PX4-Autopilot/src/drivers/navio_adc/navio_adc.cpp

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/**
 * @file navio_adc.cpp
 *
 * Navio2 ADC Driver
 *
 * This driver exports the sysfs-based ADC driver on Navio2.
 *
 * @author Nicolae Rosia <nicolae.rosia@gmail.com>
 */

#include <px4_config.h>
#include <px4_tasks.h>
#include <px4_posix.h>
#include <drivers/drv_adc.h>

#include <VirtDevObj.hpp>

#include <unistd.h>
#include <stdio.h>
#include <poll.h>
#include <string.h>

#define ADC_BASE_DEV_PATH "/dev/adc"
#define ADC_SYSFS_PATH "/sys/kernel/rcio/adc/ch0"
#define ADC_MAX_CHAN 6

/*
 * ADC Channels:
 * A0 - Board voltage (5V)
 * A1 - servo rail voltage
 * A2 - power module voltage (ADC0, POWER port)
 * A3 - power module current (ADC1, POWER port)
 * A4 - ADC2 (ADC port)
 * A5 - ADC3 (ADC port)
 */

#define NAVIO_ADC_BATTERY_VOLTAGE_CHANNEL (2)
#define NAVIO_ADC_BATTERY_CURRENT_CHANNEL (3)

__BEGIN_DECLS
__EXPORT int navio_adc_main(int argc, char *argv[]);
__END_DECLS

class NavioADC: public DriverFramework::VirtDevObj
{
public:
	NavioADC();
	virtual ~NavioADC();

	virtual int init() override;

	virtual ssize_t devRead(void *buf, size_t count) override;
	virtual int devIOCTL(unsigned long request, unsigned long arg) override;

protected:
	virtual void _measure() override;

private:
	int read_channel(px4_adc_msg_t *adc_msg, int channel);

	pthread_mutex_t _samples_lock;
	int _fd[ADC_MAX_CHAN];
	px4_adc_msg_t _samples[ADC_MAX_CHAN];
};

NavioADC::NavioADC()
	: DriverFramework::VirtDevObj("navio_adc", ADC0_DEVICE_PATH, ADC_BASE_DEV_PATH, 1e6 / 100)
{
	pthread_mutex_init(&_samples_lock, NULL);

	for (int i = 0; i < ADC_MAX_CHAN; i++) {
		_fd[i] = -1;
	}
}

NavioADC::~NavioADC()
{
	pthread_mutex_destroy(&_samples_lock);

	for (int i = 0; i < ADC_MAX_CHAN; i++) {
		if (_fd[i] != -1) {
			close(_fd[i]);
		}
	}
}

void NavioADC::_measure()
{
	px4_adc_msg_t tmp_samples[ADC_MAX_CHAN];

	for (int i = 0; i < ADC_MAX_CHAN; ++i) {
		int ret;

		/* Currently we only use these channels */
		if (i != NAVIO_ADC_BATTERY_VOLTAGE_CHANNEL &&
		    i != NAVIO_ADC_BATTERY_CURRENT_CHANNEL) {
			tmp_samples[i].am_channel = i;
			tmp_samples[i].am_data = 0;

			continue;
		}

		ret = read_channel(&tmp_samples[i], i);

		if (ret < 0) {
			PX4_ERR("read_channel(%d): %d", i, ret);
			tmp_samples[i].am_channel = i;
			tmp_samples[i].am_data = 0;
		}
	}

	tmp_samples[NAVIO_ADC_BATTERY_VOLTAGE_CHANNEL].am_channel = ADC_BATTERY_VOLTAGE_CHANNEL;
	tmp_samples[NAVIO_ADC_BATTERY_CURRENT_CHANNEL].am_channel = ADC_BATTERY_CURRENT_CHANNEL;

	pthread_mutex_lock(&_samples_lock);
	memcpy(&_samples, &tmp_samples, sizeof(tmp_samples));
	pthread_mutex_unlock(&_samples_lock);
}

int NavioADC::init()
{
	int ret;

	ret = DriverFramework::VirtDevObj::init();

	if (ret != PX4_OK) {
		PX4_ERR("init failed");
		return ret;
	}

	for (int i = 0; i < ADC_MAX_CHAN; i++) {
		char channel_path[sizeof(ADC_SYSFS_PATH)];
		strncpy(channel_path, ADC_SYSFS_PATH, sizeof(ADC_SYSFS_PATH));
		channel_path[sizeof(ADC_SYSFS_PATH) - 2] += i;

