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authorClemens Ladisch <clemens@ladisch.de>2011-11-20 16:22:24 +0100
committerTakashi Iwai <tiwai@suse.de>2012-07-16 10:02:10 +0200
commitb5b9eb546762c4015c67c31364a6ec6f83fd2ada (patch)
tree51915b26a33c7bafb68b9759856129798a403c8a /include/sound/tlv.h
parent1464189f8c2a5341722437ef916786afaf241c44 (diff)
downloadlinux-b5b9eb546762c4015c67c31364a6ec6f83fd2ada.tar.bz2
ALSA: tlv: compute TLV_*_ITEM lengths automatically
Add helper macros with a little bit of preprocessor magic to automatically compute the length of a TLV item. This lets us avoid having to compute this by hand, and will allow to use items that do not use a fixed length. Signed-off-by: Clemens Ladisch <clemens@ladisch.de> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'include/sound/tlv.h')
-rw-r--r--include/sound/tlv.h20
1 files changed, 12 insertions, 8 deletions
diff --git a/include/sound/tlv.h b/include/sound/tlv.h
index 7067e2dfb0b9..137d1654e8d6 100644
--- a/include/sound/tlv.h
+++ b/include/sound/tlv.h
@@ -38,21 +38,26 @@
#define SNDRV_CTL_TLVT_DB_MINMAX 4 /* dB scale with min/max */
#define SNDRV_CTL_TLVT_DB_MINMAX_MUTE 5 /* dB scale with min/max with mute */
+#define TLV_ITEM(type, ...) \
+ (type), TLV_LENGTH(__VA_ARGS__), __VA_ARGS__
+#define TLV_LENGTH(...) \
+ ((unsigned int)sizeof((const unsigned int[]) { __VA_ARGS__ }))
+
#define TLV_DB_SCALE_MASK 0xffff
#define TLV_DB_SCALE_MUTE 0x10000
#define TLV_DB_SCALE_ITEM(min, step, mute) \
- SNDRV_CTL_TLVT_DB_SCALE, 2 * sizeof(unsigned int), \
- (min), ((step) & TLV_DB_SCALE_MASK) | ((mute) ? TLV_DB_SCALE_MUTE : 0)
+ TLV_ITEM(SNDRV_CTL_TLVT_DB_SCALE, \
+ (min), \
+ ((step) & TLV_DB_SCALE_MASK) | \
+ ((mute) ? TLV_DB_SCALE_MUTE : 0))
#define DECLARE_TLV_DB_SCALE(name, min, step, mute) \
unsigned int name[] = { TLV_DB_SCALE_ITEM(min, step, mute) }
/* dB scale specified with min/max values instead of step */
#define TLV_DB_MINMAX_ITEM(min_dB, max_dB) \
- SNDRV_CTL_TLVT_DB_MINMAX, 2 * sizeof(unsigned int), \
- (min_dB), (max_dB)
+ TLV_ITEM(SNDRV_CTL_TLVT_DB_MINMAX, (min_dB), (max_dB))
#define TLV_DB_MINMAX_MUTE_ITEM(min_dB, max_dB) \
- SNDRV_CTL_TLVT_DB_MINMAX_MUTE, 2 * sizeof(unsigned int), \
- (min_dB), (max_dB)
+ TLV_ITEM(SNDRV_CTL_TLVT_DB_MINMAX_MUTE, (min_dB), (max_dB))
#define DECLARE_TLV_DB_MINMAX(name, min_dB, max_dB) \
unsigned int name[] = { TLV_DB_MINMAX_ITEM(min_dB, max_dB) }
#define DECLARE_TLV_DB_MINMAX_MUTE(name, min_dB, max_dB) \
@@ -60,8 +65,7 @@
/* linear volume between min_dB and max_dB (.01dB unit) */
#define TLV_DB_LINEAR_ITEM(min_dB, max_dB) \
- SNDRV_CTL_TLVT_DB_LINEAR, 2 * sizeof(unsigned int), \
- (min_dB), (max_dB)
+ TLV_ITEM(SNDRV_CTL_TLVT_DB_LINEAR, (min_dB), (max_dB))
#define DECLARE_TLV_DB_LINEAR(name, min_dB, max_dB) \
unsigned int name[] = { TLV_DB_LINEAR_ITEM(min_dB, max_dB) }