unit gpio;

interface

procedure setup_input(port : string);
procedure setup_output(port : string);
procedure port_write(port : string; value : string);
function port_read(port : string) : string;
procedure release(port : string);

implementation

procedure write_to_file(filename : string; msg : string);
var
  f : text;
begin
  Assign(f, filename);
  Append(f);
  Writeln(f, msg);
  Close(f);
end;

function read_from_file(filename : string) : string;
var
  f : text;
  res : string;
begin
  Assign(f, filename);
  Reset(f);
  Readln(f, res);
  read_from_file := res;
end;

procedure setup_input(port : string);
begin
  write_to_file ('/sys/class/gpio/export', port);
  write_to_file ('/sys/class/gpio/gpio' + port + '/direction', 'in');
end;

procedure setup_output(port : string);
begin
  write_to_file ('/sys/class/gpio/export', port);
  write_to_file ('/sys/class/gpio/gpio' + port + '/direction', 'out');
end;

procedure port_write(port : string; value : string);
begin
  write_to_file ('/sys/class/gpio/gpio' + port + '/value', value);
end;

function port_read(port : string) : string;
begin
  port_read := read_from_file ('/sys/class/gpio/gpio' + port + '/value');
end;

procedure release(port : string);
begin
  write_to_file ('/sys/class/gpio/unexport', port);
end;


begin
end.