block/UART:
  description: UART register block, compatible with 8250
  items:
    - name: RBR
      description: Receiver buffer register.
      byte_offset: 0
      access: Read
      fieldset: RBR
    - name: THR
      description: Transmitter holding register.
      byte_offset: 0
      access: Write
      fieldset: THR
    - name: IER
      description: Interrupt enable register.
      byte_offset: 4
      fieldset: IER
    - name: IIR
      description: Interrupt identification register.
      byte_offset: 8
      access: Read
      fieldset: IIR
    - name: LCR
      description: Line control register.
      byte_offset: 12
      fieldset: LCR
    - name: MCR
      description: Modem control register.
      byte_offset: 16
      fieldset: MCR
    - name: LSR
      description: Line status register.
      byte_offset: 20
      fieldset: LSR
    - name: MSR
      description: Modem status register.
      byte_offset: 24
      fieldset: MSR
    - name: SCR
      description: Scratch register.
      byte_offset: 28
      fieldset: SCR
    - name: DLL
      description: Divisor latch low.
      byte_offset: 0
      fieldset: DLL
    - name: DLH
      description: Divisor latch high.
      byte_offset: 4
      fieldset: DLH
fieldset/RBR:
  description: Receiver buffer register
  fields:
    - name: RBR
      description: Data
      bit_offset: 0
      bit_size: 8
fieldset/THR:
  description: Transmitter holding register
  fields:
    - name: THR
      description: Data
      bit_offset: 0
      bit_size: 8
fieldset/IER:
  description: Interrupt enable register
  fields:
    - name: ERBFI
      description: Enable received data available interrupt
      bit_offset: 0
      bit_size: 1
    - name: ETBEI
      description: Enable transmitter holding register empty interrupt
      bit_offset: 1
      bit_size: 1
    - name: ELSI
      description: Enable receiver line status interrupt
      bit_offset: 2
      bit_size: 1
    - name: EDSSI
      description: Enable modem status interrupt
      bit_offset: 3
      bit_size: 1
fieldset/IIR:
  description: Interrupt identification register
  fields:
    - name: IP
      description: Interrupt pending
      bit_offset: 0
      bit_size: 1
    - name: IID
      description: Interrupt identification
      bit_offset: 1
      bit_size: 3 # 2 bits
fieldset/LCR:
  description: Line control register
  fields:
    - name: WLS
      description: Word length select, aka. DLS
      bit_offset: 0
      bit_size: 2
      enum: DATA_BITS
    - name: STOP
      description: Number of stop bits, aka. STB
      bit_offset: 2
      bit_size: 1
      enum: STOP_BITS
    - name: PEN
      description: Parity enable
      bit_offset: 3
      bit_size: 1
    - name: EPS
      description: Even parity select
      bit_offset: 4
      bit_size: 1
      enum: PARITY_SELECT
    - name: SP
      description: Stick parity
      bit_offset: 5
      bit_size: 1
    - name: SB
      description: Set break
      bit_offset: 6
      bit_size: 1
    - name: DLAB
      description: Divisor latch access bit
      bit_offset: 7
      bit_size: 1
fieldset/MCR:
  description: Modem control register
  fields:
    - name: DTR
      description: Data terminal ready
      bit_offset: 0
      bit_size: 1
    - name: RTS
      description: Request to send
      bit_offset: 1
      bit_size: 1
    - name: OUT1
      description: Output 1
      bit_offset: 2
      bit_size: 1
    - name: OUT2
      description: Output 2
      bit_offset: 3
      bit_size: 1
    - name: LB
      description: Loopback mode, aka. LOOP
      bit_offset: 4
      bit_size: 1
fieldset/LSR:
  description: Line status register
  fields:
    - name: DR
      description: Data ready
      bit_offset: 0
      bit_size: 1
    - name: OE
      description: Overrun error
      bit_offset: 1
      bit_size: 1
    - name: PE
      description: Parity error
      bit_offset: 2
      bit_size: 1
    - name: FE
      description: Framing error
      bit_offset: 3
      bit_size: 1
    - name: BI
      description: Break interrupt
      bit_offset: 4
      bit_size: 1
    - name: THRE
      description: Transmitter holding register empty
      bit_offset: 5
      bit_size: 1
    - name: TEMT
      description: Transmitter empty
      bit_offset: 6
      bit_size: 1
fieldset/MSR:
  description: Modem status register
  fields:
    - name: DCTS
      description: Delta clear to send
      bit_offset: 0
      bit_size: 1
    - name: DDSR
      description: Delta data set ready
      bit_offset: 1
      bit_size: 1
    - name: TERI
      description: Trailing edge ring indicator
      bit_offset: 2
      bit_size: 1
    - name: DDCD
      description: Delta data carrier detect
      bit_offset: 3
      bit_size: 1
    - name: CTS
      description: Clear to send
      bit_offset: 4
      bit_size: 1
    - name: DSR
      description: Data set ready
      bit_offset: 5
      bit_size: 1
    - name: RI
      description: Ring indicator
      bit_offset: 6
      bit_size: 1
    - name: DCD
      description: Data carrier detect
      bit_offset: 7
      bit_size: 1
fieldset/SCR:
  description: Scratch register
  fields:
    - name: SCR
      description: Data
      bit_offset: 0
      bit_size: 8
fieldset/DLL:
  description: Divisor latch low
  fields:
    - name: DLL
      description: Data
      bit_offset: 0
      bit_size: 8
fieldset/DLH:
  description: Divisor latch high
  fields:
    - name: DLH
      description: Data
      bit_offset: 0
      bit_size: 8
enum/DATA_BITS:
  bit_size: 2
  variants:
    - name: Bit5
      description: 5 bits
      value: 0b00
    - name: Bit6
      description: 6 bits
      value: 0b01
    - name: Bit7
      description: 7 bits
      value: 0b10
    - name: Bit8
      description: 8 bits
      value: 0b11
enum/STOP_BITS:
  bit_size: 1
  variants:
    - name: Stop1
      description: 1 stop bit
      value: 0
    - name: Stop2
      description: 2 stop bits (1.5 when 5 bits)
      value: 1
enum/PARITY_SELECT:
  bit_size: 1
  variants:
    - name: Odd
      description: Odd parity (one)
      value: 0
    - name: Even
      description: Even parity (zero)
      value: 1