/****************************************************************************
 *
 *   Copyright (c) 2012-2014 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.
 *
 ****************************************************************************/

/**
 * @file px4io.cpp
 * Driver for the PX4IO board.
 *
 * PX4IO is connected via I2C or DMA enabled high-speed UART.
 */

#include <nuttx/config.h>

#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <assert.h>
#include <debug.h>
#include <time.h>
#include <queue.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <math.h>
#include <crc32.h>

#include <arch/board/board.h>

#include <drivers/device/device.h>
#include <drivers/drv_rc_input.h>
#include <drivers/drv_pwm_output.h>
#include <drivers/drv_gpio.h>
#include <drivers/drv_hrt.h>
#include <drivers/drv_mixer.h>

#include <systemlib/mixer/mixer.h>
#include <systemlib/perf_counter.h>
#include <systemlib/err.h>
#include <systemlib/systemlib.h>
#include <systemlib/scheduling_priorities.h>
#include <systemlib/param/param.h>

#include <uORB/topics/actuator_controls.h>
#include <uORB/topics/actuator_outputs.h>
#include <uORB/topics/actuator_armed.h>
#include <uORB/topics/safety.h>
#include <uORB/topics/vehicle_control_mode.h>
#include <uORB/topics/vehicle_command.h>
#include <uORB/topics/rc_channels.h>
#include <uORB/topics/battery_status.h>
#include <uORB/topics/servorail_status.h>
#include <uORB/topics/parameter_update.h>

#include <debug.h>

#include <mavlink/mavlink_log.h>
#include <modules/px4iofirmware/protocol.h>

#include "uploader.h"

extern device::Device *PX4IO_i2c_interface() weak_function;
extern device::Device *PX4IO_serial_interface() weak_function;

#define PX4IO_SET_DEBUG			_IOC(0xff00, 0)
#define PX4IO_INAIR_RESTART_ENABLE	_IOC(0xff00, 1)
#define PX4IO_REBOOT_BOOTLOADER		_IOC(0xff00, 2)
#define PX4IO_CHECK_CRC			_IOC(0xff00, 3)

#define UPDATE_INTERVAL_MIN		2			// 2 ms	-> 500 Hz
#define ORB_CHECK_INTERVAL		200000		// 200 ms -> 5 Hz
#define IO_POLL_INTERVAL		20000		// 20 ms -> 50 Hz

/**
 * The PX4IO class.
 *
 * Encapsulates PX4FMU to PX4IO communications modeled as file operations.
 */
class PX4IO : public device::CDev
{
public:
	/**
	 * Constructor.
	 *
	 * Initialize all class variables.
	 */
	PX4IO(device::Device *interface);

	/**
	 * Destructor.
	 *
	 * Wait for worker thread to terminate.
	 */
	virtual ~PX4IO();

	/**
	 * Initialize the PX4IO class.
	 *
	 * Retrieve relevant initial system parameters. Initialize PX4IO registers.
	 */
	virtual int		init();

	/**
	 * Detect if a PX4IO is connected.
	 *
	 * Only validate if there is a PX4IO to talk to.
	 */
	virtual int		detect();

	/**
	 * IO Control handler.
	 *
	 * Handle all IOCTL calls to the PX4IO file descriptor.
	 *
	 * @param[in] filp file handle (not used). This function is always called directly through object reference
	 * @param[in] cmd the IOCTL command
	 * @param[in] the IOCTL command parameter (optional)
	 */
	virtual int		ioctl(file *filp, int cmd, unsigned long arg);

	/**
	 * write handler.
	 *
	 * Handle writes to the PX4IO file descriptor.
	 *
	 * @param[in] filp file handle (not used). This function is always called directly through object reference
	 * @param[in] buffer pointer to the data buffer to be written
	 * @param[in] len size in bytes to be written
	 * @return number of bytes written
	 */
	virtual ssize_t		write(file *filp, const char *buffer, size_t len);

	/**
	* Set the update rate for actuator outputs from FMU to IO.
	*
	* @param[in] rate		The rate in Hz actuator outpus are sent to IO.
	* 			Min 10 Hz, max 400 Hz
	*/
	int      		set_update_rate(int rate);

	/**
	* Set the battery current scaling and bias
	*
	* @param[in] amp_per_volt
	* @param[in] amp_bias
	*/
	void      		set_battery_current_scaling(float amp_per_volt, float amp_bias);

	/**
	 * Push failsafe values to IO.
	 *
	 * @param[in] vals	Failsafe control inputs: in us PPM (900 for zero, 1500 for centered, 2100 for full)
	 * @param[in] len	Number of channels, could up to 8
	 */
	int			set_failsafe_values(const uint16_t *vals, unsigned len);

	/**
	 * Disable RC input handling
	 */
	int			disable_rc_handling();

	/**
	 * Print IO status.
	 *
	 * Print all relevant IO status information
	 */
	void			print_status();

	/**
	 * Fetch and print debug console output.
	 */
	int			print_debug();

#ifdef CONFIG_ARCH_BOARD_PX4FMU_V1
	/**
	 * Set the DSM VCC is controlled by relay one flag
	 *
	 * @param[in] enable true=DSM satellite VCC is controlled by relay1, false=DSM satellite VCC not controlled
	 */
	inline void		set_dsm_vcc_ctl(bool enable) {
		_dsm_vcc_ctl = enable;
	};

	/**
	 * Get the DSM VCC is controlled by relay one flag
	 *
	 * @return true=DSM satellite VCC is controlled by relay1, false=DSM satellite VCC not controlled
	 */
	inline bool		get_dsm_vcc_ctl() {
		return _dsm_vcc_ctl;
	};
#endif

	inline uint16_t		system_status() const {return _status;}

private:
	device::Device		*_interface;

	// XXX
	unsigned		_hardware;		///< Hardware revision
	unsigned		_max_actuators;		///< Maximum # of actuators supported by PX4IO
	unsigned		_max_controls;		///< Maximum # of controls supported by PX4IO
	unsigned		_max_rc_input;		///< Maximum receiver channels supported by PX4IO
	unsigned		_max_relays;		///< Maximum relays supported by PX4IO
	unsigned		_max_transfer;		///< Maximum number of I2C transfers supported by PX4IO

	unsigned 		_update_interval;	///< Subscription interval limiting send rate
	bool			_rc_handling_disabled;	///< If set, IO does not evaluate, but only forward the RC values
	unsigned		_rc_chan_count;		///< Internal copy of the last seen number of RC channels

	volatile int		_task;			///< worker task id
	volatile bool		_task_should_exit;	///< worker terminate flag

	int			_mavlink_fd;		///< mavlink file descriptor. This is opened by class instantiation and Doesn't appear to be usable in main thread.
	int			_thread_mavlink_fd;	///< mavlink file descriptor for thread.

	perf_counter_t		_perf_update;		///<local performance counter for status updates
	perf_counter_t		_perf_write;		///<local performance counter for PWM control writes
	perf_counter_t		_perf_chan_count;	///<local performance counter for channel number changes

	/* cached IO state */
	uint16_t		_status;		///< Various IO status flags
	uint16_t		_alarms;		///< Various IO alarms

	/* subscribed topics */
	int			_t_actuator_controls_0;	///< actuator controls group 0 topic
	int			_t_actuator_controls_1;	///< actuator controls group 1 topic
	int			_t_actuator_controls_2;	///< actuator controls group 2 topic
	int			_t_actuator_controls_3;	///< actuator controls group 3 topic
	int			_t_actuator_armed;	///< system armed control topic
	int 			_t_vehicle_control_mode;///< vehicle control mode topic
	int			_t_param;		///< parameter update topic
	int			_t_vehicle_command;	///< vehicle command topic

	/* advertised topics */
	orb_advert_t 		_to_input_rc;		///< rc inputs from io
	orb_advert_t		_to_outputs;		///< mixed servo outputs topic
	orb_advert_t		_to_battery;		///< battery status / voltage
	orb_advert_t		_to_servorail;		///< servorail status
	orb_advert_t		_to_safety;		///< status of safety

	actuator_outputs_s	_outputs;		///< mixed outputs
	servorail_status_s	_servorail_status;	///< servorail status

	bool			_primary_pwm_device;	///< true if we are the default PWM output

	float			_battery_amp_per_volt;	///< current sensor amps/volt
	float			_battery_amp_bias;	///< current sensor bias
	float			_battery_mamphour_total;///< amp hours consumed so far
	uint64_t		_battery_last_timestamp;///< last amp hour calculation timestamp

#ifdef CONFIG_ARCH_BOARD_PX4FMU_V1
	bool			_dsm_vcc_ctl;		///< true if relay 1 controls DSM satellite RX power
#endif

	/**
	 * Trampoline to the worker task
	 */
	static void		task_main_trampoline(int argc, char *argv[]);

	/**
	 * worker task
	 */
	void			task_main();

	/**
	 * Send controls for one group to IO
	 */
	int			io_set_control_state(unsigned group);

	/**
	 * Send all controls to IO
	 */
	int			io_set_control_groups();

	/**
	 * Update IO's arming-related state
	 */
	int			io_set_arming_state();

	/**
	 * Push RC channel configuration to IO.
	 */
	int			io_set_rc_config();

	/**
	 * Fetch status and alarms from IO
	 *
	 * Also publishes battery voltage/current.
	 */
	int			io_get_status();

	/**
	 * Disable RC input handling
	 */
	int			io_disable_rc_handling();

	/**
	 * Fetch RC inputs from IO.
	 *
	 * @param input_rc	Input structure to populate.
	 * @return		OK if data was returned.
	 */
	int			io_get_raw_rc_input(rc_input_values &input_rc);

	/**
	 * Fetch and publish raw RC input data.
	 */
	int			io_publish_raw_rc();

	/**
	 * Fetch and publish the PWM servo outputs.
	 */
	int			io_publish_pwm_outputs();

	/**
	 * write register(s)
	 *
	 * @param page		Register page to write to.
	 * @param offset	Register offset to start writing at.
	 * @param values	Pointer to array of values to write.
	 * @param num_values	The number of values to write.
	 * @return		OK if all values were successfully written.
	 */
	int			io_reg_set(uint8_t page, uint8_t offset, const uint16_t *values, unsigned num_values);

	/**
	 * write a register
	 *
	 * @param page		Register page to write to.
	 * @param offset	Register offset to write to.
	 * @param value		Value to write.
	 * @return		OK if the value was written successfully.
	 */
	int			io_reg_set(uint8_t page, uint8_t offset, const uint16_t value);

	/**
	 * read register(s)
	 *
	 * @param page		Register page to read from.
	 * @param offset	Register offset to start reading from.
	 * @param values	Pointer to array where values should be stored.
	 * @param num_values	The number of values to read.
	 * @return		OK if all values were successfully read.
	 */
	int			io_reg_get(uint8_t page, uint8_t offset, uint16_t *values, unsigned num_values);

	/**
	 * read a register
	 *
	 * @param page		Register page to read from.
	 * @param offset	Register offset to start reading from.
	 * @return		Register value that was read, or _io_reg_get_error on error.
	 */
	uint32_t		io_reg_get(uint8_t page, uint8_t offset);
	static const uint32_t	_io_reg_get_error = 0x80000000;

	/**
	 * modify a register
	 *
	 * @param page		Register page to modify.
	 * @param offset	Register offset to modify.
	 * @param clearbits	Bits to clear in the register.
	 * @param setbits	Bits to set in the register.
	 */
	int			io_reg_modify(uint8_t page, uint8_t offset, uint16_t clearbits, uint16_t setbits);

	/**
	 * Send mixer definition text to IO
	 */
	int			mixer_send(const char *buf, unsigned buflen, unsigned retries = 3);

