miniuart-bt-overlay.dts

/dts-v1/;
/plugin/;

/* Switch Pi3 Bluetooth function to use the mini-UART (ttyS0) and restore
   UART0/ttyAMA0 over GPIOs 14 & 15. Note that this may reduce the maximum
   usable baudrate.

   It is also necessary to edit /lib/systemd/system/hciuart.service and
   replace ttyAMA0 with ttyS0, unless you have a system with udev rules
   that create /dev/serial0 and /dev/serial1, in which case use /dev/serial1
   instead because it will always be correct.

   If cmdline.txt uses the alias serial0 to refer to the user-accessable port
   then the firmware will replace with the appropriate port whether or not
   this overlay is used.
*/

#include <dt-bindings/gpio/gpio.h>

/{
	compatible = "brcm,bcm2835";

	fragment@0 {
		target = <&uart0>;
		__overlay__ {
			pinctrl-names = "default";
			pinctrl-0 = <&uart0_pins>;
			status = "okay";
		};
	};

	fragment@1 {
		target = <&bt>;
		__overlay__ {
			status = "disabled";
		};
	};

	fragment@2 {
		target = <&uart1>;
		__overlay__ {
			pinctrl-names = "default";
			pinctrl-0 = <&uart1_pins &bt_pins &fake_bt_cts>;
			status = "okay";
		};
	};

	fragment@3 {
		target = <&uart0_pins>;
		__overlay__ {
			brcm,pins;
			brcm,function;
			brcm,pull;
		};
	};

	fragment@4 {
		target = <&uart1_pins>;
		__overlay__ {
			brcm,pins = <32 33>;
			brcm,function = <2>; /* alt5=UART1 */
			brcm,pull = <0 2>;
		};
	};

	fragment@5 {
		target = <&gpio>;
		__overlay__ {
			fake_bt_cts: fake_bt_cts {
				brcm,pins = <31>;
				brcm,function = <1>; /* output */
			};
		};
	};

	fragment@6 {
		target-path = "/aliases";
		__overlay__ {
			serial0 = "/soc/serial@7e201000";
			serial1 = "/soc/serial@7e215040";
		};
	};

	fragment@7 {
		target = <&minibt>;
		minibt_frag: __overlay__ {
		};
	};

	__overrides__ {
		krnbt = <&minibt_frag>,"status";
	};
};