[PATCH 10/28] ASoC: ops: Accept patterns in snd_soc_limit_volume

[James Calligeros <jcalligeros99@gmail.com>]

From: Martin Povišer <povik+lin@cutebit.org>

In snd_soc_limit_volume, instead of looking up a single control by name,
also understand wildcard-starting patterns like '* Amp Gain Volume' to
touch many controls at one.

Signed-off-by: Martin Povišer <povik+lin@cutebit.org>
Signed-off-by: James Calligeros <jcalligeros99@gmail.com>
---
 sound/soc/soc-ops.c | 51 ++++++++++++++++++++++---
 1 file changed, 45 insertions(+), 6 deletions(-)

diff --git a/sound/soc/soc-ops.c b/sound/soc/soc-ops.c
index e572b05840b4..2f91ee7946bb 100644
--- a/sound/soc/soc-ops.c
+++ b/sound/soc/soc-ops.c
@@ -403,6 +403,29 @@ int snd_soc_put_volsw_sx(struct snd_kcontrol *kcontrol,
 }
 EXPORT_SYMBOL_GPL(snd_soc_put_volsw_sx);
 
+static bool soc_control_matches(struct snd_kcontrol *kctl,
+	const char *pattern)
+{
+	const char *name = kctl->id.name;
+
+	if (pattern[0] == '*') {
+		int namelen;
+		int patternlen;
+
+		pattern++;
+		if (pattern[0] == ' ')
+			pattern++;
+
+		namelen = strlen(name);
+		patternlen = strlen(pattern);
+
+		if (namelen > patternlen)
+			name += namelen - patternlen;
+	}
+
+	return !strcmp(name, pattern);
+}
+
 static int snd_soc_clip_to_platform_max(struct snd_kcontrol *kctl)
 {
 	struct soc_mixer_control *mc = (struct soc_mixer_control *)kctl->private_value;
@@ -445,31 +468,47 @@ static int soc_limit_volume(struct snd_kcontrol *kctl, int max)
 }
 
 /**
- * snd_soc_limit_volume - Set new limit to an existing volume control.
+ * snd_soc_limit_volume - Set new limit to existing volume controls.
  *
  * @card: where to look for the control
- * @name: Name of the control
+ * @name: name pattern
  * @max: new maximum limit
  *
- * Return 0 for success, else error.
+ * Finds controls matching the given name (which can be either a name
+ * verbatim, or a pattern starting with the wildcard '*') and sets
+ * a platform volume limit on them.
+ *
+ * Return number of matching controls on success, else error. At least
+ * one control needs to match the pattern.
  */
 int snd_soc_limit_volume(struct snd_soc_card *card, const char *name, int max)
 {
 	struct snd_kcontrol *kctl;
+	int hits = 0;
+	int ret;
 
 	/* Sanity check for name */
 	if (unlikely(!name))
 		return -EINVAL;
 
-	kctl = snd_soc_card_get_kcontrol(card, name);
-	if (!kctl) {
+	list_for_each_entry(kctl, &card->snd_card->controls, list) {
+		if (!soc_control_matches(kctl, name))
+			continue;
+
+		ret = soc_limit_volume(kctl, max);
+		if (ret < 0)
+			return ret;
+		hits++;
+	}
+
+	if (!hits) {
 		/* Some cards blindly add limits for multiple variants. */
 		dev_dbg(card->dev, "Volume limit for unknown control '%s'\n",
 			name);
 		return -EINVAL;
 	}
 
-	return soc_limit_volume(kctl, max);
+	return hits;
 }
 EXPORT_SYMBOL_GPL(snd_soc_limit_volume);
 

-- 
2.55.0