRV_CTL_IOCTL_CARD_INFO = _IOR('U', 0x01, struct snd_ctl_card_info),
@@ -831,6 +837,7 @@
SNDRV_CTL_IOCTL_ELEM_ADD = _IOWR('U', 0x17, struct snd_ctl_elem_info),
SNDRV_CTL_IOCTL_ELEM_REPLACE = _IOWR('U', 0x18, struct snd_ctl_elem_info),
SNDRV_CTL_IOCTL_ELEM_REMOVE = _IOWR('U', 0x19, struct snd_ctl_elem_id),
+ SNDRV_CTL_IOCTL_TLV_READ = _IOWR('U', 0x1a, struct snd_ctl_tlv),
SNDRV_CTL_IOCTL_HWDEP_NEXT_DEVICE = _IOWR('U', 0x20, int),
SNDRV_CTL_IOCTL_HWDEP_INFO = _IOR('U', 0x21, struct snd_hwdep_info),
SNDRV_CTL_IOCTL_PCM_NEXT_DEVICE = _IOR('U', 0x30, int),