ASoC: meson: axg-tdm-interface: manage formatters in trigger

So far, the formatters have been reset/enabled using the .prepare()
callback. This was done in this callback because walking the formatters use
a mutex. A mutex is used because formatter handling require dealing
possibly slow clock operation.

With the support of non-atomic, .trigger() callback may be used which also
allows to properly enable and disable formatters on start but also
pause/resume.

This solve a random shift on TDMIN as well repeated samples on for TDMOUT.

Fixes: d60e4f1e ("ASoC: meson: add tdm interface driver")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/20240426152946.3078805-4-jbrunet@baylibre.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/meson/axg-tdm-interface.c

@@ -349,26 +349,31 @@ static int axg_tdm_iface_hw_params(struct snd_pcm_substream *substream,
 	return 0;
 }
 
-static int axg_tdm_iface_hw_free(struct snd_pcm_substream *substream,
+static int axg_tdm_iface_trigger(struct snd_pcm_substream *substream,
+				 int cmd,
 				 struct snd_soc_dai *dai)
 {
-	struct axg_tdm_stream *ts = snd_soc_dai_get_dma_data(dai, substream);
+	struct axg_tdm_stream *ts =
+		snd_soc_dai_get_dma_data(dai, substream);
 
-	/* Stop all attached formatters */
-	axg_tdm_stream_stop(ts);
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		axg_tdm_stream_start(ts);
+		break;
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+	case SNDRV_PCM_TRIGGER_STOP:
+		axg_tdm_stream_stop(ts);
+		break;
+	default:
+		return -EINVAL;
+	}
 
 	return 0;
 }
 
-static int axg_tdm_iface_prepare(struct snd_pcm_substream *substream,
-				 struct snd_soc_dai *dai)
-{
-	struct axg_tdm_stream *ts = snd_soc_dai_get_dma_data(dai, substream);
-
-	/* Force all attached formatters to update */
-	return axg_tdm_stream_reset(ts);
-}
-
 static int axg_tdm_iface_remove_dai(struct snd_soc_dai *dai)
 {
 	int stream;
@@ -412,8 +417,7 @@ static const struct snd_soc_dai_ops axg_tdm_iface_ops = {
 	.set_fmt	= axg_tdm_iface_set_fmt,
 	.startup	= axg_tdm_iface_startup,
 	.hw_params	= axg_tdm_iface_hw_params,
-	.prepare	= axg_tdm_iface_prepare,
-	.hw_free	= axg_tdm_iface_hw_free,
+	.trigger	= axg_tdm_iface_trigger,
 };
 
 /* TDM Backend DAIs */