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/*
* Generic I2C bus interface for RTEMS
*
* Copyright (C) 2000 OKTET Ltd., St.-Petersburg, Russia
* Author: Victor V. Vengerov <vvv@oktet.ru>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
*
* http://www.rtems.com/license/LICENSE.
*
* @(#) $Id$
*/
#ifndef __RTEMS__I2C_H__
#define __RTEMS__I2C_H__
#include <rtems.h>
#include <bsp.h>
/* This header file define the generic interface to i2c buses available in
* system. This interface may be used by user applications or i2c-device
* drivers (like RTC, NVRAM, etc).
*
* Functions i2c_initialize and i2c_transfer declared in this header usually
* implemented in particular board support package. Usually this
* implementation is a simple wrapper or multiplexor to I2C controller
* driver which is available in system. It may be generic "software
* controller" I2C driver which control SDA and SCL signals directly (if SDA
* and SCL is general-purpose I/O pins), or driver for hardware I2C
* controller (standalone or integrated with processors: MBus controller in
* ColdFire processors, I2C controller in PowerQUICC and so on).
*
* i2c_transfer is a very generic low-level function. Higher-level function
* i2c_write, i2c_read, i2c_wrrd, i2c_wbrd is defined here too.
*/
/* I2C Bus Number type */
typedef uint32_t i2c_bus_number;
/* I2C device address */
typedef uint16_t i2c_address;
/* I2C error codes generated during message transfer */
typedef enum i2c_message_status {
I2C_SUCCESSFUL = 0,
I2C_TIMEOUT,
I2C_NO_DEVICE,
I2C_ARBITRATION_LOST,
I2C_NO_ACKNOWLEDGE,
I2C_NO_DATA,
I2C_RESOURCE_NOT_AVAILABLE
} i2c_message_status;
/* I2C Message */
typedef struct i2c_message {
i2c_address addr; /* I2C slave device address */
uint16_t flags; /* message flags (see below) */
i2c_message_status status; /* message transfer status code */
uint16_t len; /* Number of bytes to read or write */
uint8_t *buf; /* pointer to data array */
} i2c_message;
/* I2C message flag */
#define I2C_MSG_ADDR_10 (0x01) /* 10-bit address */
#define I2C_MSG_WR (0x02) /* transfer direction for this message
from master to slave */
#define I2C_MSG_ERRSKIP (0x04) /* Skip message if last transfered message
is failed */
/* Type for function which is called when transfer over I2C bus is finished */
typedef void (*i2c_transfer_done) (void *arg);
/* i2c_initialize --
* I2C driver initialization. This function usually called on device
* driver initialization state, before initialization task. All I2C
* buses are initialized; reasonable slow data transfer rate is
* selected for each bus.
*
* PARAMETERS:
* major - I2C device major number
* minor - I2C device minor number
* arg - RTEMS driver initialization argument
*
* RETURNS:
* RTEMS status code
*/
rtems_device_driver
i2c_initialize(rtems_device_major_number major,
rtems_device_minor_number minor,
void *arg);
/* i2c_select_clock_rate --
* select I2C bus clock rate for specified bus. Some bus controller do not
* allow to select arbitrary clock rate; in this case nearest possible
* slower clock rate is selected.
*
* PARAMETERS:
* bus - I2C bus number
* bps - data transfer rate for this bytes in bits per second
*
* RETURNS:
* RTEMS_SUCCESSFUL, if operation performed successfully,
* RTEMS_INVALID_NUMBER, if wrong bus number is specified,
* RTEMS_UNSATISFIED, if bus do not support data transfer rate selection
* or specified data transfer rate could not be used.
*/
rtems_status_code
i2c_select_clock_rate(i2c_bus_number bus, int bps);
/* i2c_transfer --
* Initiate multiple-messages transfer over specified I2C bus or
* put request into queue if bus or some other resource is busy. (This
* is non-blocking function).
*
* PARAMETERS:
* bus - I2C bus number
* nmsg - number of messages
* msg - pointer to messages array
* done - function which is called when transfer is finished
* done_arg_ptr - arbitrary argument ptr passed to done funciton
*
* RETURNS:
* RTEMS_SUCCESSFUL if transfer initiated successfully, or error
* code if something failed.
*/
rtems_status_code
i2c_transfer(i2c_bus_number bus, int nmsg, i2c_message *msg,
i2c_transfer_done done, void * done_arg_ptr);
/* i2c_transfer_wait --
* Initiate I2C bus transfer and block until this transfer will be
* finished. This function wait the semaphore if system in
* SYSTEM_STATE_UP state, or poll done flag in other states.
*
* PARAMETERS:
* bus - I2C bus number
* msg - pointer to transfer messages array
* nmsg - number of messages in transfer
*
* RETURNS:
* I2C_SUCCESSFUL, if tranfer finished successfully,
* I2C_RESOURCE_NOT_AVAILABLE, if semaphore operations has failed,
* value of status field of first error-finished message in transfer,
* if something wrong.
*/
i2c_message_status
i2c_transfer_wait(i2c_bus_number bus, i2c_message *msg, int nmsg);
/* i2c_poll --
* Poll I2C bus controller for events and hanle it. This function is
* used when I2C driver operates in poll-driven mode.
*
* PARAMETERS:
* bus - bus number to be polled
*
* RETURNS:
* none
*/
void
i2c_poll(i2c_bus_number bus);
/* i2c_write --
* Send single message over specified I2C bus to addressed device and
* wait while transfer is finished.
*
* PARAMETERS:
* bus - I2C bus number
* addr - address of I2C device
* buf - data to be sent to device
* size - data buffer size
*
* RETURNS:
* transfer status
*/
i2c_message_status
i2c_write(i2c_bus_number bus, i2c_address addr, void *buf, int size);
/* i2c_wrbyte --
* Send single one-byte long message over specified I2C bus to
* addressed device and wait while transfer is finished.
*
* PARAMETERS:
* bus - I2C bus number
* addr - address of I2C device
* cmd - byte message to be sent to device
*
* RETURNS:
* transfer status
*/
i2c_message_status
i2c_wrbyte(i2c_bus_number bus, i2c_address addr, uint8_t cmd);
/* i2c_read --
* receive single message over specified I2C bus from addressed device.
* This call will wait while transfer is finished.
*
* PARAMETERS:
* bus - I2C bus number
* addr - address of I2C device
* buf - buffer for received message
* size - receive buffer size
*
* RETURNS:
* transfer status
*/
i2c_message_status
i2c_read(i2c_bus_number bus, i2c_address addr, void *buf, int size);
/* i2c_wrrd --
* Send message over I2C bus to specified device and receive message
* from the same device during single transfer.
*
* PARAMETERS:
* bus - I2C bus number
* addr - address of I2C device
* bufw - data to be sent to device
* sizew - send data buffer size
* bufr - buffer for received message
* sizer - receive buffer size
*
* RETURNS:
* transfer status
*/
i2c_message_status
i2c_wrrd(i2c_bus_number bus, i2c_address addr, void *bufw, int sizew,
void *bufr, int sizer);
/* i2c_wbrd --
* Send one-byte message over I2C bus to specified device and receive
* message from the same device during single transfer.
*
* PARAMETERS:
* bus - I2C bus number
* addr - address of I2C device
* cmd - one-byte message to be sent over I2C bus
* bufr - buffer for received message
* sizer - receive buffer size
*
* RETURNS:
* transfer status
*/
i2c_message_status
i2c_wbrd(i2c_bus_number bus, i2c_address addr, uint8_t cmd,
void *bufr, int sizer);
#endif
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