ASoC: Add bias level data to DAPM context debugfs

This is also in the old sysfs diagnostics but it's nice to have everything
in one place.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/soc-dapm.c

@@ -1304,6 +1304,47 @@ static const struct file_operations dapm_widget_power_fops = {
 	.llseek = default_llseek,
 };
 
+static int dapm_bias_open_file(struct inode *inode, struct file *file)
+{
+	file->private_data = inode->i_private;
+	return 0;
+}
+
+static ssize_t dapm_bias_read_file(struct file *file, char __user *user_buf,
+				   size_t count, loff_t *ppos)
+{
+	struct snd_soc_dapm_context *dapm = file->private_data;
+	char *level;
+
+	switch (dapm->bias_level) {
+	case SND_SOC_BIAS_ON:
+		level = "On\n";
+		break;
+	case SND_SOC_BIAS_PREPARE:
+		level = "Prepare\n";
+		break;
+	case SND_SOC_BIAS_STANDBY:
+		level = "Standby\n";
+		break;
+	case SND_SOC_BIAS_OFF:
+		level = "Off\n";
+		break;
+	default:
+		BUG();
+		level = "Unknown\n";
+		break;
+	}
+
+	return simple_read_from_buffer(user_buf, count, ppos, level,
+				       strlen(level));
+}
+
+static const struct file_operations dapm_bias_fops = {
+	.open = dapm_bias_open_file,
+	.read = dapm_bias_read_file,
+	.llseek = default_llseek,
+};
+
 void snd_soc_dapm_debugfs_init(struct snd_soc_dapm_context *dapm)
 {
 	struct snd_soc_dapm_widget *w;
@@ -1312,6 +1353,13 @@ void snd_soc_dapm_debugfs_init(struct snd_soc_dapm_context *dapm)
 	if (!dapm->debugfs_dapm)
 		return;
 
+	d = debugfs_create_file("bias_level", 0444,
+				dapm->debugfs_dapm, dapm,
+				&dapm_bias_fops);
+	if (!d)
+		dev_warn(dapm->dev,
+			 "ASoC: Failed to create bias level debugfs file\n");
+
 	list_for_each_entry(w, &dapm->card->widgets, list) {
 		if (!w->name || w->dapm != dapm)
 			continue;