text: /****************************************************************************
   *
   *   Copyright (C) 2015 Mark Charlebois. All rights reserved.
   *   Copyright (C) 2016 PX4 Development Team. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   * 3. Neither the name PX4 nor the names of its contributors may be
   *    used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
   * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   ****************************************************************************/
  
  #include "NavioSysRCInput.hpp"
  
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <fcntl.h>
  
  using namespace time_literals;
  
  namespace navio_sysfs_rc_in
  {
  
  NavioSysRCInput::NavioSysRCInput() :
  	ScheduledWorkItem(MODULE_NAME, px4::wq_configurations::hp_default)
  {
  	_isRunning = true;
  };
  
  NavioSysRCInput::~NavioSysRCInput()
  {
  	ScheduleClear();
  
  	_isRunning = false;
  
  	for (int i = 0; i < CHANNELS; ++i) {
  		::close(_channel_fd[i]);
  	}
  
  	::close(_connected_fd);
  
  	perf_free(_publish_interval_perf);
  }
  
  int NavioSysRCInput::navio_rc_init()
  {
  	_connected_fd = ::open("/sys/kernel/rcio/rcin/connected", O_RDONLY);
  
  	for (int i = 0; i < CHANNELS; ++i) {
  		char buf[80] {};
  		::snprintf(buf, sizeof(buf), "%s/ch%d", "/sys/kernel/rcio/rcin", i);
  		int fd = ::open(buf, O_RDONLY);
  
  		if (fd < 0) {
  			PX4_ERR("open %s (%d) failed", buf, i);
  			break;
  		}
  
  		_channel_fd[i] = fd;
  	}
  
  	return PX4_OK;
  }
  
  int NavioSysRCInput::start()
  {
  	navio_rc_init();
  
  	_should_exit.store(false);
  
  	ScheduleOnInterval(10_ms); // 100 Hz
  
  	return PX4_OK;
  }
  
  void NavioSysRCInput::stop()
  {
  	_should_exit.store(true);
  }
  
  void NavioSysRCInput::Run()
  {
  	if (_should_exit.load()) {
  		ScheduleClear();
  		return;
  	}
  
  	char connected_buf[12] {};
  	int ret_connected = ::pread(_connected_fd, connected_buf, sizeof(connected_buf) - 1, 0);
  
  	if (ret_connected < 0) {
  		return;
  	}
  
  	input_rc_s data{};
  
  	connected_buf[sizeof(connected_buf) - 1] = '\0';
  	_connected = (atoi(connected_buf) == 1);
  
  	data.rc_lost = !_connected;
  
  	uint64_t timestamp_sample = hrt_absolute_time();
  
  	for (int i = 0; i < CHANNELS; ++i) {
  		char buf[12] {};
  		int res = ::pread(_channel_fd[i], buf, sizeof(buf) - 1, 0);
  
  		if (res < 0) {
  			continue;
  		}
  
  		buf[sizeof(buf) - 1] = '\0';
  
  		data.values[i] = atoi(buf);
  	}
  
  	// check if all channels are 0
  	bool all_zero = true;
  
  	for (int i = 0; i < CHANNELS; ++i) {
  		if (data.values[i] != 0) {
  			all_zero = false;
  		}
  	}
  
  	if (all_zero) {
  		return;
  	}
  
  	data.timestamp_last_signal = timestamp_sample;
  	data.channel_count = CHANNELS;
  	data.input_source = input_rc_s::RC_INPUT_SOURCE_PX4FMU_PPM;
  	data.timestamp = hrt_absolute_time();
  
  	_input_rc_pub.publish(data);
  	perf_count(_publish_interval_perf);
  }
  
  int NavioSysRCInput::print_status()
  {
  	PX4_INFO("Running");
  	PX4_INFO("connected: %d", _connected);
  
  	perf_print_counter(_publish_interval_perf);
  
  	return 0;
  }
  
  }; // namespace navio_sysfs_rc_in
  