ASoC: Intel: boards: kbl_da7219_max98927: add dai_trigger function

amplifier feedback is not modeled as being dependent on any active
output. Even when there is no playback happening, parts of the graph,
specifically the IV sense->speaker protection->output remains active
and this prevents the DSP from entering low-power states.

This patch suggest a machine driver level approach where the speaker
pins are enabled/disabled dynamically depending on stream start/stop
events. DPAM graph representations show the feedback loop is indeed
disabled and low-power states can be reached.
Signed-off-by: Jenny TC <jenny.tc@intel.com>
Signed-off-by: Harshapriya.n <harshapriya.n@intel.com>
Signed-off-by: Mac Chiang <mac.chiang@intel.com>
Acked-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/boards/kbl_da7219_max98927.c

@@ -219,8 +219,60 @@ static int kabylake_ssp0_hw_params(struct snd_pcm_substream *substream,
 	return 0;
 }
 
+static int kabylake_ssp0_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	int j, ret;
+
+	for (j = 0; j < rtd->num_codecs; j++) {
+		struct snd_soc_dai *codec_dai = rtd->codec_dais[j];
+		const char *name = codec_dai->component->name;
+		struct snd_soc_component *component = codec_dai->component;
+		struct snd_soc_dapm_context *dapm =
+				snd_soc_component_get_dapm(component);
+		char pin_name[20];
+
+		if (strcmp(name, MAX98927_DEV0_NAME) &&
+			strcmp(name, MAX98927_DEV1_NAME) &&
+			strcmp(name, MAX98373_DEV0_NAME) &&
+			strcmp(name, MAX98373_DEV1_NAME))
+			continue;
+
+		snprintf(pin_name, ARRAY_SIZE(pin_name), "%s Spk",
+			codec_dai->component->name_prefix);
+
+		switch (cmd) {
+		case SNDRV_PCM_TRIGGER_START:
+		case SNDRV_PCM_TRIGGER_RESUME:
+		case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+			ret = snd_soc_dapm_enable_pin(dapm, pin_name);
+			if (ret) {
+				dev_err(rtd->dev, "failed to enable %s: %d\n",
+				pin_name, ret);
+				return ret;
+			}
+			snd_soc_dapm_sync(dapm);
+			break;
+		case SNDRV_PCM_TRIGGER_STOP:
+		case SNDRV_PCM_TRIGGER_SUSPEND:
+		case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+			ret = snd_soc_dapm_disable_pin(dapm, pin_name);
+			if (ret) {
+				dev_err(rtd->dev, "failed to disable %s: %d\n",
+				pin_name, ret);
+				return ret;
+			}
+			snd_soc_dapm_sync(dapm);
+			break;
+		}
+	}
+
+	return 0;
+}
+
 static struct snd_soc_ops kabylake_ssp0_ops = {
 	.hw_params = kabylake_ssp0_hw_params,
+	.trigger = kabylake_ssp0_trigger,
 };
 
 static int kabylake_ssp_fixup(struct snd_soc_pcm_runtime *rtd,
@@ -950,6 +1002,7 @@ static int kabylake_card_late_probe(struct snd_soc_card *card)
 {
 	struct kbl_codec_private *ctx = snd_soc_card_get_drvdata(card);
 	struct kbl_hdmi_pcm *pcm;
+	struct snd_soc_dapm_context *dapm = &card->dapm;
 	struct snd_soc_component *component = NULL;
 	int err, i = 0;
 	char jack_name[NAME_SIZE];
@@ -976,9 +1029,25 @@ static int kabylake_card_late_probe(struct snd_soc_card *card)
 	if (!component)
 		return -EINVAL;
 
-	return hdac_hdmi_jack_port_init(component, &card->dapm);
 
-	return 0;
+	err = hdac_hdmi_jack_port_init(component, &card->dapm);
+
+	if (err < 0)
+		return err;
+
+	err = snd_soc_dapm_disable_pin(dapm, "Left Spk");
+	if (err) {
+		dev_err(card->dev, "failed to disable Left Spk: %d\n", err);
+		return err;
+	}
+
+	err = snd_soc_dapm_disable_pin(dapm, "Right Spk");
+	if (err) {
+		dev_err(card->dev, "failed to disable Right Spk: %d\n", err);
+		return err;
+	}
+
+	return snd_soc_dapm_sync(dapm);
 }
 
 /* kabylake audio machine driver for SPT + DA7219 */