ASoC: wm_adsp: Specifically propagate voice trigger event to caller

The DSP uses an IRQ to indicate data is available on the compressed
stream. For voice trigger use-cases the first such IRQ can be considered
an indication that the user has spoken the key phrase triggering the
firmware. Provide a means for the ADSP code to communicate back to the
calling driver whether an IRQ should be considered as trigger event or
not.
Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/wm_adsp.c

@@ -394,6 +394,7 @@ static const struct {
 	int compr_direction;
 	int num_caps;
 	const struct wm_adsp_fw_caps *caps;
+	bool voice_trigger;
 } wm_adsp_fw[WM_ADSP_NUM_FW] = {
 	[WM_ADSP_FW_MBC_VSS] =  { .file = "mbc-vss" },
 	[WM_ADSP_FW_HIFI] =     { .file = "hifi" },
@@ -406,6 +407,7 @@ static const struct {
 		.compr_direction = SND_COMPRESS_CAPTURE,
 		.num_caps = ARRAY_SIZE(ctrl_caps),
 		.caps = ctrl_caps,
+		.voice_trigger = true,
 	},
 	[WM_ADSP_FW_ASR] =      { .file = "asr" },
 	[WM_ADSP_FW_TRACE] =    {
@@ -2998,6 +3000,9 @@ int wm_adsp_compr_handle_irq(struct wm_adsp *dsp)
 		goto out;
 	}
 
+	if (wm_adsp_fw[dsp->fw].voice_trigger && buf->irq_count == 2)
+		ret = WM_ADSP_COMPR_VOICE_TRIGGER;
+
 out_notify:
 	if (compr && compr->stream)
 		snd_compr_fragment_elapsed(compr->stream);

sound/soc/codecs/wm_adsp.h

@@ -19,6 +19,10 @@
 
 #include "wmfw.h"
 
+/* Return values for wm_adsp_compr_handle_irq */
+#define WM_ADSP_COMPR_OK                 0
+#define WM_ADSP_COMPR_VOICE_TRIGGER      1
+
 struct wm_adsp_region {
 	int type;
 	unsigned int base;