	/**
	 * Handle a status update from IO.
	 *
	 * Publish IO status information if necessary.
	 *
	 * @param status	The status register
	 */
	int			io_handle_status(uint16_t status);

	/**
	 * Handle an alarm update from IO.
	 *
	 * Publish IO alarm information if necessary.
	 *
	 * @param alarm		The status register
	 */
	int			io_handle_alarms(uint16_t alarms);

	/**
	 * Handle issuing dsm bind ioctl to px4io.
	 *
	 * @param dsmMode	0:dsm2, 1:dsmx
	 */
	void			dsm_bind_ioctl(int dsmMode);

	/**
	 * Handle a battery update from IO.
	 *
	 * Publish IO battery information if necessary.
	 *
	 * @param vbatt		vbatt register
	 * @param ibatt		ibatt register
	 */
	void			io_handle_battery(uint16_t vbatt, uint16_t ibatt);

	/**
	 * Handle a servorail update from IO.
	 *
	 * Publish servo rail information if necessary.
	 *
	 * @param vservo	vservo register
	 * @param vrssi 	vrssi register
	 */
	void			io_handle_vservo(uint16_t vbatt, uint16_t ibatt);

};

namespace
{

PX4IO	*g_dev;

}

PX4IO::PX4IO(device::Device *interface) :
	CDev("px4io", PX4IO_DEVICE_PATH),
	_interface(interface),
	_hardware(0),
	_max_actuators(0),
	_max_controls(0),
	_max_rc_input(0),
	_max_relays(0),
	_max_transfer(16),	/* sensible default */
	_update_interval(0),
	_rc_handling_disabled(false),
	_rc_chan_count(0),
	_task(-1),
	_task_should_exit(false),
	_mavlink_fd(-1),
	_thread_mavlink_fd(-1),
	_perf_update(perf_alloc(PC_ELAPSED, "io update")),
	_perf_write(perf_alloc(PC_ELAPSED, "io write")),
	_perf_chan_count(perf_alloc(PC_COUNT, "io rc #")),
	_status(0),
	_alarms(0),
	_t_actuator_controls_0(-1),
	_t_actuator_controls_1(-1),
	_t_actuator_controls_2(-1),
	_t_actuator_controls_3(-1),
	_t_actuator_armed(-1),
	_t_vehicle_control_mode(-1),
	_t_param(-1),
	_t_vehicle_command(-1),
	_to_input_rc(0),
	_to_outputs(0),
	_to_battery(0),
	_to_servorail(0),
	_to_safety(0),
	_primary_pwm_device(false),
	_battery_amp_per_volt(90.0f / 5.0f), // this matches the 3DR current sensor
	_battery_amp_bias(0),
	_battery_mamphour_total(0),
	_battery_last_timestamp(0)
#ifdef CONFIG_ARCH_BOARD_PX4FMU_V1
	, _dsm_vcc_ctl(false)
#endif

{
	/* we need this potentially before it could be set in task_main */
	g_dev = this;

	/* open MAVLink text channel */
	_mavlink_fd = ::open(MAVLINK_LOG_DEVICE, 0);

	_debug_enabled = false;
	_servorail_status.rssi_v = 0;
}

PX4IO::~PX4IO()
{
	/* tell the task we want it to go away */
	_task_should_exit = true;

	/* spin waiting for the task to stop */
	for (unsigned i = 0; (i < 10) && (_task != -1); i++) {
		/* give it another 100ms */
		usleep(100000);
	}

	/* well, kill it anyway, though this will probably crash */
	if (_task != -1)
		task_delete(_task);

	if (_interface != nullptr)
		delete _interface;

	g_dev = nullptr;
}

int
PX4IO::detect()
{
	int ret;

	if (_task == -1) {

		/* do regular cdev init */
		ret = CDev::init();

		if (ret != OK)
			return ret;

		/* get some parameters */
		unsigned protocol = io_reg_get(PX4IO_PAGE_CONFIG, PX4IO_P_CONFIG_PROTOCOL_VERSION);

		if (protocol != PX4IO_PROTOCOL_VERSION) {
			if (protocol == _io_reg_get_error) {
				log("IO not installed");

			} else {
				log("IO version error");
				mavlink_log_emergency(_mavlink_fd, "IO VERSION MISMATCH, PLEASE UPGRADE SOFTWARE!");
			}

			return -1;
		}
	}

	log("IO found");

	return 0;
}

int
PX4IO::init()
{
	int ret;

	ASSERT(_task == -1);

	/* do regular cdev init */
	ret = CDev::init();

	if (ret != OK)
		return ret;

	/* get some parameters */
	unsigned protocol = io_reg_get(PX4IO_PAGE_CONFIG, PX4IO_P_CONFIG_PROTOCOL_VERSION);

	if (protocol == _io_reg_get_error) {
		log("failed to communicate with IO");
		mavlink_log_emergency(_mavlink_fd, "[IO] failed to communicate with IO, abort.");
		return -1;
	}

	if (protocol != PX4IO_PROTOCOL_VERSION) {
		log("protocol/firmware mismatch");
		mavlink_log_emergency(_mavlink_fd, "[IO] protocol/firmware mismatch, abort.");
		return -1;
	}

	_hardware      = io_reg_get(PX4IO_PAGE_CONFIG, PX4IO_P_CONFIG_HARDWARE_VERSION);
	_max_actuators = io_reg_get(PX4IO_PAGE_CONFIG, PX4IO_P_CONFIG_ACTUATOR_COUNT);
	_max_controls  = io_reg_get(PX4IO_PAGE_CONFIG, PX4IO_P_CONFIG_CONTROL_COUNT);
	_max_relays    = io_reg_get(PX4IO_PAGE_CONFIG, PX4IO_P_CONFIG_RELAY_COUNT);
	_max_transfer  = io_reg_get(PX4IO_PAGE_CONFIG, PX4IO_P_CONFIG_MAX_TRANSFER) - 2;
	_max_rc_input  = io_reg_get(PX4IO_PAGE_CONFIG, PX4IO_P_CONFIG_RC_INPUT_COUNT);

	if ((_max_actuators < 1) || (_max_actuators > 255) ||
	    (_max_relays > 32)   ||
	    (_max_transfer < 16) || (_max_transfer > 255)  ||
	    (_max_rc_input < 1)  || (_max_rc_input > 255)) {

		log("config read error");
		mavlink_log_emergency(_mavlink_fd, "[IO] config read fail, abort.");
		return -1;
	}

	if (_max_rc_input > RC_INPUT_MAX_CHANNELS)
		_max_rc_input = RC_INPUT_MAX_CHANNELS;

	/*
	 * Check for IO flight state - if FMU was flagged to be in
	 * armed state, FMU is recovering from an in-air reset.
	 * Read back status and request the commander to arm
	 * in this case.
	 */

	uint16_t reg;

	/* get IO's last seen FMU state */
	ret = io_reg_get(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_ARMING, &reg, sizeof(reg));

	if (ret != OK)
		return ret;

	/*
	 * in-air restart is only tried if the IO board reports it is
	 * already armed, and has been configured for in-air restart
	 */
	if ((reg & PX4IO_P_SETUP_ARMING_INAIR_RESTART_OK) &&
	    (reg & PX4IO_P_SETUP_ARMING_FMU_ARMED)) {

		/* get a status update from IO */
		io_get_status();

		mavlink_log_emergency(_mavlink_fd, "[IO] RECOVERING FROM FMU IN-AIR RESTART");
		log("INAIR RESTART RECOVERY (needs commander app running)");

		/* WARNING: COMMANDER app/vehicle status must be initialized.
		 * If this fails (or the app is not started), worst-case IO
		 * remains untouched (so manual override is still available).
		 */

		int safety_sub = orb_subscribe(ORB_ID(actuator_armed));
		/* fill with initial values, clear updated flag */
		struct actuator_armed_s safety;
		uint64_t try_start_time = hrt_absolute_time();
		bool updated = false;

		/* keep checking for an update, ensure we got a arming information,
		   not something that was published a long time ago. */
		do {
			orb_check(safety_sub, &updated);

			if (updated) {
				/* got data, copy and exit loop */
				orb_copy(ORB_ID(actuator_armed), safety_sub, &safety);
				break;
			}

			/* wait 10 ms */
			usleep(10000);

			/* abort after 5s */
			if ((hrt_absolute_time() - try_start_time) / 1000 > 3000) {
				log("failed to recover from in-air restart (1), aborting IO driver init.");
				return 1;
			}

		} while (true);

		/* send command to arm system via command API */
		vehicle_command_s cmd;
		/* request arming */
		cmd.param1 = 1.0f;
		cmd.param2 = 0;
		cmd.param3 = 0;
		cmd.param4 = 0;
		cmd.param5 = 0;
		cmd.param6 = 0;
		cmd.param7 = 0;
		cmd.command = VEHICLE_CMD_COMPONENT_ARM_DISARM;
		// cmd.target_system = status.system_id;
		// cmd.target_component = status.component_id;
		// cmd.source_system = status.system_id;
		// cmd.source_component = status.component_id;
		/* ask to confirm command */
		cmd.confirmation =  1;

		/* send command once */
		orb_advert_t pub = orb_advertise(ORB_ID(vehicle_command), &cmd);

		/* spin here until IO's state has propagated into the system */
		do {
			orb_check(safety_sub, &updated);

			if (updated) {
				orb_copy(ORB_ID(actuator_armed), safety_sub, &safety);
			}

			/* wait 50 ms */
			usleep(50000);

			/* abort after 5s */
			if ((hrt_absolute_time() - try_start_time) / 1000 > 2000) {
				log("failed to recover from in-air restart (2), aborting IO driver init.");
				return 1;
			}

			/* re-send if necessary */
			if (!safety.armed) {
				orb_publish(ORB_ID(vehicle_command), pub, &cmd);
				log("re-sending arm cmd");
			}

			/* keep waiting for state change for 2 s */
		} while (!safety.armed);

		/* regular boot, no in-air restart, init IO */

	} else {

		/* dis-arm IO before touching anything */
		io_reg_modify(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_ARMING,
			      PX4IO_P_SETUP_ARMING_FMU_ARMED |
			      PX4IO_P_SETUP_ARMING_INAIR_RESTART_OK |
			      PX4IO_P_SETUP_ARMING_MANUAL_OVERRIDE_OK |
			      PX4IO_P_SETUP_ARMING_ALWAYS_PWM_ENABLE, 0);

		if (_rc_handling_disabled) {
			ret = io_disable_rc_handling();

		} else {
			/* publish RC config to IO */
			ret = io_set_rc_config();

			if (ret != OK) {
				log("failed to update RC input config");
				mavlink_log_info(_mavlink_fd, "[IO] RC config upload fail");
				return ret;
			}
		}

	}

	/* try to claim the generic PWM output device node as well - it's OK if we fail at this */
	ret = register_driver(PWM_OUTPUT_DEVICE_PATH, &fops, 0666, (void *)this);

	if (ret == OK) {
		log("default PWM output device");
		_primary_pwm_device = true;
	}

	/* start the IO interface task */
	_task = task_create("px4io", SCHED_PRIORITY_ACTUATOR_OUTPUTS, 2048, (main_t)&PX4IO::task_main_trampoline, nullptr);

	if (_task < 0) {
		debug("task start failed: %d", errno);
		return -errno;
	}

	mavlink_log_info(_mavlink_fd, "[IO] init ok");

	return OK;
}

void
PX4IO::task_main_trampoline(int argc, char *argv[])
{
	g_dev->task_main();
}

void
PX4IO::task_main()
{
	hrt_abstime poll_last = 0;
	hrt_abstime orb_check_last = 0;

	log("starting");

	_thread_mavlink_fd = ::open(MAVLINK_LOG_DEVICE, 0);

