Documentation/devicetree/bindings/arm/vexpress-sysreg.txt

   1 ARM Versatile Express system registers
   2 --------------------------------------
   3
   4 This is a system control registers block, providing multiple low level
   5 platform functions like board detection and identification, software
   6 interrupt generation, MMC and NOR Flash control etc.
   7
   8 Required node properties:
   9 - compatible value : = "arm,vexpress,sysreg";
  10 - reg : physical base address and the size of the registers window
  11 - gpio-controller : specifies that the node is a GPIO controller
  12 - #gpio-cells : size of the GPIO specifier, should be 2:
  13   - first cell is the pseudo-GPIO line number:
  14     0 - MMC CARDIN
  15     1 - MMC WPROT
  16     2 - NOR FLASH WPn
  17   - second cell can take standard GPIO flags (currently ignored).
  18
  19 Example:
  20         v2m_sysreg: sysreg@10000000 {
  21                 compatible = "arm,vexpress-sysreg";
  22                 reg = <0x10000000 0x1000>;
  23                 gpio-controller;
  24                 #gpio-cells = <2>;
  25         };
  26
  27 This block also can also act a bridge to the platform's configuration
  28 bus via "system control" interface, addressing devices with site number,
  29 position in the board stack, config controller, function and device
  30 numbers - see motherboard's TRM for more details. All configuration
  31 controller accessible via this interface must reference the sysreg
  32 node via "arm,vexpress,config-bridge" phandle and define appropriate
  33 topology properties - see main vexpress node documentation for more
  34 details. Each child of such node describes one function and must
  35 define the following properties:
  36 - compatible value : must be one of (corresponding to the TRM):
  37         "arm,vexpress-amp"
  38         "arm,vexpress-dvimode"
  39         "arm,vexpress-energy"
  40         "arm,vexpress-muxfpga"
  41         "arm,vexpress-osc"
  42         "arm,vexpress-power"
  43         "arm,vexpress-reboot"
  44         "arm,vexpress-reset"
  45         "arm,vexpress-scc"
  46         "arm,vexpress-shutdown"
  47         "arm,vexpress-temp"
  48         "arm,vexpress-volt"
  49 - arm,vexpress-sysreg,func : must contain a set of two cells long groups:
  50   - first cell of each group defines the function number
  51     (eg. 1 for clock generator, 2 for voltage regulators etc.)
  52   - second cell of each group defines device number (eg. osc 0,
  53     osc 1 etc.)
  54   - some functions (eg. energy meter, with its 64 bit long counter)
  55     are using more than one function/device number pair
  56
  57 Example:
  58         mcc {
  59                 compatible = "arm,vexpress,config-bus";
  60                 arm,vexpress,config-bridge = <&v2m_sysreg>;
  61
  62                 osc@0 {
  63                         compatible = "arm,vexpress-osc";
  64                         arm,vexpress-sysreg,func = <1 0>;
  65                 };
  66
  67                 energy@0 {
  68                         compatible = "arm,vexpress-energy";
  69                         arm,vexpress-sysreg,func = <13 0>, <13 1>;
  70                 };
  71         };