/* SPDX-License-Identifier: BSD-2-Clause */
/**
* @file
*
* @brief Inter-Integrated Circuit (I2C) Driver API
*
* @ingroup I2C
*/
/*
* Copyright (C) 2014, 2017 embedded brains GmbH & Co. KG
*
* 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.
*
* 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.
*/
#ifndef _DEV_I2C_I2C_H
#define _DEV_I2C_I2C_H
#include <linux/i2c.h>
#include <linux/i2c-dev.h>
#include <rtems.h>
#include <rtems/seterr.h>
#include <rtems/thread.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
typedef struct i2c_msg i2c_msg;
typedef struct i2c_bus i2c_bus;
typedef struct i2c_dev i2c_dev;
typedef struct i2c_rdwr_ioctl_data i2c_rdwr_ioctl_data;
/**
* @defgroup I2C Inter-Integrated Circuit (I2C) Driver
*
* @ingroup RTEMSDeviceDrivers
*
* @brief Inter-Integrated Circuit (I2C) bus and device driver support.
*
* @{
*/
/**
* @defgroup I2CBus I2C Bus Driver
*
* @ingroup I2C
*
* @{
*/
/**
* @name I2C IO Control Commands
*
* @{
*/
/**
* @brief Obtains the bus.
*
* This command has no argument.
*/
#define I2C_BUS_OBTAIN 0x800
/**
* @brief Releases the bus.
*
* This command has no argument.
*/
#define I2C_BUS_RELEASE 0x801
/**
* @brief Gets the bus control.
*
* The argument type is a pointer to i2c_bus pointer.
*/
#define I2C_BUS_GET_CONTROL 0x802
/**
* @brief Sets the bus clock in Hz.
*
* The argument type is unsigned long.
*/
#define I2C_BUS_SET_CLOCK 0x803
/** @} */
/**
* @brief Default I2C bus clock in Hz.
*/
#define I2C_BUS_CLOCK_DEFAULT 100000
/**
* @brief I2C bus control.
*/
struct i2c_bus {
/**
* @brief Transfers I2C messages.
*
* @param[in] bus The bus control.
* @param[in] msgs The messages to transfer.
* @param[in] msg_count The count of messages to transfer. It must be
* positive.
*
* @retval 0 Successful operation.
* @retval negative Negative error number in case of an error.
*/
int (*transfer)(i2c_bus *bus, i2c_msg *msgs, uint32_t msg_count);
/**
* @brief Sets the bus clock.
*
* @param[in] bus The bus control.
* @param[in] clock The desired bus clock in Hz.
*
* @retval 0 Successful operation.
* @retval negative Negative error number in case of an error.
*/
int (*set_clock)(i2c_bus *bus, unsigned long clock);
/**
* @brief Destroys the bus.
*
* @param[in] bus The bus control.
*/
void (*destroy)(i2c_bus *bus);
/**
* @brief Mutex to protect the bus access.
*/
rtems_recursive_mutex mutex;
/**
* @brief Default slave device address.
*/
uint16_t default_address;
/**
* @brief Use 10-bit addresses.
*/
bool ten_bit_address;
/**
* @brief Use SMBus PEC.
*/
bool use_pec;
/**
* @brief Transfer retry count.
*/
unsigned long retries;
/**
* @brief Transaction timeout in ticks.
*/
rtems_interval timeout;
/**
* @brief Controller functionality.
*/
unsigned long functionality;
};
/**
* @brief Initializes a bus control.
*
* After a sucessful initialization the bus control must be destroyed via
* i2c_bus_destroy(). A registered bus control will be automatically destroyed
* in case the device file is unlinked. Make sure to call i2c_bus_destroy() in
* a custom destruction handler.
*
* @param[in] bus The bus control.
*
* @retval 0 Successful operation.
* @retval -1 An error occurred. The errno is set to indicate the error.
*
* @see i2c_bus_register()
*/
int i2c_bus_init(i2c_bus *bus);
/**
* @brief Allocates a bus control from the heap and initializes it.
*
* After a sucessful allocation and initialization the bus control must be
* destroyed via i2c_bus_destroy_and_free(). A registered bus control will be
* automatically destroyed in case the device file is unlinked. Make sure to
* call i2c_bus_destroy_and_free() in a custom destruction handler.
*
* @param[in] size The size of the bus control. This enables the addition of
* bus controller specific data to the base bus control. The bus control is
* zero initialized.
*
* @retval non-NULL The new bus control.
* @retval NULL An error occurred. The errno is set to indicate the error.
*
* @see i2c_bus_register()
*/
i2c_bus *i2c_bus_alloc_and_init(size_t size);
/**
* @brief Destroys a bus control.
*
* @param[in] bus The bus control.
*/
void i2c_bus_destroy(i2c_bus *bus);
/**
* @brief Destroys a bus control and frees its memory.
*
* @param[in] bus The bus control.
*/
void i2c_bus_destroy_and_free(i2c_bus *bus);
/**
* @brief Registers a bus control.
*
* This function claims ownership of the bus control regardless if the
* registration is successful or not.
*
* @param[in] bus The bus control.
* @param[in] bus_path The path to the bus device file.
*
* @retval 0 Successful operation.
* @retval -1 An error occurred. The errno is set to indicate the error.
*/
int i2c_bus_register(
i2c_bus *bus,
const char *bus_path
);
/**
* @brief Try to obtain the bus.
*
* @param[in] bus The bus control.
*
* @retval 0 Successful operation.
* @retval EBUSY if mutex is already locked.
*/
int i2c_bus_try_obtain(i2c_bus *bus);
/**
* @brief Obtains the bus.