	/*
	 * Subscribe to the appropriate PWM output topic based on whether we are the
	 * primary PWM output or not.
	 */
	_t_actuator_controls_0 = orb_subscribe(ORB_ID(actuator_controls_0));
	orb_set_interval(_t_actuator_controls_0, 20);		/* default to 50Hz */
	_t_actuator_controls_1 = orb_subscribe(ORB_ID(actuator_controls_1));
	orb_set_interval(_t_actuator_controls_1, 33);		/* default to 30Hz */
	_t_actuator_controls_2 = orb_subscribe(ORB_ID(actuator_controls_2));
	orb_set_interval(_t_actuator_controls_2, 33);		/* default to 30Hz */
	_t_actuator_controls_3 = orb_subscribe(ORB_ID(actuator_controls_3));
	orb_set_interval(_t_actuator_controls_3, 33);		/* default to 30Hz */
	_t_actuator_armed = orb_subscribe(ORB_ID(actuator_armed));
	_t_vehicle_control_mode = orb_subscribe(ORB_ID(vehicle_control_mode));
	_t_param = orb_subscribe(ORB_ID(parameter_update));
	_t_vehicle_command = orb_subscribe(ORB_ID(vehicle_command));

	if ((_t_actuator_controls_0 < 0) ||
	    (_t_actuator_armed < 0) ||
	    (_t_vehicle_control_mode < 0) ||
	    (_t_param < 0) ||
	    (_t_vehicle_command < 0)) {
		log("subscription(s) failed");
		goto out;
	}

	/* poll descriptor */
	pollfd fds[1];
	fds[0].fd = _t_actuator_controls_0;
	fds[0].events = POLLIN;

	log("ready");

	/* lock against the ioctl handler */
	lock();

	/* loop talking to IO */
	while (!_task_should_exit) {

		/* adjust update interval */
		if (_update_interval != 0) {
			if (_update_interval < UPDATE_INTERVAL_MIN)
				_update_interval = UPDATE_INTERVAL_MIN;

			if (_update_interval > 100)
				_update_interval = 100;

			orb_set_interval(_t_actuator_controls_0, _update_interval);
			/*
			 * NOT changing the rate of groups 1-3 here, because only attitude
			 * really needs to run fast.
			 */
			_update_interval = 0;
		}

		/* sleep waiting for topic updates, but no more than 20ms */
		unlock();
		int ret = ::poll(fds, 1, 20);
		lock();

		/* this would be bad... */
		if (ret < 0) {
			log("poll error %d", errno);
			continue;
		}

		perf_begin(_perf_update);
		hrt_abstime now = hrt_absolute_time();

		/* if we have new control data from the ORB, handle it */
		if (fds[0].revents & POLLIN) {

			/* we're not nice to the lower-priority control groups and only check them
			   when the primary group updated (which is now). */
			(void)io_set_control_groups();
		}

		if (now >= poll_last + IO_POLL_INTERVAL) {
			/* run at 50Hz */
			poll_last = now;

			/* pull status and alarms from IO */
			io_get_status();

			/* get raw R/C input from IO */
			io_publish_raw_rc();

			/* fetch PWM outputs from IO */
			io_publish_pwm_outputs();
		}

		if (now >= orb_check_last + ORB_CHECK_INTERVAL) {
			/* run at 5Hz */
			orb_check_last = now;

			/* check updates on uORB topics and handle it */
			bool updated = false;

			/* arming state */
			orb_check(_t_actuator_armed, &updated);

			if (!updated) {
				orb_check(_t_vehicle_control_mode, &updated);
			}

			if (updated) {
				io_set_arming_state();
			}

			/* vehicle command */
			orb_check(_t_vehicle_command, &updated);

			if (updated) {
				struct vehicle_command_s cmd;
				orb_copy(ORB_ID(vehicle_command), _t_vehicle_command, &cmd);

				// Check for a DSM pairing command
				if (((int)cmd.command == VEHICLE_CMD_START_RX_PAIR) && ((int)cmd.param1 == 0)) {
					dsm_bind_ioctl((int)cmd.param2);
				}
			}

			/*
			 * If parameters have changed, re-send RC mappings to IO
			 *
			 * XXX this may be a bit spammy
			 */
			orb_check(_t_param, &updated);

			if (updated) {
				parameter_update_s pupdate;
				orb_copy(ORB_ID(parameter_update), _t_param, &pupdate);

				int32_t dsm_bind_val;
				param_t dsm_bind_param;

				/* see if bind parameter has been set, and reset it to -1 */
				param_get(dsm_bind_param = param_find("RC_DSM_BIND"), &dsm_bind_val);

				if (dsm_bind_val > -1) {
					dsm_bind_ioctl(dsm_bind_val);
					dsm_bind_val = -1;
					param_set(dsm_bind_param, &dsm_bind_val);
				}

				/* re-upload RC input config as it may have changed */
				io_set_rc_config();

				/* re-set the battery scaling */
				int32_t voltage_scaling_val;
				param_t voltage_scaling_param;

				/* set battery voltage scaling */
				param_get(voltage_scaling_param = param_find("BAT_V_SCALE_IO"), &voltage_scaling_val);

				/* send scaling voltage to IO */
				uint16_t scaling = voltage_scaling_val;
				int pret = io_reg_set(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_VBATT_SCALE, &scaling, 1);

				if (pret != OK) {
					log("voltage scaling upload failed");
				}
			}

		}

		perf_end(_perf_update);
	}

	unlock();

out:
	debug("exiting");

	/* clean up the alternate device node */
	if (_primary_pwm_device)
		unregister_driver(PWM_OUTPUT_DEVICE_PATH);

	/* tell the dtor that we are exiting */
	_task = -1;
	_exit(0);
}

int
PX4IO::io_set_control_groups()
{
	int ret = io_set_control_state(0);

	/* send auxiliary control groups */
	(void)io_set_control_state(1);
	(void)io_set_control_state(2);
	(void)io_set_control_state(3);

	return ret;
}

int
PX4IO::io_set_control_state(unsigned group)
{
	actuator_controls_s	controls;	///< actuator outputs
	uint16_t 		regs[_max_actuators];

	/* get controls */
	bool changed;

	switch (group) {
		case 0:
		{
			orb_check(_t_actuator_controls_0, &changed);

			if (changed) {
				orb_copy(ORB_ID(actuator_controls_0), _t_actuator_controls_0, &controls);
			}
		}
		break;
		case 1:
		{
			orb_check(_t_actuator_controls_1, &changed);

			if (changed) {
				orb_copy(ORB_ID(actuator_controls_1), _t_actuator_controls_1, &controls);
			}
		}
		break;
		case 2:
		{
			orb_check(_t_actuator_controls_2, &changed);

			if (changed) {
				orb_copy(ORB_ID(actuator_controls_2), _t_actuator_controls_2, &controls);
			}
		}
		break;
		case 3:
		{
			orb_check(_t_actuator_controls_3, &changed);

			if (changed) {
				orb_copy(ORB_ID(actuator_controls_3), _t_actuator_controls_3, &controls);
			}
		}
		break;
	}

	if (!changed)
		return -1;

	for (unsigned i = 0; i < _max_controls; i++)
		regs[i] = FLOAT_TO_REG(controls.control[i]);

	/* copy values to registers in IO */
	return io_reg_set(PX4IO_PAGE_CONTROLS, group * PX4IO_PROTOCOL_MAX_CONTROL_COUNT, regs, _max_controls);
}


int
PX4IO::io_set_arming_state()
{
	actuator_armed_s	armed;		///< system armed state
	vehicle_control_mode_s	control_mode;	///< vehicle_control_mode

	orb_copy(ORB_ID(actuator_armed), _t_actuator_armed, &armed);
	orb_copy(ORB_ID(vehicle_control_mode), _t_vehicle_control_mode, &control_mode);

	uint16_t set = 0;
	uint16_t clear = 0;

	if (armed.armed && !armed.lockdown) {
		set |= PX4IO_P_SETUP_ARMING_FMU_ARMED;

	} else {
		clear |= PX4IO_P_SETUP_ARMING_FMU_ARMED;
	}

	if (armed.ready_to_arm) {
		set |= PX4IO_P_SETUP_ARMING_IO_ARM_OK;

	} else {
		clear |= PX4IO_P_SETUP_ARMING_IO_ARM_OK;
	}

	if (control_mode.flag_external_manual_override_ok) {
		set |= PX4IO_P_SETUP_ARMING_MANUAL_OVERRIDE_OK;

	} else {
		clear |= PX4IO_P_SETUP_ARMING_MANUAL_OVERRIDE_OK;
	}

	return io_reg_modify(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_ARMING, clear, set);
}

int
PX4IO::disable_rc_handling()
{
	return io_disable_rc_handling();
}

int
PX4IO::io_disable_rc_handling()
{
	uint16_t set = PX4IO_P_SETUP_ARMING_RC_HANDLING_DISABLED;
	uint16_t clear = 0;

	return io_reg_modify(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_ARMING, clear, set);
}

int
PX4IO::io_set_rc_config()
{
	unsigned offset = 0;
	int input_map[_max_rc_input];
	int32_t ichan;
	int ret = OK;

	/*
	 * Generate the input channel -> control channel mapping table;
	 * assign RC_MAP_ROLL/PITCH/YAW/THROTTLE to the canonical
	 * controls.
	 */

	/* fill the mapping with an error condition triggering value */
	for (unsigned i = 0; i < _max_rc_input; i++)
		input_map[i] = UINT8_MAX;

	/*
	 * NOTE: The indices for mapped channels are 1-based
	 *       for compatibility reasons with existing
	 *       autopilots / GCS'.
	 */
	param_get(param_find("RC_MAP_ROLL"), &ichan);

	if ((ichan >= 0) && (ichan < (int)_max_rc_input))
		input_map[ichan - 1] = 0;

	param_get(param_find("RC_MAP_PITCH"), &ichan);

	if ((ichan >= 0) && (ichan < (int)_max_rc_input))
		input_map[ichan - 1] = 1;

	param_get(param_find("RC_MAP_YAW"), &ichan);

	if ((ichan >= 0) && (ichan < (int)_max_rc_input))
		input_map[ichan - 1] = 2;

	param_get(param_find("RC_MAP_THROTTLE"), &ichan);

	if ((ichan >= 0) && (ichan < (int)_max_rc_input))
		input_map[ichan - 1] = 3;

	param_get(param_find("RC_MAP_MODE_SW"), &ichan);

	if ((ichan >= 0) && (ichan < (int)_max_rc_input))
		input_map[ichan - 1] = 4;

	/*
	 * Iterate all possible RC inputs.
	 */
	for (unsigned i = 0; i < _max_rc_input; i++) {
		uint16_t regs[PX4IO_P_RC_CONFIG_STRIDE];
		char pname[16];
		float fval;

		/*
		 * RC params are floats, but do only
		 * contain integer values. Do not scale
		 * or cast them, let the auto-typeconversion
		 * do its job here.
		 * Channels: 500 - 2500
		 * Inverted flag: -1 (inverted) or 1 (normal)
		 */

		sprintf(pname, "RC%d_MIN", i + 1);
		param_get(param_find(pname), &fval);
		regs[PX4IO_P_RC_CONFIG_MIN] = fval;

		sprintf(pname, "RC%d_TRIM", i + 1);
		param_get(param_find(pname), &fval);
		regs[PX4IO_P_RC_CONFIG_CENTER] = fval;

		sprintf(pname, "RC%d_MAX", i + 1);
		param_get(param_find(pname), &fval);
		regs[PX4IO_P_RC_CONFIG_MAX] = fval;

		sprintf(pname, "RC%d_DZ", i + 1);
		param_get(param_find(pname), &fval);
		regs[PX4IO_P_RC_CONFIG_DEADZONE] = fval;

		regs[PX4IO_P_RC_CONFIG_ASSIGNMENT] = input_map[i];

		regs[PX4IO_P_RC_CONFIG_OPTIONS] = PX4IO_P_RC_CONFIG_OPTIONS_ENABLED;
		sprintf(pname, "RC%d_REV", i + 1);
		param_get(param_find(pname), &fval);

