Audio: Add codec config methods for external I2S master.

firmware/common/ak4951.cpp

@@ -46,6 +46,12 @@ void AK4951::configure_digital_interface_external_slave() {
 	update(Register::PowerManagement2);
 }
 
+void AK4951::configure_digital_interface_external_master() {
+	map.r.power_management_2.MS = 1;	// Master mode
+	map.r.power_management_2.PMPLL = 0;	// EXT mode
+	update(Register::PowerManagement2);
+}
+
 void AK4951::init() {
 	reset();
 

firmware/common/ak4951.hpp

@@ -866,6 +866,7 @@ private:
 
 	void configure_digital_interface_i2s();
 	void configure_digital_interface_external_slave();
+	void configure_digital_interface_external_master();
 	void set_digtal_volume_control(const reg_t value);
 	void set_dac_power(const bool enable);
 	void set_headphone_power(const bool enable);

firmware/common/wm8731.cpp

@@ -37,6 +37,18 @@ void WM8731::configure_interface_i2s_slave() {
 	});
 }
 
+void WM8731::configure_interface_i2s_master() {
+	write(DigitalAudioInterfaceFormat {
+		.format = 2,
+		.iwl = 0,
+		.lrp = 0,
+		.lrswap = 0,
+		.ms = 1,
+		.bclkinv = 0,
+		.reserved0 = 0,
+	});
+}
+
 void WM8731::init() {
 	reset();
 

firmware/common/wm8731.hpp

@@ -376,6 +376,7 @@ private:
 	volume_t headphone_volume = -60.0_dB;
 
 	void configure_interface_i2s_slave();
+	void configure_interface_i2s_master();
 
 	bool write(const Register reg);