topology2: Add pga class

Add the class definition for PGA widget. It can be
instantiated as follows:
        Object.Widget.pga."N" {
                format	     s24le
                index        0
		period_sink_count 2
		period_source_count 2
        }

Where N is the unique instance number for pga widget in the same
alsaconf node.

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

tools/topology2/include/common/tokens.conf

@@ -25,4 +25,9 @@ Object.Base.VendorToken {
 		size			100
 		caps			101
 	}
+
+	"sof_tkn_volume" {
+		ramp_step_type		250
+		ramp_step_ms		251
+	}
 }

tools/topology2/include/components/volume.conf

@@ -0,0 +1,118 @@
+#
+# Common pipeline volume
+#
+# A generic volume widget. All attributes defined herein are namespaced
+# by alsatplg to "Object.Widget.pga.N.attribute_name"
+#
+# Usage: this component can be used by declaring int a parent object. i.e.
+#
+# 	Object.Widget.pga."N" {
+#		index	1
+#		format	s24le
+#		no_pm	"true"
+#	}
+#
+# Where N is the unique instance number for pga widget in the same alsaconf node.
+
+Class.Widget."pga" {
+	#
+	# Pipeline ID for the pga widget object
+	#
+	DefineAttribute."index" {}
+
+	#
+	# pga object instance
+	#
+	DefineAttribute."instance" {}
+
+	#include common component definition
+	<include/components/widget-common.conf>
+
+	#
+	# pga widget UUID
+	#
+	DefineAttribute."uuid" {
+		type	"string"
+		# Token set reference name and type
+		token_ref	"sof_tkn_comp.uuid"
+	}
+
+	#
+	# Bespoke attributes for PGA
+	#
+
+	#
+	# Volume ramp step type. The values provided will be translated to integer values
+	# as specified in the tuple_values array.
+	# For example: "linear" is translated to 0, "log" to 1 etc.
+	#
+	DefineAttribute."ramp_step_type" {
+		type	"string"
+		# Token set reference name
+		token_ref	"sof_tkn_volume.word"
+		constraints {
+			!valid_values [
+				"linear"
+				"log"
+				"linear_zc"
+				"log_zc"
+			]
+			!tuple_values [
+				0
+				1
+				2
+				3
+			]
+		}
+	}
+
+	#
+	# Volume ramp step in milliseconds
+	#
+	DefineAttribute."ramp_step_ms" {
+		# Token set reference name
+		token_ref	"sof_tkn_volume.word"
+	}
+
+	# Attribute categories
+	attributes {
+		#
+		# The PGA widget name would be constructed using the index and instance attributes.
+		# For ex: "pga.1.1" or "pga.10.2" etc.
+		#
+		!constructor [
+			"index"
+			"instance"
+		]
+
+		#
+		# immutable attributes cannot be modified in the object instance
+		#
+		!immutable [
+			"uuid"
+			"type"
+		]
+
+		#
+		# deprecated attributes should not be added in the object instance
+		#
+		!deprecated [
+			"preload_count"
+		]
+
+		#
+		# pga widget objects instantiated within the same alsaconf node must have unique
+		# instance attribute
+		#
+		unique	"instance"
+	}
+
+	# Default attribute values for pga widget
+	type 			"pga"
+	uuid 			"7e:67:7e:b7:f4:5f:88:41:af:14:fb:a8:bd:bf:86:82"
+	no_pm			"true"
+	period_sink_count	2
+	period_source_count	2
+	ramp_step_type		"linear"
+	ramp_step_ms		400
+}