arch/arm/boot/dts/overlays/midi-uart1-overlay.dts

   1 /dts-v1/;
   2 /plugin/;
   3
   4 #include <dt-bindings/clock/bcm2835-aux.h>
   5
   6 /*
   7  * Fake a higher clock rate to get a larger divisor, and thereby a lower
   8  * baudrate. The real clock is 48MHz, which we scale so that requesting
   9  * 38.4kHz results in an actual 31.25kHz.
  10  *
  11  *   48000000*38400/31250 = 58982400
  12  */
  13
  14 /{
  15         compatible = "brcm,bcm2835";
  16
  17         fragment@0 {
  18                 target-path = "/clocks";
  19                 __overlay__ {
  20                         midi_clk: clock@5 {
  21                                 compatible = "fixed-factor-clock";
  22                                 #clock-cells = <0>;
  23                                 clocks = <&aux BCM2835_AUX_CLOCK_UART>;
  24                                 clock-mult = <38400>;
  25                                 clock-div  = <31250>;
  26                         };
  27                 };
  28         };
  29
  30         fragment@1 {
  31                 target = <&uart1>;
  32                 __overlay__ {
  33                         clocks = <&midi_clk>;
  34                 };
  35         };
  36
  37         fragment@2 {
  38                 target = <&aux>;
  39                 __overlay__ {
  40                         clock-output-names = "aux_uart", "aux_spi1", "aux_spi2";
  41                 };
  42         };
  43 };