BCM270x_DT: Configure UART using DT

See: raspberrypi/firmware#393

Author: Phil Elwell

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

@@ -16,6 +16,7 @@
 		intc = &intc;
 		leds = &leds;
 		sound = &sound;
+		uart0 = &uart0;
 	};
 
 	sound: sound {
@@ -53,6 +54,10 @@
 	status = "okay";
 };
 
+&uart0 {
+	status = "okay";
+};
+
 &spi0 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&spi0_pins>;
@@ -108,6 +113,8 @@
 
 / {
 	__overrides__ {
+		uart0 = <&uart0>,"status";
+		uart0_clkrate = <&clk_uart0>,"clock-frequency:0";
 		i2s = <&i2s>,"status";
 		spi = <&spi0>,"status";
 		i2c0 = <&i2c0>,"status";

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

@@ -16,6 +16,7 @@
 		intc = &intc;
 		leds = &leds;
 		sound = &sound;
+		uart0 = &uart0;
 	};
 
 	sound: sound {
@@ -53,6 +54,10 @@
 	status = "okay";
 };
 
+&uart0 {
+	status = "okay";
+};
+
 &spi0 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&spi0_pins>;
@@ -102,6 +107,8 @@
 
 / {
 	__overrides__ {
+		uart0 = <&uart0>,"status";
+		uart0_clkrate = <&clk_uart0>,"clock-frequency:0";
 		i2s = <&i2s>,"status";
 		spi = <&spi0>,"status";
 		i2c0 = <&i2c0>,"status";

arch/arm/boot/dts/bcm2708_common.dtsi

@@ -84,6 +84,17 @@
 			status = "disabled";
 		};
 
+		uart0: uart@7e201000 {
+			compatible = "arm,pl011", "arm,primecell";
+			reg = <0x7e201000 0x1000>;
+			interrupts = <2 25>;
+			clocks = <&clk_uart0 &clk_apb_p>;
+			clock-names = "uartclk","apb_pclk";
+			arm,primecell-periphid = <0x00241011>; // For an explanation, see
+			// https://github.com/raspberrypi/linux/commit/13731d862cf5219216533a3b0de052cee4cc5038
+			status = "disabled";
+		};
+
 		i2s: i2s@7e203000 {
 			compatible = "brcm,bcm2708-i2s";
 			reg = <0x7e203000 0x20>,
@@ -188,5 +199,21 @@
 			clock-output-names = "spi";
 			clock-frequency = <250000000>;
 		};
+
+		clk_uart0: clock@3 {
+			compatible = "fixed-clock";
+			reg = <3>;
+			#clock-cells = <0>;
+			clock-output-names = "uart0_pclk";
+			clock-frequency = <3000000>;
+		};
+
+		clk_apb_p: clock@4 {
+			compatible = "fixed-clock";
+			reg = <4>;
+			#clock-cells = <0>;
+			clock-output-names = "apb_pclk";
+			clock-frequency = <126000000>;
+		};
 	};
 };

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

@@ -16,6 +16,7 @@
 		intc = &intc;
 		leds = &leds;
 		sound = &sound;
+		uart0 = &uart0;
 	};
 
 	sound: sound {
@@ -53,6 +54,10 @@
 	status = "okay";
 };
 
+&uart0 {
+	status = "okay";
+};
+
 &spi0 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&spi0_pins>;
@@ -108,6 +113,8 @@
 
 / {
 	__overrides__ {
+		uart0 = <&uart0>,"status";
+		uart0_clkrate = <&clk_uart0>,"clock-frequency:0";
 		i2s = <&i2s>,"status";
 		spi = <&spi0>,"status";
 		i2c0 = <&i2c0>,"status";

arch/arm/mach-bcm2709/bcm2709.c

@@ -1043,10 +1043,11 @@ void __init bcm2709_init(void)
         i2c_register_board_info_dt(1, snd_pcm512x_i2c_devices, ARRAY_SIZE(snd_pcm512x_i2c_devices));
 #endif
 
-
-	for (i = 0; i < ARRAY_SIZE(amba_devs); i++) {
-		struct amba_device *d = amba_devs[i];
-		amba_device_register(d, &iomem_resource);
+	if (!use_dt) {
+		for (i = 0; i < ARRAY_SIZE(amba_devs); i++) {
+			struct amba_device *d = amba_devs[i];
+			amba_device_register(d, &iomem_resource);
+		}
 	}
 	system_rev = boardrev;
 	system_serial_low = serial;