ASoC: max9768: Fix event generation for playback mute

The max9768 has a custom control for playback mute which unconditionally
returns 0 from the put() operation, rather than returning 1 on change to
ensure notifications are generated to userspace. Check to see if the value
has changed and return appropriately.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://patch.msgid.link/20241112-asoc-max9768-event-v1-1-ba5d50599787@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: broonie

sound/soc/codecs/max9768.c

@@ -54,10 +54,17 @@ static int max9768_set_gpio(struct snd_kcontrol *kcontrol,
 {
 	struct snd_soc_component *c = snd_soc_kcontrol_component(kcontrol);
 	struct max9768 *max9768 = snd_soc_component_get_drvdata(c);
+	bool val = !ucontrol->value.integer.value[0];
+	int ret;
 
-	gpiod_set_value_cansleep(max9768->mute, !ucontrol->value.integer.value[0]);
+	if (val != gpiod_get_value_cansleep(max9768->mute))
+		ret = 1;
+	else
+		ret = 0;
 
-	return 0;
+	gpiod_set_value_cansleep(max9768->mute, val);
+
+	return ret;
 }
 
 static const DECLARE_TLV_DB_RANGE(volume_tlv,