xref: /linux/Documentation/sound/cards/img-spdif-in.rst (revision 9095bf25ea08135a5b74875dd0e3eeaddc4218a0)
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2Imagination Technologies SPDIF Input Controllers
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4
5The Imagination Technologies SPDIF Input controller contains the following
6controls:
7
8* name='IEC958 Capture Mask',index=0
9
10This control returns a mask that shows which of the IEC958 status bits
11can be read using the 'IEC958 Capture Default' control.
12
13* name='IEC958 Capture Default',index=0
14
15This control returns the status bits contained within the SPDIF stream that
16is being received. The 'IEC958 Capture Mask' shows which bits can be read
17from this control.
18
19* name='SPDIF In Multi Frequency Acquire',index=0
20* name='SPDIF In Multi Frequency Acquire',index=1
21* name='SPDIF In Multi Frequency Acquire',index=2
22* name='SPDIF In Multi Frequency Acquire',index=3
23
24This control is used to attempt acquisition of up to four different sample
25rates. The active rate can be obtained by reading the 'SPDIF In Lock Frequency'
26control.
27
28When the value of this control is set to {0,0,0,0}, the rate given to hw_params
29will determine the single rate the block will capture. Else, the rate given to
30hw_params will be ignored, and the block will attempt capture for each of the
31four sample rates set here.
32
33If less than four rates are required, the same rate can be specified more than
34once
35
36* name='SPDIF In Lock Frequency',index=0
37
38This control returns the active capture rate, or 0 if a lock has not been
39acquired
40
41* name='SPDIF In Lock TRK',index=0
42
43This control is used to modify the locking/jitter rejection characteristics
44of the block. Larger values increase the locking range, but reduce jitter
45rejection.
46
47* name='SPDIF In Lock Acquire Threshold',index=0
48
49This control is used to change the threshold at which a lock is acquired.
50
51* name='SPDIF In Lock Release Threshold',index=0
52
53This control is used to change the threshold at which a lock is released.
54