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 #if !defined(CFG_SPD_BUS_NUM)
  67 #define CFG_SPD_BUS_NUM         0
  68 #endif
  69
  70 /*
  71  * Initialization, must be called once on start up, may be called
  72  * repeatedly to change the speed and slave addresses.
  73  */
  74 void i2c_init(int speed, int slaveaddr);
  75 #ifdef CFG_I2C_INIT_BOARD
  76 void i2c_init_board(void);
  77 #endif
  78
  79 /*
  80  * Probe the given I2C chip address.  Returns 0 if a chip responded,
  81  * not 0 on failure.
  82  */
  83 int i2c_probe(uchar chip);
  84
  85 /*
  86  * Read/Write interface:
  87  *   chip:    I2C chip address, range 0..127
  88  *   addr:    Memory (register) address within the chip
  89  *   alen:    Number of bytes to use for addr (typically 1, 2 for larger
  90  *              memories, 0 for register type devices with only one
  91  *              register)
  92  *   buffer:  Where to read/write the data
  93  *   len:     How many bytes to read/write
  94  *
  95  *   Returns: 0 on success, not 0 on failure
  96  */
  97 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len);
  98 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len);
  99
 100 /*
 101  * Utility routines to read/write registers.
 102  */
 103 uchar i2c_reg_read (uchar chip, uchar reg);
 104 void  i2c_reg_write(uchar chip, uchar reg, uchar val);
 105
 106 /*
 107  * Functions for setting the current I2C bus and its speed
 108  */
 109
 110 /*
 111  * i2c_set_bus_num:
 112  *
 113  *  Change the active I2C bus.  Subsequent read/write calls will
 114  *  go to this one.
 115  *
 116  *      bus - bus index, zero based
 117  *
 118  *      Returns: 0 on success, not 0 on failure
 119  *
 120  */
 121 int i2c_set_bus_num(unsigned int bus);
 122
 123 /*
 124  * i2c_get_bus_num:
 125  *
 126  *  Returns index of currently active I2C bus.  Zero-based.
 127  */
 128
 129 unsigned int i2c_get_bus_num(void);
 130
 131 /*
 132  * i2c_set_bus_speed:
 133  *
 134  *  Change the speed of the active I2C bus
 135  *
 136  *      speed - bus speed in Hz
 137  *
 138  *      Returns: 0 on success, not 0 on failure
 139  *
 140  */
 141 int i2c_set_bus_speed(unsigned int);
 142
 143 /*
 144  * i2c_get_bus_speed:
 145  *
 146  *  Returns speed of currently active I2C bus in Hz
 147  */
 148
 149 unsigned int i2c_get_bus_speed(void);
 150
 151 #endif  /* _I2C_H_ */