ALSA: vmaster: Add snd_ctl_add_followers() helper

Add a new helper to add multiple vmaster followers in a shot.  The
same function was open-coded in various places, and this helper
replaces them.

Link: https://lore.kernel.org/r/20230721071643.3631-2-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/include/sound/control.h b/include/sound/control.h
index 69d950a..9a4f4f7 100644 (file)
--- a/include/sound/control.h
+++ b/include/sound/control.h
@@ -262,6 +262,9 @@ snd_ctl_add_follower(struct snd_kcontrol *master, struct snd_kcontrol *follower)
        return _snd_ctl_add_follower(master, follower, 0);
 }
 
+int snd_ctl_add_followers(struct snd_card *card, struct snd_kcontrol *master,
+                         const char * const *list);
+
 /**
  * snd_ctl_add_follower_uncached - Add a virtual follower control
  * @master: vmaster element

diff --git a/sound/core/vmaster.c b/sound/core/vmaster.c
index d0f11f3..378d2c7 100644 (file)
--- a/sound/core/vmaster.c
+++ b/sound/core/vmaster.c
@@ -280,6 +280,34 @@ int _snd_ctl_add_follower(struct snd_kcontrol *master,
 }
 EXPORT_SYMBOL(_snd_ctl_add_follower);
 
+/**
+ * snd_ctl_add_followers - add multiple followers to vmaster
+ * @card: card instance
+ * @master: the target vmaster kcontrol object
+ * @list: NULL-terminated list of name strings of followers to be added
+ *
+ * Adds the multiple follower kcontrols with the given names.
+ * Returns 0 for success or a negative error code.
+ */
+int snd_ctl_add_followers(struct snd_card *card, struct snd_kcontrol *master,
+                         const char * const *list)
+{
+       struct snd_kcontrol *follower;
+       int err;
+
+       for (; *list; list++) {
+               follower = snd_ctl_find_id_mixer(card, *list);
+               if (follower) {
+                       err = snd_ctl_add_follower(master, follower);
+                       if (err < 0)
+                               return err;
+               }
+       }
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(snd_ctl_add_followers);
+
 /*
  * ctl callbacks for master controls
  */