adc.cpp

Go to the documentation of this file.

/****************************************************************************
 *
 *   Copyright (C) 2012-2019 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 adc.cpp
 *
 * Driver for an ADC.
 *
 */
#include <stdint.h>
#include <drivers/drv_adc.h>
#include <drivers/drv_hrt.h>
#include <lib/cdev/CDev.hpp>
#include <lib/perf/perf_counter.h>
#include <px4_arch/adc.h>
#include <px4_platform_common/px4_config.h>
#include <px4_platform_common/log.h>
#include <px4_platform_common/px4_work_queue/ScheduledWorkItem.hpp>
#include <uORB/Publication.hpp>
#include <uORB/topics/adc_report.h>
#include <uORB/topics/system_power.h>


using namespace time_literals;

#ifndef ADC_CHANNELS
#error "board needs to define ADC_CHANNELS to use this driver"
#endif

#define ADC_TOTAL_CHANNELS      32


class ADC : public cdev::CDev, public px4::ScheduledWorkItem
{
public:
    ADC(uint32_t base_address, uint32_t channels);
    ~ADC();

    virtual int     init();

    virtual int     ioctl(file *filp, int cmd, unsigned long arg);
    virtual ssize_t     read(file *filp, char *buffer, size_t len);

protected:
    virtual int     open_first(struct file *filp);
    virtual int     close_last(struct file *filp);

private:
    void            Run() override;

    /**
     * Sample a single channel and return the measured value.
     *
     * @param channel       The channel to sample.
     * @return          The sampled value, or UINT32_MAX if sampling failed.
     */
    uint32_t        sample(unsigned channel);

    void            update_adc_report(hrt_abstime now);
    void            update_system_power(hrt_abstime now);


    static const hrt_abstime    kINTERVAL{10_ms};   /**< 100Hz base rate */

    perf_counter_t          _sample_perf;

    unsigned            _channel_count{0};
    const uint32_t          _base_address;
    px4_adc_msg_t           *_samples{nullptr}; /**< sample buffer */

    uORB::Publication<adc_report_s>     _to_adc_report{ORB_ID(adc_report)};
    uORB::Publication<system_power_s>   _to_system_power{ORB_ID(system_power)};
};

ADC::ADC(uint32_t base_address, uint32_t channels) :
    CDev(ADC0_DEVICE_PATH),
    ScheduledWorkItem(MODULE_NAME, px4::wq_configurations::hp_default),
    _sample_perf(perf_alloc(PC_ELAPSED, "adc_samples")),
    _base_address(base_address)
{
    /* always enable the temperature sensor */
    channels |= px4_arch_adc_temp_sensor_mask();

    /* allocate the sample array */
    for (unsigned i = 0; i < ADC_TOTAL_CHANNELS; i++) {
        if (channels & (1 << i)) {
            _channel_count++;
        }
    }

    if (_channel_count > PX4_MAX_ADC_CHANNELS) {
        PX4_ERR("PX4_MAX_ADC_CHANNELS is too small:is %d needed:%d", PX4_MAX_ADC_CHANNELS, _channel_count);
    }

    _samples = new px4_adc_msg_t[_channel_count];

    /* prefill the channel numbers in the sample array */
    if (_samples != nullptr) {
        unsigned index = 0;

        for (unsigned i = 0; i < ADC_TOTAL_CHANNELS; i++) {
            if (channels & (1 << i)) {
                _samples[index].am_channel = i;
                _samples[index].am_data = 0;
                index++;
            }
        }
    }
}

ADC::~ADC()
{
    if (_samples != nullptr) {
        delete _samples;
    }

    perf_free(_sample_perf);
    px4_arch_adc_uninit(_base_address);
}

int
ADC::init()
{
    int rv = px4_arch_adc_init(_base_address);

    if (rv < 0) {
        PX4_DEBUG("sample timeout");
        return rv;
    }

    /* create the device node */
    return CDev::init();
}

int
ADC::ioctl(file *filp, int cmd, unsigned long arg)
{
    return -ENOTTY;
}

ssize_t
ADC::read(file *filp, char *buffer, size_t len)
{
    const size_t maxsize = sizeof(px4_adc_msg_t) * _channel_count;

    if (len > maxsize) {
        len = maxsize;
    }

    /* block interrupts while copying samples to avoid racing with an update */
    irqstate_t flags = px4_enter_critical_section();
    memcpy(buffer, _samples, len);
    px4_leave_critical_section(flags);

    return len;
}

int
ADC::open_first(struct file *filp)
{
    /* get fresh data */
    Run();

    /* and schedule regular updates */
    ScheduleOnInterval(kINTERVAL, kINTERVAL);

    return 0;
}

int
ADC::close_last(struct file *filp)
{
    ScheduleClear();

    return 0;
}

void
ADC::Run()
{
    hrt_abstime now = hrt_absolute_time();

    /* scan the channel set and sample each */
    for (unsigned i = 0; i < _channel_count; i++) {
        _samples[i].am_data = sample(_samples[i].am_channel);
    }

    update_adc_report(now);
    update_system_power(now);
}

void
ADC::update_adc_report(hrt_abstime now)
{
    adc_report_s adc = {};
    adc.timestamp = now;

    unsigned max_num = _channel_count;

    if (max_num > (sizeof(adc.channel_id) / sizeof(adc.channel_id[0]))) {
        max_num = (sizeof(adc.channel_id) / sizeof(adc.channel_id[0]));
    }

    for (unsigned i = 0; i < max_num; i++) {
        adc.channel_id[i] = _samples[i].am_channel;
        adc.channel_value[i] = _samples[i].am_data * 3.3f / px4_arch_adc_dn_fullcount();
        ;
    }

