#!/bin/sh

##############################################################################
#
# GPIO teardown script for SvxLink server. Run this script to undo the GPIO
# configuration done by the svxlink_gpio_up script.
#
##############################################################################

# Exit on failed commands and undefined variables
set -eu

# Read configuration file
GPIO_CONF=${GPIO_CONF-"@SVX_SYSCONF_INSTALL_DIR@/gpio.conf"}
[ -r "${GPIO_CONF}" ] && . "${GPIO_CONF}"


# Print warning message to stderr
#
#   MSG -- The message to print
#
warning()
{
  local MSG="$1"; shift
  echo "*** WARNING: ${MSG}" 1>&2
}


# Unset GPIO IN/OUT pins, if used
for pin in ${GPIO_IN_HIGH:-} ${GPIO_IN_LOW:-} \
           ${GPIO_OUT_HIGH:-} ${GPIO_OUT_LOW:-}; do
  if [ -e "${GPIO_PATH}/${pin}" ]; then
    # Extract pinnumber from the full pin name (e.g. gpio4_pd0 -> 4)
    pinnum=$(echo "${pin}" | sed 's/^[^0-9]*\([0-9][0-9]*\).*$/\1/')
    if ! echo ${pinnum} > "${GPIO_PATH}/unexport"; then
      warning "Could not undefine GPIO pin \"${pin}\""
    fi
  fi
done
