Module: RPi::GPIO

Defined in:
lib/rpi_gpio.rb,
ext/rpi_gpio/rpi_gpio.c

Defined Under Namespace

Classes: Callback, GPIO, PWM

Class Method Summary collapse

Class Method Details

.add_callback(gpio, &block) ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 281

def self.add_callback(gpio, &block)
  @@callbacks << Callback.new(gpio, &block)
end

.add_edge_detect(gpio, edge, bounce_time = nil) ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 193

def self.add_edge_detect(gpio, edge, bounce_time = nil)
  current_edge = get_event_edge(gpio)
  if current_edge.nil?
    g = new_gpio(gpio)
    set_edge(gpio, edge)
    g.edge = edge
    g.bounce_time = bounce_time
  elsif current_edge == edge
    g = get_gpio(gpio)
    if (bounce_time && g.bounce_time != bounce_time) || g.thread_added
      raise RuntimeError, "conflicting edge detection already enabled for GPIO #{gpio}"
    end
  else
    raise RuntimeError, "conflicting edge detection already enabled for GPIO #{gpio}"
  end

  if @@epoll.nil?
    @@epoll = Epoll.create
  end

  begin
    @@epoll.add(g.value_file, Epoll::PRI)
  rescue
    remove_edge_detect(gpio)
    raise
  end

  g.thread_added = true
  if @@epoll_thread.nil? || !@@epoll_thread.alive?
    @@epoll_thread = Thread.new { poll_thread }
  end
end

.callback_exists(gpio) ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 289

def self.callback_exists(gpio)
  @@gpios.find { |g| g.gpio == gpio } != nil
end

.channel_from_gpio ⇒ Object

.clean_up ⇒ Object

.delete_gpio(gpio) ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 174

def self.delete_gpio(gpio)
  @@gpios.delete_if { |g| g.gpio == gpio }
end

.ensure_gpio_input ⇒ Object

.event_cleanup(gpio) ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 265

def self.event_cleanup(gpio)
  @@gpios.map { |g| g.gpio }.each do |gpio_|
    if gpio.nil? || gpio_ == gpio
      remove_edge_detect(gpio_)
    end
  end

  if @@gpios.empty? && @@epoll_thread
    @@epoll_thread.terminate
  end
end

.event_cleanup_all ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 277

def self.event_cleanup_all
  event_cleanup(nil)
end

.export(gpio) ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 105

def self.export(gpio)
  unless File.exist?("/sys/class/gpio/gpio#{gpio}")
    File.open("/sys/class/gpio/export", 'w') do |file|
      file.write(gpio.to_s)
    end
  end
end

.get_event_edge(gpio) ⇒ Object

gpio_event_added in python library



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# File 'lib/rpi_gpio.rb', line 186

def self.get_event_edge(gpio) # gpio_event_added in python library
  g = @@gpios.find { |g| g.gpio == gpio }
  if g
    return g.edge
  end
end

.get_gpio(gpio) ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 178

def self.get_gpio(gpio)
  @@gpios.find { |g| g.gpio == gpio }
end

.get_gpio_by_value_file(value_file) ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 182

def self.get_gpio_by_value_file(value_file)
  @@gpios.find { |g| g.value_file == value_file }
end

.get_gpio_number ⇒ Object

.high? ⇒ Boolean

Returns:

  • (Boolean)

.low? ⇒ Boolean

Returns:

  • (Boolean)

.new_gpio(gpio) ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 153

def self.new_gpio(gpio)
  g = GPIO.new
  g.gpio = gpio
  export(gpio)
  g.exported = true
  set_direction(gpio, :in)
  begin
    g.value_file = open_value_file(gpio)
  rescue
    unexport(gpio)
    raise
  end
  g.initial_thread = true
  g.initial_wait = true
  g.bounce_time = nil
  g.last_call = 0
  g.thread_added = false
  @@gpios << g
  g
end

.open_value_file(gpio) ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 149

def self.open_value_file(gpio)
  File.open("/sys/class/gpio/gpio#{gpio}/value", 'r')
end

.poll_thread ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 238

def self.poll_thread
  loop do
    begin
      events = @@epoll.wait
    rescue IOError # empty interest list
      break
    end
    events.each do |event|
      if event.events & Epoll::PRI != 0
        event.data.seek(0, IO::SEEK_SET)
        g = get_gpio_by_value_file(event.data)
        value = event.data.read.chomp.to_i
        if g.initial_thread # ignore first epoll trigger
          g.initial_thread = false
        else
          now = Time.now.to_f
          if g.bounce_time.nil? || g.last_call == 0 || g.last_call > now ||
             (now - g.last_call) * 1000 > g.bounce_time then
            g.last_call = now
            run_callbacks(g.gpio, value)
          end
        end
      end
    end
  end
end

.remove_callbacks(gpio) ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 285

def self.remove_callbacks(gpio)
  @@callbacks.delete_if { |g| g.gpio == gpio }
end

