headers/private/graphics/common/i2c.h

   1 /*
   2  * Copyright 2003, Thomas Kurschel. All Rights Reserved.
   3  * Distributed under the terms of the MIT License.
   4  */
   5 #ifndef _I2C_H
   6 #define _I2C_H
   7
   8
   9 #include <OS.h>
  10
  11
  12 // timing for i2c bus
  13 typedef struct i2c_timing {
  14         // general timing as defined by standard
  15         // (in microseconds for 100kHz/400kHz mode)
  16         int buf;                // bus free between start and stop (4.7/1.3)
  17         int hd_sta;             // hold time start condition (4.0/0.6)
  18         int low;                // low period of clock (4.7/1.3)
  19         int high;               // high period of clock (4.0/0.6)
  20         int su_sta;             // setup time of repeated start condition (4.7/0.6)
  21         int hd_dat;             // hold time data (5.0/- for CBUS, 0/0 for I2C)
  22         int su_dat;             // setup time data (0.250/0.100)
  23         int r;                  // maximum raise time of clock and data signal (1.0/0.3)
  24         int f;                  // maximum fall time of clock and data signal (0.3/0.3)
  25         int su_sto;             // setup time for stop condition (4.0/0.6)
  26
  27         // clock stretching limits, not part of i2c standard
  28         int start_timeout;      // max. delay of start condition
  29         int byte_timeout;       // max. delay of first bit of byte
  30         int bit_timeout;        // max. delay of one bit within a byte transmission
  31         int ack_start_timeout;  // max. delay of acknowledge start
  32
  33         // other timeouts, not part of i2c standard
  34         int ack_timeout;        // timeout of waiting for acknowledge
  35 } i2c_timing;
  36
  37
  38 // set signals on bus
  39 typedef status_t (*i2c_set_signals)(void *cookie, int clock, int data);
  40 // read signals from bus
  41 typedef status_t (*i2c_get_signals)(void *cookie, int *clock, int *data);
  42
  43 // i2c bus definition
  44 typedef struct i2c_bus {
  45         void *cookie;                                   // user-defined cookie
  46         i2c_timing timing;
  47         i2c_set_signals set_signals;    // callback to set signals
  48         i2c_get_signals get_signals;    // callback to detect signals
  49 } i2c_bus;
  50
  51
  52 #ifdef __cplusplus
  53 extern "C" {
  54 #endif
  55
  56 // send and receive data via i2c bus
  57 status_t i2c_send_receive(const i2c_bus *bus, int slave_address,
  58         const uint8 *writeBuffer, size_t writeLength, uint8 *readBuffer,
  59         size_t readLength);
  60
  61 // fill <timing> with standard 100kHz bus timing
  62 void i2c_get100k_timing(i2c_timing *timing);
  63
  64 // fill <timing> with standard 400kHz bus timing
  65 // (as timing resolution is 1 microsecond, we cannot reach full speed!)
  66 void i2c_get400k_timing(i2c_timing *timing);
  67
  68 #ifdef __cplusplus
  69 }
  70 #endif
  71
  72 #endif  /* _I2C_H */