Re: [PATCH 1/2] ASoc: simple-mux: add idle-state support

["Hendrik v. Raven" <h.v.raven@xxxxxxxxxxxxxx>]

Managed to send an old version. This one will fail when getting the dapm 
handle in the event. Will send a v2, sorry for the noise.

On 14/11/2024 11:38, Hendrik v. Raven wrote:
> So far the mux changes it state immediately, even when not in use. Allow
> overriding this behaviour by specifying an optional idle-state. This
> state is used whenever the mux is powered down, only switching to the
> selected state on power up. If unspecified it defaults to as-is,
> maintaining the previous behaviour.
>
> Signed-off-by: Hendrik v. Raven <h.v.raven@xxxxxxxxxxxxxx>
> ---
>   sound/soc/codecs/simple-mux.c | 40 +++++++++++++++++++++++++++++++++++++++-
>   1 file changed, 39 insertions(+), 1 deletion(-)
>
> diff --git a/sound/soc/codecs/simple-mux.c b/sound/soc/codecs/simple-mux.c
> index 240af0563283e5a9dd720d51a2cefd22bd241faa..e99fea9eedc58954af3b4381873224c280b1edd2 100644
> --- a/sound/soc/codecs/simple-mux.c
> +++ b/sound/soc/codecs/simple-mux.c
> @@ -6,6 +6,7 @@
>   
>   #include <linux/gpio/consumer.h>
>   #include <linux/module.h>
> +#include <linux/mux/driver.h>
>   #include <linux/regulator/consumer.h>
>   #include <sound/soc.h>
>   
> @@ -16,6 +17,7 @@ struct simple_mux {
>   	struct gpio_desc *gpiod_mux;
>   	unsigned int mux;
>   	const char *mux_texts[MUX_TEXT_SIZE];
> +	unsigned int idle_state;
>   	struct soc_enum mux_enum;
>   	struct snd_kcontrol_new mux_mux;
>   	struct snd_soc_dapm_widget mux_widgets[MUX_WIDGET_SIZE];
> @@ -57,6 +59,9 @@ static int simple_mux_control_put(struct snd_kcontrol *kcontrol,
>   
>   	priv->mux = ucontrol->value.enumerated.item[0];
>   
> +	if (priv->idle_state != MUX_IDLE_AS_IS && dapm->bias_level < SND_SOC_BIAS_PREPARE)
> +		return 0;
> +
>   	gpiod_set_value_cansleep(priv->gpiod_mux, priv->mux);
>   
>   	return snd_soc_dapm_mux_update_power(dapm, kcontrol,
> @@ -75,10 +80,34 @@ static unsigned int simple_mux_read(struct snd_soc_component *component,
>   static const struct snd_kcontrol_new simple_mux_mux =
>   	SOC_DAPM_ENUM_EXT("Muxer", simple_mux_enum, simple_mux_control_get, simple_mux_control_put);
>   
> +static int simple_mux_event(struct snd_soc_dapm_widget *w,
> +			    struct snd_kcontrol *kcontrol, int event)
> +{
> +	struct snd_soc_dapm_context *dapm = snd_soc_dapm_kcontrol_dapm(kcontrol);
> +	struct snd_soc_component *c = snd_soc_dapm_to_component(dapm);
> +	struct simple_mux *priv = snd_soc_component_get_drvdata(c);
> +
> +	if (priv->idle_state != MUX_IDLE_AS_IS) {
> +		switch (event) {
> +		case SND_SOC_DAPM_PRE_PMU:
> +			gpiod_set_value_cansleep(priv->gpiod_mux, priv->mux);
> +			break;
> +		case SND_SOC_DAPM_POST_PMD:
> +			gpiod_set_value_cansleep(priv->gpiod_mux, priv->idle_state);
> +			break;
> +		default:
> +			break;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
>   static const struct snd_soc_dapm_widget simple_mux_dapm_widgets[MUX_WIDGET_SIZE] = {
>   	SND_SOC_DAPM_INPUT("IN1"),
>   	SND_SOC_DAPM_INPUT("IN2"),
> -	SND_SOC_DAPM_MUX("MUX", SND_SOC_NOPM, 0, 0, &simple_mux_mux), // see simple_mux_probe()
> +	SND_SOC_DAPM_MUX_E("MUX", SND_SOC_NOPM, 0, 0, &simple_mux_mux, // see simple_mux_probe()
> +			   simple_mux_event, SND_SOC_DAPM_PRE_PMU | SND_SOC_DAPM_POST_PMD),
>   	SND_SOC_DAPM_OUTPUT("OUT"),
>   };
>   
> @@ -93,6 +122,7 @@ static int simple_mux_probe(struct platform_device *pdev)
>   	struct device *dev = &pdev->dev;
>   	struct device_node *np = dev->of_node;
>   	struct simple_mux *priv;
> +	int ret;
>   
>   	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
>   	if (!priv)
> @@ -121,6 +151,14 @@ static int simple_mux_probe(struct platform_device *pdev)
>   	/* Overwrite text ("Input 1", "Input 2") if property exists */
>   	of_property_read_string_array(np, "state-labels", priv->mux_texts, MUX_TEXT_SIZE);
>   
> +	ret = of_property_read_u32(np, "idle-state", &priv->idle_state);
> +	if (ret < 0) {
> +		priv->idle_state = MUX_IDLE_AS_IS;
> +	} else if (priv->idle_state != MUX_IDLE_AS_IS && priv->idle_state >= 2) {
> +		dev_err(dev, "invalid idle-state %u\n", priv->idle_state);
> +		return -EINVAL;
> +	}
> +
>   	/* switch to use priv data instead of default */
>   	priv->mux_enum.texts			= priv->mux_texts;
>   	priv->mux_mux.private_value		= (unsigned long)&priv->mux_enum;