Adjust brightness on HyperPixel 4

brightness.sh

#!/usr/bin/env bash

PIN=19
FREQ=100

STEP=100000
MAX=1000000
MIN=0

get_current_duty() {
  pigs gdc "$PIN"
}

set_duty() {
  local newDuty=$1

  # Clamp values
  if [ "$newDuty" -lt "$MIN" ]; then
    newDuty=$MIN
  fi
  if [ "$newDuty" -gt "$MAX" ]; then
    newDuty=$MAX
  fi

  pigs hp "$PIN" "$FREQ" "$newDuty"
}

case "$1" in
  up)
    current=$(get_current_duty)
    new=$(( current + STEP ))
    set_duty "$new"
    ;;
  down)
    current=$(get_current_duty)
    new=$(( current - STEP ))
    set_duty "$new"
    ;;
  off)
    set_duty 0
    ;;
  *)
    if [[ "$1" =~ ^[0-9]+$ ]]; then
      if [ "$1" -lt 0 ] || [ "$1" -gt 100 ]; then
        echo "Percentage must be between 0 and 100."
        exit 1
      fi
      new=$(( ( $1 * MAX ) / 100 ))
      set_duty "$new"
    else
      echo "Usage: $0 {up|down|off|<0-100>}"
      exit 1
    fi
    ;;
esac