ASoC: dpcm: Add bespoke trigger()

Some on SoC DSP HW is very tightly coupled with DMA and DAI drivers. It's
necessary to allow some flexability wrt to PCM operations here so that we
can define a bespoke DPCM trigger() PCM operation for such HW.

A bespoke DPCM trigger() allows exact ordering and timing of component
triggering by allowing a component driver to manage the final enable
and disable configurations without adding extra complexity to other
component drivers. e.g. The McPDM DAI and ABE are tightly coupled on
OMAP4 so we have a bespoke trigger to manage the trigger to improve
performance and reduce complexity when triggering new McPDM BEs.

Signed-off-by: Liam Girdwood <lrg@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/include/sound/soc.h b/include/sound/soc.h
index 153da5b..c703871 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -377,6 +377,9 @@
 int snd_soc_set_runtime_hwparams(struct snd_pcm_substream *substream,
 	const struct snd_pcm_hardware *hw);
 
+int snd_soc_platform_trigger(struct snd_pcm_substream *substream,
+		int cmd, struct snd_soc_platform *platform);
+
 /* Jack reporting */
 int snd_soc_jack_new(struct snd_soc_codec *codec, const char *id, int type,
 		     struct snd_soc_jack *jack);
@@ -753,6 +756,7 @@
 	/* platform IO - used for platform DAPM */
 	unsigned int (*read)(struct snd_soc_platform *, unsigned int);
 	int (*write)(struct snd_soc_platform *, unsigned int, unsigned int);
+	int (*bespoke_trigger)(struct snd_pcm_substream *, int);
 };
 
 struct snd_soc_platform {