Hi I am developing the ALSA ASoC part. I has some problem. Now my situation must only use the cpu_dai(AP I2S IP) to half duplex. So, I want to allocate either a capture substream or a playback substream. But ASoC(soc-pcm.c) referred to the playback(capture)_channel_min of codec_dai at the calling snd_pcm_new in soc_new_pcm. I do not want to modify the codec_dai codes. As a result, hope to see below
/dev/snd/pcmC0D0p /dev/snd/pcmC0D1c
attach the ASCII schematic diagram.
Slaves Master +--------------+ +-----------------+ |I2S.0 data_out|---------------|data_in(AIF1) | |I2S.0 bclk |-------+-------|bclk | |I2S.0 lrclk |-------|--+----|lrclk | +--------------+ | | | | +--------------+ | | | AUDIO CODEC | |I2S.1 bclk |-------+ | | | |I2S.1 lrclk |----------+ | | |I2S.1 data_in |---------------|data_out(AIF1) | +--------------+ +-----------------+
attach the i2s and dai_link codes. ----------------------------------------------------------------------------- static struct snd_soc_dai_driver board_i2s_dai_hf_playback_template = { .probe = board_i2s_probe, .playback = { .stream_name = "Playback", .channels_min = 1, .channels_max = 2, .rates = SNDRV_PCM_RATE_8000_96000, .formats = SNDRV_PCM_FMTBIT_S16_LE, }, .ops = &board_i2s_dai_ops, };
static struct snd_soc_dai_driver board_i2s_dai_hf_capture_template = { .probe = board_i2s_probe, .capture = { .stream_name = "Capture", .channels_min = 1, .channels_max = 2, .rates = SNDRV_PCM_RATE_8000_96000, .formats = SNDRV_PCM_FMTBIT_S16_LE, }, .ops = &board_i2s_dai_ops, };
static struct snd_soc_dai_link board_dai[] = { { .name = "audcodec_l0", .stream_name = "audcodec HiFi", .cpu_dai_name = "board-i2s.0", .codec_dai_name = "audcodec-aif1", .platform_name = "board-pcm-audio", .codec_name = "audcodec-codec", .ops = &board_ops, }, { .name = "audcodec_l1", .stream_name = "audcodec HiFi", .cpu_dai_name = "board-i2s.1", .codec_dai_name = "audcodec-aif1", .platform_name = "board-pcm-audio", .codec_name = "audcodec-codec", .ops = &board_ops, }, }; -----------------------------------------------------------------------------
So, I suggest the next diff.
--- a/sound/soc/soc-pcm.c +++ b/sound/soc/soc-pcm.c @@ -2014,9 +2014,11 @@ int soc_new_pcm(struct snd_soc_pcm_runtime *rtd, int num) if (cpu_dai->driver->capture.channels_min) capture = 1; } else { - if (codec_dai->driver->playback.channels_min) + if (codec_dai->driver->playback.channels_min && + cpu_dai->driver->playback.channels_min) playback = 1; - if (codec_dai->driver->capture.channels_min) + if (codec_dai->driver->playback.channels_min && + cpu_dai->driver->playback.channels_min) capture = 1; }
Thanks.