i2c.h
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/****************************************************************************
*
* Copyright (c) 2020 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
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
#pragma once
#include <board_config.h>
#define I2C_BUS_MAX_BUS_ITEMS PX4_NUMBER_I2C_BUSES
struct px4_i2c_bus_t {
int bus{-1}; ///< physical bus number (1, ...) (-1 means this is unused)
bool is_external; ///< static external configuration. Use px4_i2c_bus_external() to check if a bus is really external
};
__EXPORT extern const px4_i2c_bus_t px4_i2c_buses[I2C_BUS_MAX_BUS_ITEMS]; ///< board-specific I2C bus configuration
/**
* runtime-check if a board has a specific bus as external.
* This can be overridden by a board to add run-time checks.
*/
__EXPORT bool px4_i2c_bus_external(const px4_i2c_bus_t &bus);
/**
* runtime-check if a board has a specific bus as external.
*/
static inline bool px4_i2c_bus_external(int bus)
{
for (int i = 0; i < I2C_BUS_MAX_BUS_ITEMS; ++i) {
if (px4_i2c_buses[i].bus == bus) {
return px4_i2c_bus_external(px4_i2c_buses[i]);
}
}
return true;
}
/**
* @class I2CBusIterator
* Iterate over configured I2C buses by the board
*/
class I2CBusIterator
{
public:
enum class FilterType {
All, ///< specific or all buses
InternalBus, ///< specific or all internal buses
ExternalBus, ///< specific or all external buses
};
/**
* @param bus specify bus: starts with 1, -1=all. Internal: arch-specific bus numbering is used,
* external: n-th external bus
*/
I2CBusIterator(FilterType filter, int bus = -1)
: _filter(filter), _bus(bus) {}
bool next();
const px4_i2c_bus_t &bus() const { return px4_i2c_buses[_index]; }
int externalBusIndex() const { return _external_bus_counter; }
bool external() const { return px4_i2c_bus_external(bus()); }
private:
const FilterType _filter;
const int _bus;
int _index{-1};
int _external_bus_counter{0};
};