tools: plugin: Simplify the command line

Make the card/dev names and config names optional in the command line.
This will simplify the command line to just pass the PCM ID to start
playback using the default device as follows:

aplay -Dsof:plugin:1

Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>

Author: ranj063

tools/plugin/README.md

@@ -60,6 +60,19 @@ The command line is parsed as follows:
 - "default": The second default is the device name
 - "48k2c16b" is the config name for 48K, stereo, 16bit
 
+Config name is optional in the command line. When it is not provided, hw_params will be used to
+configure the endpoint. In this case, the command line can be simplified to:
+
+```
+aplay -Dsof:plugin:1:default:default
+```
+
+When using the default device, the command line can be further simplified to:
+
+```
+aplay -Dsof:plugin:1
+```
+
 This renders audio to the sof-pipe daemon using the sof-plugin topology playback PCM ID 1.
 The above example needs to be 48k as example pipe has no SRC/ASRC.
 

tools/plugin/alsaplug/plugin.c

@@ -270,28 +270,29 @@ static int parse_client_cmdline(snd_sof_plug_t *plug, char *cmdline, bool just_t
 
 	cmd_item = &plug->cmdline[plug->num_cmdline];
 	card = strtok_r(next, ":", &next);
+	/* card/dev names and config are all optional */
 	if (!card) {
-		SNDERR("Invalid card name\n");
-		return -EINVAL;
-	}
-	dev = strtok_r(next, ":", &next);
-	if (!dev) {
-		SNDERR("Invalid dev name\n");
-		return -EINVAL;
-	}
-	config = strtok_r(next, ":", &next);
-
-	/* tuple needs all three, any missing ? */
-	if (!config) {
-		SNDERR("invalid cmdline, expected pcm(%s):card(%s):dev(%s):config(%s) from %s",
-		       pcm, card, dev, config, tplg);
-		return -EINVAL;
+		strncpy(cmd_item->card_name, "default", sizeof(cmd_item->card_name));
+		strncpy(cmd_item->dev_name, "default", sizeof(cmd_item->dev_name));
+		fprintf(stdout, "no config name provided, will use hw_params\n");
+	} else {
+		strncpy(cmd_item->card_name, card, sizeof(cmd_item->card_name));
+		dev = strtok_r(next, ":", &next);
+		/* dev name must be provided along with card name */
+		if (!dev) {
+			SNDERR("Invalid dev name\n");
+			return -EINVAL;
+		}
+		strncpy(cmd_item->dev_name, dev, sizeof(cmd_item->dev_name));
+		config = strtok_r(next, ":", &next);
+		/* config name is optional */
+		if (!config)
+			fprintf(stdout, "no config name provided, will use hw_params\n");
+		else
+			strncpy(cmd_item->config_name, config, sizeof(cmd_item->config_name));
 	}
 
 	cmd_item->pcm = atoi(pcm);
-	strncpy(cmd_item->card_name, card, sizeof(cmd_item->card_name));
-	strncpy(cmd_item->dev_name, dev, sizeof(cmd_item->dev_name));
-	strncpy(cmd_item->config_name, config, sizeof(cmd_item->config_name));
 
 	/*
 	 * dev name is special, we cant use "," in the command line