/*
 * Copyright 2003, Thomas Kurschel. All Rights Reserved.
 * Distributed under the terms of the MIT License.
 */
#ifndef _I2C_H
#define _I2C_H


#include <OS.h>


// timing for i2c bus
typedef struct i2c_timing {
        // general timing as defined by standard 
        // (in microseconds for 100kHz/400kHz mode)
        int buf;                // bus free between start and stop (4.7/1.3)
        int hd_sta;             // hold time start condition (4.0/0.6)
        int low;                // low period of clock (4.7/1.3)
        int high;               // high period of clock (4.0/0.6)
        int su_sta;             // setup time of repeated start condition (4.7/0.6)
        int hd_dat;             // hold time data (5.0/- for CBUS, 0/0 for I2C)
        int su_dat;             // setup time data (0.250/0.100)
        int r;                  // maximum raise time of clock and data signal (1.0/0.3)
        int f;                  // maximum fall time of clock and data signal (0.3/0.3)
        int su_sto;             // setup time for stop condition (4.0/0.6)
        
        // clock stretching limits, not part of i2c standard
        int start_timeout;      // max. delay of start condition
        int byte_timeout;       // max. delay of first bit of byte
        int bit_timeout;        // max. delay of one bit within a byte transmission
        int ack_start_timeout;  // max. delay of acknowledge start
        
        // other timeouts, not part of i2c standard
        int ack_timeout;        // timeout of waiting for acknowledge
} i2c_timing;


struct i2c_bus;

// set signals on bus
typedef status_t (*i2c_set_signals)(void *cookie, int clock, int data);
// read signals from bus
typedef status_t (*i2c_get_signals)(void *cookie, int *clock, int *data);
// send/receive from bus
typedef status_t (*i2c_send_receive)(const struct i2c_bus *bus, uint32 slave_address,
                const uint8 *writeBuffer, size_t writeLength, uint8 *readBuffer,
                size_t readLength);

// i2c bus definition
typedef struct i2c_bus {
        void *cookie;                                   // user-defined cookie
        // low-level
        i2c_timing timing;
        i2c_set_signals set_signals;    // callback to set signals
        i2c_get_signals get_signals;    // callback to detect signals
        // high-level
        i2c_send_receive send_receive;
} i2c_bus;


#ifdef __cplusplus
extern "C" {
#endif

// send and receive data via i2c bus
status_t i2c_send_receive_callback(const i2c_bus *bus, uint32 slave_address,
        const uint8 *writeBuffer, size_t writeLength, uint8 *readBuffer,
        size_t readLength);

// fill <timing> with standard 100kHz bus timing
void i2c_get100k_timing(i2c_timing *timing);

// fill <timing> with standard 400kHz bus timing
// (as timing resolution is 1 microsecond, we cannot reach full speed!)
void i2c_get400k_timing(i2c_timing *timing);

#ifdef __cplusplus
}
#endif

#endif  /* _I2C_H */