uhd/mpm/lib/i2c/i2cdev_iface.cpp

//
// Copyright 2018 Ettus Research, a National Instruments Company
// Copyright 2019 Ettus Research, a National Instruments Brand
//
// SPDX-License-Identifier: GPL-3.0-or-later
//

#include "i2cdev.h"
#include <fcntl.h>
#include <linux/i2c-dev.h>
#include <linux/i2c.h>
#include <mpm/exception.hpp>
#include <mpm/i2c/i2c_iface.hpp>

using namespace mpm::i2c;

/******************************************************************************
 * Implementation
 *****************************************************************************/
class i2cdev_iface_impl : public i2c_iface
{
public:
    i2cdev_iface_impl(const std::string& device,
        const uint16_t addr,
        const bool ten_bit_addr,
        const unsigned int timeout_ms,
        const bool do_open = false)
        : _device(device)
        , _addr(addr)
        , _ten_bit_addr(ten_bit_addr)
        , _timeout_ms(timeout_ms)
    {
        if (do_open) {
            _open();
        } else {
            _fd = -ENODEV;
        }
    }

    ~i2cdev_iface_impl()
    {
        if (_fd >= 0) {
            close(_fd);
        }
    }

    int transfer(uint8_t* tx, size_t tx_len, uint8_t* rx, size_t rx_len, bool do_close)
    {
        if (_fd < 0) {
            _open();
        }

        int ret = i2cdev_transfer(_fd, _addr, _ten_bit_addr, tx, tx_len, rx, rx_len);

        if (do_close) {
            close(_fd);
            _fd = -ENODEV;
        }

        if (ret) {
            throw mpm::runtime_error("I2C Transaction failed!");
        }

        return ret;
    }

    std::vector<uint8_t> transfer(
        std::vector<uint8_t>& tx, size_t num_rx_bytes, bool do_close)
    {
        uint8_t *tx_data = NULL, *rx_data = NULL;
        size_t tx_len = 0, rx_len = 0;
        std::vector<uint8_t> rx(num_rx_bytes);

        if (!tx.empty()) {
            tx_data = tx.data();
            tx_len  = tx.size();
        }

        if (num_rx_bytes) {
            rx_data = rx.data();
            rx_len  = rx.size();
        }

        const int err = transfer(tx_data, tx_len, rx_data, num_rx_bytes, do_close);
        if (err) {
            throw mpm::runtime_error("I2C Transaction failed!");
        }

        return rx;
    }

private:
    const std::string _device;
    int _fd;
    const uint16_t _addr;
    const bool _ten_bit_addr;
    const unsigned int _timeout_ms;

    void _open(void)
    {
        if (i2cdev_open(&_fd, _device.c_str(), _timeout_ms) < 0) {
            throw mpm::runtime_error(
                std::string("Could not initialize i2cdev device ") + _device);
        }

        if (_fd < 0) {
            throw mpm::runtime_error(
                std::string("Could not open i2cdev device ") + _device);
        }
    }
};

/******************************************************************************
 * Factory
 *****************************************************************************/
i2c_iface::sptr i2c_iface::make_i2cdev(const std::string& bus,
    const uint16_t addr,
    const bool ten_bit_addr,
    const int timeout_ms)
{
    return std::make_shared<i2cdev_iface_impl>(bus, addr, ten_bit_addr, timeout_ms);
}