tinyalsa到alsa asoc driver的调用案例

以下是将TinyALSA转换为ALSA SoC驱动程序的示例代码：

1. 定义硬件描述符

static struct snd_soc_dai_driver my_dai = {
    .name = "my_dai",
    .playback = {
        .stream_name = "Playback",
        .channels_min = 1,
        .channels_max = 2,
        .rates = SNDRV_PCM_RATE_8000_48000,
        .formats = SNDRV_PCM_FMTBIT_S16_LE,
    },
    .capture = {
        .stream_name = "Capture",
        .channels_min = 1,
        .channels_max = 2,
        .rates = SNDRV_PCM_RATE_8000_48000,
        .formats = SNDRV_PCM_FMTBIT_S16_LE,
    },
};

2. 注册SoC驱动程序

static int my_probe(struct platform_device *pdev)
{
    int ret;

    ret = snd_soc_register_dai(&pdev->dev, &my_dai);
    if (ret) {
        dev_err(&pdev->dev, "Failed to register DAI: %d\n", ret);
        return ret;
    }

    return 0;
}

static int my_remove(struct platform_device *pdev)
{
    snd_soc_unregister_dai(&pdev->dev);
    return 0;
}

static const struct of_device_id my_of_match[] = {
    { .compatible = "my,codec" },
    {},
};

MODULE_DEVICE_TABLE(of, my_of_match);

static struct platform_driver my_driver = {
    .driver = {
        .name = "my-driver",
        .owner = THIS_MODULE,
        .of_match_table = my_of_match,
    },
    .probe = my_probe,
    .remove = my_remove,
};

module_platform_driver(my_driver);

3. 在SoC DAI中实现PCM操作

static int my_dai_playback_trigger(struct snd_pcm_substream *substream, int cmd)
{
    struct snd_soc_pcm_runtime *rtd = substream->private_data;
    struct snd_soc_dai *codec_dai = rtd->codec_dai;
    struct snd_soc_dai *cpu_dai = rtd->cpu_dai;

    switch (cmd) {
    case SNDRV_PCM_TRIGGER_START:
        // 实现开始播放的操作
        break;
    case SNDRV_PCM_TRIGGER_STOP:
        // 实现停止播放的操作
        break;
    }

    return 0;
}

static int my_dai_playback_prepare(struct snd_pcm_substream *substream)
{
    return 0;
}

static struct snd_soc_ops my_dai_ops = {
    .trigger = my_dai_playback_trigger,
    .prepare = my_dai_playback_prepare,
};

static struct snd_soc_dai_driver my_dai = {
    .name = "my_dai",
    .playback = {
        .stream_name = "Playback",
        .channels_min = 1,
        .channels_max = 2,
        .rates = SNDRV_PCM_RATE_8000_48000,
        .formats = SNDRV_PCM_FMTBIT_S16_LE,
    },
    .ops = &my_dai_ops,
};

以上是将TinyALSA转换为ALSA SoC驱动程序的示例代码，其中包括定义硬件描述符、注册SoC驱动程序、在SoC DAI中实现PCM操作等步骤。开发者可以根据自己的需求进行修改和扩展。