ASoC: qcom: common: Add SNDRV channel map to Q6 slot helper

Add a small helper that converts ALSA channel map positions to the Q6 PCM
channel identifiers used by Qualcomm machine drivers.

The mapping is useful beyond a single machine driver when exposing
writable channel-map controls.

Assisted-by: Codex:GPT-5.5
Link: https://patch.msgid.link/20260724-b4-sound-qcom-x1e80100-allow-ucm-channel-map-v2-1-2ca3c1250018@oss.qualcomm.com
Signed-off-by: Abel Vesa <abel.vesa@oss.qualcomm.com>

sound/soc/qcom/common.c

@@ -6,7 +6,9 @@
 #include <linux/module.h>
 #include <sound/jack.h>
 #include <linux/input-event-codes.h>
+#include <sound/pcm.h>
 #include "common.h"
+#include "qdsp6/q6dsp-common.h"
 
 #define NAME_SIZE	32
 
@@ -172,6 +174,34 @@ int qcom_snd_parse_of(struct snd_soc_card *card)
 }
 EXPORT_SYMBOL_GPL(qcom_snd_parse_of);
 
+int qcom_snd_chmap_to_q6(unsigned int pos)
+{
+	switch (pos) {
+	case SNDRV_CHMAP_FL:
+		return PCM_CHANNEL_FL;
+	case SNDRV_CHMAP_FR:
+		return PCM_CHANNEL_FR;
+	case SNDRV_CHMAP_MONO:
+	case SNDRV_CHMAP_FC:
+		return PCM_CHANNEL_FC;
+	case SNDRV_CHMAP_LFE:
+		return PCM_CHANNEL_LFE;
+	case SNDRV_CHMAP_RL:
+		return PCM_CHANNEL_LB;
+	case SNDRV_CHMAP_RR:
+		return PCM_CHANNEL_RB;
+	case SNDRV_CHMAP_SL:
+		return PCM_CHANNEL_LS;
+	case SNDRV_CHMAP_SR:
+		return PCM_CHANNEL_RS;
+	case SNDRV_CHMAP_RC:
+		return PCM_CHANNEL_CS;
+	default:
+		return -EINVAL;
+	}
+}
+EXPORT_SYMBOL_GPL(qcom_snd_chmap_to_q6);
+
 static struct snd_soc_jack_pin qcom_headset_jack_pins[] = {
 	/* Headset */
 	{

sound/soc/qcom/common.h

@@ -14,6 +14,7 @@ int qcom_snd_wcd_jack_setup(struct snd_soc_pcm_runtime *rtd,
 			    struct snd_soc_jack *jack, bool *jack_setup);
 int qcom_snd_dp_jack_setup(struct snd_soc_pcm_runtime *rtd,
 			   struct snd_soc_jack *dp_jack, int id);
+int qcom_snd_chmap_to_q6(unsigned int pos);
 
 
 #endif