ASoC: soc-dapm.c: clean up debugfs for freed widget

When a widget is added to dapm via snd_soc_dapm_new_widgets,
dapm_debugfs_add_widget is also called to create a corresponding debugfs
file. However, when a widget is freed by snd_soc_dapm_free_widget, the
corresponding debugfs is not cleared. As a result, the freed widget is
still seen in the dapm directory.

This patch adds dapm_debugfs_free_widget to free the debugfs of a
specified widget, and it's called at snd_soc_dapm_free_widget to clean
up the debugfs for freed widget.
Signed-off-by: Trevor Wu <trevor.wu@mediatek.com>
Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>
Link: https://lore.kernel.org/r/20230526093150.22923-6-trevor.wu@mediatek.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/soc-dapm.c

@@ -2216,6 +2216,16 @@ static void dapm_debugfs_add_widget(struct snd_soc_dapm_widget *w)
 			    &dapm_widget_power_fops);
 }
 
+static void dapm_debugfs_free_widget(struct snd_soc_dapm_widget *w)
+{
+	struct snd_soc_dapm_context *dapm = w->dapm;
+
+	if (!dapm->debugfs_dapm || !w->name)
+		return;
+
+	debugfs_lookup_and_remove(w->name, dapm->debugfs_dapm);
+}
+
 static void dapm_debugfs_cleanup(struct snd_soc_dapm_context *dapm)
 {
 	debugfs_remove_recursive(dapm->debugfs_dapm);
@@ -2232,6 +2242,10 @@ static inline void dapm_debugfs_add_widget(struct snd_soc_dapm_widget *w)
 {
 }
 
+static inline void dapm_debugfs_free_widget(struct snd_soc_dapm_widget *w)
+{
+}
+
 static inline void dapm_debugfs_cleanup(struct snd_soc_dapm_context *dapm)
 {
 }
@@ -2495,6 +2509,8 @@ void snd_soc_dapm_free_widget(struct snd_soc_dapm_widget *w)
 			dapm_free_path(p);
 	}
 
+	dapm_debugfs_free_widget(w);
+
 	kfree(w->kcontrols);
 	kfree_const(w->name);
 	kfree_const(w->sname);