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/* i2c.h - public I2C driver API */
/*
* Copyright (c) 2015 Intel Corporation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef __DRIVERS_I2C_H
#define __DRIVERS_I2C_H
/**
* @brief I2C Interface
* @defgroup i2c_interface I2C Interface
* @ingroup io_interfaces
* @{
*/
#ifdef __cplusplus
extern "C" {
#endif
#include <stdint.h>
#include <device.h>
/* I2C speeds */
#define I2C_SPEED_STANDARD (0x1)
#define I2C_SPEED_FAST (0x2)
#define I2C_SPEED_FAST_PLUS (0x3)
#define I2C_SPEED_HIGH (0x4)
#define I2C_SPEED_ULTRA (0x5)
/* I2C dev_config bitfields */
#define I2C_ADDR_10_BITS (1 << 0)
#define I2C_SPEED_MASK (0x7 << 1) /* 3 bits */
#define I2C_MODE_MASTER (1 << 4)
#define I2C_MODE_SLAVE_READ (1 << 5)
/* I2C Message Flags */
#define I2C_MSG_WRITE (0 << 0)
#define I2C_MSG_READ (1 << 0)
#define I2C_MSG_RW_MASK (1 << 0)
/* STOP I2C transaction (drive should take care of this) */
#define I2C_MSG_STOP (1 << 1)
/* RESTART I2C transaction */
#define I2C_MSG_RESTART (1 << 2)
struct i2c_msg {
/* Data buffer in bytes */
uint8_t *buf;
/* Length of buffer in bytes */
uint32_t len;
/* Flags for this message */
uint8_t flags;
};
union dev_config {
uint32_t raw;
struct {
uint32_t use_10_bit_addr : 1;
uint32_t speed : 3;
uint32_t is_master_device : 1;
uint32_t is_slave_read : 1;
uint32_t reserved : 26;
} bits;
};
enum i2c_cb_type {
I2C_CB_WRITE = 1,
I2C_CB_READ = 2,
I2C_CB_ERROR = 3,
};
typedef int (*i2c_api_configure_t)(struct device *dev,
uint32_t dev_config);
typedef int (*i2c_api_full_io_t)(struct device *dev,
struct i2c_msg *msgs,
uint8_t num_msgs,
uint16_t addr);
typedef int (*i2c_api_suspend_t)(struct device *dev);
typedef int (*i2c_api_resume_t)(struct device *dev);
struct i2c_driver_api {
i2c_api_configure_t configure;
i2c_api_full_io_t transfer;
i2c_api_suspend_t suspend;
i2c_api_resume_t resume;
};
/**
* @brief Configure a host controllers operation
*
* @param dev Pointer to the device structure for the driver instance
* @param dev_config Bit-packed 32-bit value to the device runtime configuration
* for the I2C controller.
*
* @return DEV_OK if successful, another DEV_* code otherwise.
*/
static inline int i2c_configure(struct device *dev, uint32_t dev_config)
{
struct i2c_driver_api *api;
api = (struct i2c_driver_api *)dev->driver_api;
return api->configure(dev, dev_config);
}
/**
* @brief Write a set amount of data to an I2C device
*
* The function is synchronous.
*
* @param dev Pointer to the device structure for the driver instance
* @param buf Memory pool that data should be transferred from
* @param len Size of the memory pool available for reading from
* @param addr Address of the I2C device to write to
*
* @return DEV_OK if successful, another DEV_* code otherwise.
*/
static inline int i2c_write(struct device *dev, uint8_t *buf,
uint32_t len, uint16_t addr)
{
struct i2c_driver_api *api;
struct i2c_msg msg;
msg.buf = buf;
msg.len = len;
msg.flags = I2C_MSG_WRITE | I2C_MSG_STOP;
api = (struct i2c_driver_api *)dev->driver_api;
return api->transfer(dev, &msg, 1, addr);
}
/**
* @brief Read a set amount of data from an I2C device
*
* The function is synchronous.
*
* @param dev Pointer to the device structure for the driver instance
* @param buf Memory pool that data should be transferred to
* @param len Size of the memory pool available for writing to
* @param addr Address of the I2C device to read from
*
* @return DEV_OK if successful, another DEV_* code otherwise.
*/
static inline int i2c_read(struct device *dev, uint8_t *buf,
uint32_t len, uint16_t addr)
{
struct i2c_driver_api *api;
struct i2c_msg msg;
msg.buf = buf;
msg.len = len;
msg.flags = I2C_MSG_READ | I2C_MSG_STOP;
api = (struct i2c_driver_api *)dev->driver_api;
return api->transfer(dev, &msg, 1, addr);
}
/**
* @brief Performs data transfer to another I2C device
*
* This provides a generic interface to perform data transfer
* to another I2C device. If a simple read or write is needed,
* use i2c_read()/i2c_write() instead. The function is synchronous.
*
* @param dev Pointer to the device structure for the driver instance
* @param msgs Array of messages
* @param num_msgs Number of messages
* @param addr Address of the I2C target device
*
* @return DEV_OK if successful, another DEV_* code otherwise.
*/
static inline int i2c_transfer(struct device *dev,
struct i2c_msg *msgs, uint8_t num_msgs,
uint16_t addr)
{
struct i2c_driver_api *api;
api = (struct i2c_driver_api *)dev->driver_api;
return api->transfer(dev, msgs, num_msgs, addr);
}
/**
* @brief Suspend an I2C driver
* @param dev Pointer to the device structure for the driver instance
*
* @return DEV_OK
*/
static inline int i2c_suspend(struct device *dev)
{
struct i2c_driver_api *api;
api = (struct i2c_driver_api *)dev->driver_api;
return api->suspend(dev);
}
/**
* @brief Resume an I2C driver
* @param dev Pointer to the device structure for the driver instance
*
* @return DEV_OK
*/
static inline int i2c_resume(struct device *dev)
{
struct i2c_driver_api *api;
api = (struct i2c_driver_api *)dev->driver_api;
return api->resume(dev);
}
#ifdef __cplusplus
}
#endif
/**
* @}
*/
#endif /* __DRIVERS_I2C_H */