		/*
		 * This has been taken for the sake of compatibility
		 * with APM's setup / mission planner: normal: 1,
		 * inverted: -1
		 */
		if (fval < 0) {
			regs[PX4IO_P_RC_CONFIG_OPTIONS] |= PX4IO_P_RC_CONFIG_OPTIONS_REVERSE;
		}

		/* send channel config to IO */
		ret = io_reg_set(PX4IO_PAGE_RC_CONFIG, offset, regs, PX4IO_P_RC_CONFIG_STRIDE);

		if (ret != OK) {
			log("rc config upload failed");
			break;
		}

		/* check the IO initialisation flag */
		if (!(io_reg_get(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_FLAGS) & PX4IO_P_STATUS_FLAGS_INIT_OK)) {
			log("config for RC%d rejected by IO", i + 1);
			break;
		}

		offset += PX4IO_P_RC_CONFIG_STRIDE;
	}

	return ret;
}

int
PX4IO::io_handle_status(uint16_t status)
{
	int ret = 1;
	/**
	 * WARNING: This section handles in-air resets.
	 */

	/* check for IO reset - force it back to armed if necessary */
	if (_status & PX4IO_P_STATUS_FLAGS_SAFETY_OFF && !(status & PX4IO_P_STATUS_FLAGS_SAFETY_OFF)
	    && !(status & PX4IO_P_STATUS_FLAGS_ARM_SYNC)) {
		/* set the arming flag */
		ret = io_reg_modify(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_FLAGS, 0, PX4IO_P_STATUS_FLAGS_SAFETY_OFF | PX4IO_P_STATUS_FLAGS_ARM_SYNC);

		/* set new status */
		_status = status;
		_status &= PX4IO_P_STATUS_FLAGS_SAFETY_OFF;

	} else if (!(_status & PX4IO_P_STATUS_FLAGS_ARM_SYNC)) {

		/* set the sync flag */
		ret = io_reg_modify(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_FLAGS, 0, PX4IO_P_STATUS_FLAGS_ARM_SYNC);
		/* set new status */
		_status = status;

	} else {
		ret = 0;

		/* set new status */
		_status = status;
	}

	/**
	 * Get and handle the safety status
	 */
	struct safety_s safety;
	safety.timestamp = hrt_absolute_time();

	if (status & PX4IO_P_STATUS_FLAGS_SAFETY_OFF) {
		safety.safety_off = true;
		safety.safety_switch_available = true;

	} else {
		safety.safety_off = false;
		safety.safety_switch_available = true;
	}

	/* lazily publish the safety status */
	if (_to_safety > 0) {
		orb_publish(ORB_ID(safety), _to_safety, &safety);

	} else {
		_to_safety = orb_advertise(ORB_ID(safety), &safety);
	}

	return ret;
}

void
PX4IO::dsm_bind_ioctl(int dsmMode)
{
	if (!(_status & PX4IO_P_STATUS_FLAGS_SAFETY_OFF)) {
		/* 0: dsm2, 1:dsmx */
		if ((dsmMode == 0) || (dsmMode == 1)) {
			mavlink_log_info(_thread_mavlink_fd, "[IO] binding dsm%s rx", (dsmMode == 0) ? "2" : ((dsmMode == 1) ? "x" : "x8"));
			ioctl(nullptr, DSM_BIND_START, (dsmMode == 0) ? DSM2_BIND_PULSES : ((dsmMode == 1) ? DSMX_BIND_PULSES : DSMX8_BIND_PULSES));
		} else {
			mavlink_log_info(_thread_mavlink_fd, "[IO] invalid dsm bind mode, bind request rejected");
		}

	} else {
		mavlink_log_info(_thread_mavlink_fd, "[IO] system armed, bind request rejected");
	}
}


int
PX4IO::io_handle_alarms(uint16_t alarms)
{

	/* XXX handle alarms */


	/* set new alarms state */
	_alarms = alarms;

	return 0;
}

void
PX4IO::io_handle_battery(uint16_t vbatt, uint16_t ibatt)
{
	/* only publish if battery has a valid minimum voltage */
	if (vbatt <= 3300) {
		return;
	}

	battery_status_s	battery_status;
	battery_status.timestamp = hrt_absolute_time();

	/* voltage is scaled to mV */
	battery_status.voltage_v = vbatt / 1000.0f;
	battery_status.voltage_filtered_v = vbatt / 1000.0f;

	/*
	  ibatt contains the raw ADC count, as 12 bit ADC
	  value, with full range being 3.3v
	*/
	battery_status.current_a = ibatt * (3.3f / 4096.0f) * _battery_amp_per_volt;
	battery_status.current_a += _battery_amp_bias;

	/*
	  integrate battery over time to get total mAh used
	*/
	if (_battery_last_timestamp != 0) {
		_battery_mamphour_total += battery_status.current_a *
					   (battery_status.timestamp - _battery_last_timestamp) * 1.0e-3f / 3600;
	}

	battery_status.discharged_mah = _battery_mamphour_total;
	_battery_last_timestamp = battery_status.timestamp;

	/* lazily publish the battery voltage */
	if (_to_battery > 0) {
		orb_publish(ORB_ID(battery_status), _to_battery, &battery_status);

	} else {
		_to_battery = orb_advertise(ORB_ID(battery_status), &battery_status);
	}
}

void
PX4IO::io_handle_vservo(uint16_t vservo, uint16_t vrssi)
{
	_servorail_status.timestamp = hrt_absolute_time();

	/* voltage is scaled to mV */
	_servorail_status.voltage_v = vservo * 0.001f;
	_servorail_status.rssi_v    = vrssi * 0.001f;

	/* lazily publish the servorail voltages */
	if (_to_servorail > 0) {
		orb_publish(ORB_ID(servorail_status), _to_servorail, &_servorail_status);

	} else {
		_to_servorail = orb_advertise(ORB_ID(servorail_status), &_servorail_status);
	}
}

int
PX4IO::io_get_status()
{
	uint16_t	regs[6];
	int		ret;

	/* get STATUS_FLAGS, STATUS_ALARMS, STATUS_VBATT, STATUS_IBATT in that order */
	ret = io_reg_get(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_FLAGS, &regs[0], sizeof(regs) / sizeof(regs[0]));

	if (ret != OK)
		return ret;

	io_handle_status(regs[0]);
	io_handle_alarms(regs[1]);

#ifdef CONFIG_ARCH_BOARD_PX4FMU_V1
	io_handle_battery(regs[2], regs[3]);
#endif

#ifdef CONFIG_ARCH_BOARD_PX4FMU_V2
	io_handle_vservo(regs[4], regs[5]);
#endif

	return ret;
}

int
PX4IO::io_get_raw_rc_input(rc_input_values &input_rc)
{
	uint32_t channel_count;
	int	ret;

	/* we don't have the status bits, so input_source has to be set elsewhere */
	input_rc.input_source = RC_INPUT_SOURCE_UNKNOWN;

	static const unsigned prolog = (PX4IO_P_RAW_RC_BASE - PX4IO_P_RAW_RC_COUNT);
	uint16_t regs[RC_INPUT_MAX_CHANNELS + prolog];

	/*
	 * Read the channel count and the first 9 channels.
	 *
	 * This should be the common case (9 channel R/C control being a reasonable upper bound).
	 */
	input_rc.timestamp = hrt_absolute_time();
	ret = io_reg_get(PX4IO_PAGE_RAW_RC_INPUT, PX4IO_P_RAW_RC_COUNT, &regs[0], prolog + 9);

	if (ret != OK)
		return ret;

	/*
	 * Get the channel count any any extra channels. This is no more expensive than reading the
	 * channel count once.
	 */
	channel_count = regs[0];

	if (channel_count != _rc_chan_count)
		perf_count(_perf_chan_count);

	_rc_chan_count = channel_count;

	if (channel_count > 9) {
		ret = io_reg_get(PX4IO_PAGE_RAW_RC_INPUT, PX4IO_P_RAW_RC_BASE + 9, &regs[prolog + 9], channel_count - 9);

		if (ret != OK)
			return ret;
	}

	input_rc.channel_count = channel_count;
	memcpy(input_rc.values, &regs[prolog], channel_count * 2);

	return ret;
}

int
PX4IO::io_publish_raw_rc()
{
	/* if no raw RC, just don't publish */
	if (!(_status & PX4IO_P_STATUS_FLAGS_RC_OK))
		return OK;

	/* fetch values from IO */
	rc_input_values	rc_val;
	rc_val.timestamp = hrt_absolute_time();

	int ret = io_get_raw_rc_input(rc_val);

	if (ret != OK)
		return ret;

	/* sort out the source of the values */
	if (_status & PX4IO_P_STATUS_FLAGS_RC_PPM) {
		rc_val.input_source = RC_INPUT_SOURCE_PX4IO_PPM;

	} else if (_status & PX4IO_P_STATUS_FLAGS_RC_DSM) {
		rc_val.input_source = RC_INPUT_SOURCE_PX4IO_SPEKTRUM;

	} else if (_status & PX4IO_P_STATUS_FLAGS_RC_SBUS) {
		rc_val.input_source = RC_INPUT_SOURCE_PX4IO_SBUS;

	} else {
		rc_val.input_source = RC_INPUT_SOURCE_UNKNOWN;
	}

	/* set RSSI */

	if (rc_val.input_source != RC_INPUT_SOURCE_PX4IO_SBUS) {
		// XXX the correct scaling needs to be validated here
		rc_val.rssi = (_servorail_status.rssi_v / 3.3f) * UINT8_MAX;
	}

	/* lazily advertise on first publication */
	if (_to_input_rc == 0) {
		_to_input_rc = orb_advertise(ORB_ID(input_rc), &rc_val);

	} else {
		orb_publish(ORB_ID(input_rc), _to_input_rc, &rc_val);
	}

	return OK;
}

int
PX4IO::io_publish_pwm_outputs()
{
	/* if no FMU comms(!) just don't publish */
	if (!(_status & PX4IO_P_STATUS_FLAGS_FMU_OK))
		return OK;

	/* data we are going to fetch */
	actuator_outputs_s outputs;
	outputs.timestamp = hrt_absolute_time();

	/* get servo values from IO */
	uint16_t ctl[_max_actuators];
	int ret = io_reg_get(PX4IO_PAGE_SERVOS, 0, ctl, _max_actuators);

	if (ret != OK)
		return ret;

	/* convert from register format to float */
	for (unsigned i = 0; i < _max_actuators; i++)
		outputs.output[i] = ctl[i];

	outputs.noutputs = _max_actuators;

	/* lazily advertise on first publication */
	if (_to_outputs == 0) {
		_to_outputs = orb_advertise((_primary_pwm_device ?
					     ORB_ID_VEHICLE_CONTROLS :
					     ORB_ID(actuator_outputs_1)),
					    &outputs);

