From 42750b04c5baa7c5ffdf0a8be2b9b320efdf069f Mon Sep 17 00:00:00 2001 From: Jaroslav Kysela Date: Thu, 1 Jun 2006 18:34:01 +0200 Subject: [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 Signed-off-by: Jaroslav Kysela --- include/sound/tlv.h | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 include/sound/tlv.h (limited to 'include/sound/tlv.h') diff --git a/include/sound/tlv.h b/include/sound/tlv.h new file mode 100644 index 00000000000..b826e1df1da --- /dev/null +++ b/include/sound/tlv.h @@ -0,0 +1,43 @@ +#ifndef __SOUND_TLV_H +#define __SOUND_TLV_H + +/* + * Advanced Linux Sound Architecture - ALSA - Driver + * Copyright (c) 2006 by Jaroslav Kysela + * + * + * 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 */ -- cgit v1.2.3-70-g09d2