diff options
author | Takashi Iwai <tiwai@suse.de> | 2016-11-11 16:55:29 +0100 |
---|---|---|
committer | Takashi Iwai <tiwai@suse.de> | 2016-11-11 17:35:10 +0100 |
commit | c6ab9e57e84ee015bb9c5de213d9f85e5fd4e085 (patch) | |
tree | adcc13f5864783da1342be5be836447a75d03b54 /Documentation/sound/alsa | |
parent | 76228a2b541daebcc8f6d5d7dd65bdea90d173f1 (diff) | |
download | talos-obmc-linux-c6ab9e57e84ee015bb9c5de213d9f85e5fd4e085.tar.gz talos-obmc-linux-c6ab9e57e84ee015bb9c5de213d9f85e5fd4e085.zip |
ASoC: doc: ReSTize codec_to_codec.txt
Yet another simple conversion from a plain text file.
Renamed to codec-to-codec.rst to align with others.
Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'Documentation/sound/alsa')
-rw-r--r-- | Documentation/sound/alsa/soc/codec_to_codec.txt | 103 |
1 files changed, 0 insertions, 103 deletions
diff --git a/Documentation/sound/alsa/soc/codec_to_codec.txt b/Documentation/sound/alsa/soc/codec_to_codec.txt deleted file mode 100644 index 704a6483652c..000000000000 --- a/Documentation/sound/alsa/soc/codec_to_codec.txt +++ /dev/null @@ -1,103 +0,0 @@ -Creating codec to codec dai link for ALSA dapm -=================================================== - -Mostly the flow of audio is always from CPU to codec so your system -will look as below: - - --------- --------- -| | dai | | - CPU -------> codec -| | | | - --------- --------- - -In case your system looks as below: - --------- - | | - codec-2 - | | - --------- - | - dai-2 - | - ---------- --------- -| | dai-1 | | - CPU -------> codec-1 -| | | | - ---------- --------- - | - dai-3 - | - --------- - | | - codec-3 - | | - --------- - -Suppose codec-2 is a bluetooth chip and codec-3 is connected to -a speaker and you have a below scenario: -codec-2 will receive the audio data and the user wants to play that -audio through codec-3 without involving the CPU.This -aforementioned case is the ideal case when codec to codec -connection should be used. - -Your dai_link should appear as below in your machine -file: - -/* - * this pcm stream only supports 24 bit, 2 channel and - * 48k sampling rate. - */ -static const struct snd_soc_pcm_stream dsp_codec_params = { - .formats = SNDRV_PCM_FMTBIT_S24_LE, - .rate_min = 48000, - .rate_max = 48000, - .channels_min = 2, - .channels_max = 2, -}; - -{ - .name = "CPU-DSP", - .stream_name = "CPU-DSP", - .cpu_dai_name = "samsung-i2s.0", - .codec_name = "codec-2, - .codec_dai_name = "codec-2-dai_name", - .platform_name = "samsung-i2s.0", - .dai_fmt = SND_SOC_DAIFMT_I2S | SND_SOC_DAIFMT_NB_NF - | SND_SOC_DAIFMT_CBM_CFM, - .ignore_suspend = 1, - .params = &dsp_codec_params, -}, -{ - .name = "DSP-CODEC", - .stream_name = "DSP-CODEC", - .cpu_dai_name = "wm0010-sdi2", - .codec_name = "codec-3, - .codec_dai_name = "codec-3-dai_name", - .dai_fmt = SND_SOC_DAIFMT_I2S | SND_SOC_DAIFMT_NB_NF - | SND_SOC_DAIFMT_CBM_CFM, - .ignore_suspend = 1, - .params = &dsp_codec_params, -}, - -Above code snippet is motivated from sound/soc/samsung/speyside.c. - -Note the "params" callback which lets the dapm know that this -dai_link is a codec to codec connection. - -In dapm core a route is created between cpu_dai playback widget -and codec_dai capture widget for playback path and vice-versa is -true for capture path. In order for this aforementioned route to get -triggered, DAPM needs to find a valid endpoint which could be either -a sink or source widget corresponding to playback and capture path -respectively. - -In order to trigger this dai_link widget, a thin codec driver for -the speaker amp can be created as demonstrated in wm8727.c file, it -sets appropriate constraints for the device even if it needs no control. - -Make sure to name your corresponding cpu and codec playback and capture -dai names ending with "Playback" and "Capture" respectively as dapm core -will link and power those dais based on the name. - -Note that in current device tree there is no way to mark a dai_link -as codec to codec. However, it may change in future. |