ASoC: core: add optional pcm_new callback for DAI driver

During probe, DAIs can need to perform some actions that requests
the knowledge of the pcm runtime handle.
The callback is called during DAIs linking, after PCM device creation.
For instance this can be used to add relationship between a DAI pcm
control and the pcm device.

Signed-off-by: Arnaud Pouliquen <[e-mail]>
Signed-off-by: Mark Brown <[e-mail]>

include/sound/soc-dai.h

···
 	int (*resume)(struct snd_soc_dai *dai);
 	/* compress dai */
 	int (*compress_new)(struct snd_soc_pcm_runtime *rtd, int num);
+	/* Optional Callback used at pcm creation*/
+	int (*pcm_new)(struct snd_soc_pcm_runtime *rtd,
+		       struct snd_soc_dai *dai);
 	/* DAI is also used for the control bus */
 	bool bus_control;
 

sound/soc/soc-core.c

···
 	return 0;
 }
 
+static int soc_link_dai_pcm_new(struct snd_soc_dai **dais, int num_dais,
+				struct snd_soc_pcm_runtime *rtd)
+{
+	int i, ret = 0;
+
+	for (i = 0; i < num_dais; ++i) {
+		struct snd_soc_dai_driver *drv = dais[i]->driver;
+
+		if (!rtd->dai_link->no_pcm && drv->pcm_new)
+			ret = drv->pcm_new(rtd, dais[i]);
+		if (ret < 0) {
+			dev_err(dais[i]->dev,
+				"ASoC: Failed to bind %s with pcm device\n",
+				dais[i]->name);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
 static int soc_link_dai_widgets(struct snd_soc_card *card,
 				struct snd_soc_dai_link *dai_link,
 				struct snd_soc_pcm_runtime *rtd)
···
 				       dai_link->stream_name, ret);
 				return ret;
 			}
+			ret = soc_link_dai_pcm_new(&cpu_dai, 1, rtd);
+			if (ret < 0)
+				return ret;
+			ret = soc_link_dai_pcm_new(rtd->codec_dais,
+						   rtd->num_codecs, rtd);
+			if (ret < 0)
+				return ret;
 		} else {
 			INIT_DELAYED_WORK(&rtd->delayed_work,
 						codec2codec_close_delayed_work);