I2C.hpp

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/**
 * @file i2c.h
 *
 * Base class for devices connected via I2C.
 */

#ifndef _DEVICE_I2C_H
#define _DEVICE_I2C_H

#include "../CDev.hpp"

#include <px4_platform_common/i2c.h>

#if !defined(CONFIG_I2C)
#  error I2C support requires CONFIG_I2C
#endif

namespace device __EXPORT
{

/**
 * Abstract class for character device on I2C
 */
class __EXPORT I2C : public CDev
{

public:

    // no copy, assignment, move, move assignment
    I2C(const I2C &) = delete;
    I2C &operator=(const I2C &) = delete;
    I2C(I2C &&) = delete;
    I2C &operator=(I2C &&) = delete;

    virtual int init() override;

    static int  set_bus_clock(unsigned bus, unsigned clock_hz);

    static unsigned int _bus_clocks[BOARD_NUMBER_I2C_BUSES];

protected:
    /**
     * The number of times a read or write operation will be retried on
     * error.
     */
    uint8_t     _retries{0};

    /**
     * @ Constructor
     *
     * @param name      Driver name
     * @param devname   Device node name
     * @param bus       I2C bus on which the device lives
     * @param address   I2C bus address, or zero if set_address will be used
     * @param frequency I2C bus frequency for the device (currently not used)
     */
    I2C(const char *name, const char *devname, const int bus, const uint16_t address, const uint32_t frequency);
    virtual ~I2C();

    /**
     * Check for the presence of the device on the bus.
     */
    virtual int probe() { return PX4_OK; }

    /**
     * Perform an I2C transaction to the device.
     *
     * At least one of send_len and recv_len must be non-zero.
     *
     * @param send      Pointer to bytes to send.
     * @param send_len  Number of bytes to send.
     * @param recv      Pointer to buffer for bytes received.
     * @param recv_len  Number of bytes to receive.
     * @return      OK if the transfer was successful, -errno
     *          otherwise.
     */
    int     transfer(const uint8_t *send, const unsigned send_len, uint8_t *recv, const unsigned recv_len);

    virtual bool    external() const override { return px4_i2c_bus_external(_device_id.devid_s.bus); }

private:
    uint32_t        _frequency{0};
    px4_i2c_dev_t       *_dev{nullptr};

};

} // namespace device

#endif /* _DEVICE_I2C_H */