.remove_edge_detect(gpio) ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 226

def self.remove_edge_detect(gpio)
  g = get_gpio(gpio)
  if g and @@epoll
    @@epoll.del(g.value_file)
    set_edge(gpio, :none)
    g.edge = :none
    g.value_file.close
    unexport(gpio)
    delete_gpio(gpio)
  end
end

.reset ⇒ Object

.run_callbacks(gpio, value) ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 293

def self.run_callbacks(gpio, value)
  @@callbacks.each do |callback|
    if callback.gpio == gpio
      callback.block.call(channel_from_gpio(gpio), value)
    end
  end
end

.set_direction(gpio, direction) ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 119

def self.set_direction(gpio, direction)
  validate_direction(direction)
  tries = 0
  begin
    File.open("/sys/class/gpio/gpio#{gpio}/direction", 'w') do |file|
      file.write(direction.to_s)
    end
  rescue
    raise if tries > 5
    sleep 0.1
    tries += 1
    retry
  end
end

.set_edge(gpio, edge) ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 134

def self.set_edge(gpio, edge)
  validate_edge(edge)
  tries = 0
  begin
    File.open("/sys/class/gpio/gpio#{gpio}/edge", 'w') do |file|
      file.write(edge.to_s)
    end
  rescue
    raise if tries > 5
    sleep 0.1
    tries += 1
    retry
  end
end

.set_high ⇒ Object

.set_low ⇒ Object

.set_numbering ⇒ Object

.set_warnings ⇒ Object

.stop_watching(channel) ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 17

def self.stop_watching(channel)
  gpio = get_gpio_number(channel)
  ensure_gpio_input(gpio)
  remove_edge_detect(gpio)
  remove_callbacks(gpio)
end

.unexport(gpio) ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 113

def self.unexport(gpio)
  File.open("/sys/class/gpio/unexport", 'w') do |file|
    file.write(gpio.to_s)
  end
end

.validate_direction(direction) ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 301

def self.validate_direction(direction)
  direction = direction.to_s
  if direction != 'in' && direction != 'out'
    raise ArgumentError, "`direction` must be 'in' or 'out'; given '#{direction}'"
  end
end

.validate_edge(edge) ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 308

def self.validate_edge(edge)
  edge = edge.to_s
  if edge != 'rising' && edge != 'falling' && edge != 'both' && edge != 'none'
    raise ArgumentError, "`edge` must be 'rising', 'falling', 'both', or 'none'; given '#{edge}'"
  end
end

.wait_for_edge(channel, edge, bounce_time: nil, timeout: -1)) ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 24

def self.wait_for_edge(channel, edge, bounce_time: nil, timeout: -1)
  gpio = get_gpio_number(channel)
  if callback_exists(gpio)
    raise RuntimeError, "conflicting edge detection already enabled for GPIO #{gpio}"
  end

  ensure_gpio_input(gpio)
  validate_edge(edge)
  was_gpio_new = false
  current_edge = get_event_edge(gpio)
  if current_edge == edge
    g = get_gpio(gpio)
    if g.bounce_time && g.bounce_time != bounce_time
      raise RuntimeError, "conflicting edge detection already enabled for GPIO #{gpio}"
    end
  elsif current_edge.nil?
    was_gpio_new = true
    g = new_gpio(gpio)
    set_edge(gpio, edge)
    g.edge = edge
    g.bounce_time = bounce_time
  else
    g = get_gpio(gpio)
    set_edge(gpio, edge)
    g.edge = edge
    g.bounce_time = bounce_time
    g.initial_wait = 1
  end

  if @@epoll_blocking.nil?
    @@epoll_blocking = Epoll.create
  end
  @@epoll_blocking.add(g.value_file, Epoll::PRI)

  initial_edge = true
  the_value = nil
  timed_out = false
  begin
    while the_value.nil? && !timed_out do
      events = @@epoll_blocking.wait(timeout)
      if events.empty?
        timed_out = true
      end
      events.each do |event|
        if event.events & Epoll::PRI != 0
          event.data.seek(0, IO::SEEK_SET)
          value = event.data.read.chomp.to_i
          if event.data == g.value_file
            if initial_edge # ignore first epoll trigger
              initial_edge = false
            else
              now = Time.now.to_f
              if g.bounce_time.nil? || g.last_call == 0 || g.last_call > now ||
                 (now - g.last_call) * 1000 > g.bounce_time then
                g.last_call = now
                the_value = value
              end
            end
          end
        end
      end
    end

    if the_value
      return the_value
    end
  ensure
    @@epoll_blocking.del(g.value_file)
    if was_gpio_new
      delete_gpio(gpio)
    end
  end
end

.watch(channel, on:, bounce_time: nil, &block) ⇒ Object 



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# File 'lib/rpi_gpio.rb', line 6

def self.watch(channel, on:, bounce_time: nil, &block) 
  gpio = get_gpio_number(channel)
  ensure_gpio_input(gpio)
  validate_edge(on)
  if bounce_time && bounce_time <= 0
    raise ArgumentError, "`bounce_time` must be greater than 0; given #{bounce_time}"
  end
  add_edge_detect(gpio, on, bounce_time)
  add_callback(gpio, &block)
end