soundwire: Intel: add trigger callback

When a pipeline is split into FE and BE parts, the BE pipeline may need to
be triggered separately in the BE trigger op. So add the trigger callback
in the link_res ops that will be invoked during BE DAI trigger.
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Acked-by: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20220708061312.25878-2-yung-chuan.liao@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/soundwire/intel.c

@@ -1004,9 +1004,18 @@ static int intel_trigger(struct snd_pcm_substream *substream, int cmd, struct sn
 {
 	struct sdw_cdns *cdns = snd_soc_dai_get_drvdata(dai);
 	struct sdw_intel *sdw = cdns_to_intel(cdns);
+	struct sdw_intel_link_res *res = sdw->link_res;
 	struct sdw_cdns_dma_data *dma;
 	int ret = 0;
 
+	/*
+	 * The .trigger callback is used to send required IPC to audio
+	 * firmware. The .free_stream callback will still be called
+	 * by intel_free_stream() in the TRIGGER_SUSPEND case.
+	 */
+	if (res->ops && res->ops->trigger)
+		res->ops->trigger(dai, cmd, substream->stream);
+
 	dma = snd_soc_dai_get_dma_data(dai, substream);
 	if (!dma) {
 		dev_err(dai->dev, "failed to get dma data in %s\n",

include/linux/soundwire/sdw_intel.h

@@ -121,6 +121,7 @@ struct sdw_intel_ops {
 			     struct sdw_intel_stream_params_data *params_data);
 	int (*free_stream)(struct device *dev,
 			   struct sdw_intel_stream_free_data *free_data);
+	int (*trigger)(struct snd_soc_dai *dai, int cmd, int stream);
 };
 
 /**