ASoC: qdsp6: q6routing: Fix return value from msm_routing_put_audio_mixer

msm_routing_put_audio_mixer() can return incorrect value in various scenarios.

scenario 1:
amixer cset iface=MIXER,name='SLIMBUS_0_RX Audio Mixer MultiMedia1' 1
amixer cset iface=MIXER,name='SLIMBUS_0_RX Audio Mixer MultiMedia1' 0

return value is 0 instead of 1 eventhough value was changed

scenario 2:
amixer cset iface=MIXER,name='SLIMBUS_0_RX Audio Mixer MultiMedia1' 1
amixer cset iface=MIXER,name='SLIMBUS_0_RX Audio Mixer MultiMedia1' 1

return value is 1 instead of 0 eventhough the value was not changed

scenario 3:
amixer cset iface=MIXER,name='SLIMBUS_0_RX Audio Mixer MultiMedia1' 0
return value is 1 instead of 0 eventhough the value was not changed

Fix this by adding checks, so that change notifications are sent correctly.

Fixes: e3a33673 ("ASoC: qdsp6: q6routing: Add q6routing driver")
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20211130163110.5628-1-srinivas.kandagatla@linaro.orgSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/qcom/qdsp6/q6routing.c

@@ -498,14 +498,16 @@ static int msm_routing_put_audio_mixer(struct snd_kcontrol *kcontrol,
 	struct session_data *session = &data->sessions[session_id];
 
 	if (ucontrol->value.integer.value[0]) {
+		if (session->port_id == be_id)
+			return 0;
+
 		session->port_id = be_id;
 		snd_soc_dapm_mixer_update_power(dapm, kcontrol, 1, update);
 	} else {
-		if (session->port_id == be_id) {
-			session->port_id = -1;
+		if (session->port_id == -1 || session->port_id != be_id)
 			return 0;
-		}
 
+		session->port_id = -1;
 		snd_soc_dapm_mixer_update_power(dapm, kcontrol, 0, update);
 	}