	} else {
		orb_publish((_primary_pwm_device ?
			     ORB_ID_VEHICLE_CONTROLS :
			     ORB_ID(actuator_outputs_1)),
			    _to_outputs,
			    &outputs);
	}

	return OK;
}

int
PX4IO::io_reg_set(uint8_t page, uint8_t offset, const uint16_t *values, unsigned num_values)
{
	/* range check the transfer */
	if (num_values > ((_max_transfer) / sizeof(*values))) {
		debug("io_reg_set: too many registers (%u, max %u)", num_values, _max_transfer / 2);
		return -EINVAL;
	}

	int ret =  _interface->write((page << 8) | offset, (void *)values, num_values);

	if (ret != (int)num_values) {
		debug("io_reg_set(%u,%u,%u): error %d", page, offset, num_values, ret);
		return -1;
	}

	return OK;
}

int
PX4IO::io_reg_set(uint8_t page, uint8_t offset, uint16_t value)
{
	return io_reg_set(page, offset, &value, 1);
}

int
PX4IO::io_reg_get(uint8_t page, uint8_t offset, uint16_t *values, unsigned num_values)
{
	/* range check the transfer */
	if (num_values > ((_max_transfer) / sizeof(*values))) {
		debug("io_reg_get: too many registers (%u, max %u)", num_values, _max_transfer / 2);
		return -EINVAL;
	}

	int ret = _interface->read((page << 8) | offset, reinterpret_cast<void *>(values), num_values);

	if (ret != (int)num_values) {
		debug("io_reg_get(%u,%u,%u): data error %d", page, offset, num_values, ret);
		return -1;
	}

	return OK;
}

uint32_t
PX4IO::io_reg_get(uint8_t page, uint8_t offset)
{
	uint16_t value;

	if (io_reg_get(page, offset, &value, 1) != OK)
		return _io_reg_get_error;

	return value;
}

int
PX4IO::io_reg_modify(uint8_t page, uint8_t offset, uint16_t clearbits, uint16_t setbits)
{
	int ret;
	uint16_t value;

	ret = io_reg_get(page, offset, &value, 1);

	if (ret != OK)
		return ret;

	value &= ~clearbits;
	value |= setbits;

	return io_reg_set(page, offset, value);
}

int
PX4IO::print_debug()
{
#ifdef CONFIG_ARCH_BOARD_PX4FMU_V2
	int io_fd = -1;

	if (io_fd < 0) {
		io_fd = ::open("/dev/ttyS0", O_RDONLY | O_NONBLOCK | O_NOCTTY);
	}

	/* read IO's output */
	if (io_fd > 0) {
		pollfd fds[1];
		fds[0].fd = io_fd;
		fds[0].events = POLLIN;

		usleep(500);
		int pret = ::poll(fds, sizeof(fds) / sizeof(fds[0]), 0);

		if (pret > 0) {
			int count;
			char buf[65];

			do {
				count = ::read(io_fd, buf, sizeof(buf) - 1);

				if (count > 0) {
					/* enforce null termination */
					buf[count] = '\0';
					warnx("IO CONSOLE: %s", buf);
				}

			} while (count > 0);
		}

		::close(io_fd);
		return 0;
	}

#endif
	return 1;

}

int
PX4IO::mixer_send(const char *buf, unsigned buflen, unsigned retries)
{
	/* get debug level */
	int debuglevel = io_reg_get(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_SET_DEBUG);

	uint8_t	frame[_max_transfer];

	do {

		px4io_mixdata *msg = (px4io_mixdata *)&frame[0];
		unsigned max_len = _max_transfer - sizeof(px4io_mixdata);

		msg->f2i_mixer_magic = F2I_MIXER_MAGIC;
		msg->action = F2I_MIXER_ACTION_RESET;

		do {
			unsigned count = buflen;

			if (count > max_len)
				count = max_len;

			if (count > 0) {
				memcpy(&msg->text[0], buf, count);
				buf += count;
				buflen -= count;

			} else {
				continue;
			}

			/*
			 * We have to send an even number of bytes.  This
			 * will only happen on the very last transfer of a
			 * mixer, and we are guaranteed that there will be
			 * space left to round up as _max_transfer will be
			 * even.
			 */
			unsigned total_len = sizeof(px4io_mixdata) + count;

			if (total_len % 2) {
				msg->text[count] = '\0';
				total_len++;
			}

			int ret = io_reg_set(PX4IO_PAGE_MIXERLOAD, 0, (uint16_t *)frame, total_len / 2);

			/* print mixer chunk */
			if (debuglevel > 5 || ret) {

				warnx("fmu sent: \"%s\"", msg->text);

				/* read IO's output */
				print_debug();
			}

			if (ret) {
				log("mixer send error %d", ret);
				return ret;
			}

			msg->action = F2I_MIXER_ACTION_APPEND;

		} while (buflen > 0);

		/* ensure a closing newline */
		msg->text[0] = '\n';
		msg->text[1] = '\0';

		int ret = io_reg_set(PX4IO_PAGE_MIXERLOAD, 0, (uint16_t *)frame, (sizeof(px4io_mixdata) + 2) / 2);

		if (ret)
			return ret;

		retries--;

		log("mixer sent");

	} while (retries > 0 && (!(io_reg_get(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_FLAGS) & PX4IO_P_STATUS_FLAGS_MIXER_OK)));

	/* check for the mixer-OK flag */
	if (io_reg_get(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_FLAGS) & PX4IO_P_STATUS_FLAGS_MIXER_OK) {
		mavlink_log_info(_mavlink_fd, "[IO] mixer upload ok");
		return 0;
	}

	log("mixer rejected by IO");
	mavlink_log_info(_mavlink_fd, "[IO] mixer upload fail");

	/* load must have failed for some reason */
	return -EINVAL;
}

void
PX4IO::print_status()
{
	/* basic configuration */
	printf("protocol %u hardware %u bootloader %u buffer %uB crc 0x%04x%04x\n",
	       io_reg_get(PX4IO_PAGE_CONFIG, PX4IO_P_CONFIG_PROTOCOL_VERSION),
	       io_reg_get(PX4IO_PAGE_CONFIG, PX4IO_P_CONFIG_HARDWARE_VERSION),
	       io_reg_get(PX4IO_PAGE_CONFIG, PX4IO_P_CONFIG_BOOTLOADER_VERSION),
	       io_reg_get(PX4IO_PAGE_CONFIG, PX4IO_P_CONFIG_MAX_TRANSFER),
	       io_reg_get(PX4IO_PAGE_SETUP,  PX4IO_P_SETUP_CRC),
	       io_reg_get(PX4IO_PAGE_SETUP,  PX4IO_P_SETUP_CRC+1));
	printf("%u controls %u actuators %u R/C inputs %u analog inputs %u relays\n",
	       io_reg_get(PX4IO_PAGE_CONFIG, PX4IO_P_CONFIG_CONTROL_COUNT),
	       io_reg_get(PX4IO_PAGE_CONFIG, PX4IO_P_CONFIG_ACTUATOR_COUNT),
	       io_reg_get(PX4IO_PAGE_CONFIG, PX4IO_P_CONFIG_RC_INPUT_COUNT),
	       io_reg_get(PX4IO_PAGE_CONFIG, PX4IO_P_CONFIG_ADC_INPUT_COUNT),
	       io_reg_get(PX4IO_PAGE_CONFIG, PX4IO_P_CONFIG_RELAY_COUNT));

	/* status */
	printf("%u bytes free\n",
	       io_reg_get(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_FREEMEM));
	uint16_t flags = io_reg_get(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_FLAGS);
	printf("status 0x%04x%s%s%s%s%s%s%s%s%s%s%s%s%s\n",
	       flags,
	       ((flags & PX4IO_P_STATUS_FLAGS_OUTPUTS_ARMED) ? " OUTPUTS_ARMED" : ""),
	       ((flags & PX4IO_P_STATUS_FLAGS_SAFETY_OFF) ? " SAFETY_OFF" : " SAFETY_SAFE"),
	       ((flags & PX4IO_P_STATUS_FLAGS_OVERRIDE) ? " OVERRIDE" : ""),
	       ((flags & PX4IO_P_STATUS_FLAGS_RC_OK)    ? " RC_OK" : " RC_FAIL"),
	       ((flags & PX4IO_P_STATUS_FLAGS_RC_PPM)   ? " PPM" : ""),
	       (((flags & PX4IO_P_STATUS_FLAGS_RC_DSM) && (!(flags & PX4IO_P_STATUS_FLAGS_RC_DSM11))) ? " DSM10" : ""),
	       (((flags & PX4IO_P_STATUS_FLAGS_RC_DSM) && (flags & PX4IO_P_STATUS_FLAGS_RC_DSM11)) ? " DSM11" : ""),
	       ((flags & PX4IO_P_STATUS_FLAGS_RC_SBUS)  ? " SBUS" : ""),
	       ((flags & PX4IO_P_STATUS_FLAGS_FMU_OK)   ? " FMU_OK" : " FMU_FAIL"),
	       ((flags & PX4IO_P_STATUS_FLAGS_RAW_PWM)  ? " RAW_PWM_PASSTHROUGH" : ""),
	       ((flags & PX4IO_P_STATUS_FLAGS_MIXER_OK) ? " MIXER_OK" : " MIXER_FAIL"),
	       ((flags & PX4IO_P_STATUS_FLAGS_ARM_SYNC) ? " ARM_SYNC" : " ARM_NO_SYNC"),
	       ((flags & PX4IO_P_STATUS_FLAGS_INIT_OK)  ? " INIT_OK" : " INIT_FAIL"),
	       ((flags & PX4IO_P_STATUS_FLAGS_FAILSAFE)  ? " FAILSAFE" : ""));
	uint16_t alarms = io_reg_get(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_ALARMS);
	printf("alarms 0x%04x%s%s%s%s%s%s%s%s\n",
	       alarms,
	       ((alarms & PX4IO_P_STATUS_ALARMS_VBATT_LOW)     ? " VBATT_LOW" : ""),
	       ((alarms & PX4IO_P_STATUS_ALARMS_TEMPERATURE)   ? " TEMPERATURE" : ""),
	       ((alarms & PX4IO_P_STATUS_ALARMS_SERVO_CURRENT) ? " SERVO_CURRENT" : ""),
	       ((alarms & PX4IO_P_STATUS_ALARMS_ACC_CURRENT)   ? " ACC_CURRENT" : ""),
	       ((alarms & PX4IO_P_STATUS_ALARMS_FMU_LOST)      ? " FMU_LOST" : ""),
	       ((alarms & PX4IO_P_STATUS_ALARMS_RC_LOST)       ? " RC_LOST" : ""),
	       ((alarms & PX4IO_P_STATUS_ALARMS_PWM_ERROR)     ? " PWM_ERROR" : ""),
	       ((alarms & PX4IO_P_STATUS_ALARMS_VSERVO_FAULT)  ? " VSERVO_FAULT" : ""));
	/* now clear alarms */
	io_reg_set(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_ALARMS, 0xFFFF);

	if (_hardware == 1) {
		printf("vbatt mV %u ibatt mV %u vbatt scale %u\n",
		       io_reg_get(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_VBATT),
		       io_reg_get(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_IBATT),
		       io_reg_get(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_VBATT_SCALE));
		printf("amp_per_volt %.3f amp_offset %.3f mAh discharged %.3f\n",
		       (double)_battery_amp_per_volt,
		       (double)_battery_amp_bias,
		       (double)_battery_mamphour_total);

