[PATCH 2/2 v2] ASoC: soc-core: Add helper function to handle dynamic update of controls

[Dimitris Papastamos <dp@opensource.wolfsonmicro.com>]

This function can be used to update or add controls at runtime.  It will
always try to add a given control if it does not already exist.

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
---
 include/sound/soc.h  |    2 ++
 sound/soc/soc-core.c |   33 +++++++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 0 deletions(-)

diff --git a/include/sound/soc.h b/include/sound/soc.h
index bfa4836..509c1ea 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -344,6 +344,8 @@ struct snd_kcontrol *snd_soc_cnew(const struct snd_kcontrol_new *_template,
 				  const char *prefix);
 int snd_soc_add_controls(struct snd_soc_codec *codec,
 	const struct snd_kcontrol_new *controls, int num_controls);
+int snd_soc_update_controls(struct snd_soc_codec *codec,
+	const struct snd_kcontrol_new *controls, int num_controls);
 int snd_soc_info_enum_double(struct snd_kcontrol *kcontrol,
 	struct snd_ctl_elem_info *uinfo);
 int snd_soc_info_enum_ext(struct snd_kcontrol *kcontrol,
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 17efacd..815103a 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -2420,6 +2420,39 @@ int snd_soc_add_controls(struct snd_soc_codec *codec,
 EXPORT_SYMBOL_GPL(snd_soc_add_controls);
 
 /**
+ * snd_soc_update_controls - update an array of controls
+ * Convienience function to update a list of controls.
+ *
+ * @codec: codec to update controls of
+ * @controls: array of controls to update
+ * @num_controls: number of elements in the array
+ *
+ * Return 0 for success, else error.
+ */
+int snd_soc_update_controls(struct snd_soc_codec *codec,
+	const struct snd_kcontrol_new *controls, int num_controls)
+{
+	struct snd_card *card = codec->card->snd_card;
+	int err, i;
+
+	for (i = 0; i < num_controls; i++) {
+		const struct snd_kcontrol_new *control = &controls[i];
+		/* always add on update if not already added */
+		err = snd_ctl_update(card, snd_soc_cnew(control, codec,
+							control->name,
+							codec->name_prefix), 1);
+		if (err < 0) {
+			dev_err(codec->dev, "%s: Failed to update %s: %d\n",
+				codec->name, control->name, err);
+			return err;
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_soc_update_controls);
+
+/**
  * snd_soc_info_enum_double - enumerated double mixer info callback
  * @kcontrol: mixer control
  * @uinfo: control element information
-- 
1.7.4.1