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_ */ 152