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authorDaniel Mack <daniel@caiaq.de>2010-05-31 14:51:31 +0200
committerTakashi Iwai <tiwai@suse.de>2010-05-31 18:16:59 +0200
commit79f920fbff566ffc9de44111eb1456a3cef310f0 (patch)
tree97b574ee648320163fcbcf8793b23e826fb3a1f8 /sound/usb/card.h
parent7176d37a28fa4ea7e32815007673f578cdcebf51 (diff)
downloadlinux-79f920fbff566ffc9de44111eb1456a3cef310f0.tar.bz2
ALSA: usb-audio: parse clock topology of UAC2 devices
Audio devices which comply to the UAC2 standard can export complex clock topologies in its descriptors and set up links between them. The entities that are defined are - clock sources, which define the end-leafs. - clock selectors, which act as switch to select one out of many possible clocks sources. - clock multipliers, which have an input clock source, and act as clock source again. They can be used to derive one clock from another. All sample rate changes, clock validity queries and the like must go to clock source elements, while clock selectors and multipliers can be used as terminal clock source. The following patch adds a parser for these elements and functions to iterate over the tree and find the leaf nodes (clock sources). The samplerate set functions were moved to the new clock.c file. Signed-off-by: Daniel Mack <daniel@caiaq.de> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb/card.h')
-rw-r--r--sound/usb/card.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/sound/usb/card.h b/sound/usb/card.h
index ed92420c1095..1febf2f23754 100644
--- a/sound/usb/card.h
+++ b/sound/usb/card.h
@@ -25,6 +25,7 @@ struct audioformat {
unsigned int rate_min, rate_max; /* min/max rates */
unsigned int nr_rates; /* number of rate table entries */
unsigned int *rate_table; /* rate table */
+ unsigned char clock; /* associated clock */
};
struct snd_usb_substream;