doc/device-tree-bindings/chosen.txt

   1 The chosen node
   2 ---------------
   3 The chosen node does not represent a real device, but serves as a place
   4 for passing data like which serial device to used to print the logs etc
   5
   6
   7 stdout-path property
   8 --------------------
   9 Device trees may specify the device to be used for boot console output
  10 with a stdout-path property under /chosen.
  11
  12 Example
  13 -------
  14 / {
  15         chosen {
  16                 stdout-path = "/serial@f00:115200";
  17         };
  18
  19         serial@f00 {
  20                 compatible = "vendor,some-uart";
  21                 reg = <0xf00 0x10>;
  22         };
  23 };
  24
  25 tick-timer property
  26 -------------------
  27 In a system there are multiple timers, specify which timer to be used
  28 as the tick-timer. Earlier it was hardcoded in the timer driver now
  29 since device tree has all the timer nodes. Specify which timer to be
  30 used as tick timer.
  31
  32 Example
  33 -------
  34 / {
  35         chosen {
  36                 tick-timer = "/timer2@f00";
  37         };
  38
  39         timer2@f00 {
  40                 compatible = "vendor,some-timer";
  41                 reg = <0xf00 0x10>;
  42         };
  43 };
  44
  45 u-boot,spl-boot-order property
  46 ------------------------------
  47
  48 In a system using an SPL stage and having multiple boot sources
  49 (e.g. SPI NOR flash, on-board eMMC and a removable SD-card), the boot
  50 device may be probed by reading the image and verifying an image
  51 signature.
  52
  53 If the SPL is configured through the device-tree, the boot-order can
  54 be configured with the spl-boot-order property under the /chosen node.
  55 Each list element of the property should specify a device to be probed
  56 in the order they are listed: references (i.e. implicit paths), a full
  57 path or an alias is expected for each entry.
  58
  59 Example
  60 -------
  61 / {
  62         chosen {
  63                 u-boot,spl-boot-order = &sdmmc, "/sdhci@fe330000";
  64         };
  65 };