refactor: simplify libgpiod implementation

include/sensor_trigger/jetson_gpio.hpp

@@ -25,8 +25,8 @@
 
 #define SYSFS_GPIO_DIR "/sys/class/gpio"
 #define BUFFER_SIZE 64
-#define GPIO_OUTPUT 1
-#define GPIO_INPUT 0
+#define GPIO_OUTPUT gpiod::line_request::DIRECTION_OUTPUT
+#define GPIO_INPUT gpiod::line_request::DIRECTION_INPUT
 #define GPIO_HIGH 1
 #define GPIO_LOW 0
 
@@ -35,29 +35,22 @@ typedef int gpio_state;
 
 namespace jetson_gpio
 {
-// Mapping of GPIO number to pin number for ROSCubeX
-// Note: pin 5->216 is pin 5 on the DB50 connector, run by GPIO chip 216 (starting at GPIO number
-// 216)
-static std::map<int, int> pin_gpio_mapping{{5, 216}, {51, 408}, {52, 350}, {53, 446}, {54, 445}};
-
 class JetsonGpio
 {
 public:
- JetsonGpio() : state_file_descriptor_(-1) {}
+ JetsonGpio() = default;
  ~JetsonGpio();
  bool init_gpio_pin(unsigned int gpio_chip, unsigned int gpio_line, gpio_direction direction);
  bool set_gpio_pin_state(gpio_state state);
 
 protected:
- bool export_gpio();
- bool unexport_gpio();
+ bool close_gpio();
  bool set_gpio_direction(gpio_direction direction);
 
- int state_file_descriptor_;
  int gpio_;
 
  gpiod::chip gpio_chip_;
- gpiod::line_bulk gpio_lines_;
+ gpiod::line gpio_line_;
  gpiod::line_request gpio_request_;
 };
 } // namespace jetson_gpio

src/jetson_gpio.cpp

@@ -22,15 +22,11 @@ namespace jetson_gpio
 {
 JetsonGpio::~JetsonGpio()
 {
- if (state_file_descriptor_ > -1) {
- close(state_file_descriptor_);
- }
-
  // Regardless of the existence of other processes that uses the same GPIO pin
  // (incl. zombie GPIO port opening because of failure exit),
- // this unexport closes the target GPIO pin anyway.
+ // this function closes the target GPIO pin anyway.
  // This behavior intends to make next try to use this GPIO pin success.
- unexport_gpio();
+ close_gpio();
 }
 
 bool JetsonGpio::init_gpio_pin(
@@ -39,49 +35,29 @@ bool JetsonGpio::init_gpio_pin(
  std::string gpio_character_device = "/dev/gpiochip" + std::to_string(gpio_chip);
 
  gpio_chip_ = gpiod::chip(gpio_character_device);
- gpio_lines_ = gpio_chip_.get_lines(
- std::vector<unsigned int>({gpio_line})); // XXX: 143 = Anvil misc.I/O GP_Out_1, 108 = PWM_Out_0
+ gpio_line_ = gpio_chip_.get_line(gpio_line);
  gpio_request_ = {
- "sensor_trigger", // consumer name. XXX: fixed name may conflict for multiple instances
- gpiod::line_request::DIRECTION_OUTPUT, // request_type
- 0  // flag
+ "sensor_trigger",  // consumer name
+ direction,  // request_type
+ 0 // flag
  };
 
- if (!set_gpio_direction(direction)) {
- return false;
- }
 
- gpio_lines_.request(gpio_request_, std::vector<int>({GPIO_LOW}));
+ gpio_line_.request(gpio_request_, GPIO_LOW);
 
  return true;
 }
 
-bool JetsonGpio::export_gpio() { return true; }
-
-bool JetsonGpio::unexport_gpio()
+bool JetsonGpio::close_gpio()
 {
  gpio_chip_.~chip();
 
  return true;
 }
 
-bool JetsonGpio::set_gpio_direction(gpio_direction direction)
-{
- switch (direction) {
- case GPIO_INPUT:
- gpio_request_.request_type = gpiod::line_request::DIRECTION_INPUT;
- break;
- case GPIO_OUTPUT:
- gpio_request_.request_type = gpiod::line_request::DIRECTION_OUTPUT;
- break;
- }
-
- return true;
-}
-
 bool JetsonGpio::set_gpio_pin_state(gpio_state state)
 {
- gpio_lines_.set_values(std::vector<int>({state}));
+ gpio_line_.set_value(state);
 
  return true;
 }

src/sensor_trigger.cpp

@@ -136,14 +136,13 @@ void SensorTrigger::run()
  target_nsec = start_nsec;
  wait_nsec = 1e9 - now_nsec + start_nsec - 1e7;
  }
- // Keep waiting for half the remaining time until the last millisecond.
+ // Keep waiting for half the remaining time until the last 10 milliseconds.
  // This is required as sleep_for tends to oversleep significantly
  if (wait_nsec > 1e7) {
  rclcpp::sleep_for(std::chrono::nanoseconds(wait_nsec / 2));
  }
  } while (wait_nsec > 1e7);
- // std::lock_guard<std::mutex> guard(iomutex_);
- // Block the last millisecond
+ // Block the last 10 milliseconds
  now_nsec = rclcpp::Clock{RCL_SYSTEM_TIME}.now().nanoseconds() % (uint64_t)1e9;
  if (start_nsec == end_nsec) {
  while (now_nsec > 1e7) {