snapdragon_pwm_out.cpp

Go to the documentation of this file.

/****************************************************************************
 *
 *   Copyright (c) 2015-2016 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 <stdint.h>

#include <px4_platform_common/tasks.h>
#include <px4_platform_common/getopt.h>
#include <px4_platform_common/posix.h>
#include <errno.h>
#include <math.h>   // NAN
#include <string.h>

#include <uORB/Subscription.hpp>
#include <uORB/topics/actuator_controls.h>
#include <uORB/topics/actuator_outputs.h>
#include <uORB/topics/actuator_armed.h>
#include <uORB/topics/parameter_update.h>

#include <drivers/drv_hrt.h>
#include <drivers/drv_mixer.h>
#include <lib/mixer/MultirotorMixer/MultirotorMixer.hpp>
#include <lib/mixer/MixerGroup.hpp>
#include <lib/mixer/mixer_load.h>
#include <lib/parameters/param.h>
#include <lib/perf/perf_counter.h>
#include <lib/output_limit/output_limit.h>

#include <dev_fs_lib_pwm.h>

/*
 * PWM Driver for snapdragon.
 * @author: Dennis Mannhart <dennis.mannhart@gmail.com>
 */
namespace snapdragon_pwm
{

static px4_task_t _task_handle = -1;
volatile bool _task_should_exit = false;
static bool _is_running = false;
static const int NUM_PWM = 4;
static char _device[] = "/dev/pwm-1";

// snapdragon pins 27,28,29,30 configured for pwm (port J13)
static const int PIN_GPIO = 27;
static struct ::dspal_pwm_ioctl_signal_definition _signal_definition;
static struct ::dspal_pwm _pwm_gpio[NUM_PWM];
static struct ::dspal_pwm_ioctl_update_buffer *_update_buffer;
static struct ::dspal_pwm *_pwm;

// TODO: check frequency required
static const int FREQUENCY_PWM_HZ = 400;

/* TODO: copied from pwm_out_rc_in: check how that works
 * filename: /dev/fs is mapped to /usr/share/data/adsp */
static char _mixer_filename[32] = "/dev/fs/quad_x.main.mix";

// subscriptions
int _controls_subs[actuator_controls_s::NUM_ACTUATOR_CONTROL_GROUPS];
int _armed_sub;
int _fd = -1;

// publications
orb_advert_t    _outputs_pub = nullptr;

// topic structures
actuator_controls_s _controls[actuator_controls_s::NUM_ACTUATOR_CONTROL_GROUPS];
orb_id_t _controls_topics[actuator_controls_s::NUM_ACTUATOR_CONTROL_GROUPS];
actuator_outputs_s  _outputs;
actuator_armed_s    _armed;

// polling
uint8_t _poll_fds_num = 0;
px4_pollfd_struct_t _poll_fds[actuator_controls_s::NUM_ACTUATOR_CONTROL_GROUPS];

// control group
uint32_t    _groups_required = 0;

// limit for pwm
output_limit_t     _pwm_limit;

// esc parameters
int32_t _pwm_disarmed;
int32_t _pwm_min;
int32_t _pwm_max;

MultirotorMixer *_mixer = nullptr;

perf_counter_t  _perf_control_latency = nullptr;

/*
 * forward declaration
 */

static void usage();

static void start();

static void stop();

static int pwm_initialize(const char *device);

static void pwm_deinitialize();

static void send_outputs_pwm(const uint16_t *pwm);

static void task_main_trampoline(int argc, char *argv[]);

static void subscribe();

static void task_main(int argc, char *argv[]);

static void update_params(Mixer::Airmode &airmode);

int initialize_mixer(const char *mixer_filename);

int mixer_control_callback(uintptr_t handle, uint8_t control_group, uint8_t control_index, float &input);



