arch/arm/boot/dts/overlays/miniuart-bt-overlay.dts

   1 /dts-v1/;
   2 /plugin/;
   3
   4 /* Switch Pi3 Bluetooth function to use the mini-UART (ttyS0) and restore
   5    UART0/ttyAMA0 over GPIOs 14 & 15. Note that this may reduce the maximum
   6    usable baudrate.
   7
   8    It is also necessary to edit /lib/systemd/system/hciuart.service and
   9    replace ttyAMA0 with ttyS0, unless you have a system with udev rules
  10    that create /dev/serial0 and /dev/serial1, in which case use /dev/serial1
  11    instead because it will always be correct.
  12
  13    If cmdline.txt uses the alias serial0 to refer to the user-accessable port
  14    then the firmware will replace with the appropriate port whether or not
  15    this overlay is used.
  16 */
  17
  18 /{
  19         compatible = "brcm,bcm2835";
  20
  21         fragment@0 {
  22                 target = <&uart0>;
  23                 __overlay__ {
  24                         pinctrl-names = "default";
  25                         pinctrl-0 = <&uart0_pins>;
  26                         status = "okay";
  27                 };
  28         };
  29
  30         fragment@1 {
  31                 target = <&uart1>;
  32                 __overlay__ {
  33                         pinctrl-names = "default";
  34                         pinctrl-0 = <&uart1_pins &bt_pins &fake_bt_cts>;
  35                         status = "okay";
  36                 };
  37         };
  38
  39         fragment@2 {
  40                 target = <&uart0_pins>;
  41                 __overlay__ {
  42                         brcm,pins;
  43                         brcm,function;
  44                         brcm,pull;
  45                 };
  46         };
  47
  48         fragment@3 {
  49                 target = <&uart1_pins>;
  50                 __overlay__ {
  51                         brcm,pins = <32 33>;
  52                         brcm,function = <2>; /* alt5=UART1 */
  53                         brcm,pull = <0 2>;
  54                 };
  55         };
  56
  57         fragment@4 {
  58                 target = <&gpio>;
  59                 __overlay__ {
  60                         fake_bt_cts: fake_bt_cts {
  61                                 brcm,pins = <31>;
  62                                 brcm,function = <1>; /* output */
  63                         };
  64                 };
  65         };
  66
  67         fragment@5 {
  68                 target-path = "/aliases";
  69                 __overlay__ {
  70                         serial0 = "/soc/serial@7e201000";
  71                         serial1 = "/soc/serial@7e215040";
  72                 };
  73         };
  74 };