bcm2835-audio: Create the platform device if the DT node is disabled

For backwards compatibility, allow the built-in ALSA driver to be enabled
either by loading the module from /etc/modules or by enabling the "/audio"
node in DT.

Author: Phil Elwell

arch/arm/boot/dts/bcm2708-rpi-b-plus.dts

@@ -53,10 +53,6 @@
 	status = "okay";
 };
 
-&audio {
-	status = "okay";
-};
-
 &spi0 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&spi0_pins>;

arch/arm/boot/dts/bcm2708-rpi-b.dts

@@ -53,10 +53,6 @@
 	status = "okay";
 };
 
-&audio {
-	status = "okay";
-};
-
 &spi0 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&spi0_pins>;

arch/arm/boot/dts/bcm2709-rpi-2-b.dts

@@ -53,10 +53,6 @@
 	status = "okay";
 };
 
-&audio {
-	status = "okay";
-};
-
 &spi0 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&spi0_pins>;

arch/arm/mach-bcm2708/bcm2708.c

@@ -963,8 +963,14 @@ void __init bcm2708_init(void)
 	bcm_register_device_dt(&bcm2835_emmc_device);
 #endif
 	bcm2708_init_led();
-	for (i = 0; i < ARRAY_SIZE(bcm2708_alsa_devices); i++)
-		bcm_register_device_dt(&bcm2708_alsa_devices[i]);
+
+	/* Only create the platform devices for the ALSA driver in the
+	   absence of an enabled "audio" DT node */
+	if (!use_dt ||
+	    !of_device_is_available(of_find_node_by_path("/audio"))) {
+		for (i = 0; i < ARRAY_SIZE(bcm2708_alsa_devices); i++)
+			bcm_register_device(&bcm2708_alsa_devices[i]);
+	}
 
 	bcm_register_device_dt(&bcm2708_spi_device);
 

arch/arm/mach-bcm2709/bcm2709.c

@@ -986,8 +986,14 @@ void __init bcm2709_init(void)
 	bcm_register_device_dt(&bcm2835_emmc_device);
 #endif
 	bcm2709_init_led();
-	for (i = 0; i < ARRAY_SIZE(bcm2708_alsa_devices); i++)
-		bcm_register_device_dt(&bcm2708_alsa_devices[i]);
+
+	/* Only create the platform devices for the ALSA driver in the
+	   absence of an enabled "audio" DT node */
+	if (!use_dt ||
+	    !of_device_is_available(of_find_node_by_path("/audio"))) {
+		for (i = 0; i < ARRAY_SIZE(bcm2708_alsa_devices); i++)
+			bcm_register_device(&bcm2708_alsa_devices[i]);
+	}
 
 	bcm_register_device_dt(&bcm2708_spi_device);