[PATCH] ASoC: nau8315: add codec driver

[CTLIN0]

On 2020/11/2 下午 10:42, Pierre-Louis Bossart wrote:
>
>> +struct nau8315_priv {
>> +    struct gpio_desc *enable;
>> +    int enpin_switch;
>> +};
>> +
>> +static int nau8315_daiops_trigger(struct snd_pcm_substream *substream,
>> +        int cmd, struct snd_soc_dai *dai)
>> +{
>> +    struct snd_soc_component *component = dai->component;
>> +    struct nau8315_priv *nau8315 =
>> +        snd_soc_component_get_drvdata(component);
>> +
>> +    if (!nau8315->enable)
>> +        return 0;
>> +
>> +    switch (cmd) {
>> +    case SNDRV_PCM_TRIGGER_START:
>> +    case SNDRV_PCM_TRIGGER_RESUME:
>> +    case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
>> +        if (nau8315->enpin_switch) {
>> +            gpiod_set_value(nau8315->enable, 1);
>> +            dev_dbg(component->dev, "set enable to 1");
>> +        }
>
> I know the code is modeled after max98357a.c but I keep wondering if
> this enpin_switch state is actually useful for anything.
>
> Is there actually a case where the trigger happens before the
> DAPM_POST_PMU event handled below [1]?
>
Yes. Currently, I set event on DAPM just with SND_SOC_DAPM_POST_PMU or
SND_SOC_DAPM_POST_PMD, so these two specified events will be caught.

If I set SND_SOC_DAPM_PRE_PMU event, it can be caught, too.

>> +        break;
>> +    case SNDRV_PCM_TRIGGER_STOP:
>> +    case SNDRV_PCM_TRIGGER_SUSPEND:
>> +    case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
>> +        gpiod_set_value(nau8315->enable, 0);
>> +        dev_dbg(component->dev, "set enable to 0");
>> +        break;
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +static int nau8315_enpin_event(struct snd_soc_dapm_widget *w,
>> +        struct snd_kcontrol *kcontrol, int event)
>> +{
>> +    struct snd_soc_component *component =
>> +        snd_soc_dapm_to_component(w->dapm);
>> +    struct nau8315_priv *nau8315 =
>> +        snd_soc_component_get_drvdata(component);
>> +
>
> [1]
>
>> +    if (event & SND_SOC_DAPM_POST_PMU)
>> +        nau8315->enpin_switch = 1;
>> +    else if (event & SND_SOC_DAPM_POST_PMD)
>> +        nau8315->enpin_switch = 0;
>
> And even if this variable was useful, for symmetry should it be
> PRE_PMU/POST_PMD?
>
Yes, I agree with your opinion.

 From the above description, I suppose you might want to point whether
the dapm widget of EN_PIN is redundant, right? That's a reason the
physical hardware pin is set to high/low in trigger function point of
snd_soc_dai_ops, it always occurred after dapm event.
If yes, from my current platform of verification, even if the dapm
widget of EN_PIN is removed, the result of sound output is same yet.
Maybe the first version, I should submit a simpler version.

>> +
>> +    return 0;
>> +}
>> +
>> +static const struct snd_soc_dapm_widget nau8315_dapm_widgets[] = {
>> +    SND_SOC_DAPM_OUTPUT("Speaker"),
>> +    SND_SOC_DAPM_OUT_DRV_E("EN_Pin", SND_SOC_NOPM, 0, 0, NULL, 0,
>> +            nau8315_enpin_event,
>> +            SND_SOC_DAPM_POST_PMU | SND_SOC_DAPM_POST_PMD),
>> +};
>> +
>> +static const struct snd_soc_dapm_route nau8315_dapm_routes[] = {
>> +    {"EN_Pin", NULL, "HiFi Playback"},
>> +    {"Speaker", NULL, "EN_Pin"},
>> +};
>> +
>> +static const struct snd_soc_component_driver
>> nau8315_component_driver = {
>> +    .dapm_widgets        = nau8315_dapm_widgets,
>> +    .num_dapm_widgets    = ARRAY_SIZE(nau8315_dapm_widgets),
>> +    .dapm_routes        = nau8315_dapm_routes,
>> +    .num_dapm_routes    = ARRAY_SIZE(nau8315_dapm_routes),
>> +    .idle_bias_on        = 1,
>> +    .use_pmdown_time    = 1,
>
> is this necessary? This has the side effect of powering-down
> immediately instead of after a delay.
Yes, I follow most of drivers to use this flag.
>
>> +    .endianness        = 1,
>> +    .non_legacy_dai_naming    = 1,
>> +};
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