include/i2c.h

   1 /*
   2  * (C) Copyright 2001
   3  * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
   4  *
   5  * See file CREDITS for list of people who contributed to this
   6  * project.
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21  * MA 02111-1307 USA
  22  *
  23  * The original I2C interface was
  24  *   (C) 2000 by Paolo Scaffardi (arsenio@tin.it)
  25  *   AIRVENT SAM s.p.a - RIMINI(ITALY)
  26  * but has been changed substantially.
  27  */
  28
  29 #ifndef _I2C_H_
  30 #define _I2C_H_
  31
  32 /*
  33  * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
  34  *
  35  * The implementation MUST NOT use static or global variables if the
  36  * I2C routines are used to read SDRAM configuration information
  37  * because this is done before the memories are initialized. Limited
  38  * use of stack-based variables are OK (the initial stack size is
  39  * limited).
  40  *
  41  * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
  42  */
  43
  44 /*
  45  * Configuration items.
  46  */
  47 #define I2C_RXTX_LEN    128     /* maximum tx/rx buffer length */
  48
  49 #if defined(CONFIG_I2C_MULTI_BUS)
  50 #define CFG_MAX_I2C_BUS         2
  51 #define I2C_GET_BUS()           i2c_get_bus_num()
  52 #define I2C_SET_BUS(a)          i2c_set_bus_num(a)
  53 #else
  54 #define CFG_MAX_I2C_BUS         1
  55 #define I2C_GET_BUS()           0
  56 #define I2C_SET_BUS(a)
  57 #endif
  58
  59 /* define the I2C bus number for RTC and DTT if not already done */
  60 #if !defined(CFG_RTC_BUS_NUM)
  61 #define CFG_RTC_BUS_NUM         0
  62 #endif
  63 #if !defined(CFG_DTT_BUS_NUM)
  64 #define CFG_DTT_BUS_NUM         0
  65 #endif
  66
  67 /*
  68  * Initialization, must be called once on start up, may be called
  69  * repeatedly to change the speed and slave addresses.
  70  */
  71 void i2c_init(int speed, int slaveaddr);
  72 #ifdef CFG_I2C_INIT_BOARD
  73 void i2c_init_board(void);
  74 #endif
  75
  76 /*
  77  * Probe the given I2C chip address.  Returns 0 if a chip responded,
  78  * not 0 on failure.
  79  */
  80 int i2c_probe(uchar chip);
  81
  82 /*
  83  * Read/Write interface:
  84  *   chip:    I2C chip address, range 0..127
  85  *   addr:    Memory (register) address within the chip
  86  *   alen:    Number of bytes to use for addr (typically 1, 2 for larger
  87  *              memories, 0 for register type devices with only one
  88  *              register)
  89  *   buffer:  Where to read/write the data
  90  *   len:     How many bytes to read/write
  91  *
  92  *   Returns: 0 on success, not 0 on failure
  93  */
  94 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len);
  95 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len);
  96
  97 /*
  98  * Utility routines to read/write registers.
  99  */
 100 uchar i2c_reg_read (uchar chip, uchar reg);
 101 void  i2c_reg_write(uchar chip, uchar reg, uchar val);
 102
 103 /*
 104  * Functions for setting the current I2C bus and its speed
 105  */
 106
 107 /*
 108  * i2c_set_bus_num:
 109  *
 110  *  Change the active I2C bus.  Subsequent read/write calls will
 111  *  go to this one.
 112  *
 113  *      bus - bus index, zero based
 114  *
 115  *      Returns: 0 on success, not 0 on failure
 116  *
 117  */
 118 int i2c_set_bus_num(unsigned int bus);
 119
 120 /*
 121  * i2c_get_bus_num:
 122  *
 123  *  Returns index of currently active I2C bus.  Zero-based.
 124  */
 125
 126 unsigned int i2c_get_bus_num(void);
 127
 128 /*
 129  * i2c_set_bus_speed:
 130  *
 131  *  Change the speed of the active I2C bus
 132  *
 133  *      speed - bus speed in Hz
 134  *
 135  *      Returns: 0 on success, not 0 on failure
 136  *
 137  */
 138 int i2c_set_bus_speed(unsigned int);
 139
 140 /*
 141  * i2c_get_bus_speed:
 142  *
 143  *  Returns speed of currently active I2C bus in Hz
 144  */
 145
 146 unsigned int i2c_get_bus_speed(void);
 147
 148 #endif  /* _I2C_H_ */