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ALSA: Add kernel-doc comments to vmaster stuff

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Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2009-02-09 14:47:19 +01:00
parent f5b1db6342
commit 79c7cdd544
3 changed files with 50 additions and 2 deletions
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4
Documentation/sound/alsa/DocBook/alsa-driver-api.tmpl
View file

@ -71,6 +71,10 @@
!Esound/pci/ac97/ac97_codec.c
!Esound/pci/ac97/ac97_pcm.c
</sect1>
<sect1><title>Virtual Master Control API</title>
!Esound/core/vmaster.c
!Iinclude/sound/control.h
</sect1>
</chapter>
<chapter><title>MIDI API</title>
<sect1><title>Raw MIDI API</title>

32
include/sound/control.h
View file

@ -176,12 +176,44 @@ int _snd_ctl_add_slave(struct snd_kcontrol *master, struct snd_kcontrol *slave,
/* 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)

16
sound/core/vmaster.c
View file

@ -340,8 +340,20 @@ static void master_free(struct snd_kcontrol *kcontrol)
}
/*
* Create a virtual master control with the given name
/**
* snd_ctl_make_virtual_master - Create a virtual master control
* @name: name string of the control element to create
* @tlv: optional TLV int array for dB information
*
* Creates a virtual matster control with the given name string.
* Returns the created control element, or NULL for errors (ENOMEM).
*
* After creating a vmaster element, you can add the slave controls
* via snd_ctl_add_slave() or snd_ctl_add_slave_uncached().
*
* The optional argument @tlv can be used to specify the TLV information
* for dB scale of the master control. It should be a single element
* with #SNDRV_CTL_TLVT_DB_SCALE type, and should be the max 0dB.
*/
struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,
const unsigned int *tlv)