linux-4.4.1/dapm_connect_mux()

参照元†

• linux-4.4.1/dapm_new_mux()
• linux-4.4.1/snd_soc_dapm_add_path()

説明†

• パス: linux-4.4.1/sound/soc/soc-dapm.c

• FIXME: これは何？
  • 説明

引数†

• struct snd_soc_dapm_context *dapm
  • linux-4.4.1/snd_soc_dapm_context
• struct snd_soc_dapm_path *path
  • linux-4.4.1/snd_soc_dapm_path
• const char *control_name
• struct snd_soc_dapm_widget *w
  • linux-4.4.1/snd_soc_dapm_widget

返り値†

• int

参考†

実装†

/* connect mux widget to its interconnecting audio paths */
static int dapm_connect_mux(struct snd_soc_dapm_context *dapm,
	struct snd_soc_dapm_path *path, const char *control_name,
	struct snd_soc_dapm_widget *w)
{
	const struct snd_kcontrol_new *kcontrol = &w->kcontrol_news[0];
	struct soc_enum *e = (struct soc_enum *)kcontrol->private_value;
	unsigned int val, item;
	int i;

• • linux-4.4.1/snd_kcontrol_new
  • linux-4.4.1/soc_enum

	if (e->reg != SND_SOC_NOPM) {
		soc_dapm_read(dapm, e->reg, &val);
		val = (val >> e->shift_l) & e->mask;
		item = snd_soc_enum_val_to_item(e, val);
	} else {
		/* since a virtual mux has no backing registers to
		 * decide which path to connect, it will try to match
		 * with the first enumeration.  This is to ensure
		 * that the default mux choice (the first) will be
		 * correctly powered up during initialization.
		 */
		item = 0;
	}

• • linux-4.4.1/soc_dapm_read()
  • linux-4.4.1/snd_soc_enum_val_to_item()

	for (i = 0; i < e->items; i++) {
		if (!(strcmp(control_name, e->texts[i]))) {
			path->name = e->texts[i];

• コントロール名と、列挙値の名前が一致していたら、パス名を設定する。
  • 具体例を書くと、

    static const char *sinkaaa_srcsel_text[] = {
    	"ValueA", "ValueB", "ValueC", //e->texts[i]
    };
    
    static SOC_ENUM_SINGLE_DECL(sinkaaa_srcsel_enum,
    	REG_ADDR, REG_SHIFT,
    	sinkaaa_srcsel_text);
    
    static const struct snd_kcontrol_new sinkaaa_mux[] = {
    	SOC_DAPM_ENUM("SinkAAA Source", sinkaaa_srcsel_enum),
    };
    
    static const struct snd_soc_dapm_route foo_routes[] = {
    	// sink       control   source
    	//            = control_name
    	{ "SinkAAA", "ValueA", "SourceA" },
    	{ "SinkAAA", "ValueB", "SourceB" },
    	{ "SinkAAA", "ValueC", "SourceC" },
    
    	//...
    };

  • snd_soc_dapm_route の control が、この関数の control_name に指定される。

			if (i == item)
				path->connect = 1;
			else
				path->connect = 0;
			return 0;
		}
	}

	return -ENODEV;
}

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