PX4-Autopilot/src/lib/drivers/device/qurt/I2C.cpp

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/**
 * @file I2C.cpp
 *
 * Base class for devices attached via the I2C bus.
 *
 * @todo Bus frequency changes; currently we do nothing with the value
 *       that is supplied.  Should we just depend on the bus knowing?
 */

#include "I2C.hpp"

#include <dev_fs_lib_i2c.h>

#include <px4_platform_common/i2c_spi_buses.h>

namespace device
{

I2C::I2C(uint8_t device_type, const char *name, const int bus, const uint16_t address, const uint32_t frequency) :
	CDev(name, nullptr),
	_frequency(frequency)
{
	// fill in _device_id fields for a I2C device
	_device_id.devid_s.devtype = device_type;
	_device_id.devid_s.bus_type = DeviceBusType_I2C;
	_device_id.devid_s.bus = bus;
	_device_id.devid_s.address = address;
}

I2C::I2C(const I2CSPIDriverConfig &config)
	: I2C(config.devid_driver_index, config.module_name, config.bus, config.i2c_address, config.bus_frequency)
{
}

I2C::~I2C()
{
	if (_fd >= 0) {
		::close(_fd);
		_fd = -1;
	}
}

int
I2C::init()
{
	int ret = PX4_ERROR;

	// Open the actual I2C device
	char dev_path[16] {};
	snprintf(dev_path, sizeof(dev_path), DEV_FS_I2C_DEVICE_TYPE_STRING"%i", get_device_bus());
	_fd = ::open(dev_path, O_RDWR);

	if (_fd < 0) {
		DEVICE_DEBUG("failed to init I2C");
		ret = -ENOENT;
		goto out;
	}

	// call the probe function to check whether the device is present
	ret = probe();

	if (ret != OK) {
		DEVICE_DEBUG("probe failed");
		goto out;
	}

	// do base class init, which will create device node, etc
	ret = CDev::init();

	if (ret != OK) {
		DEVICE_DEBUG("cdev init failed");
		goto out;
	}

	// tell the world where we are
	DEVICE_DEBUG("on I2C bus %d at 0x%02x", get_device_bus(), get_device_address());

out:

	if ((ret != OK) && !(_fd < 0)) {
		::close(_fd);
		_fd = -1;
	}

	return ret;
}

int
I2C::transfer(const uint8_t *send, const unsigned send_len, uint8_t *recv, const unsigned recv_len)
{
	int ret = PX4_ERROR;
	unsigned retry_count = 0;

	if (_fd < 0) {
		PX4_ERR("I2C device not opened");
		return PX4_ERROR;
	}

	do {
		DEVICE_DEBUG("transfer out %p/%u  in %p/%u", send, send_len, recv, recv_len);

		dspal_i2c_ioctl_slave_config slave_config{};
		slave_config.slave_address = get_device_address();
		slave_config.bus_frequency_in_khz = _frequency / 1000;
		slave_config.byte_transer_timeout_in_usecs = 10000; // 10 ms
		int ret_config = ::ioctl(_fd, I2C_IOCTL_SLAVE, &slave_config);

		if (ret_config < 0) {
			DEVICE_DEBUG("Could not set slave config, result: %d", ret_config);
		}


		dspal_i2c_ioctl_combined_write_read ioctl_write_read{};

		ioctl_write_read.write_buf = (uint8_t *)send;
		ioctl_write_read.write_buf_len = send_len;
		ioctl_write_read.read_buf = recv;
		ioctl_write_read.read_buf_len = recv_len;

		int bytes_read = ::ioctl(_fd, I2C_IOCTL_RDWR, &ioctl_write_read);

		if (bytes_read != (int)recv_len) {
			DEVICE_DEBUG("I2C transfer failed, bytes read %d", bytes_read);
			ret = PX4_ERROR;

		} else {
			// success
			ret = PX4_OK;
			break;
		}

	} while (retry_count++ < _retries);

	return ret;
}

} // namespace device