/*
 * functions
 */

int mixer_control_callback(uintptr_t handle,
               uint8_t control_group,
               uint8_t control_index,
               float &input)
{
    const actuator_controls_s *controls = (actuator_controls_s *)handle;

    input = controls[control_group].control[control_index];

    return 0;
}

void update_params(Mixer::Airmode &airmode)
{
    // multicopter air-mode
    param_t param_handle = param_find("MC_AIRMODE");

    if (param_handle != PARAM_INVALID) {
        param_get(param_handle, &airmode);
    }
}

int initialize_mixer(const char *mixer_filename)
{
    char buf[2048];
    size_t buflen = sizeof(buf);
    PX4_INFO("Trying to initialize mixer from config file %s", mixer_filename);
    int fd_load = ::open(mixer_filename, O_RDONLY);

    int nRead = ::read(fd_load, buf, buflen);
    close(fd_load);

    if (nRead > 0) {
        _mixer = MultirotorMixer::from_text(mixer_control_callback, (uintptr_t)&_controls, buf, buflen);

        if (_mixer != nullptr) {
            PX4_INFO("Successfully initialized mixer from config file");
            return 0;

        } else {
            PX4_ERR("Unable to parse from mixer config file");
            return -1;
        }

    } else {
        PX4_WARN("Unable to read from mixer config file");
        return -2;
    }
}

void subscribe()
{
    memset(_controls, 0, sizeof(_controls));
    memset(_poll_fds, 0, sizeof(_poll_fds));

    /*
     * ORB topic names to msg actuator_controls
     */
    _controls_topics[0] = ORB_ID(actuator_controls_0);
    _controls_topics[1] = ORB_ID(actuator_controls_1);
    _controls_topics[2] = ORB_ID(actuator_controls_2);
    _controls_topics[3] = ORB_ID(actuator_controls_3);


    /*
     * subscibe to orb topic
     */
    for (uint8_t i = 0; i < actuator_controls_s::NUM_ACTUATOR_CONTROL_GROUPS; i++) {

        if (_groups_required & (1 << i)) {

            PX4_DEBUG("subscribe to actuator_controls_%d", i);

            _controls_subs[i] = orb_subscribe(_controls_topics[i]);

        } else {

            _controls_subs[i] = -1;

        }

        if (_controls_subs[i] >= 0) {

            _poll_fds[_poll_fds_num].fd = _controls_subs[i];
            _poll_fds[_poll_fds_num].events = POLLIN;
            _poll_fds_num++;

        }

    }

    _armed_sub = orb_subscribe(ORB_ID(actuator_armed));

}



int pwm_initialize(const char *device)
{
    /*
     * open PWM device
     */
    _fd = open(_device, 0);

    if (_fd < 0) {
        PX4_ERR("failed to open PWM device!");
        return -1;
    }

    /*
     * configure PWM
     */
    for (int i = 0; i < NUM_PWM; i++) {
        _pwm_gpio[i].gpio_id = PIN_GPIO + i;
    }

    /*
     * description of signal
     */
    _signal_definition.num_gpios = NUM_PWM;
    _signal_definition.period_in_usecs = 1000000 / FREQUENCY_PWM_HZ;
    _signal_definition.pwm_signal = _pwm_gpio;


    /*
     * send signal definition to DSP
     */
    if (::ioctl(_fd, PWM_IOCTL_SIGNAL_DEFINITION, &_signal_definition) != 0) {
        PX4_ERR("failed to send signal to DSP");
        return -1;
    }

    /*
     * retrieve shared buffer which will be used to update desired pulse width
     */
    if (::ioctl(_fd, PWM_IOCTL_GET_UPDATE_BUFFER, &_update_buffer) != 0) {
        PX4_ERR("failed to receive update buffer ");
        return -1;
    }

    _pwm = _update_buffer->pwm_signal;


    return 0;
}

void pwm_deinitialize()
{
    delete _mixer;
    close(_fd);

}

void send_outputs_pwm(const uint16_t *pwm)
{
    /*
     * send pwm in us: TODO: check if it is in us
     */
    for (unsigned i = 0; i < NUM_PWM; ++i) {
        _pwm[i].pulse_width_in_usecs = pwm[i];
    }
}

void task_main(int argc, char *argv[])
{
    if (pwm_initialize(_device) < 0) {
        PX4_ERR("Failed to initialize PWM.");
        return;
    }

    if (initialize_mixer(_mixer_filename) < 0) {
        PX4_ERR("Mixer initialization failed.");
        return;
    }