		_fd[i] = ::open(channel_path, O_RDONLY);

		if (_fd[i] == -1) {
			int err = errno;
			ret = -1;
			PX4_ERR("init: open: %s (%d)", strerror(err), err);
			goto cleanup;
		}
	}

	return PX4_OK;

cleanup:

	for (int i = 0; i < ADC_MAX_CHAN; i++) {
		if (_fd[i] != -1) {
			close(_fd[i]);
		}
	}

	return ret;
}

int NavioADC::devIOCTL(unsigned long request, unsigned long arg)
{
	return -ENOTTY;
}

ssize_t NavioADC::devRead(void *buf, size_t count)
{
	const size_t maxsize = sizeof(_samples);
	int ret;

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

	ret = pthread_mutex_trylock(&_samples_lock);

	if (ret != 0) {
		return 0;
	}

	memcpy(buf, &_samples, count);
	pthread_mutex_unlock(&_samples_lock);

	return count;
}

int NavioADC::read_channel(px4_adc_msg_t *adc_msg, int channel)
{
	char buffer[11]; /* 32bit max INT has maximum 10 chars */
	int ret;

	if (channel < 0 || channel >= ADC_MAX_CHAN) {
		return -EINVAL;
	}

	ret = lseek(_fd[channel], 0, SEEK_SET);

	if (ret == -1) {
		ret = errno;
		PX4_ERR("read_channel %d: lseek: %s (%d)", channel, strerror(ret), ret);
		return  ret;
	}

	ret = ::read(_fd[channel], buffer, sizeof(buffer) - 1);

	if (ret == -1) {
		ret = errno;
		PX4_ERR("read_channel %d: read: %s (%d)", channel, strerror(ret), ret);
		return  ret;

	} else if (ret == 0) {
		PX4_ERR("read_channel %d: read empty", channel);
		ret = -EINVAL;
		return ret;
	}

	buffer[ret] = 0;

	adc_msg->am_channel = channel;
	adc_msg->am_data = strtol(buffer, NULL, 10);
	ret = 0;

	return ret;
}

static NavioADC *instance = nullptr;

int navio_adc_main(int argc, char *argv[])
{
	int ret;

	if (argc < 2) {
		PX4_WARN("usage: <start/stop>");
		return PX4_ERROR;
	}

	if (!strcmp(argv[1], "start")) {
		if (instance) {
			PX4_WARN("already started");
			return PX4_OK;
		}

		instance = new NavioADC;

		if (!instance) {
			PX4_WARN("not enough memory");
			return PX4_ERROR;
		}

		if (instance->init() != PX4_OK) {
			delete instance;
			instance = nullptr;
			PX4_WARN("init failed");
			return PX4_ERROR;
		}

		return PX4_OK;

	} else if (!strcmp(argv[1], "stop")) {
		if (!instance) {
			PX4_WARN("already stopped");
			return PX4_OK;
		}

		delete instance;
		instance = nullptr;
		return PX4_OK;

	} else if (!strcmp(argv[1], "test")) {
		if (!instance) {
			PX4_ERR("start first");
			return PX4_ERROR;
		}

		px4_adc_msg_t adc_msgs[ADC_MAX_CHAN];

		ret = instance->devRead((char *)&adc_msgs, sizeof(adc_msgs));

		if (ret < 0) {
			PX4_ERR("ret: %s (%d)\n", strerror(ret), ret);
			return ret;

		} else if (ret != sizeof(adc_msgs)) {
			PX4_ERR("incomplete read: %d expected %d", ret, sizeof(adc_msgs));
			return ret;
		}

		for (int i = 0; i < ADC_MAX_CHAN; ++i) {
			PX4_INFO("chan: %d; value: %d", (int)adc_msgs[i].am_channel,
				 adc_msgs[i].am_data);
		}

		return PX4_OK;

	} else {
		PX4_WARN("action (%s) not supported", argv[1]);

		return PX4_ERROR;
	}

	return PX4_OK;

}