anchor.diff:  ----
   
   One Open PIC interrupt controller is represented and is identified as an
  -interrupt controller with an interrupt-controller property.
  +interrupt controller with an _interrupt-controller_ property.
   
   Each row in the interrupt-map table consists of five parts—a child unit
  -address and interrupt specifier, which is mapped to an interrupt-parent
  +address and interrupt specifier, which is mapped to an _interrupt-parent_
   node with a specified parent unit address and interrupt specifier.
   
   For example, the first row of the interrupt-map table specifies the
  
positive.code: [cols="10,90"]
  |===
  |Property |_device_type_
  |Value type |<string>
  |===
  .Description
  The device_type property was used in IEEE 1275 to describe the device's
  FCode programming model. Because {spec} does not have FCode, new use of
  the property is deprecated, and it should be included only on cpu and
  memory nodes for compatibility with IEEE 1275–derived device trees.
  
  === Interrupts and Interrupt Mapping
  The {spec} adopts the interrupt tree model of representing interrupts
  specified in Open Firmware Recommended Practice: Interrupt Mapping,
  Version 0.9 <<7>>. Within the device tree a logical interrupt tree exists
  that represents the hierarchy and routing of interrupts in the platform
  hardware. While generically referred to as an interrupt tree it is more
  technically a directed acyclic graph.
  
  The physical wiring of an interrupt source to an interrupt controller is
  represented in the device tree with the interrupt-parent property. Nodes
  that represent interrupt-generating devices contain an interrupt-parent
  property which has a phandle value that points to the device to which
  the device's interrupts are routed, typically an interrupt controller.
  If an interrupt-generating device does not have an interrupt-parent
  property, its interrupt parent is assumed to be its device tree parent.
  
  Each interrupt generating device contains an interrupts property with a
  value describing one or more interrupt sources for that device—each
  source represented with information called an interrupt specifier. The
  format and meaning of an interrupt specifier is interrupt domain
  specific, i.e., it is dependent on properties on the node at the root of
  its interrupt domain. The #interrupt-cells property is used by the root
  of an interrupt domain to define the number of <u32> values needed to
  encode an interrupt specifier. For example, for an Open PIC interrupt
  controller, an interrupt-specifer takes two 32-bit values and consists
  of an interrupt number and level/sense information for the interrupt.
  
negative.code: |===
  |Property Name |Usage |Value Type |Definition
  |#address-cells |R |<u32> |Specifies the number of <u32> cells to
  represent the address in the _reg_ property in children of root.
  |#size-cells |R |<u32> |Specifies the number of <u32> cells to represent
  the size in the _reg_ property in children of root.
  |model |R |<string> |Specifies a string that uniquely identifies the
  model of the system board. The recommended format is
  “manufacturer,model-number”.
  