*
* @param[in] bus The bus control.
*/
void i2c_bus_obtain(i2c_bus *bus);
/**
* @brief Releases the bus.
*
* @param[in] bus The bus control.
*/
void i2c_bus_release(i2c_bus *bus);
/**
* @brief Transfers I2C messages.
*
* The bus is obtained before the transfer and released afterwards. This is the
* same like calling @ref i2c_bus_do_transfer with flags set to 0.
*
* @param[in] bus The bus control.
* @param[in] msgs The messages to transfer.
* @param[in] msg_count The count of messages to transfer. It must be
* positive.
*
* @retval 0 Successful operation.
* @retval negative Negative error number in case of an error.
*/
int i2c_bus_transfer(i2c_bus *bus, i2c_msg *msgs, uint32_t msg_count);
/**
* @brief Transfers I2C messages with optional flags.
*
* The bus is obtained before the transfer and released afterwards. If the flag
* I2C_BUS_NOBLOCK is set and the bus is already obtained, nothing will be
* transfered and the function returns with an -EAGAIN.
*
* @param[in] bus The bus control.
* @param[in] msgs The messages to transfer.
* @param[in] msg_count The count of messages to transfer. It must be
* positive.
* @param[in] flags Options for the whole transfer.
*
* @retval 0 Successful operation.
* @retval -EAGAIN if @ref I2C_BUS_NOBLOCK is set and the bus is already
* obtained.
* @retval negative Negative error number in case of an error.
*/
int i2c_bus_do_transfer(
i2c_bus *bus,
i2c_msg *msgs,
uint32_t msg_count,
uint32_t flags
);
/**
* @brief I2C bus transfer flag to indicate that the task should not block if
* the bus is busy on a new transfer.
*/
#define I2C_BUS_NOBLOCK (1u << 0)
/** @} */
/**
* @defgroup I2CDevice I2C Device Driver
*
* @ingroup I2C
*
* @{
*/
/**
* @brief Base number for device IO control commands.
*/
#define I2C_DEV_IO_CONTROL 0x900
/**
* @brief I2C slave device control.
*/
struct i2c_dev {
/**
* @brief Reads from the device.
*
* @retval non-negative Bytes transferred from device.
* @retval negative Negative error number in case of an error.
*/
ssize_t (*read)(i2c_dev *dev, void *buf, size_t n, off_t offset);
/**
* @brief Writes to the device.
*
* @retval non-negative Bytes transferred to device.
* @retval negative Negative error number in case of an error.
*/
ssize_t (*write)(i2c_dev *dev, const void *buf, size_t n, off_t offset);
/**
* @brief Device IO control.
*
* @retval 0 Successful operation.
* @retval negative Negative error number in case of an error.
*/
int (*ioctl)(i2c_dev *dev, ioctl_command_t command, void *arg);
/**
* @brief Gets the file size.
*/
off_t (*get_size)(i2c_dev *dev);
/**
* @brief Gets the file block size.
*/
blksize_t (*get_block_size)(i2c_dev *dev);
/**
* @brief Destroys the device.
*/
void (*destroy)(i2c_dev *dev);
/**
* @brief The bus control.
*/
i2c_bus *bus;
/**
* @brief The device address.
*/
uint16_t address;
/**
* @brief File descriptor of the bus.
*
* This prevents destruction of the bus since we hold a reference to it with
* this.
*/
int bus_fd;
};
/**
* @brief Initializes a device control.
*
* After a sucessful initialization the device control must be destroyed via
* i2c_dev_destroy(). A registered device control will be automatically
* destroyed in case the device file is unlinked. Make sure to call
* i2c_dev_destroy_and_free() in a custom destruction handler.
*
* @param[in] device The device control.
* @param[in] bus_path The path to the bus device file.
* @param[in] address The address of the device.
*
* @retval 0 Successful operation.
* @retval -1 An error occurred. The errno is set to indicate the error.
*
* @see i2c_dev_register()
*/
int i2c_dev_init(i2c_dev *dev, const char *bus_path, uint16_t address);
/**
* @brief Allocates a device control from the heap and initializes it.
*
* After a sucessful allocation and initialization the device control must be
* destroyed via i2c_dev_destroy_and_free(). A registered device control will
* be automatically destroyed in case the device file is unlinked. Make sure
* to call i2c_dev_destroy_and_free() in a custom destruction handler.
*
* @param[in] size The size of the device control. This enables the addition
* of device specific data to the base device control. The device control is
* zero initialized.
* @param[in] bus_path The path to the bus device file.
* @param[in] address The address of the device.
*
* @retval non-NULL The new device control.
* @retval NULL An error occurred. The errno is set to indicate the error.
*
* @see i2c_dev_register()
*/
i2c_dev *i2c_dev_alloc_and_init(
size_t size,
const char *bus_path,
uint16_t address
);
/**
* @brief Destroys a device control.
*
* @param[in] dev The device control.
*/
void i2c_dev_destroy(i2c_dev *dev);
/**
* @brief Destroys a device control and frees its memory.
*
* @param[in] dev The device control.
*/
void i2c_dev_destroy_and_free(i2c_dev *dev);
/**
* @brief Registers a device control.
*
* This function claims ownership of the device control regardless if the
* registration is successful or not.
*
* @param[in] dev The dev control.
* @param[in] dev_path The path to the device file of the device.
*
* @retval 0 Successful operation.
* @retval -1 An error occurred. The errno is set to indicate the error.
*/
int i2c_dev_register(
i2c_dev *dev,
const char *dev_path
);
/** @} */ /* end of i2c device driver */
/** @} */
#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* _DEV_I2C_I2C_H */
