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authorDavid S. Miller <davem@davemloft.net>2009-03-26 15:23:24 -0700
committerDavid S. Miller <davem@davemloft.net>2009-03-26 15:23:24 -0700
commit08abe18af1f78ee80c3c3a5ac47c3e0ae0beadf6 (patch)
tree2be39bf8942edca1bcec735145e144a682ca9cd3 /include/sound/control.h
parentf0de70f8bb56952f6e016a65a8a8d006918f5bf6 (diff)
parent0384e2959127a56d0640505d004d8dd92f9c29f5 (diff)
Merge branch 'master' of /home/davem/src/GIT/linux-2.6/
Conflicts: drivers/net/wimax/i2400m/usb-notif.c
Diffstat (limited to 'include/sound/control.h')
-rw-r--r--include/sound/control.h52
1 files changed, 50 insertions, 2 deletions
diff --git a/include/sound/control.h b/include/sound/control.h
index 4721b4bba05..ef96f07aa03 100644
--- a/include/sound/control.h
+++ b/include/sound/control.h
@@ -171,6 +171,54 @@ int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
*/
struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,
const unsigned int *tlv);
-int snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave);
-
+int _snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave,
+ unsigned int flags);
+/* optional flags for slave */
+#define SND_CTL_SLAVE_NEED_UPDATE (1 << 0)
+
+/**
+ * snd_ctl_add_slave - Add a virtual slave control
+ * @master: vmaster element
+ * @slave: slave element to add
+ *
+ * Add a virtual slave control to the given master element created via
+ * snd_ctl_create_virtual_master() beforehand.
+ * Returns zero if successful or a negative error code.
+ *
+ * All slaves must be the same type (returning the same information
+ * via info callback). The fucntion doesn't check it, so it's your
+ * responsibility.
+ *
+ * Also, some additional limitations:
+ * at most two channels,
+ * logarithmic volume control (dB level) thus no linear volume,
+ * master can only attenuate the volume without gain
+ */
+static inline int
+snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave)
+{
+ return _snd_ctl_add_slave(master, slave, 0);
+}
+
+/**
+ * snd_ctl_add_slave_uncached - Add a virtual slave control
+ * @master: vmaster element
+ * @slave: slave element to add
+ *
+ * Add a virtual slave control to the given master.
+ * Unlike snd_ctl_add_slave(), the element added via this function
+ * is supposed to have volatile values, and get callback is called
+ * at each time quried from the master.
+ *
+ * When the control peeks the hardware values directly and the value
+ * can be changed by other means than the put callback of the element,
+ * this function should be used to keep the value always up-to-date.
+ */
+static inline int
+snd_ctl_add_slave_uncached(struct snd_kcontrol *master,
+ struct snd_kcontrol *slave)
+{
+ return _snd_ctl_add_slave(master, slave, SND_CTL_SLAVE_NEED_UPDATE);
+}
+
#endif /* __SOUND_CONTROL_H */