	} else if (_hardware == 2) {
		printf("vservo %u mV vservo scale %u\n",
		       io_reg_get(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_VSERVO),
		       io_reg_get(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_VSERVO_SCALE));
		printf("vrssi %u\n", io_reg_get(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_VRSSI));
	}

	printf("actuators");

	for (unsigned i = 0; i < _max_actuators; i++)
		printf(" %u", io_reg_get(PX4IO_PAGE_ACTUATORS, i));

	printf("\n");
	printf("servos");

	for (unsigned i = 0; i < _max_actuators; i++)
		printf(" %u", io_reg_get(PX4IO_PAGE_SERVOS, i));

	printf("\n");
	uint16_t raw_inputs = io_reg_get(PX4IO_PAGE_RAW_RC_INPUT, PX4IO_P_RAW_RC_COUNT);
	printf("%d raw R/C inputs", raw_inputs);

	for (unsigned i = 0; i < raw_inputs; i++)
		printf(" %u", io_reg_get(PX4IO_PAGE_RAW_RC_INPUT, PX4IO_P_RAW_RC_BASE + i));

	printf("\n");

	if ((flags & PX4IO_P_STATUS_FLAGS_RC_PPM)) {
		int frame_len = io_reg_get(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_RC_DATA);
		printf("RC data (PPM frame len) %u us\n", frame_len);

		if ((frame_len - raw_inputs * 2000 - 3000) < 0) {
			printf("WARNING  WARNING  WARNING! This RC receiver does not allow safe frame detection.\n");
		}
	}

	uint16_t mapped_inputs = io_reg_get(PX4IO_PAGE_RC_INPUT, PX4IO_P_RC_VALID);
	printf("mapped R/C inputs 0x%04x", mapped_inputs);

	for (unsigned i = 0; i < _max_rc_input; i++) {
		if (mapped_inputs & (1 << i))
			printf(" %u:%d", i, REG_TO_SIGNED(io_reg_get(PX4IO_PAGE_RC_INPUT, PX4IO_P_RC_BASE + i)));
	}

	printf("\n");
	uint16_t adc_inputs = io_reg_get(PX4IO_PAGE_CONFIG, PX4IO_P_CONFIG_ADC_INPUT_COUNT);
	printf("ADC inputs");

	for (unsigned i = 0; i < adc_inputs; i++)
		printf(" %u", io_reg_get(PX4IO_PAGE_RAW_ADC_INPUT, i));

	printf("\n");

	/* setup and state */
	printf("features 0x%04x\n", io_reg_get(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_FEATURES));
	uint16_t arming = io_reg_get(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_ARMING);
	printf("arming 0x%04x%s%s%s%s%s%s\n",
	       arming,
	       ((arming & PX4IO_P_SETUP_ARMING_FMU_ARMED)          ? " FMU_ARMED" : " FMU_DISARMED"),
	       ((arming & PX4IO_P_SETUP_ARMING_IO_ARM_OK)	    ? " IO_ARM_OK" : " IO_ARM_DENIED"),
	       ((arming & PX4IO_P_SETUP_ARMING_MANUAL_OVERRIDE_OK) ? " MANUAL_OVERRIDE_OK" : ""),
	       ((arming & PX4IO_P_SETUP_ARMING_FAILSAFE_CUSTOM)   ? " FAILSAFE_CUSTOM" : ""),
	       ((arming & PX4IO_P_SETUP_ARMING_INAIR_RESTART_OK)   ? " INAIR_RESTART_OK" : ""),
	       ((arming & PX4IO_P_SETUP_ARMING_ALWAYS_PWM_ENABLE)  ? " ALWAYS_PWM_ENABLE" : ""));
#ifdef CONFIG_ARCH_BOARD_PX4FMU_V1
	printf("rates 0x%04x default %u alt %u relays 0x%04x\n",
	       io_reg_get(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_PWM_RATES),
	       io_reg_get(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_PWM_DEFAULTRATE),
	       io_reg_get(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_PWM_ALTRATE),
	       io_reg_get(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_RELAYS));
#endif
#ifdef CONFIG_ARCH_BOARD_PX4FMU_V2
	printf("rates 0x%04x default %u alt %u\n",
	       io_reg_get(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_PWM_RATES),
	       io_reg_get(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_PWM_DEFAULTRATE),
	       io_reg_get(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_PWM_ALTRATE));
#endif
	printf("debuglevel %u\n", io_reg_get(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_SET_DEBUG));
	printf("controls");

	for (unsigned i = 0; i < _max_controls; i++)
		printf(" %u", io_reg_get(PX4IO_PAGE_CONTROLS, i));

	printf("\n");

	for (unsigned i = 0; i < _max_rc_input; i++) {
		unsigned base = PX4IO_P_RC_CONFIG_STRIDE * i;
		uint16_t options = io_reg_get(PX4IO_PAGE_RC_CONFIG, base + PX4IO_P_RC_CONFIG_OPTIONS);
		printf("input %u min %u center %u max %u deadzone %u assigned %u options 0x%04x%s%s\n",
		       i,
		       io_reg_get(PX4IO_PAGE_RC_CONFIG, base + PX4IO_P_RC_CONFIG_MIN),
		       io_reg_get(PX4IO_PAGE_RC_CONFIG, base + PX4IO_P_RC_CONFIG_CENTER),
		       io_reg_get(PX4IO_PAGE_RC_CONFIG, base + PX4IO_P_RC_CONFIG_MAX),
		       io_reg_get(PX4IO_PAGE_RC_CONFIG, base + PX4IO_P_RC_CONFIG_DEADZONE),
		       io_reg_get(PX4IO_PAGE_RC_CONFIG, base + PX4IO_P_RC_CONFIG_ASSIGNMENT),
		       options,
		       ((options & PX4IO_P_RC_CONFIG_OPTIONS_ENABLED) ? " ENABLED" : ""),
		       ((options & PX4IO_P_RC_CONFIG_OPTIONS_REVERSE) ? " REVERSED" : ""));
	}

	printf("failsafe");

	for (unsigned i = 0; i < _max_actuators; i++)
		printf(" %u", io_reg_get(PX4IO_PAGE_FAILSAFE_PWM, i));

	printf("\ndisarmed values");

	for (unsigned i = 0; i < _max_actuators; i++)
		printf(" %u", io_reg_get(PX4IO_PAGE_DISARMED_PWM, i));

	printf("\n");
}

int
PX4IO::ioctl(file * /*filep*/, int cmd, unsigned long arg)
/* Make it obvious that file * isn't used here */
{
	int ret = OK;

	/* regular ioctl? */
	switch (cmd) {
	case PWM_SERVO_ARM:
		/* set the 'armed' bit */
		ret = io_reg_modify(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_ARMING, 0, PX4IO_P_SETUP_ARMING_FMU_ARMED);
		break;

	case PWM_SERVO_SET_ARM_OK:
		/* set the 'OK to arm' bit */
		ret = io_reg_modify(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_ARMING, 0, PX4IO_P_SETUP_ARMING_IO_ARM_OK);
		break;

	case PWM_SERVO_CLEAR_ARM_OK:
		/* clear the 'OK to arm' bit */
		ret = io_reg_modify(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_ARMING, PX4IO_P_SETUP_ARMING_IO_ARM_OK, 0);
		break;

	case PWM_SERVO_DISARM:
		/* clear the 'armed' bit */
		ret = io_reg_modify(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_ARMING, PX4IO_P_SETUP_ARMING_FMU_ARMED, 0);
		break;

	case PWM_SERVO_GET_DEFAULT_UPDATE_RATE:
		/* get the default update rate */
		*(unsigned *)arg = io_reg_get(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_PWM_DEFAULTRATE);
		break;

	case PWM_SERVO_SET_UPDATE_RATE:
		/* set the requested alternate rate */
		ret = io_reg_set(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_PWM_ALTRATE, arg);
		break;

	case PWM_SERVO_GET_UPDATE_RATE:
		/* get the alternative update rate */
		*(unsigned *)arg = io_reg_get(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_PWM_ALTRATE);
		break;

	case PWM_SERVO_SET_SELECT_UPDATE_RATE: {

			/* blindly clear the PWM update alarm - might be set for some other reason */
			io_reg_set(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_ALARMS, PX4IO_P_STATUS_ALARMS_PWM_ERROR);

			/* attempt to set the rate map */
			io_reg_set(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_PWM_RATES, arg);

			/* check that the changes took */
			uint16_t alarms = io_reg_get(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_ALARMS);

			if (alarms & PX4IO_P_STATUS_ALARMS_PWM_ERROR) {
				ret = -EINVAL;
				io_reg_set(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_ALARMS, PX4IO_P_STATUS_ALARMS_PWM_ERROR);
			}

			break;
		}

	case PWM_SERVO_GET_SELECT_UPDATE_RATE:

		*(unsigned *)arg = io_reg_get(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_PWM_RATES);
		break;

	case PWM_SERVO_SET_FAILSAFE_PWM: {
		struct pwm_output_values* pwm = (struct pwm_output_values*)arg;
		if (pwm->channel_count > _max_actuators)
			/* fail with error */
			return E2BIG;

		/* copy values to registers in IO */
		ret = io_reg_set(PX4IO_PAGE_FAILSAFE_PWM, 0, pwm->values, pwm->channel_count);
		break;
	}

	case PWM_SERVO_GET_FAILSAFE_PWM:

		ret = io_reg_get(PX4IO_PAGE_FAILSAFE_PWM, 0, (uint16_t*)arg, _max_actuators);
		if (ret != OK) {
			ret = -EIO;
		}
		break;

	case PWM_SERVO_SET_DISARMED_PWM: {
		struct pwm_output_values* pwm = (struct pwm_output_values*)arg;
		if (pwm->channel_count > _max_actuators)
			/* fail with error */
			return E2BIG;

		/* copy values to registers in IO */
		ret = io_reg_set(PX4IO_PAGE_DISARMED_PWM, 0, pwm->values, pwm->channel_count);
		break;
	}

	case PWM_SERVO_GET_DISARMED_PWM:

		ret = io_reg_get(PX4IO_PAGE_DISARMED_PWM, 0, (uint16_t*)arg, _max_actuators);
		if (ret != OK) {
			ret = -EIO;
		}
		break;

	case PWM_SERVO_SET_MIN_PWM: {
		struct pwm_output_values* pwm = (struct pwm_output_values*)arg;
		if (pwm->channel_count > _max_actuators)
			/* fail with error */
			return E2BIG;

		/* copy values to registers in IO */
		ret = io_reg_set(PX4IO_PAGE_CONTROL_MIN_PWM, 0, pwm->values, pwm->channel_count);
		break;
	}

	case PWM_SERVO_GET_MIN_PWM:

		ret = io_reg_get(PX4IO_PAGE_CONTROL_MIN_PWM, 0, (uint16_t*)arg, _max_actuators);
		if (ret != OK) {
			ret = -EIO;
		}
		break;

	case PWM_SERVO_SET_MAX_PWM: {
		struct pwm_output_values* pwm = (struct pwm_output_values*)arg;
		if (pwm->channel_count > _max_actuators)
			/* fail with error */
			return E2BIG;

		/* copy values to registers in IO */
		ret = io_reg_set(PX4IO_PAGE_CONTROL_MAX_PWM, 0, pwm->values, pwm->channel_count);
		break;
	}

	case PWM_SERVO_GET_MAX_PWM:

		ret = io_reg_get(PX4IO_PAGE_CONTROL_MAX_PWM, 0, (uint16_t*)arg, _max_actuators);
		if (ret != OK) {
			ret = -EIO;
		}
		break;

	case PWM_SERVO_GET_COUNT:
		*(unsigned *)arg = _max_actuators;
		break;

	case DSM_BIND_START:
		io_reg_set(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_DSM, dsm_bind_power_down);
		usleep(500000);
		io_reg_set(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_DSM, dsm_bind_set_rx_out);
		io_reg_set(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_DSM, dsm_bind_power_up);
		usleep(72000);
		io_reg_set(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_DSM, dsm_bind_send_pulses | (arg << 4));
		usleep(50000);
		io_reg_set(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_DSM, dsm_bind_reinit_uart);
		break;

	case DSM_BIND_POWER_UP:
		io_reg_set(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_DSM, dsm_bind_power_up);
		break;

	case PWM_SERVO_SET(0) ... PWM_SERVO_SET(PWM_OUTPUT_MAX_CHANNELS - 1): {

			/* TODO: we could go lower for e.g. TurboPWM */
			unsigned channel = cmd - PWM_SERVO_SET(0);

			if ((channel >= _max_actuators) || (arg < PWM_LOWEST_MIN) || (arg > PWM_HIGHEST_MAX)) {
				ret = -EINVAL;

