BCM270x: Add onboard sound device to Device Tree

Add Device Tree support to alsa driver.
Add device to Device Tree.
Don't add platform devices when booting in DT mode.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>

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

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

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

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

arch/arm/boot/dts/bcm2708-rpi-cm.dtsi

@@ -34,6 +34,10 @@
 	status = "okay";
 };
 
+&audio {
+	status = "okay";
+};
+
 / {
 	__overrides__ {
 		act_led_gpio = <&act_led>,"gpios:4";

arch/arm/boot/dts/bcm2708_common.dtsi

@@ -3,6 +3,13 @@
 / {
 	interrupt-parent = <&intc>;
 
+	/* Onboard audio */
+	audio: audio {
+		compatible = "brcm,bcm2835-audio";
+		brcm,pwm-channels = <8>;
+		status = "disabled";
+	};
+
 	soc: soc {
 		compatible = "simple-bus";
 		#address-cells = <1>;

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

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

arch/arm/mach-bcm2708/bcm2708.c

@@ -964,7 +964,7 @@ void __init bcm2708_init(void)
 #endif
 	bcm2708_init_led();
 	for (i = 0; i < ARRAY_SIZE(bcm2708_alsa_devices); i++)
-		bcm_register_device(&bcm2708_alsa_devices[i]);
+		bcm_register_device_dt(&bcm2708_alsa_devices[i]);
 
 	bcm_register_device_dt(&bcm2708_spi_device);
 

arch/arm/mach-bcm2709/bcm2709.c

@@ -987,7 +987,7 @@ void __init bcm2709_init(void)
 #endif
 	bcm2709_init_led();
 	for (i = 0; i < ARRAY_SIZE(bcm2708_alsa_devices); i++)
-		bcm_register_device(&bcm2708_alsa_devices[i]);
+		bcm_register_device_dt(&bcm2708_alsa_devices[i]);
 
 	bcm_register_device_dt(&bcm2708_spi_device);
 

sound/arm/Kconfig

@@ -41,7 +41,8 @@ config SND_PXA2XX_AC97
 
 config SND_BCM2835
 	tristate "BCM2835 ALSA driver"
-	depends on (ARCH_BCM2708 || ARCH_BCM2709) && BCM2708_VCHIQ && SND
+	depends on (ARCH_BCM2708 || ARCH_BCM2709 || ARCH_BCM2835) \
+		   && BCM2708_VCHIQ && SND
 	select SND_PCM
 	help
 	  Say Y or M if you want to support BCM2835 Alsa pcm card driver

sound/arm/bcm2835.c

@@ -17,6 +17,7 @@
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/module.h>
+#include <linux/of.h>
 
 #include "bcm2835.h"
 
@@ -81,6 +82,86 @@ static int snd_bcm2835_create(struct snd_card *card,
 	return 0;
 }
 
+static int snd_bcm2835_alsa_probe_dt(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	bcm2835_chip_t *chip;
+	struct snd_card *card;
+	u32 numchans;
+	int err, i;
+
+	err = of_property_read_u32(dev->of_node, "brcm,pwm-channels",
+				   &numchans);
+	if (err) {
+		dev_err(dev, "Failed to get DT property 'brcm,pwm-channels'");
+		return err;
+	}
+
+	if (numchans == 0 || numchans > MAX_SUBSTREAMS) {
+		numchans = MAX_SUBSTREAMS;
+		dev_warn(dev, "Illegal 'brcm,pwm-channels' value, will use %u\n",
+			 numchans);
+	}
+
+	err = snd_card_new(NULL, -1, NULL, THIS_MODULE, 0, &card);
+	if (err) {
+		dev_err(dev, "Failed to create soundcard structure\n");
+		return err;
+	}
+
+	snd_card_set_dev(card, dev);
+	strcpy(card->driver, "bcm2835");
+	strcpy(card->shortname, "bcm2835 ALSA");
+	sprintf(card->longname, "%s", card->shortname);
+
+	err = snd_bcm2835_create(card, pdev, &chip);
+	if (err < 0) {
+		dev_err(dev, "Failed to create bcm2835 chip\n");
+		goto err_free;
+	}
+
+	err = snd_bcm2835_new_pcm(chip);
+	if (err < 0) {
+		dev_err(dev, "Failed to create new bcm2835 pcm device\n");
+		goto err_free;
+	}
+
+	err = snd_bcm2835_new_spdif_pcm(chip);
+	if (err < 0) {
+		dev_err(dev, "Failed to create new bcm2835 spdif pcm device\n");
+		goto err_free;
+	}
+
+	err = snd_bcm2835_new_ctl(chip);
+	if (err < 0) {
+		dev_err(dev, "Failed to create new bcm2835 ctl\n");
+		goto err_free;
+	}
+
+	for (i = 0; i < numchans; i++) {
+		chip->avail_substreams |= (1 << i);
+		chip->pdev[i] = pdev;
+	}
+
+	err = snd_card_register(card);
+	if (err) {
+		dev_err(dev, "Failed to register bcm2835 ALSA card \n");
+		goto err_free;
+	}
+
+	g_card = card;
+	g_chip = chip;
+	platform_set_drvdata(pdev, card);
+	audio_info("bcm2835 ALSA card created with %u channels\n", numchans);
+
+	return 0;
+
+err_free:
+	snd_card_free(card);
+
+	return err;
+}
+
 static int snd_bcm2835_alsa_probe(struct platform_device *pdev)
 {
 	static int dev;
@@ -88,6 +169,9 @@ static int snd_bcm2835_alsa_probe(struct platform_device *pdev)
 	struct snd_card *card;
 	int err;
 
+	if (pdev->dev.of_node)
+		return snd_bcm2835_alsa_probe_dt(pdev);
+
 	if (dev >= MAX_SUBSTREAMS)
 		return -ENODEV;
 
@@ -224,6 +308,12 @@ static int snd_bcm2835_alsa_resume(struct platform_device *pdev)
 
 #endif
 
+static const struct of_device_id snd_bcm2835_of_match_table[] = {
+	{ .compatible = "brcm,bcm2835-audio", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, snd_bcm2835_of_match_table);
+
 static struct platform_driver bcm2835_alsa0_driver = {
 	.probe = snd_bcm2835_alsa_probe,
 	.remove = snd_bcm2835_alsa_remove,
@@ -234,6 +324,7 @@ static struct platform_driver bcm2835_alsa0_driver = {
 	.driver = {
 		   .name = "bcm2835_AUD0",
 		   .owner = THIS_MODULE,
+		   .of_match_table = snd_bcm2835_of_match_table,
 		   },
 };