    _mixer->groups_required(_groups_required);

    // subscribe and set up polling
    subscribe();

    Mixer::Airmode airmode = Mixer::Airmode::disabled;
    update_params(airmode);
    uORB::Subscription parameter_update_sub{ORB_ID(parameter_update)};

    // Start disarmed
    _armed.armed = false;
    _armed.prearmed = false;

    // set max min pwm
    output_limit_init(&_pwm_limit);

    _perf_control_latency = perf_alloc(PC_ELAPSED, "snapdragon_pwm_out control latency");

    _is_running = true;

    // Main loop
    while (!_task_should_exit) {

        if (_mixer) {
            _mixer->set_airmode(airmode);
        }

        /* wait up to 10ms for data */
        int pret = px4_poll(_poll_fds, _poll_fds_num, 10);

        /* Timed out, do a periodic check for _task_should_exit. */
        bool timeout = false;

        if (pret == 0) {
            timeout = true;
        }

        /* This is undesirable but not much we can do. */
        if (pret < 0) {
            PX4_WARN("poll error %d, %d", pret, errno);
            /* sleep a bit before next try */
            usleep(10000);
            continue;
        }

        bool updated;
        orb_check(_armed_sub, &updated);

        if (updated) {
            orb_copy(ORB_ID(actuator_armed), _armed_sub, &_armed);
        }

        /* get controls for required topics */
        unsigned poll_id = 0;

        for (uint8_t i = 0; i < actuator_controls_s::NUM_ACTUATOR_CONTROL_GROUPS; i++) {
            if (_controls_subs[i] >= 0) {
                if (_poll_fds[poll_id].revents & POLLIN) {
                    orb_copy(_controls_topics[i], _controls_subs[i], &_controls[i]);
                }

                poll_id++;
            }
        }

        if (_mixer == nullptr) {
            PX4_ERR("Could not mix output! Exiting...");
            _task_should_exit = true;
            continue;
        }

        /* do  mixing for virtual control group */
        _outputs.noutputs = _mixer->mix(_outputs.output, _outputs.NUM_ACTUATOR_OUTPUTS);

        //set max, min and disarmed pwm
        const uint16_t reverse_mask = 0;
        uint16_t disarmed_pwm[4];
        uint16_t min_pwm[4];
        uint16_t max_pwm[4];
        uint16_t pwm[4];

        for (unsigned int i = 0; i < 4; i++) {
            disarmed_pwm[i] = _pwm_disarmed;
            min_pwm[i] = _pwm_min;
            max_pwm[i] = _pwm_max;
        }


        // TODO FIXME: pre-armed seems broken -> copied and pasted from pwm_out_rc_in: needs to be tested
        output_limit_calc(_armed.armed,
                  false/*_armed.prearmed*/, _outputs.noutputs, reverse_mask, disarmed_pwm,
                  min_pwm, max_pwm, _outputs.output, pwm, &_pwm_limit);

        // send and publish outputs
        if (_armed.lockdown || _armed.manual_lockdown || timeout) {
            send_outputs_pwm(disarmed_pwm);

        } else {
            send_outputs_pwm(pwm);
        }

        _outputs.timestamp = hrt_absolute_time();

        if (_outputs_pub != nullptr) {
            orb_publish(ORB_ID(actuator_outputs), _outputs_pub, &_outputs);

        } else {
            _outputs_pub = orb_advertise(ORB_ID(actuator_outputs), &_outputs);
        }

        // use first valid timestamp_sample for latency tracking
        for (int i = 0; i < actuator_controls_s::NUM_ACTUATOR_CONTROL_GROUPS; i++) {
            const bool required = _groups_required & (1 << i);
            const hrt_abstime &timestamp_sample = _controls[i].timestamp_sample;

            if (required && (timestamp_sample > 0)) {
                perf_set_elapsed(_perf_control_latency, _outputs.timestamp - timestamp_sample);
                break;
            }
        }