    _to_adc_report.publish(adc);
}

void
ADC::update_system_power(hrt_abstime now)
{
#if defined (BOARD_ADC_USB_CONNECTED)
    system_power_s system_power {};
    system_power.timestamp = now;

    /* Assume HW provides only ADC_SCALED_V5_SENSE */
    int cnt = 1;
    /* HW provides both ADC_SCALED_V5_SENSE and ADC_SCALED_V3V3_SENSORS_SENSE */
#  if defined(ADC_SCALED_V5_SENSE) && defined(ADC_SCALED_V3V3_SENSORS_SENSE)
    cnt++;
#  endif

    for (unsigned i = 0; i < _channel_count; i++) {
#  if defined(ADC_SCALED_V5_SENSE)

        if (_samples[i].am_channel == ADC_SCALED_V5_SENSE) {
            // it is 2:1 scaled
            system_power.voltage5v_v = _samples[i].am_data * (ADC_V5_V_FULL_SCALE / px4_arch_adc_dn_fullcount());
            cnt--;

        } else
#  endif
#  if defined(ADC_SCALED_V3V3_SENSORS_SENSE)
        {
            if (_samples[i].am_channel == ADC_SCALED_V3V3_SENSORS_SENSE) {
                // it is 2:1 scaled
                system_power.voltage3v3_v = _samples[i].am_data * (ADC_3V3_SCALE * (3.3f / px4_arch_adc_dn_fullcount()));
                system_power.v3v3_valid = 1;
                cnt--;
            }
        }

#  endif

        if (cnt == 0) {
            break;
        }
    }

    /* Note once the board_config.h provides BOARD_ADC_USB_CONNECTED,
     * It must provide the true logic GPIO BOARD_ADC_xxxx macros.
     */
    // these are not ADC related, but it is convenient to
    // publish these to the same topic

    system_power.usb_connected = BOARD_ADC_USB_CONNECTED;
    /* If provided used the Valid signal from HW*/
#if defined(BOARD_ADC_USB_VALID)
    system_power.usb_valid = BOARD_ADC_USB_VALID;
#else
    /* If not provided then use connected */
    system_power.usb_valid  = system_power.usb_connected;
#endif

    /* The valid signals (HW dependent) are associated with each brick */
#if !defined(BOARD_NUMBER_DIGITAL_BRICKS)
    bool  valid_chan[BOARD_NUMBER_BRICKS] = BOARD_BRICK_VALID_LIST;
    system_power.brick_valid = 0;

    for (int b = 0; b < BOARD_NUMBER_BRICKS; b++) {
        system_power.brick_valid |=  valid_chan[b] ? 1 << b : 0;
    }

#endif

    system_power.servo_valid   = BOARD_ADC_SERVO_VALID;

#ifdef BOARD_ADC_PERIPH_5V_OC
    // OC pins are active low
    system_power.periph_5v_oc  = BOARD_ADC_PERIPH_5V_OC;
#endif

#ifdef BOARD_ADC_HIPOWER_5V_OC
    system_power.hipower_5v_oc = BOARD_ADC_HIPOWER_5V_OC;
#endif

    /* lazily publish */
    _to_system_power.publish(system_power);

#endif // BOARD_ADC_USB_CONNECTED
}

uint32_t
ADC::sample(unsigned channel)
{
    perf_begin(_sample_perf);
    uint32_t result = px4_arch_adc_sample(_base_address, channel);

    if (result == UINT32_MAX) {
        PX4_ERR("sample timeout");
    }

    perf_end(_sample_perf);
    return result;
}

/*
 * Driver 'main' command.
 */
extern "C" __EXPORT int adc_main(int argc, char *argv[]);

namespace
{
ADC *g_adc{nullptr};

int
test(void)
{

    int fd = open(ADC0_DEVICE_PATH, O_RDONLY);

    if (fd < 0) {
        PX4_ERR("can't open ADC device %d", errno);
        return 1;
    }

    for (unsigned i = 0; i < 20; i++) {
        px4_adc_msg_t data[ADC_TOTAL_CHANNELS];
        ssize_t count = read(fd, data, sizeof(data));

        if (count < 0) {
            PX4_ERR("read error");
            return 1;
        }

        unsigned channels = count / sizeof(data[0]);

        for (unsigned j = 0; j < channels; j++) {
            printf("%d: %u  ", data[j].am_channel, data[j].am_data);
        }

        printf("\n");
        px4_usleep(500000);
    }

    return 0;
}
}

int
adc_main(int argc, char *argv[])
{
    if (g_adc == nullptr) {
        g_adc = new ADC(SYSTEM_ADC_BASE, ADC_CHANNELS);

        if (g_adc == nullptr) {
            PX4_ERR("couldn't allocate the ADC driver");
            return 1;
        }

        if (g_adc->init() != OK) {
            delete g_adc;
            PX4_ERR("ADC init failed");
            return 1;
        }
    }

    if (argc > 1) {
        if (!strcmp(argv[1], "test")) {
            return test();
        }
    }

    return 0;
}