#!/bin/sh
#
# Configure LTC2145 ADC via SPI.
#
# This only works on a 4-input Red Pitaya.
#

# Run spi-pipe with the correct parameters.
run_spi_pipe() {
    spi-pipe -d "$1" -m 0 -s 1000000 -l 0 -B 8 -b 2 -n 1 >/dev/null
}

# Initialize both ADCs.
adc_init() {

    force=
    dcs=0

    shift
    while [ -n "$1" ]; do
        case "$1" in
          --force)
            force=1
            ;;
          --dcs)
            dcs=1
            ;;
          *)
            echo "ERROR: Unknown option '$1'" >&2
            exit 1
        esac
        shift
    done

    if [ -z "$force" ]; then
        echo "ERROR: Not initializing ADC without --force option." >&2
        exit 1
    fi

    for spidev in /dev/spidev0.0 /dev/spidev0.1 ; do

        echo "Initializing ADC via $spidev"

	# Reset register (address = 0x00)
	#
	# bit 7 = RESET
	#
	printf '\000\200' | run_spi_pipe $spidev

	# Timing register (address = 0x02)
	#
	# bit 0    = DCS
	# bits 2:1 = CLKPHASE
	# bit 3    = CLKINV
	#
	printf '\002\20'"$dcs" | run_spi_pipe $spidev

	# Output mode register (address = 0x03)
	#
	# bits 1:0 = OUTMODE  (2 = double data rate CMOS output mode)
	# bit 2    = OUTOFF
	# bit 3    = TERMON
	# bits 6:4 = ILVDS
	#
	printf '\003\002' | run_spi_pipe $spidev

    done
}

# Write data format register.
adc_format() {

    # Data format register (address = 0x04)
    #
    # bit 0    = TWOSCOMP
    # bit 1    = RAND
    # bit 2    = ABP
    # bits 5:3 = OUTTEST

    d1=0  # octal digit 1 = OUTTEST
    d0=0  # octal digit 0 = RAND*2

    shift
    while [ -n "$1" ]; do
        case "$1" in
          --testzero)
            d1=1
            ;;
          --testone)
            d1=3
            ;;
          --testchecker)
            d1=5
            ;;
          --testalter)
            d1=7
            ;;
          --rand)
            d0=2
            ;;
          *)
            echo "ERROR: Unknown option '$1'" >&2
            exit 1
        esac
        shift
    done

    for spidev in /dev/spidev0.0 /dev/spidev0.1 ; do
        printf '\004\0'"${d1}${d0}" | run_spi_pipe $spidev
    done
}

case "$1" in
  init)
    adc_init "$@"
    ;;
  format)
    adc_format "$@"
    ;;
  *)
    script="${0##*/}"
    cat <<EOF
Usage: $script {init|format}

  $script init {options}
    Reset ADCs and initialize timing and output mode.
    This must NOT be done while the FPGA is active.

    options:
      --force               Required option to override warning.
      --dcs                 Enable clock duty cycle stabilizer.

  $script format {options}
    Configure data format.
    By default, disables test patterns and disables output randomizer.

    options:
      --testzero            Enable all-zero test pattern.
      --testone             Enable all-one test pattern.
      --testchecker         Enable checkerboard test pattern.
      --testalter           Enable alternating test pattern.
      --rand                Enable output randomizer mode.

EOF
    exit 1
    ;;
esac

exit $?