			} else {
				/* send a direct PWM value */
				ret = io_reg_set(PX4IO_PAGE_DIRECT_PWM, channel, arg);
			}

			break;
		}

	case PWM_SERVO_GET(0) ... PWM_SERVO_GET(PWM_OUTPUT_MAX_CHANNELS - 1): {

			unsigned channel = cmd - PWM_SERVO_GET(0);

			if (channel >= _max_actuators) {
				ret = -EINVAL;

			} else {
				/* fetch a current PWM value */
				uint32_t value = io_reg_get(PX4IO_PAGE_SERVOS, channel);

				if (value == _io_reg_get_error) {
					ret = -EIO;

				} else {
					*(servo_position_t *)arg = value;
				}
			}

			break;
		}

	case PWM_SERVO_GET_RATEGROUP(0) ... PWM_SERVO_GET_RATEGROUP(PWM_OUTPUT_MAX_CHANNELS - 1): {

			unsigned channel = cmd - PWM_SERVO_GET_RATEGROUP(0);

			*(uint32_t *)arg = io_reg_get(PX4IO_PAGE_PWM_INFO, PX4IO_RATE_MAP_BASE + channel);

			if (*(uint32_t *)arg == _io_reg_get_error)
				ret = -EIO;

			break;
		}

	case GPIO_RESET: {
#ifdef CONFIG_ARCH_BOARD_PX4FMU_V1
			uint32_t bits = (1 << _max_relays) - 1;

			/* don't touch relay1 if it's controlling RX vcc */
			if (_dsm_vcc_ctl)
				bits &= ~PX4IO_P_SETUP_RELAYS_POWER1;

			ret = io_reg_modify(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_RELAYS, bits, 0);
#endif
#ifdef CONFIG_ARCH_BOARD_PX4FMU_V2
			ret = -EINVAL;
#endif
			break;
		}

	case GPIO_SET:
#ifdef CONFIG_ARCH_BOARD_PX4FMU_V1
		arg &= ((1 << _max_relays) - 1);

		/* don't touch relay1 if it's controlling RX vcc */
		if (_dsm_vcc_ctl & (arg & PX4IO_P_SETUP_RELAYS_POWER1)) {
			ret = -EINVAL;
			break;
		}

		ret = io_reg_modify(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_RELAYS, 0, arg);
#endif
#ifdef CONFIG_ARCH_BOARD_PX4FMU_V2
		ret = -EINVAL;
#endif
		break;

	case GPIO_CLEAR:
#ifdef CONFIG_ARCH_BOARD_PX4FMU_V1
		arg &= ((1 << _max_relays) - 1);

		/* don't touch relay1 if it's controlling RX vcc */
		if (_dsm_vcc_ctl & (arg & PX4IO_P_SETUP_RELAYS_POWER1)) {
			ret = -EINVAL;
			break;
		}

		ret = io_reg_modify(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_RELAYS, arg, 0);
#endif
#ifdef CONFIG_ARCH_BOARD_PX4FMU_V2
		ret = -EINVAL;
#endif
		break;

	case GPIO_GET:
#ifdef CONFIG_ARCH_BOARD_PX4FMU_V1
		*(uint32_t *)arg = io_reg_get(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_RELAYS);

		if (*(uint32_t *)arg == _io_reg_get_error)
			ret = -EIO;

#endif
#ifdef CONFIG_ARCH_BOARD_PX4FMU_V2
		ret = -EINVAL;
#endif
		break;

	case MIXERIOCGETOUTPUTCOUNT:
		*(unsigned *)arg = _max_actuators;
		break;

	case MIXERIOCRESET:
		ret = 0;	/* load always resets */
		break;

	case MIXERIOCLOADBUF: {
			const char *buf = (const char *)arg;
			ret = mixer_send(buf, strnlen(buf, 2048));
			break;
		}

	case RC_INPUT_GET: {
			uint16_t status;
			rc_input_values *rc_val = (rc_input_values *)arg;

			ret = io_reg_get(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_FLAGS, &status, 1);

			if (ret != OK)
				break;

			/* if no R/C input, don't try to fetch anything */
			if (!(status & PX4IO_P_STATUS_FLAGS_RC_OK)) {
				ret = -ENOTCONN;
				break;
			}

			/* sort out the source of the values */
			if (status & PX4IO_P_STATUS_FLAGS_RC_PPM) {
				rc_val->input_source = RC_INPUT_SOURCE_PX4IO_PPM;

			} else if (status & PX4IO_P_STATUS_FLAGS_RC_DSM) {
				rc_val->input_source = RC_INPUT_SOURCE_PX4IO_SPEKTRUM;

			} else if (status & PX4IO_P_STATUS_FLAGS_RC_SBUS) {
				rc_val->input_source = RC_INPUT_SOURCE_PX4IO_SBUS;

			} else {
				rc_val->input_source = RC_INPUT_SOURCE_UNKNOWN;
			}

			/* read raw R/C input values */
			ret = io_reg_get(PX4IO_PAGE_RAW_RC_INPUT, PX4IO_P_RAW_RC_BASE, &(rc_val->values[0]), _max_rc_input);
			break;
		}

	case PX4IO_SET_DEBUG:
		/* set the debug level */
		ret = io_reg_set(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_SET_DEBUG, arg);
		break;

	case PX4IO_REBOOT_BOOTLOADER:
		if (system_status() & PX4IO_P_STATUS_FLAGS_SAFETY_OFF)
			return -EINVAL;

		/* reboot into bootloader - arg must be PX4IO_REBOOT_BL_MAGIC */
		io_reg_set(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_REBOOT_BL, arg);
		// we don't expect a reply from this operation
		ret = OK;
		break;

	case PX4IO_CHECK_CRC: {
		/* check IO firmware CRC against passed value */		
		uint32_t io_crc = 0;
		ret = io_reg_get(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_CRC, (uint16_t *)&io_crc, 2);
		if (ret != OK)
			return ret;
		if (io_crc != arg) {
			debug("crc mismatch 0x%08x 0x%08x", (unsigned)io_crc, arg);
			return -EINVAL;
		}
		break;
	}

	case PX4IO_INAIR_RESTART_ENABLE:

		/* set/clear the 'in-air restart' bit */
		if (arg) {
			ret = io_reg_modify(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_ARMING, 0, PX4IO_P_SETUP_ARMING_INAIR_RESTART_OK);

		} else {
			ret = io_reg_modify(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_ARMING, PX4IO_P_SETUP_ARMING_INAIR_RESTART_OK, 0);
		}

		break;

	default:
		/* not a recognized value */
		ret = -ENOTTY;
	}

	return ret;
}

ssize_t
PX4IO::write(file * /*filp*/, const char *buffer, size_t len)
/* Make it obvious that file * isn't used here */
{
	unsigned count = len / 2;

	if (count > _max_actuators)
		count = _max_actuators;

	if (count > 0) {

		perf_begin(_perf_write);
		int ret = io_reg_set(PX4IO_PAGE_DIRECT_PWM, 0, (uint16_t *)buffer, count);
		perf_end(_perf_write);

		if (ret != OK)
			return ret;
	}

	return count * 2;
}

int
PX4IO::set_update_rate(int rate)
{
	int interval_ms = 1000 / rate;

	if (interval_ms < UPDATE_INTERVAL_MIN) {
		interval_ms = UPDATE_INTERVAL_MIN;
		warnx("update rate too high, limiting interval to %d ms (%d Hz).", interval_ms, 1000 / interval_ms);
	}

	if (interval_ms > 100) {
		interval_ms = 100;
		warnx("update rate too low, limiting to %d ms (%d Hz).", interval_ms, 1000 / interval_ms);
	}

	_update_interval = interval_ms;
	return 0;
}

void
PX4IO::set_battery_current_scaling(float amp_per_volt, float amp_bias)
{
	_battery_amp_per_volt = amp_per_volt;
	_battery_amp_bias = amp_bias;
}

extern "C" __EXPORT int px4io_main(int argc, char *argv[]);

namespace
{

device::Device *
get_interface()
{
	device::Device *interface = nullptr;

#ifndef CONFIG_ARCH_BOARD_PX4FMU_V1

	/* try for a serial interface */
	if (PX4IO_serial_interface != nullptr)
		interface = PX4IO_serial_interface();

	if (interface != nullptr)
		goto got;

#endif

	/* try for an I2C interface if we haven't got a serial one */
	if (PX4IO_i2c_interface != nullptr)
		interface = PX4IO_i2c_interface();

	if (interface != nullptr)
		goto got;

	errx(1, "cannot alloc interface");

got:

	if (interface->init() != OK) {
		delete interface;
		errx(1, "interface init failed");
	}

	return interface;
}

void
start(int argc, char *argv[])
{
	if (g_dev != nullptr)
		errx(0, "already loaded");

	/* allocate the interface */
	device::Device *interface = get_interface();

	/* create the driver - it will set g_dev */
	(void)new PX4IO(interface);

	if (g_dev == nullptr) {
		delete interface;
		errx(1, "driver alloc failed");
	}

	if (OK != g_dev->init()) {
		delete g_dev;
		g_dev = nullptr;
		errx(1, "driver init failed");
	}

	/* disable RC handling on request */
	if (argc > 1) {
		if (!strcmp(argv[1], "norc")) {

			if (g_dev->disable_rc_handling())
				warnx("Failed disabling RC handling");

		} else {
			warnx("unknown argument: %s", argv[1]);
		}
	}

#ifdef CONFIG_ARCH_BOARD_PX4FMU_V1
	int dsm_vcc_ctl;

	if (param_get(param_find("RC_RL1_DSM_VCC"), &dsm_vcc_ctl) == OK) {
		if (dsm_vcc_ctl) {
			g_dev->set_dsm_vcc_ctl(true);
			g_dev->ioctl(nullptr, DSM_BIND_POWER_UP, 0);
		}
	}

#endif
	exit(0);
}

void
detect(int argc, char *argv[])
{
	if (g_dev != nullptr)
		errx(0, "already loaded");

	/* allocate the interface */
	device::Device *interface = get_interface();

	/* create the driver - it will set g_dev */
	(void)new PX4IO(interface);

	if (g_dev == nullptr)
		errx(1, "driver alloc failed");

	int ret = g_dev->detect();

	delete g_dev;
	g_dev = nullptr;

	if (ret) {
		/* nonzero, error */
		exit(1);

	} else {
		exit(0);
	}
}

void
checkcrc(int argc, char *argv[])
{
	bool keep_running = false;

	if (g_dev == nullptr) {
		/* allocate the interface */
		device::Device *interface = get_interface();

		/* create the driver - it will set g_dev */
		(void)new PX4IO(interface);

		if (g_dev == nullptr)
			errx(1, "driver alloc failed");
	} else {
		/* its already running, don't kill the driver */
		keep_running = true;
	}

