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Viewing changes to alsa-kernel/Documentation/soc/codec.txt

  • Committer: Bazaar Package Importer
  • Author(s): Luke Yelavich
  • Date: 2011-02-21 18:06:40 UTC
  • mfrom: (1.1.15 upstream)
  • Revision ID: james.westby@ubuntu.com-20110221180640-a8p2yxtvgf7xbxub
Tags: 1.0.24+dfsg-0ubuntu1
* New upstream release
* Refreshed patches:
  - distinguish_kernel_makefile_and_source_dirs.patch
  - debian_dfsg_configure.patch
* debian/control: Update Vcs-bzr field to point to new branch location

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alsa-kernel/Documentation/soc/codec.txt
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1 - Codec DAI and PCM configuration
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-----------------------------------
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Each codec driver must have a struct snd_soc_codec_dai to define its DAI and
 
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Each codec driver must have a struct snd_soc_dai_driver to define its DAI and
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PCM capabilities and operations. This struct is exported so that it can be
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registered with the core by your machine driver.
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e.g.
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struct snd_soc_codec_dai wm8731_dai = {
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        .name = "WM8731",
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        /* playback capabilities */
 
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static struct snd_soc_dai_ops wm8731_dai_ops = {
 
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        .prepare        = wm8731_pcm_prepare,
 
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        .hw_params      = wm8731_hw_params,
 
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        .shutdown       = wm8731_shutdown,
 
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        .digital_mute   = wm8731_mute,
 
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        .set_sysclk     = wm8731_set_dai_sysclk,
 
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        .set_fmt        = wm8731_set_dai_fmt,
 
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};
 
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struct snd_soc_dai_driver wm8731_dai = {
 
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        .name = "wm8731-hifi",
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        .playback = {
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                .stream_name = "Playback",
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                .channels_min = 1,
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                .channels_max = 2,
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                .rates = WM8731_RATES,
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                .formats = WM8731_FORMATS,},
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        /* capture capabilities */
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        .capture = {
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                .stream_name = "Capture",
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                .channels_min = 1,
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                .channels_max = 2,
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                .rates = WM8731_RATES,
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                .formats = WM8731_FORMATS,},
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        /* pcm operations - see section 4 below */
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        .ops = {
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                .prepare = wm8731_pcm_prepare,
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                .hw_params = wm8731_hw_params,
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                .shutdown = wm8731_shutdown,
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        },
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        /* DAI operations - see DAI.txt */
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        .dai_ops = {
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                .digital_mute = wm8731_mute,
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                .set_sysclk = wm8731_set_dai_sysclk,
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                .set_fmt = wm8731_set_dai_fmt,
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        }
 
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        .ops = &wm8731_dai_ops,
 
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        .symmetric_rates = 1,
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};
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EXPORT_SYMBOL_GPL(wm8731_dai);
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2 - Codec control IO
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};
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Please refer to the ALSA driver PCM documentation for details.
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http://www.alsa-project.org/~iwai/writing-an-alsa-driver/c436.htm
 
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http://www.alsa-project.org/~iwai/writing-an-alsa-driver/
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5 - DAPM description.
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i.e.
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static int wm8974_mute(struct snd_soc_codec *codec,
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        struct snd_soc_codec_dai *dai, int mute)
 
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static int wm8974_mute(struct snd_soc_dai *dai, int mute)
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{
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        u16 mute_reg = wm8974_read_reg_cache(codec, WM8974_DAC) & 0xffbf;
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        if(mute)
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                wm8974_write(codec, WM8974_DAC, mute_reg | 0x40);
 
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        struct snd_soc_codec *codec = dai->codec;
 
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        u16 mute_reg = snd_soc_read(codec, WM8974_DAC) & 0xffbf;
 
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        if (mute)
 
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                snd_soc_write(codec, WM8974_DAC, mute_reg | 0x40);
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        else
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                wm8974_write(codec, WM8974_DAC, mute_reg);
 
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                snd_soc_write(codec, WM8974_DAC, mute_reg);
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        return 0;
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}