        // check for parameter updates
        if (parameter_update_sub.updated()) {
            // clear update
            parameter_update_s pupdate;
            parameter_update_sub.copy(&pupdate);

            // update parameters from storage
            update_params(airmode);
        }
    }

    pwm_deinitialize();

    for (uint8_t i = 0; i < actuator_controls_s::NUM_ACTUATOR_CONTROL_GROUPS; i++) {
        if (_controls_subs[i] >= 0) {
            orb_unsubscribe(_controls_subs[i]);
        }
    }

    orb_unsubscribe(_armed_sub);

    perf_free(_perf_control_latency);

    _is_running = false;
}

void task_main_trampoline(int argc, char *argv[])
{
    task_main(argc, argv);
}

void start()
{
    _task_should_exit = false;

    /* start the task */
    _task_handle = px4_task_spawn_cmd("snapdragon_pwm_out_main",
                      SCHED_DEFAULT,
                      SCHED_PRIORITY_MAX,
                      1500,
                      (px4_main_t)&task_main_trampoline,
                      nullptr);

    if (_task_handle < 0) {
        PX4_ERR("task start failed");
        return;
    }

}

void stop()
{
    _task_should_exit = true;

    while (_is_running) {
        usleep(200000);
        PX4_INFO(".");
    }

    _task_handle = -1;
}

void usage()
{

    PX4_INFO("usage: snapdragon_pwm_out start [-d pwmdevice] [-m mixerfile]");
    PX4_INFO("       -d pwmdevice : device for pwm generation");
    PX4_INFO("                       (default /dev/pwm-1)");
    PX4_INFO("       -m mixerfile : path to mixerfile");
    PX4_INFO("                       (default /dev/fs/quad_x.main.mix");
    PX4_INFO("       pwm_out stop");
    PX4_INFO("       pwm_out status");

}

} // namespace snapdragon_pwm

/* driver 'main' command */
extern "C" __EXPORT int snapdragon_pwm_out_main(int argc, char *argv[]);

int snapdragon_pwm_out_main(int argc, char *argv[])
{


    int ch;
    int myoptind = 1;
    const char *myoptarg = nullptr;

    char *verb = nullptr;

    if (argc >= 2) {
        verb = argv[1];

    } else {
        return 1;
    }

    while ((ch = px4_getopt(argc, argv, "d:m", &myoptind, &myoptarg)) != EOF) {
        switch (ch) {
        case 'd':
            strncpy(snapdragon_pwm::_device, myoptarg, sizeof(snapdragon_pwm::_device));
            break;

        case 'm':
            strncpy(snapdragon_pwm::_mixer_filename, myoptarg, sizeof(snapdragon_pwm::_mixer_filename));
            break;
        }
    }

    // gets the parameters for the esc's pwm
    param_get(param_find("PWM_DISARMED"), &snapdragon_pwm::_pwm_disarmed);
    param_get(param_find("PWM_MIN"), &snapdragon_pwm::_pwm_min);
    param_get(param_find("PWM_MAX"), &snapdragon_pwm::_pwm_max);

    /*
     * Start/load the driver.
     */
    if (!strcmp(verb, "start")) {
        if (snapdragon_pwm::_is_running) {
            PX4_WARN("pwm_out already running");
            return 1;
        }

        snapdragon_pwm::start();
    }

    else if (!strcmp(verb, "stop")) {
        if (!snapdragon_pwm::_is_running) {
            PX4_WARN("pwm_out is not running");
            return 1;
        }

        snapdragon_pwm::stop();
    }

    else if (!strcmp(verb, "status")) {
        PX4_INFO("pwm_out is %s", snapdragon_pwm::_is_running ? "running" : "not running");
        return 0;

    } else {
        snapdragon_pwm::usage();
        return 1;
    }

    return 0;
}