	/*
	  check IO CRC against CRC of a file
	 */
	if (argc < 2) {
		printf("usage: px4io checkcrc filename\n");
		exit(1);
	}
	int fd = open(argv[1], O_RDONLY);
	if (fd == -1) {
		printf("open of %s failed - %d\n", argv[1], errno);
		exit(1);			
	}
	const uint32_t app_size_max = 0xf000;
	uint32_t fw_crc = 0;
	uint32_t nbytes = 0;
	while (true) {
		uint8_t buf[16];
		int n = read(fd, buf, sizeof(buf));
		if (n <= 0) break;
		fw_crc = crc32part(buf, n, fw_crc);
		nbytes += n;
	}
	close(fd);
	while (nbytes < app_size_max) {
		uint8_t b = 0xff;
		fw_crc = crc32part(&b, 1, fw_crc);			
		nbytes++;
	}

	int ret = g_dev->ioctl(nullptr, PX4IO_CHECK_CRC, fw_crc);

	if (!keep_running) {
		delete g_dev;
		g_dev = nullptr;
	}

	if (ret != OK) {
		printf("check CRC failed - %d\n", ret);
		exit(1);			
	}
	printf("CRCs match\n");
	exit(0);
}

void
bind(int argc, char *argv[])
{
	int pulses;

	if (g_dev == nullptr)
		errx(1, "px4io must be started first");

#ifdef CONFIG_ARCH_BOARD_PX4FMU_V1

	if (!g_dev->get_dsm_vcc_ctl())
		errx(1, "DSM bind feature not enabled");

#endif

	if (argc < 3)
		errx(0, "needs argument, use dsm2 or dsmx");

	if (!strcmp(argv[2], "dsm2"))
		pulses = DSM2_BIND_PULSES;
	else if (!strcmp(argv[2], "dsmx"))
		pulses = DSMX_BIND_PULSES;
	else if (!strcmp(argv[2], "dsmx8"))
		pulses = DSMX8_BIND_PULSES;
	else 
		errx(1, "unknown parameter %s, use dsm2 or dsmx", argv[2]);
	// Test for custom pulse parameter
	if (argc > 3)
		pulses = atoi(argv[3]);
	if (g_dev->system_status() & PX4IO_P_STATUS_FLAGS_SAFETY_OFF) 
		errx(1, "system must not be armed");

#ifdef CONFIG_ARCH_BOARD_PX4FMU_V1
	warnx("This command will only bind DSM if satellite VCC (red wire) is controlled by relay 1.");
#endif
	g_dev->ioctl(nullptr, DSM_BIND_START, pulses);

	exit(0);

}

void
test(void)
{
	int		fd;
	unsigned	servo_count = 0;
	unsigned	pwm_value = 1000;
	int		direction = 1;
	int		ret;

	fd = open(PX4IO_DEVICE_PATH, O_WRONLY);

	if (fd < 0)
		err(1, "failed to open device");

	if (ioctl(fd, PWM_SERVO_GET_COUNT, (unsigned long)&servo_count))
		err(1, "failed to get servo count");

	/* tell IO that its ok to disable its safety with the switch */
	ret = ioctl(fd, PWM_SERVO_SET_ARM_OK, 0);

	if (ret != OK)
		err(1, "PWM_SERVO_SET_ARM_OK");

	if (ioctl(fd, PWM_SERVO_ARM, 0))
		err(1, "failed to arm servos");

	struct pollfd fds;
	fds.fd = 0; /* stdin */
	fds.events = POLLIN;

	warnx("Press CTRL-C or 'c' to abort.");

	for (;;) {

		/* sweep all servos between 1000..2000 */
		servo_position_t servos[servo_count];

		for (unsigned i = 0; i < servo_count; i++)
			servos[i] = pwm_value;

		ret = write(fd, servos, sizeof(servos));

		if (ret != (int)sizeof(servos))
			err(1, "error writing PWM servo data, wrote %u got %d", sizeof(servos), ret);

		if (direction > 0) {
			if (pwm_value < 2000) {
				pwm_value++;

			} else {
				direction = -1;
			}

		} else {
			if (pwm_value > 1000) {
				pwm_value--;

			} else {
				direction = 1;
			}
		}

		/* readback servo values */
		for (unsigned i = 0; i < servo_count; i++) {
			servo_position_t value;

			if (ioctl(fd, PWM_SERVO_GET(i), (unsigned long)&value))
				err(1, "error reading PWM servo %d", i);

			if (value != servos[i])
				errx(1, "servo %d readback error, got %u expected %u", i, value, servos[i]);
		}

		/* Check if user wants to quit */
		char c;
		ret = poll(&fds, 1, 0);

		if (ret > 0) {

			read(0, &c, 1);

			if (c == 0x03 || c == 0x63 || c == 'q') {
				warnx("User abort\n");
				exit(0);
			}
		}
	}
}

void
monitor(void)
{
	/* clear screen */
	printf("\033[2J");

	unsigned cancels = 3;

	for (;;) {
		pollfd fds[1];

		fds[0].fd = 0;
		fds[0].events = POLLIN;
		poll(fds, 1, 2000);

		if (fds[0].revents == POLLIN) {
			int c;
			read(0, &c, 1);

			if (cancels-- == 0) {
				printf("\033[2J\033[H"); /* move cursor home and clear screen */
				exit(0);
			}
		}

		if (g_dev != nullptr) {

			printf("\033[2J\033[H"); /* move cursor home and clear screen */
			(void)g_dev->print_status();
			(void)g_dev->print_debug();
			printf("\n\n\n[ Use 'px4io debug <N>' for more output. Hit <enter> three times to exit monitor mode ]\n");

		} else {
			errx(1, "driver not loaded, exiting");
		}
	}
}

void
if_test(unsigned mode)
{
	device::Device *interface = get_interface();

	int result = interface->ioctl(1, mode); /* XXX magic numbers */
	delete interface;

	errx(0, "test returned %d", result);
}

} /* namespace */

int
px4io_main(int argc, char *argv[])
{
	/* check for sufficient number of arguments */
	if (argc < 2)
		goto out;

	if (!strcmp(argv[1], "start"))
		start(argc - 1, argv + 1);

	if (!strcmp(argv[1], "detect"))
		detect(argc - 1, argv + 1);

	if (!strcmp(argv[1], "checkcrc"))
		checkcrc(argc - 1, argv + 1);

	if (!strcmp(argv[1], "update")) {

		if (g_dev != nullptr) {
			printf("[px4io] loaded, detaching first\n");
			/* stop the driver */
			delete g_dev;
		}

		PX4IO_Uploader *up;
		const char *fn[4];

		/* work out what we're uploading... */
		if (argc > 2) {
			fn[0] = argv[2];
			fn[1] = nullptr;

		} else {
#if defined(CONFIG_ARCH_BOARD_PX4FMU_V1)
			fn[0] = "/etc/extras/px4io-v1_default.bin";
			fn[1] =	"/fs/microsd/px4io1.bin";
			fn[2] =	"/fs/microsd/px4io.bin";
			fn[3] =	nullptr;
#elif defined(CONFIG_ARCH_BOARD_PX4FMU_V2)
			fn[0] = "/etc/extras/px4io-v2_default.bin";
			fn[1] =	"/fs/microsd/px4io2.bin";
			fn[2] =	"/fs/microsd/px4io.bin";
			fn[3] =	nullptr;
#else
#error "unknown board"
#endif
		}

		up = new PX4IO_Uploader;
		int ret = up->upload(&fn[0]);
		delete up;

		switch (ret) {
		case OK:
			break;

		case -ENOENT:
			errx(1, "PX4IO firmware file not found");

		case -EEXIST:
		case -EIO:
			errx(1, "error updating PX4IO - check that bootloader mode is enabled");

		case -EINVAL:
			errx(1, "verify failed - retry the update");

		case -ETIMEDOUT:
			errx(1, "timed out waiting for bootloader - power-cycle and try again");

		default:
			errx(1, "unexpected error %d", ret);
		}

		return ret;
	}

	if (!strcmp(argv[1], "iftest")) {
		if (g_dev != nullptr)
			errx(1, "can't iftest when started");

		if_test((argc > 2) ? strtol(argv[2], NULL, 0) : 0);
	}

	if (!strcmp(argv[1], "forceupdate")) {
		/*
		  force update of the IO firmware without requiring
		  the user to hold the safety switch down
		 */
		if (argc <= 3) {
			warnx("usage: px4io forceupdate MAGIC filename");
			exit(1);
		}
		if (g_dev == nullptr) {
			warnx("px4io is not started, still attempting upgrade");

			/* allocate the interface */
			device::Device *interface = get_interface();

			/* create the driver - it will set g_dev */
			(void)new PX4IO(interface);

			if (g_dev == nullptr) {
				delete interface;
				errx(1, "driver alloc failed");
			}

			if (OK != g_dev->init()) {
				warnx("driver init failed, still trying..");
			}
		}

		uint16_t arg = atol(argv[2]);
		int ret = g_dev->ioctl(nullptr, PX4IO_REBOOT_BOOTLOADER, arg);
		if (ret != OK) {
			printf("reboot failed - %d\n", ret);
			exit(1);
		}

		// tear down the px4io instance
		delete g_dev;

		// upload the specified firmware
		const char *fn[2];
		fn[0] = argv[3];
		fn[1] = nullptr;
		PX4IO_Uploader *up = new PX4IO_Uploader;
		up->upload(&fn[0]);
		delete up;
		exit(0);
	}

	/* commands below here require a started driver */

	if (g_dev == nullptr)
		errx(1, "not started");

	if (!strcmp(argv[1], "limit")) {

		if ((argc > 2)) {
			g_dev->set_update_rate(atoi(argv[2]));

		} else {
			errx(1, "missing argument (50 - 500 Hz)");
			return 1;
		}

		exit(0);
	}

	if (!strcmp(argv[1], "current")) {
		if ((argc > 3)) {
			g_dev->set_battery_current_scaling(atof(argv[2]), atof(argv[3]));

		} else {
			errx(1, "missing argument (apm_per_volt, amp_offset)");
			return 1;
		}

		exit(0);
	}



	if (!strcmp(argv[1], "recovery")) {

		/*
		 * Enable in-air restart support.
		 * We can cheat and call the driver directly, as it
		 * doesn't reference filp in ioctl()
		 */
		g_dev->ioctl(NULL, PX4IO_INAIR_RESTART_ENABLE, 1);
		exit(0);
	}

	if (!strcmp(argv[1], "stop")) {

		/* stop the driver */
		delete g_dev;
		exit(0);
	}


	if (!strcmp(argv[1], "status")) {

		printf("[px4io] loaded\n");
		g_dev->print_status();

		exit(0);
	}

	if (!strcmp(argv[1], "debug")) {
		if (argc <= 2) {
			printf("usage: px4io debug LEVEL\n");
			exit(1);
		}

		if (g_dev == nullptr) {
			printf("px4io is not started\n");
			exit(1);
		}

		uint8_t level = atoi(argv[2]);
		/* we can cheat and call the driver directly, as it
		 * doesn't reference filp in ioctl()
		 */
		int ret = g_dev->ioctl(nullptr, PX4IO_SET_DEBUG, level);

		if (ret != 0) {
			printf("SET_DEBUG failed - %d\n", ret);
			exit(1);
		}

		printf("SET_DEBUG %u OK\n", (unsigned)level);
		exit(0);
	}

	if (!strcmp(argv[1], "rx_dsm") ||
	    !strcmp(argv[1], "rx_dsm_10bit") ||
	    !strcmp(argv[1], "rx_dsm_11bit") ||
	    !strcmp(argv[1], "rx_sbus") ||
	    !strcmp(argv[1], "rx_ppm"))
		errx(0, "receiver type is automatically detected, option '%s' is deprecated", argv[1]);

	if (!strcmp(argv[1], "test"))
		test();

	if (!strcmp(argv[1], "monitor"))
		monitor();

	if (!strcmp(argv[1], "bind"))
		bind(argc, argv);

out:
	errx(1, "need a command, try 'start', 'stop', 'status', 'test', 'monitor', 'debug',\n 'recovery', 'limit', 'current', 'bind', 'checkcrc', 'forceupdate' or 'update'");
}