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| author | Clemens Ladisch <clemens@ladisch.de> | 2011-11-20 16:22:24 +0100 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2016-01-22 21:40:04 +0000 |
| commit | 56929bfbedb1fa88408d74e5d8a3a848020aa89f (patch) | |
| tree | d675fb6e9dba1d8f672a420c6be9b9da3de2fd07 /include | |
| parent | b23324ffa8ef8cc96865db76db938905d61d949a (diff) | |
| download | lwn-56929bfbedb1fa88408d74e5d8a3a848020aa89f.tar.gz lwn-56929bfbedb1fa88408d74e5d8a3a848020aa89f.zip | |
ALSA: tlv: compute TLV_*_ITEM lengths automatically
commit b5b9eb546762c4015c67c31364a6ec6f83fd2ada upstream.
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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'include')
| -rw-r--r-- | include/sound/tlv.h | 20 |
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) } |