/****************************************************************************
*
* Copyright (C) 2012 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
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****************************************************************************/
/**
* @file i2c.h
*
* Base class for devices connected via I2C.
*/
#ifndef _DEVICE_I2C_H
#define _DEVICE_I2C_H
#include "device.h"
#include <nuttx/i2c.h>
namespace device __EXPORT
{
/**
* Abstract class for character device on I2C
*/
class __EXPORT I2C : public CDev
{
public:
/**
* Get the address
*/
int16_t get_address() const { return _address; }
static int set_bus_clock(unsigned bus, unsigned clock_hz);
static unsigned int _bus_clocks[3];
protected:
/**
* The number of times a read or write operation will be retried on
* error.
*/
unsigned _retries;
/**
* The I2C bus number the device is attached to.
*/
int _bus;
/**
* @ 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)
* @param irq Interrupt assigned to the device (or zero if none)
*/
I2C(const char *name,
const char *devname,
int bus,
uint16_t address,
uint32_t frequency,
int irq = 0);
virtual ~I2C();
virtual int init();
/**
* Check for the presence of the device on the bus.
*/
virtual int probe();
/**
* 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, unsigned send_len,
uint8_t *recv, unsigned recv_len);
/**
* Perform a multi-part I2C transaction to the device.
*
* @param msgv An I2C message vector.
* @param msgs The number of entries in the message vector.
* @return OK if the transfer was successful, -errno
* otherwise.
*/
int transfer(i2c_msg_s *msgv, unsigned msgs);
/**
* Change the bus address.
*
* Most often useful during probe() when the driver is testing
* several possible bus addresses.
*
* @param address The new bus address to set.
*/
void set_address(uint16_t address) {
_address = address;
_device_id.devid_s.address = _address;
}
private:
uint16_t _address;
uint32_t _frequency;
struct i2c_dev_s *_dev;
I2C(const device::I2C &);
I2C operator=(const device::I2C &);
};
} // namespace device
#endif /* _DEVICE_I2C_H */
