161 lines
5.6 KiB
C
161 lines
5.6 KiB
C
/***************************************************************************
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* Copyright (C) 2024 - 2025 by Federico Amedeo Izzo IU2NUO, *
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* Niccolò Izzo IU2KIN *
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* Frederik Saraci IU2NRO *
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* Silvano Seva IU2KWO *
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 3 of the License, or *
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* (at your option) any later version. *
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* *
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* This program is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* GNU General Public License for more details. *
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* *
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* You should have received a copy of the GNU General Public License *
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* along with this program; if not, see <http://www.gnu.org/licenses/> *
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***************************************************************************/
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#ifndef I2C_H
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#define I2C_H
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#include <stdint.h>
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#include <pthread.h>
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#include <stdbool.h>
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/**
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* Enumeration type for I2C bus speeds
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*/
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enum I2CSpeed
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{
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I2C_SPEED_LOW = 0, ///< Generic, implementation-specific, low speed
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I2C_SPEED_100kHz, ///< Standard I2C speed
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I2C_SPEED_400kHz, ///< Fast I2C speed
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I2C_SPEED_1MHz ///< Fast Plus I2C speed
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};
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struct i2cDevice;
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/**
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* I2C driver API.
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*/
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struct i2cApi
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{
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/**
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* Perform a read operation on an I2C device.
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*
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* @param dev: pointer to the device managing the bus.
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* @param addr: 7-bit address of the remote peripheral.
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* @param data: pointer to the destination buffer for data read.
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* @param len: number of bytes to read.
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* @param stop: set to true to send a stop condition at the end of the transfer.
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* @return zero on success, a negative error code otherwise.
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*/
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int (*read)(const struct i2cDevice *dev, const uint8_t addr, void *data,
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const size_t len, const bool stop);
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/**
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* Perform a write operation on an I2C device.
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*
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* @param dev: pointer to the device managing the bus.
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* @param addr: 7-bit address of the remote peripheral.
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* @param data: data to be written.
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* @param len: number of bytes to read.
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* @param stop: set to true to send a stop condition at the end of the transfer.
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* @return zero on success, a negative error code otherwise.
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*/
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int (*write)(const struct i2cDevice *dev, const uint8_t addr,
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const void *data, const size_t len, const bool stop);
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};
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/**
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* I2C peripheral descriptor.
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*/
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struct i2cDevice
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{
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const struct i2cApi *driver; ///< Driver API
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const void *periph; ///< Underlying hardware peripheral
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const pthread_mutex_t *mutex; ///< Mutex for exclusive access
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};
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/**
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* Acquire exclusive ownership on an I2C peripheral.
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*
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* @param dev: pointer to peripheral descriptor.
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* @return zero on success, a negative error code on failure.
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*/
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static inline int i2c_acquire(const struct i2cDevice *dev)
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{
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if(dev->mutex == NULL)
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return 0;
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return pthread_mutex_lock((pthread_mutex_t *) dev->mutex);
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}
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/**
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* Attempt to acquire exclusive ownership on an I2C peripheral.
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*
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* @param dev: pointer to peripheral descriptor.
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* @return zero on success, a negative error code on failure.
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*/
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static inline int i2c_tryAcquire(const struct i2cDevice *dev)
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{
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if(dev->mutex == NULL)
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return 0;
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return pthread_mutex_trylock((pthread_mutex_t *) dev->mutex);
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}
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/**
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* Release exclusive ownership on an I2C peripheral.
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*
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* @param dev: pointer to peripheral descriptor.
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* @return zero on success, a negative error code on failure.
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*/
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static inline int i2c_release(const struct i2cDevice *dev)
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{
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if(dev->mutex == NULL)
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return 0;
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return pthread_mutex_unlock((pthread_mutex_t *) dev->mutex);
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}
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/**
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* Read data from an I2C device connected on the bus managed by the peripheral.
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*
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* @param dev: pointer to peripheral descriptor.
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* @param addr: 7-bit device address.
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* @param data: pointer to a buffer where to store the received data.
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* @param len: number of bytes to read.
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* @param stop: if true, an I2C stop condition is generated at the end of the
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* transfer.
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* @return zero on success, a negative error code on failure.
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*/
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static inline int i2c_read(const struct i2cDevice *dev, const uint8_t addr,
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void *data, const size_t len, const bool stop)
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{
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return dev->driver->read(dev, addr, data, len, stop);
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}
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/**
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* Send data to an I2C device connected on the bus managed by the peripheral.
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*
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* @param dev: pointer to peripheral descriptor.
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* @param addr: 7-bit device address.
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* @param data: pointer to the data to be sent.
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* @param len: number of bytes to send.
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* @param stop: if true, an I2C stop condition is generated at the end of the
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* transfer.
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* @return zero on success, a negative error code on failure.
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*/
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static inline int i2c_write(const struct i2cDevice *dev, const uint8_t addr,
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const void *data, const size_t len, const bool stop)
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{
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return dev->driver->write(dev, addr, data, len, stop);
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}
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#endif /* I2C_H */
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