linux/include/sound/tlv.h
Jaroslav Kysela 42750b04c5 [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>
2006-09-23 10:36:42 +02:00

44 lines
1.5 KiB
C

#ifndef __SOUND_TLV_H
#define __SOUND_TLV_H
/*
* Advanced Linux Sound Architecture - ALSA - Driver
* Copyright (c) 2006 by Jaroslav Kysela <perex@suse.cz>
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
/*
* TLV structure is right behind the struct snd_ctl_tlv:
* unsigned int type - see SNDRV_CTL_TLVT_*
* unsigned int length
* .... data aligned to sizeof(unsigned int), use
* block_length = (length + (sizeof(unsigned int) - 1)) &
* ~(sizeof(unsigned int) - 1)) ....
*/
#define SNDRV_CTL_TLVT_CONTAINER 0 /* one level down - group of TLVs */
#define SNDRV_CTL_TLVT_DB_SCALE 1 /* dB scale */
#define DECLARE_TLV_DB_SCALE(name, min, step, mute) \
unsigned int name[] = { \
SNDRV_CTL_TLVT_DB_SCALE, 2 * sizeof(unsigned int), \
(min), ((step) & 0xffff) | ((mute) ? 0x10000 : 0) \
}
#endif /* __SOUND_TLV_H */